This is what TH-cam was actually made for. I remember the long long ago. Thanks for Keeping that spirit alive and encouraging others by publishing a video such as this.
I would love a video where you take everything out and show how everything is wired together. Please let us know at a later date how well its working. Thanks, I was happy to sub!!
Loved this video & the idea execution was super sweet. I think having a typed & laminated card instead of a handwritten one would really enhance how official this looked in the field as well
Learnings... are good. This is amateur radio....and the fun is in your journey! Technical inspiration: Words provide context. But the answers are always in the numbers! And for a repeater, it is all about isolation between TX and RX, etc. With those antenna's so close, yes you have "some" isolation, but I'm thinking only 20dB. So you are transmitting at say 5W (+37 dBm) - 20 dB = +17 dBm at your receiver. The Third Order intercept of a cheap radio is likely -50 dBm and you are 67dB stronger into it! Your transmitter noise has been reported by many as only -45dBc, so +37 dBm - 45 dB = -8dBm noise. You have two issues affecting your "open" receiver... being mixer overload making it deaf, as well as TX noise which covers up weak signals. A weak signal into your receiver without any TX or noise affecting it could be -120dBm for 12dB SINAD. Now look at the numbers.... -120dBm operating floor but with the TX noise producing -8 dBm! These are extreme numbers... reality may be a bit different... this setup will not work for anything but nearby radios. You can tell you are experiencing desense, when you can trip your repeater, but it goes deaf the instant the TX comes up... you get that roger beep, but nothing more. Add a mobile duplexer... they are compact enough, but generally require 3MHz or more separation between TX and RX. And mobile duplexers at these freq's are notch type devices, never bandpass. If you go cross-band repeat (146.520/446.000), now you have 300 MHz to work with. A simple High Pass / Low Pass filter like a mobile antenna duplexer will do the trick and you will have your lunchbox repeater on one dual band mobile whip antenna. This is another reason some use a "simplex" repeater module instead where it records your message and then keys up and repeats it after you are done. No duplexing or desense issues. Good luck in this most excellent hobby!
Awesome experimentation and learning. You will find you need more (and unfortunately big, expensive ,and heavy) parts in the system to get this to be reasonably functional. For a repeater to work, it needs to be able to receive a very weak signal while transmitting a relatively large signal. To be able to do that on relatively close frequencies, you need some very powerful filtering in the form of a duplexer. Without that, this device may be able to function ok as a cross-band repeater using 2m and 70cm, but desensitization may still be a problem with a Baofeng as the receiver. Keep tinkering, have fun, and please be sure to share your progress as you develop this further.
The powerbank is not USB 2! USB 1/2/3/4 is the standart for Bandwith. i dont think they follow an official standart, the official standart was 5V at 200ma, 500ma only after getting the ok from the power source. The "new" usb pd standart is whats used for higher power, in the newest version up to 240w.
Lots of good feedback here for you regarding desense (the rx won’t do weak signals since the tx antenna is inches away from the rx antenna). You can reduce some of that desense by putting one antenna on top of the box and the other on the bottom. This gives them vertical separation AND also gets them farther away from one another. Another even better separation would be to hang one antenna a few feet below the box (let the antenna swing freely on its coax). Have fun experimenting. I did almost exactly the same thing 25 yrs ago and had a blast doing it!
It's tough, I tried one and it seems that a duplexer is the way to go for meaningful gains. I made the mistake and got a cheap UHF duplexer from aliexpress. Only gave 40db of isolation as opposed to a good 80-100. Trying for a digital repeater now using TDMA on a radioditty GD-88
So cool to see you put together a working baofeng repeater. I tried one this spring, but the TX radio (TH-UV98) would deafen the RX radio (TH-UV88) and my range was worse than simplex. Tried a cheapo chinese duplexer on UHF but it only gave me 40db of isolation which didn't help. Currently have a radioditty GD-88 with extended battery set up in that same apache 1800 case, trying for single-frequency-repeat on DMR. Your video is an inspiration to get back to the analog project, and to probably use different radios without spurious emissions
Neat Project! Would be nice if you had a diagram of the goal with the device (max range communication) as well as the maximum number of repeater hops you can have in the mix for clandestine long range communications in case of an EMP pulse. Would love to set something like this up on a mountain so I would be able to communicate with family 100 miles a way to check in with them. Would like to also give family some sort raspberry pi communicator in a an aluminum faraday briefcase so that they can foldable solar panel power it and type a message on their unit and my unit could log it for reading when I am in front of it. Do drills with it every week to make sure system is operational. Solar powered repeater high in the hills.
LOOOOVE me a lunchbox, particularly for a simplex repeater. These things are basically perfect for non-permissive environments where you need to extend range or get around obstacles in an emergency.
Really good stuff! It's good to see more AZ folk Doing radio/motorcycle/outdoor content. It makes youtube feel like a smaller community for us other AZ folk.
Use two roll-up j-poles hang them on the same line the top pointing up and the bottom pointing down. That way your lines are in each others nulls. Do a wide split on 2m, portables work better on a wider split. Common Joe or even rangers do not know what a "Lunch Box" repeater is. Get a card that explains it is a temporary remote radio station licensed under FCC (cite code) with your information and call sign. And lastly get an ID on the unit so you are actually legal.
If your concerned about it getting stolen I would recommend either rattlecanning it or getting some surplus KLMK camo variant, especially if you plan to use it in pine trees.
Lol. I've built one of those with that cable and those radios. Even cross band ur lucky to get 200yrds unobstructed. Let's see a true test video. I switched to a simplex repeater controller using a single radio with the receive and transmit frequencies swapped so it works just as a repeater would and a single antenna. Very slight delay and you hear yourself back but then you know what everyone else heard. I get 20 miles easy unobstructed with 5 watts with a roll up j-pole in a tree.
Nice setup. I’ve been modifying a Retivis RT97S right now to get it to push 50 watt before duplexer. Installed the BTech amp and removed the tiny 10 watt duplexer and added a 50 watt notch duplexer. Still trying to fine tune everything but it’s a fun project
If you insist on using a pair of UV5R? put one on 145 and the other on 440MHz then put a couple of 5Meter long 2.5mm and a 3.5mm stereo extention leads on the repeater box get the UV5R in two boxes as far and vertically separate as possible
For a repeater ya need the spacing between the antennae but if ya use a cross band repeater it would be better and ya can make a dual band duplexer for AMSAT's as its really cheap and easy to build
I wanted to do something like this a while back as well, and I was informed that boxes like this that a) don't self identify every 10 minutes or so, and b) don't have an operator (or some way of remotely controlling the radios) aren't legal according to FCC guidelines. So caveat emptor
The FCC says any station owned by a license control operator may be a repeater, and also says that repeaters may be under automatic control. Automatic control is defined as a control station that can operate within compliance without the control operator present. With these mobile repeaters, you’re pretty much safe operating without a callsign on the repeater, since you’re using your callsign from your end every 10 minutes while it is transmitting. As long as it’s being used personally. However, I’m currently working on a way to inject a small MP3 player into the radio. But, I’m still having audio sensitivity issues, and my best solution right now is just a third radio that plays the Morse code audio file on repeat every 10 minutes. I also have some voice callouts mixed in, and I can use it as a signal quality beacon. On a side note if you’re worried about malfunctions such as a stuck open key, a station is permitted to malfunction up to 3 minutes before it’s in violation.
@@AZREDFERNyou could probably hook up a microcontroller into the mic on the transmit radio, and if it interferes with how the receiver connects to the transmitter... maybe you can use a diode? or something? Also if you used battery eliminators you could hook both radios up to a single 12 volt battery or something, maybe a LiFePO4 battery with a bms to prevent overdischarge? and then the batteries won't turn off on you by surprise and also you won't have any issues from one battery running out before the other like i imagine you might have with two separate batteries connected to different radios that do different jobs.
@@JacobZigenis A LORA ESP32 device could do it without metastatic. But metastatic does have some other useful features. You could use it to track the box if it wandered off. Range might be an issue with 900mhz. As this is a Ham setup, I was thinking maybe a relay controlled by APRS. Like a RP message to trigger a relay maybe...It might take some coding and a sound card to make it work I'm not 100% sure.
Pofung radios are not clones, it's the same brand. Over in China the legal system isn't very strong (especially with enforcement on companies), so lots of companies don't bother playing by the rules. Because of this, brand names in China are kind of worthless. Most places will have multiple different names they're registered under. Baofeng/Pofung/BTech has managed some name recognition, so they have been sticking with the Baofeng name but they're the same no-matter what brand you see them under. I believe that they were trying to switch to the Pofung branding for a while because they thought it would be easier to say properly in English, but they stopped for the most part when they noticed that they had no reputation under that name.
Wow! I didn’t think they existed at that price point. Maybe I’ll make a second one some day. A single unit would be more reliable and less complex. Ultimately, you best bet would just having a mobile unit in your vehicle, like a Wouxun 800H or 1000G and leave that with a crossband repeater on. But it’s still fun to design and build all options.
Its going to be a challenge (nice way of saying impossible) to create enough isolation on the same band. 90db is about as low as you should go, and that will require some cans. If you moved it to 70cm, you could use one of those smallish mobile duplexers that will give you 60ish. The far better way is to use a cross-band setup, then a simple duplexer will work. Personally, i would use a used dual band mobile on a 24ish AH lifo batter. Will be more than 100, but will work a lot better.
I would like to hear how the setup dealt with the freezing temps on the pouch battery cells, 32 and so forth - negatively.. It sounds great if you're always warm..
That was my original plan, but I wanted the option of setting it on a table, or on top of a vehicle in camp. Realistically, it probably would be best doing top and bottom antennas, different Rx/Tx antenna types, and pull it up in to a tree.
Your design gets an A+ for ingenuity and common sense. But has desensing been an issue? If you're using the same band for transmit and receive, I would expect it would be; your receive side will lose its hearing over time and the receive radio will be damaged. If you use a diplexer (not a duplexer) and the cross-band capabilities of the UV-5R, you can avoid the desensing issue and get away with using one dual-band antenna for both transmit and receive. What's nice about the Baofengs is you can set a huge offset so you can receive on VHF and transmit on UHF (or vice versa). That feature is missing on many of the more expensive HTs. Or, you could just configure your transmit and receive antennas on your existing repeater to be far apart. I would recommend at least 20 feet. If you opt for a cross-band repeater, desensing isn't an issue because the frequencies are so far apart. Anyway, nice work! I hope you continue to work on this and put out more videos with more details covered.
The only thing I'd point out is the length of the antennas, they should be two different lengths.....the RX side doent have to be that long. The TX has to have the longer antenna. Having them the same length can cause cross bleeding, thus creating interference with itself.
Why do you need the bi directional box between the two radios rather than just a single cord from the speaker of the receive radio to the mic of the transmit radio?
This is exactly what I am looking to build for our cabin in the hills. Do you have a link to CHIRP files for the repeaters? Or would you be willing to create another video showcasing how to set up the repeater radio settings, and repeater radio frequencies, as well as how to transmit from another radio through the repeater? Great job!
I think my problem was using them for GMRS. And my Tx radio was desensitizing the rx radio. Even with the +5.0 offset. I’m trying to research why, but I believe I need myself a duplexer. I guess the UHF Is too high a frequency. I’m currently studying for my ham license!! Then I will probably learn along the way, why this didn’t work
@@rallymadness8105 I returned them, desensitization due to antennas being too close. I wanted to have them in the box with antennas mounted on there, so I gave up.
hey man, great video! question, i have been asking everyone on the you tubes but no one has answered, in the metro Detroit area, i am on the south side and i have family on the north side, which is about 25 miles of fairly flat terrain, but mots of buildings and other obstacles. i am concerned that is we lose power for a while, and generators run dry, cell communications go down, and all other forms of electronic "traditional" forms of communication are down, that i will not be able to check on my family. Do you know of any way we could set up some sort of radio system that could run off solar panels and would reach that far?
This could work if you had access to the tallest point between your homes. Or you could go HF NVIS which carries a ton of advantages but requires general icense and equipment. But I’d super reliable and fun
Buildings are kind of a bane to radios. For all your handhelds, you have VHF (6M, 2M, MURS, 1.25 meter) and UHF (70cm, GMRS). UHF does better within the city, and VHF does better over distance. Both modes work best with line of sight, meaning no obstacles or earth in the way. The real problem is 2 equal height people can only “see” each other for 6 miles over the curvature of the earth at ground level. I’ve hit repeaters from 40 miles away, but I was on one mountain side, and the repeater was on a mountain top. A 5 watt handheld “can” reach 50+ miles in perfect conditions. In your situation, you’ll both need to be on top of buildings, or near the top and next to a window facing each other (RF isn’t bothered by glass). An even safer bet is to slowly learn about all the repeaters in your area, and test them when the power is out. For radios, you’ll be fine with GMRS radios. One $35 permit covers all immediate family members for 10 years, and you can practice it regularly. You “can” use a ham radio without a license to prevent the loss of life and limb, but power outages normally are not that kind of situation, and you won’t be able to practice on a regular basis. All handheld radios have similar output performance, but receiving performance is what sets radios apart. Wouxun, like the KG-805G, has the best receivers when it comes to the cheap Chinese radios. Anything cheaper than $80 is basically going to be the same radio. They still work great, but have problems with the squelch. I would recommend the “UV-5G Plus” as a great budget to function radio. Don’t fret over the wattage output of handhelds, it’s all the same. What’s most important is the antenna. If you want maximum performance, the ABBREE 42.5” Tactical GMRS antenna will make the distance. But it’s heavy and a lot to handle. Everyone’s favorite middle ground antenna is the Nagoya 771G, and I’ve tested that one to 40 miles. To connect to repeaters, use the Repeater Book app on your phone to see all local GMRS repeaters. Down the road, you may want to learn how to use CHiRP on your computer to program presets into your radio. As far as power goes, the Chinese radios are all moving towards USB-C. Unfortunately it’s only a 5 watt charge standard. But that means you only need a 5-10 watt folding solar panel, and it’ll take 4 hours to charge. GMRS is moderately easy to learn, and “Not A Rubicon” has plenty of great videos, especially when it comes to Baofengs and the new UV-5G Plus. On one final side note, there is no privacy on public radio. But if you want to send texts to each other that the average person can’t understand, get Rattlegram on your phones. Basically turn your phone volume all the way up with VOX on the radio right next to your phone, and you’re ready to text. It does cut your reliable distance in half, and anyone else can open up Rattlegram and intercept your conversation. That’s what keeps it legal. BUT…. If it really matters, you can cypher your texts. But that’s illegal for both all public radio services, unless you’re controlling a satellite.
thank you for your time on this. i wonder if i got a couple tall antenna to go on the roof, if that would work. or, come up with some other solution.@@AZREDFERN
@@chrisc0276 the thing with radio is, you can make anything happen if you know what you’re doing. Anything can become an antenna. Any antenna will work with a handheld with the right adapters from amazon, and a cheap MFJ antenna tuner. You can turn a mobile (vehicle) radio into a base (desktop) station with a 13.8v power supply. You can make a lot of Ham equipment work for GMRS. Only the transmitter needs to be GMRS specific. A lot of apartment hams just run a “random wire antenna” out of their window and down the wall, and some antenna tuners come ready to hook up random wire antennas. Like I said earlier, the antenna is the most important part. Finally, it’s a little harder to find for GMRS, but a “Yagi” antenna can be used with handhelds, and are VERY directional. Strong enough to talk to the ISS 150km away. That would be your best bet to make a GMRS handheld reach wherever you can see without obstruction. You just need to know where to point it, and either mount it on a roof, or hold it the entire time. Arrow makes some nice lightweight Yagi handhelds that can break down, out of archery arrows.
Fairly new to all of this but was curious if this setup would work for me as a GMRS user trying to build a DIY/budget repeater to put at the top of a canyon for my camping trip?
Awesome! Any idea why I’d have a squelch tail come back, roger beep coming back but audio is very quiet. Volume is up one TX radio. I’ve played with volume, and I’ve also unplugged receiver radio to make sure that’s working and it is loud with the speaker. I think I got a bad k1 box.
@@Mountainmancomtech thanks yes I believe the k1 is good. After doing 4 minutes of research lmao. Why wouldn’t you get the desensitization on the 2m band, but on GMRS I would? Is it just the properties of the higher frequency wave?
I have one and yes, it is a much simpler way to do this. I throw it in a box with a battery and I'm all set. Or I leave it hooked up in my truck and leave it on top of the hill.
Just 2 miles and 2 ridges away. But the volume was left all the way down, so I was only getting a Rodger beep. I still need to do a week long test, hiding it on a peak and testing it until I go back up for my next hike. That’ll be a good 15 mile test.
Hello from a ham radio user in Canada, is there not a license required for this? How did you select the frequencies, are you using the 2m simplex frequencies?
I was interested in comms in high school and did sattelite comms in the Army but now making a leap into it. I live in a hilly area and building this to extend range. I have learned a lot just from TH-cam and looking forward to getting my license and doing more
Experiment, experiment, experiment! That’s what it’s all about. Plenty of us have fried some circuitry a time or two with experiments. But this is how you learn. Hands on, get in there and build, tinker and be creative. That’s what the ham radio hobby is all about… Well, and making contacts and talking to other people 😊
I've never seen so many RFI filters used in my life!.. and I build commercial repeaters for a living. What exactly was the reasoning?.. were you out of nylon ties that day? So is there any front end protection provided for your RX radio? You can get pin diode shunts that go inline for this purpose, saves your RX front end from the beating it gets from the TX radio having no separation. I know with duplex suitcase designs, you can get >45dB separation with a duplexer, It just makes me cringe with the antennas having very little horizontal separation. You would be better to have them on top of each other with a ground plane in between, like your RX on top of your box with a 1/4 wave ground plane and the TX on the bottom. A ground plane between both antennas will also improve their performance greatly and alleviate anything from going back in your plastic box. The RF amps used in most of these radios is usually rated at 7.2V to get the 4.5W RF power, there must be a switcher in the radio to use USB 5.0V power from the Li-ion bricks or these radios are only outputting 2.5W max. Beofeng is kinda the antichrist in my trade, so I'm not sure how they're doing that power conversion. A company I worked for was heavily into supplying the aviation and rapid deployment communications in sar and fire scenes etc.. We saw chinese suppliers putting the whole controller/15Wradio/solar charger in one unit in a box with the duplexer tuned to your pair FOC for under $300USD! You would supply a solar panel and a 9ah Li-fepo4 battery. Only one problem, they were about as legal as those Beofengs.. absolutely no FCC/IC certification. They 'work' but non compliant to any standards, but yet used motorola rss for a ht750.. dunno.
dont use that junk radio get a pair of uv13 pro v2 .. miles better and kicks out 7.5watts and is 5 dollas cheaper , way better recive ,and not a bleed box liek the uv5r
Is this project not $100 for the 2 radios(without the batteries), and 2 repeater cables(without the adapters or ferrite chokes) alone? The two antennas bring it up to $140. If you factor everything you have here, your box is closer to $200 Than $100. That's the bare minimum. And then if you factored everything in the video with the extras, you bring it closer to $250-$300 with extended batteries, external power bank used, ferrite chokes, locks, cables. I get trying to hook people, but the viewer can feel taken advantage of when they see titles like that, invest time watching and the promise wasn't delivered. The AI thumbnail also kind of hid that fact away by disguising the true product.
I break down the required parts to make a $100, weatherproof, repeater. You do have to keep an eye on sales to get it to exactly $100. The batteries are optional, and you don’t need the chokes at all.
@@jamiedumanski2508this repeater is under $100. But it can't work very far due to a lack of a duplexer filter and very close TX and RX frequency and antenna. So it's a very ineffective design and that it can't be very practical.
Some of us are on a budget and still want to experiment with radios, is that really a problem? Don’t be a Sad Ham, encourage others to experiment, I thought that was what amateur radio was about!
@@Taco_Syndicate Not a sad ham, just wont work, the UV5R's without serious filtering will simply block. Go cross band repeater 145MHz and 440MHz will save you a lot of problems alone, and use superhet on the RX, like a HYT TC700, used less than 50bucks and windows programable, and if you can also get a UHF one for the TX you are good to go
@@phillipsmiley5930 it’s funny how Sad Hams only talk about the first iteration of UV-5Rs and their spurious emissions. They do work, I’ve seen it first hand. Gotta love those who repeat Sad Ham lore. You should report this video to the FCCs pronto, as this guy clearly needs a $25,000 fine and 10 years in a cell to think about his mistake (joking). I agree there are much better ways to make a repeater with HTs, I just don’t feel the need to correct someone who tries things out for himself. In the video he talks about using cross band frequencies as well. This is a neat little project, but not something I’d do myself. Heck, I let my friend do it first back in 2017, and learned from his experiment. Have a great day!
@@Taco_Syndicate Are you calling me a sad ham? I'm an RF tech thats worked on LMR radios for the last 40 years, ive seen SDR arrive and replace superhet not because its better but because its much cheaper
@@phillipsmiley5930 I would never call, You, a Sad Ham. But I do find it funny those boxes are being checked in short order. I'm guessing the might and power of the FCCs won't be touched since I joked about it, but man you guys are all the same. I'm not trying be rude, it's just hard to not notice patterns once you see them. Then again, I could be the idiot chatting with a bot... Have a great day! I'm off to play on HF radio.
This is what TH-cam was actually made for. I remember the long long ago. Thanks for Keeping that spirit alive and encouraging others by publishing a video such as this.
I am pretty sure that TH-cam was made for cat videos and anti-Trump propaganda...
I would love a video where you take everything out and show how everything is wired together. Please let us know at a later date how well its working. Thanks, I was happy to sub!!
I'll be doing a follow-up video soon once I'm confident I can keep it charged for a week unattended, and get the callsign working.
Especially how those batteries are doing
@@AZREDFERN I have a similar setup for GMRS backpack repeater. I used goal zero batteries and added their 10w solar panel to the setup.
That's what i wanna do also @@Oberkaptain
Loved this video & the idea execution was super sweet.
I think having a typed & laminated card instead of a handwritten one would really enhance how official this looked in the field as well
Learnings... are good. This is amateur radio....and the fun is in your journey! Technical inspiration: Words provide context. But the answers are always in the numbers! And for a repeater, it is all about isolation between TX and RX, etc. With those antenna's so close, yes you have "some" isolation, but I'm thinking only 20dB. So you are transmitting at say 5W (+37 dBm) - 20 dB = +17 dBm at your receiver. The Third Order intercept of a cheap radio is likely -50 dBm and you are 67dB stronger into it! Your transmitter noise has been reported by many as only -45dBc, so +37 dBm - 45 dB = -8dBm noise. You have two issues affecting your "open" receiver... being mixer overload making it deaf, as well as TX noise which covers up weak signals. A weak signal into your receiver without any TX or noise affecting it could be -120dBm for 12dB SINAD. Now look at the numbers.... -120dBm operating floor but with the TX noise producing -8 dBm! These are extreme numbers... reality may be a bit different... this setup will not work for anything but nearby radios. You can tell you are experiencing desense, when you can trip your repeater, but it goes deaf the instant the TX comes up... you get that roger beep, but nothing more. Add a mobile duplexer... they are compact enough, but generally require 3MHz or more separation between TX and RX. And mobile duplexers at these freq's are notch type devices, never bandpass. If you go cross-band repeat (146.520/446.000), now you have 300 MHz to work with. A simple High Pass / Low Pass filter like a mobile antenna duplexer will do the trick and you will have your lunchbox repeater on one dual band mobile whip antenna. This is another reason some use a "simplex" repeater module instead where it records your message and then keys up and repeats it after you are done. No duplexing or desense issues. Good luck in this most excellent hobby!
Awesome experimentation and learning. You will find you need more (and unfortunately big, expensive ,and heavy) parts in the system to get this to be reasonably functional. For a repeater to work, it needs to be able to receive a very weak signal while transmitting a relatively large signal. To be able to do that on relatively close frequencies, you need some very powerful filtering in the form of a duplexer. Without that, this device may be able to function ok as a cross-band repeater using 2m and 70cm, but desensitization may still be a problem with a Baofeng as the receiver. Keep tinkering, have fun, and please be sure to share your progress as you develop this further.
Bro, love the vibe here, very uplifting.
The powerbank is not USB 2! USB 1/2/3/4 is the standart for Bandwith. i dont think they follow an official standart, the official standart was 5V at 200ma, 500ma only after getting the ok from the power source.
The "new" usb pd standart is whats used for higher power, in the newest version up to 240w.
Lots of good feedback here for you regarding desense (the rx won’t do weak signals since the tx antenna is inches away from the rx antenna).
You can reduce some of that desense by putting one antenna on top of the box and the other on the bottom. This gives them vertical separation AND also gets them farther away from one another. Another even better separation would be to hang one antenna a few feet below the box (let the antenna swing freely on its coax).
Have fun experimenting. I did almost exactly the same thing 25 yrs ago and had a blast doing it!
Looks like a fun project. I think I will steal your idea for myself and build one.
Please dont, look for other videos on how to do it
It's tough, I tried one and it seems that a duplexer is the way to go for meaningful gains. I made the mistake and got a cheap UHF duplexer from aliexpress. Only gave 40db of isolation as opposed to a good 80-100. Trying for a digital repeater now using TDMA on a radioditty GD-88
So cool to see you put together a working baofeng repeater. I tried one this spring, but the TX radio (TH-UV98) would deafen the RX radio (TH-UV88) and my range was worse than simplex. Tried a cheapo chinese duplexer on UHF but it only gave me 40db of isolation which didn't help. Currently have a radioditty GD-88 with extended battery set up in that same apache 1800 case, trying for single-frequency-repeat on DMR.
Your video is an inspiration to get back to the analog project, and to probably use different radios without spurious emissions
Neat Project! Would be nice if you had a diagram of the goal with the device (max range communication) as well as the maximum number of repeater hops you can have in the mix for clandestine long range communications in case of an EMP pulse. Would love to set something like this up on a mountain so I would be able to communicate with family 100 miles a way to check in with them. Would like to also give family some sort raspberry pi communicator in a an aluminum faraday briefcase so that they can foldable solar panel power it and type a message on their unit and my unit could log it for reading when I am in front of it. Do drills with it every week to make sure system is operational. Solar powered repeater high in the hills.
LOOOOVE me a lunchbox, particularly for a simplex repeater. These things are basically perfect for non-permissive environments where you need to extend range or get around obstacles in an emergency.
Really good stuff! It's good to see more AZ folk Doing radio/motorcycle/outdoor content. It makes youtube feel like a smaller community for us other AZ folk.
An idea to make things even more apparent would be an ID tag stamped out of aluminum that has your callsign, phone number, and "radio repeater".
Use two roll-up j-poles hang them on the same line the top pointing up and the bottom pointing down. That way your lines are in each others nulls. Do a wide split on 2m, portables work better on a wider split. Common Joe or even rangers do not know what a "Lunch Box" repeater is. Get a card that explains it is a temporary remote radio station licensed under FCC (cite code) with your information and call sign. And lastly get an ID on the unit so you are actually legal.
If your concerned about it getting stolen I would recommend either rattlecanning it or getting some surplus KLMK camo variant, especially if you plan to use it in pine trees.
Lol. I've built one of those with that cable and those radios. Even cross band ur lucky to get 200yrds unobstructed. Let's see a true test video. I switched to a simplex repeater controller using a single radio with the receive and transmit frequencies swapped so it works just as a repeater would and a single antenna. Very slight delay and you hear yourself back but then you know what everyone else heard. I get 20 miles easy unobstructed with 5 watts with a roll up j-pole in a tree.
Do you have a tutorial on how to build your setup? Id like to build your simplex type repeater. Can you include a parts list?
Not everyone knows what a repeater is, so n your note I’d spell it out that you want it left in the tree. Neat set up
Nice setup. I’ve been modifying a Retivis RT97S right now to get it to push 50 watt before duplexer. Installed the BTech amp and removed the tiny 10 watt duplexer and added a 50 watt notch duplexer. Still trying to fine tune everything but it’s a fun project
Awesome video. I’ve been wanting to try making a cheap repeater using Boefangs with a duplexer.
If you insist on using a pair of UV5R? put one on 145 and the other on 440MHz
then put a couple of 5Meter long 2.5mm and a 3.5mm stereo extention leads
on the repeater box get the UV5R in two boxes as far and vertically separate as possible
For a repeater ya need the spacing between the antennae but if ya use a cross band repeater it would be better and ya can make a dual band duplexer for AMSAT's as its really cheap and easy to build
Awesome build.. Great explanation video. Needs a trail cam added.
I wanted to do something like this a while back as well, and I was informed that boxes like this that a) don't self identify every 10 minutes or so, and b) don't have an operator (or some way of remotely controlling the radios) aren't legal according to FCC guidelines. So caveat emptor
The FCC says any station owned by a license control operator may be a repeater, and also says that repeaters may be under automatic control. Automatic control is defined as a control station that can operate within compliance without the control operator present. With these mobile repeaters, you’re pretty much safe operating without a callsign on the repeater, since you’re using your callsign from your end every 10 minutes while it is transmitting. As long as it’s being used personally. However, I’m currently working on a way to inject a small MP3 player into the radio. But, I’m still having audio sensitivity issues, and my best solution right now is just a third radio that plays the Morse code audio file on repeat every 10 minutes. I also have some voice callouts mixed in, and I can use it as a signal quality beacon. On a side note if you’re worried about malfunctions such as a stuck open key, a station is permitted to malfunction up to 3 minutes before it’s in violation.
@@AZREDFERNyou could probably hook up a microcontroller into the mic on the transmit radio, and if it interferes with how the receiver connects to the transmitter... maybe you can use a diode? or something?
Also if you used battery eliminators you could hook both radios up to a single 12 volt battery or something, maybe a LiFePO4 battery with a bms to prevent overdischarge? and then the batteries won't turn off on you by surprise and also you won't have any issues from one battery running out before the other like i imagine you might have with two separate batteries connected to different radios that do different jobs.
The other concern is the ability to remotely or locally turn the repeater off is required by the FCC as part of the "control" bit.
@@EthosAtheos ESP32 + Meshtastic to control a relay that'll cut power to both radios perhaps?
@@JacobZigenis A LORA ESP32 device could do it without metastatic. But metastatic does have some other useful features. You could use it to track the box if it wandered off.
Range might be an issue with 900mhz. As this is a Ham setup, I was thinking maybe a relay controlled by APRS. Like a RP message to trigger a relay maybe...It might take some coding and a sound card to make it work I'm not 100% sure.
Looking forward to seeing a follow-up video. I have two Pofungs (Baofang clones)...
Pofung radios are not clones, it's the same brand. Over in China the legal system isn't very strong (especially with enforcement on companies), so lots of companies don't bother playing by the rules. Because of this, brand names in China are kind of worthless. Most places will have multiple different names they're registered under. Baofeng/Pofung/BTech has managed some name recognition, so they have been sticking with the Baofeng name but they're the same no-matter what brand you see them under. I believe that they were trying to switch to the Pofung branding for a while because they thought it would be easier to say properly in English, but they stopped for the most part when they noticed that they had no reputation under that name.
Check quansheng UV5R Plus
There must be significant de-sense of the RX with a 5W TX only 600KHz away!
Im a noob to ham and love watching vids like this.
Take a look the the TYT TH-UV8000D it’s an analog HT that has cross band repeat built in. I think it would be perfect for this application.
Wow! I didn’t think they existed at that price point. Maybe I’ll make a second one some day. A single unit would be more reliable and less complex. Ultimately, you best bet would just having a mobile unit in your vehicle, like a Wouxun 800H or 1000G and leave that with a crossband repeater on. But it’s still fun to design and build all options.
The only downside to the TH-uv800D is I don’t think there’s a usb-c battery however there is a 12vdc “battery eliminator”
Its going to be a challenge (nice way of saying impossible) to create enough isolation on the same band. 90db is about as low as you should go, and that will require some cans. If you moved it to 70cm, you could use one of those smallish mobile duplexers that will give you 60ish. The far better way is to use a cross-band setup, then a simple duplexer will work. Personally, i would use a used dual band mobile on a 24ish AH lifo batter. Will be more than 100, but will work a lot better.
I would like to hear how the setup dealt with the freezing temps on the pouch battery cells, 32 and so forth - negatively.. It sounds great if you're always warm..
You ought to figure out much of a solar panel it would take to keep the batteries charged. ;.)
I would think maybe having the antennas coming out opposite sides of the box would be a better option.
That was my original plan, but I wanted the option of setting it on a table, or on top of a vehicle in camp. Realistically, it probably would be best doing top and bottom antennas, different Rx/Tx antenna types, and pull it up in to a tree.
@@AZREDFERN from the sad ham section LoL. That is the preferred setup .
Or maybe have them 90º to each other, so you get somewhere around 20dB attenuation from opposite polarization?
This is a fantastic video and very inspiring. Now i have some ideas that i may also want to try.
Your design gets an A+ for ingenuity and common sense. But has desensing been an issue? If you're using the same band for transmit and receive, I would expect it would be; your receive side will lose its hearing over time and the receive radio will be damaged.
If you use a diplexer (not a duplexer) and the cross-band capabilities of the UV-5R, you can avoid the desensing issue and get away with using one dual-band antenna for both transmit and receive. What's nice about the Baofengs is you can set a huge offset so you can receive on VHF and transmit on UHF (or vice versa). That feature is missing on many of the more expensive HTs.
Or, you could just configure your transmit and receive antennas on your existing repeater to be far apart. I would recommend at least 20 feet.
If you opt for a cross-band repeater, desensing isn't an issue because the frequencies are so far apart.
Anyway, nice work! I hope you continue to work on this and put out more videos with more details covered.
time for some cavity filters! :)
The only thing I'd point out is the length of the antennas, they should be two different lengths.....the RX side doent have to be that long.
The TX has to have the longer antenna.
Having them the same length can cause cross bleeding, thus creating interference with itself.
Ive watched the video, bought the stuff and waiting to see whats what. If it doesnt work i can play around with it and learn from others
probably be better served by running the cable through the locks on the box as well. those handles can be ripped off easily.
Sounds like you got some testing and experiments coming up
small upgrade for antenna would be an n9tax labs slim jim or other roll up j pole
Why do you need the bi directional box between the two radios rather than just a single cord from the speaker of the receive radio to the mic of the transmit radio?
Great video, thank you. You inspired me to put one of these together.
This is exactly what I am looking to build for our cabin in the hills. Do you have a link to CHIRP files for the repeaters? Or would you be willing to create another video showcasing how to set up the repeater radio settings, and repeater radio frequencies, as well as how to transmit from another radio through the repeater?
Great job!
Yup. You earned a subscriber. Gonna try to copy your setup
Thank you for this great video, really helpful. Cheers from Sweden!
I think my problem was using them for GMRS. And my Tx radio was desensitizing the rx radio. Even with the +5.0 offset. I’m trying to research why, but I believe I need myself a duplexer. I guess the UHF Is too high a frequency. I’m currently studying for my ham license!! Then I will probably learn along the way, why this didn’t work
Did you ever figure out how to get this to work for GMRS?
@@rallymadness8105 I returned them, desensitization due to antennas being too close. I wanted to have them in the box with antennas mounted on there, so I gave up.
can you do a programming video of this, I have built one but am having issues
Good stuff Great Build
hey man, great video! question, i have been asking everyone on the you tubes but no one has answered, in the metro Detroit area, i am on the south side and i have family on the north side, which is about 25 miles of fairly flat terrain, but mots of buildings and other obstacles. i am concerned that is we lose power for a while, and generators run dry, cell communications go down, and all other forms of electronic "traditional" forms of communication are down, that i will not be able to check on my family. Do you know of any way we could set up some sort of radio system that could run off solar panels and would reach that far?
This could work if you had access to the tallest point between your homes. Or you could go HF NVIS which carries a ton of advantages but requires general icense and equipment. But I’d super reliable and fun
Buildings are kind of a bane to radios. For all your handhelds, you have VHF (6M, 2M, MURS, 1.25 meter) and UHF (70cm, GMRS). UHF does better within the city, and VHF does better over distance. Both modes work best with line of sight, meaning no obstacles or earth in the way. The real problem is 2 equal height people can only “see” each other for 6 miles over the curvature of the earth at ground level. I’ve hit repeaters from 40 miles away, but I was on one mountain side, and the repeater was on a mountain top. A 5 watt handheld “can” reach 50+ miles in perfect conditions. In your situation, you’ll both need to be on top of buildings, or near the top and next to a window facing each other (RF isn’t bothered by glass). An even safer bet is to slowly learn about all the repeaters in your area, and test them when the power is out. For radios, you’ll be fine with GMRS radios. One $35 permit covers all immediate family members for 10 years, and you can practice it regularly. You “can” use a ham radio without a license to prevent the loss of life and limb, but power outages normally are not that kind of situation, and you won’t be able to practice on a regular basis. All handheld radios have similar output performance, but receiving performance is what sets radios apart. Wouxun, like the KG-805G, has the best receivers when it comes to the cheap Chinese radios. Anything cheaper than $80 is basically going to be the same radio. They still work great, but have problems with the squelch. I would recommend the “UV-5G Plus” as a great budget to function radio. Don’t fret over the wattage output of handhelds, it’s all the same. What’s most important is the antenna. If you want maximum performance, the ABBREE 42.5” Tactical GMRS antenna will make the distance. But it’s heavy and a lot to handle. Everyone’s favorite middle ground antenna is the Nagoya 771G, and I’ve tested that one to 40 miles. To connect to repeaters, use the Repeater Book app on your phone to see all local GMRS repeaters. Down the road, you may want to learn how to use CHiRP on your computer to program presets into your radio. As far as power goes, the Chinese radios are all moving towards USB-C. Unfortunately it’s only a 5 watt charge standard. But that means you only need a 5-10 watt folding solar panel, and it’ll take 4 hours to charge. GMRS is moderately easy to learn, and “Not A Rubicon” has plenty of great videos, especially when it comes to Baofengs and the new UV-5G Plus. On one final side note, there is no privacy on public radio. But if you want to send texts to each other that the average person can’t understand, get Rattlegram on your phones. Basically turn your phone volume all the way up with VOX on the radio right next to your phone, and you’re ready to text. It does cut your reliable distance in half, and anyone else can open up Rattlegram and intercept your conversation. That’s what keeps it legal. BUT…. If it really matters, you can cypher your texts. But that’s illegal for both all public radio services, unless you’re controlling a satellite.
thank you for your time on this. i wonder if i got a couple tall antenna to go on the roof, if that would work. or, come up with some other solution.@@AZREDFERN
@@chrisc0276 the thing with radio is, you can make anything happen if you know what you’re doing. Anything can become an antenna. Any antenna will work with a handheld with the right adapters from amazon, and a cheap MFJ antenna tuner. You can turn a mobile (vehicle) radio into a base (desktop) station with a 13.8v power supply. You can make a lot of Ham equipment work for GMRS. Only the transmitter needs to be GMRS specific. A lot of apartment hams just run a “random wire antenna” out of their window and down the wall, and some antenna tuners come ready to hook up random wire antennas. Like I said earlier, the antenna is the most important part. Finally, it’s a little harder to find for GMRS, but a “Yagi” antenna can be used with handhelds, and are VERY directional. Strong enough to talk to the ISS 150km away. That would be your best bet to make a GMRS handheld reach wherever you can see without obstruction. You just need to know where to point it, and either mount it on a roof, or hold it the entire time. Arrow makes some nice lightweight Yagi handhelds that can break down, out of archery arrows.
Great information
Thank you again!!
Fairly new to all of this but was curious if this setup would work for me as a GMRS user trying to build a DIY/budget repeater to put at the top of a canyon for my camping trip?
Can you please tell me where the $7 SMA adapters (flex glued to case) can be purchased from? Thank you!
Great video. Please, give your advice where the repeater need to be installed?
Very fun build. Does it have a CW identifier portion or is this one running raw?
Good video other then the random distracting music i thought my phone messages was going off for a minute or so
Thanks for the video
cool project !!
Love the keychain. Have one as well.
I think this is awesome, thanks for making it! 73, KG1USA
Awesome! Any idea why I’d have a squelch tail come back, roger beep coming back but audio is very quiet. Volume is up one TX radio. I’ve played with volume, and I’ve also unplugged receiver radio to make sure that’s working and it is loud with the speaker. I think I got a bad k1 box.
Probably receive desensitization.
@@Mountainmancomtech thanks yes I believe the k1 is good. After doing 4 minutes of research lmao. Why wouldn’t you get the desensitization on the 2m band, but on GMRS I would? Is it just the properties of the higher frequency wave?
Would love to hear if the contact could ping it from 10 to 12 away.
I may be wrong, but if you are trying to setup a cross-band repeater (use cans for filtering) possibly you can consider this radio TYT TH-UV8000D ?
I have one and yes, it is a much simpler way to do this. I throw it in a box with a battery and I'm all set. Or I leave it hooked up in my truck and leave it on top of the hill.
Cool!
Nice build!
A radio rePeaper? Was that a deliberate typo? (in the thumbnail text)
Have you done a range test?
Just 2 miles and 2 ridges away. But the volume was left all the way down, so I was only getting a Rodger beep. I still need to do a week long test, hiding it on a peak and testing it until I go back up for my next hike. That’ll be a good 15 mile test.
Hello from a ham radio user in Canada, is there not a license required for this? How did you select the frequencies, are you using the 2m simplex frequencies?
Looks like a claymore haha
Have you done a range test? I'm trying to build a repeater box just like yours. It works fine within 500m. After that I hear nothing
realy cool !
Interested in selling pre-made ones
I have a question for you and other viewers. How do you learn all this stuff? Were you comms in military? Just a hobby? It's daunting to get into.
I was interested in comms in high school and did sattelite comms in the Army but now making a leap into it. I live in a hilly area and building this to extend range. I have learned a lot just from TH-cam and looking forward to getting my license and doing more
Experiment, experiment, experiment! That’s what it’s all about. Plenty of us have fried some circuitry a time or two with experiments. But this is how you learn. Hands on, get in there and build, tinker and be creative. That’s what the ham radio hobby is all about… Well, and making contacts and talking to other people 😊
I LIKE THIS ON AND GREAT EXPLANATION.
Woa... this saved me a ton of $$$$ and time.
Thanks!
Very, very cool.
Could you use this setup for GMRS?
Looks great.
Thumbnail says repeaper?
So where is the duplex filter? Tell me you're not just doing two antennas straight of the radios.
I've never seen so many RFI filters used in my life!.. and I build commercial repeaters for a living. What exactly was the reasoning?.. were you out of nylon ties that day? So is there any front end protection provided for your RX radio? You can get pin diode shunts that go inline for this purpose, saves your RX front end from the beating it gets from the TX radio having no separation. I know with duplex suitcase designs, you can get >45dB separation with a duplexer, It just makes me cringe with the antennas having very little horizontal separation. You would be better to have them on top of each other with a ground plane in between, like your RX on top of your box with a 1/4 wave ground plane and the TX on the bottom. A ground plane between both antennas will also improve their performance greatly and alleviate anything from going back in your plastic box. The RF amps used in most of these radios is usually rated at 7.2V to get the 4.5W RF power, there must be a switcher in the radio to use USB 5.0V power from the Li-ion bricks or these radios are only outputting 2.5W max. Beofeng is kinda the antichrist in my trade, so I'm not sure how they're doing that power conversion.
A company I worked for was heavily into supplying the aviation and rapid deployment communications in sar and fire scenes etc.. We saw chinese suppliers putting the whole controller/15Wradio/solar charger in one unit in a box with the duplexer tuned to your pair FOC for under $300USD! You would supply a solar panel and a 9ah Li-fepo4 battery. Only one problem, they were about as legal as those Beofengs.. absolutely no FCC/IC certification. They 'work' but non compliant to any standards, but yet used motorola rss for a ht750.. dunno.
You got enough chokes on all the wires there?
No. I ran out…
@@AZREDFERN
FlightRadar24 tag spotted 🧐🧐
Yer family out of Montana butte area?
I’m the AZ variant of Redferns.
@@AZREDFERN Crazy. you're the only person I Hvae seen with the same spelling as mine
without duplexer this will newer work
this is so awesome but the electronics part throws me off.
It's either a lunch box repeater
or
keep talking and nobody explodes
You are totally desensing the rx radio by the tx radio. Eventually you will burn out the diodes...
dont use that junk radio get a pair of uv13 pro v2 .. miles better and kicks out 7.5watts and is 5 dollas cheaper , way better recive ,and not a bleed box liek the uv5r
hahahahaahaha .
That thumbnail is awful 😂 AI really doesn't know how to write text still does it 😂
I’ve kinda been having fun with it. It’s eye catching at first, and then gets worse the more you look at it.
@@AZREDFERN Yeah definitely, I thought it was a really good and distinctive thumbnail but you look closer and it's clear an AI has made it 😂
Is this project not $100 for the 2 radios(without the batteries), and 2 repeater cables(without the adapters or ferrite chokes) alone? The two antennas bring it up to $140.
If you factor everything you have here, your box is closer to $200 Than $100.
That's the bare minimum. And then if you factored everything in the video with the extras, you bring it closer to $250-$300 with extended batteries, external power bank used, ferrite chokes, locks, cables.
I get trying to hook people, but the viewer can feel taken advantage of when they see titles like that, invest time watching and the promise wasn't delivered.
The AI thumbnail also kind of hid that fact away by disguising the true product.
Thanks for looking out for us, Karen.
Box cones from harbor freight. They are cheap. Less the 50$
I break down the required parts to make a $100, weatherproof, repeater. You do have to keep an eye on sales to get it to exactly $100. The batteries are optional, and you don’t need the chokes at all.
Ahhh yes. The modern Ham here to save us. Tell me you didn't watch the video without watching the video. You're a clown
2 x UV5R, no duplexer filters, both on 2M, 600k split = Junk
How not to build a cheap repeater
Well why don't you take the time to make a video and show us the correct way for under $100
@@jamiedumanski2508 there are already hundreds of repeater videos on YT
@@jamiedumanski2508this repeater is under $100. But it can't work very far due to a lack of a duplexer filter and very close TX and RX frequency and antenna. So it's a very ineffective design and that it can't be very practical.
@@nine7295 If he adds a Duplex splitter for like $50, he will only need to run 1 antenna. Or just a simplex repeater would work for what he wants it.
This is a joke! Build a portable repeater the correct way with good equipment and a duplexer or dont waste your time.
Some of us are on a budget and still want to experiment with radios, is that really a problem? Don’t be a Sad Ham, encourage others to experiment, I thought that was what amateur radio was about!
@@Taco_Syndicate Not a sad ham, just wont work, the UV5R's without serious filtering will simply block.
Go cross band repeater 145MHz and 440MHz will save you a lot of problems alone, and use superhet on the RX, like a HYT TC700, used less than 50bucks and windows programable, and if you can also get a UHF one for the TX you are good to go
@@phillipsmiley5930 it’s funny how Sad Hams only talk about the first iteration of UV-5Rs and their spurious emissions. They do work, I’ve seen it first hand. Gotta love those who repeat Sad Ham lore. You should report this video to the FCCs pronto, as this guy clearly needs a $25,000 fine and 10 years in a cell to think about his mistake (joking). I agree there are much better ways to make a repeater with HTs, I just don’t feel the need to correct someone who tries things out for himself. In the video he talks about using cross band frequencies as well. This is a neat little project, but not something I’d do myself. Heck, I let my friend do it first back in 2017, and learned from his experiment. Have a great day!
@@Taco_Syndicate Are you calling me a sad ham? I'm an RF tech thats worked on LMR radios for the last 40 years, ive seen SDR arrive and replace superhet not because its better but because its much cheaper
@@phillipsmiley5930 I would never call, You, a Sad Ham. But I do find it funny those boxes are being checked in short order. I'm guessing the might and power of the FCCs won't be touched since I joked about it, but man you guys are all the same. I'm not trying be rude, it's just hard to not notice patterns once you see them. Then again, I could be the idiot chatting with a bot... Have a great day! I'm off to play on HF radio.