I love miniature 27Mhz radios. These are wonderful devices. hardly anyone understands it when it is only a consumer, what else when you are a designer and knows how much effort of the best scientific groups has cost the work of such radio stations. These are the children of military radio stations, the same principles, cheaper parts, weaker enclosures but these are the early models of military radio stations. Now mobile phones are developing computers, they were developed by real people, the best of the best. I love mini AM radio stations. Hello again, I write from Poland, I am a scientific designer of a portable radio 27hz. These devices have 100mW of power "Input" meaning they have about 10 to 25 mW of output power. 100mW is a long-established standard for radio stations without permission, in the past it was not possible to measure the output power in a cheap way. many radio services did not have an output power meter. Therefore, the amount of power consumed by the last transistor power transmitter was measured. So power power, input power (power supply) was measured. The tapping current of the last stage of the transmitter was measured and the result was multiplied by the power supply voltage. The output power is much lower, usually 3-6 times lower. These are very delicate and sensitive radio devices, treat them more gently, they can not stand vibrations / shocks, the antenna is delicate and expensive $ 50-100, it should be regularly oiled, and disassembled and assembled after each telescope. Do not move the radio so that there is no strain on the antenna. Subsequent scientific research has proved that when using a metal housing, the transmitter radiates best at 60-80cm antenna but loses some of the signal during the set because the antenna has lower radiation resistance and is lower than the ground. When you use BNC sockets and very short helical antennas, the transmission range will be larger but the receiver will lose sensitivity, as a whole the effect will be similar. Unfortunately, these studies were confirmed only at the end of the eighties. Clear potentiometers :-), it's amazing that the Japanese have tried this way and these devices still work and the American ones much more expensive do not work anymore. The Japanese were slaves to the US, but they worked with all their heart, these devices and other electronic devices were their devotion, full dedication and resignation from pleasure / family, their work was worth hundreds of times more. A long time ago when the CB 27 Mhz radio was to be heard over the band between 40 and 60 Mhz, 54MHz tested, the results were unbelievably good. However, it was not decided because the portable AM radio at 54 Mhz had better coverage than the portable FM radio at 30-40 Mhz used by the military. It was not enough for civilians to have such a good radio. The 27 Mhz band was deliberately designed to significantly reduce the range of portable radios, to require a significant counterweight, a significant antenna length to be clearly visible to the police and other services. This is in case the CB user can not be anonymous, all for the purpose of national security and public control. The army got a band of 40-60 Mhz because the human body has a resonance length of around 45 Mhz, at this frequency the antenna receives a high voltage when the counterweight (human body) has a low input resistance, this is a very advantageous distribution in the differential. In addition, the higher the frequency of the loss of the eddy currents, because the antenna is higher above the ground in relation to the wavelength. 27 Mhz requires a significant amount for effective work. The reduction of the portable CB range was supposed to be a security guarantee that civilian CB portable radio will not be better than then used by 40Mhz by the military. Therefore antennas with a central coil are so beneficial for portable devices, initially such antennas were illegal, and their use at 27Mhz could lead to imprisonment. The antenna with the center coil radiates effectively only from the height of the coil, increasing the height of the radiation, this significantly reduces losses at 27Mhz and lower frequencies. Test radios after rainfall, as a result of much better ground-level propagation the range will be noticeably better, 27Mhz when carrying out portable work very badly tolerates dry terrain underfoot. Best wishes.
Arek, thank you so much for your comments! I recently have gotten into collecting and using 27mhz CB walkie-talkies and I learned a lot just now from you!
I had a TRC25A when I was 12 (1972). Not knowing how antennas worked, I wrapped a wire about 30' feet long around the antenna and ran it on top of my house. It actually worked and I could talk all over town with it. I also hooked two 9-volt batteries in series ( I would NOT recommend this on these old radios) and that worked even better. BTW, it looked like you were about 1/4 mile away when you were at the bridge. Your Ch 2 position is for an optional set of crystals. These radios were way ahead of their time for walkie-talkies.
Here some four years after you posted your video. That was fun. Thanks for posting it. I still have my Radio Shack TRC-74 walkie talkies that I got for Christmas as a kid back in the mid 70's. They don't see much use anymore... just not practical. But now and again I put a battery in each of them and enjoy bringing them to life once again. Be well, and God bless.
Loved the vid. Great little low power radios. In the 70's these were radios I would have given my right arm for. Remember on those frequencies, ANY and ALL obstacles will effect range. VERY COOL VID! Keep it up!
My Dad bought me one of these for Christmas 1975. I wanted a Midland 2 watt. But my Dad didn't want to spend that much on a noisy CB walkie talkie! My buddy DID get a Midland. We easily heard him a mile away in the suburbs. Sadly he could not hear me. I never did care for the radio after that. But I tried not show it. Thanks for the look back!😄
TR1 2SC645 is the RF final power amplifier transistor ,emitter resistor controls current flow of TR1 and power so be careful changing that value,L1 is used to match antenna and optimize radiation of telescopic antenna,so if say put ch40 xtal in you need a field strength meter or build one very simple.Adjust core L1 with proper trimmer tool (not a metal screw driver) for max defelection of field stregth meter ull see a peak point.I would advise you cover speaker grill as dont want modulation or do it a quiet area,you only want carrier power not modulated power as its Am system.If you want to measure the RF power ull need a 50ohm dummy load,a RF power meter able to read 0 to 1watts and a patch lead in thin 50ohm coax to hook up to walkie talkies -braid of coax goes to ground point and centre of coax goes to the coomon contact of R\T switch just below L1 coil,make sure telescopic is push inside set when making RF power measurements.Also bear in mind this is Am,with AM you have a carrier and a audio modulator TR7,8 and T5.Rule of thumb here is carrier is 4 times less than final output power so say its 100mWatts carrier ull need 4 times more to get 100% moulation and max total power PEP so ie 100mW x4 time power =400mW PEP at 100% modulation .The T5 transformer is used to ramp up the DC voltage 4 times while at same time is modulated by voice. onto the carrier ie 27.125mhz.At T5 point if battery volts are 9V the total when modulated to max voice (say 100%) will be around 9V x 4=36Volts max hence why u must set the carrier power (no voice) at 4 times less again ie 1W carrier (no voice) with voice or tone 1w carrier but 4W PEP (peak envelope power) at 100% modulation .IF modulation say 60% then out pep will drop in value but carrier will not.Hope that makes sense im not the best explaining stuff,better in a workshop to show you.So if you change power transistor TRI and mover carrier from 100mW to say 500mW,ur gonna need more audio power to get get 2W PEP output at 100% modulation ideally.A bit of tinkering prob could get u 100-250mW carrier x4 =400mW PEP to 1W PEP thats assuming can modulate the carrier with TR7,8 T5.Thats all said a good tune and some switch cleaner may help it along,also on old vintage gear electrolytic capacitors do often go bad and have to be swapped out ,dead cheap and easy to do with soldering iron and solder pump.Great vid love the retro USA cb have a few my self work really well crystal controlled stuff! A little trick i do is add a trailing single core insulated wire 2.75metres in length (about 8-9ft) and use a ring solder tag and screw it onto the metal case of WT,normally a screw on case of WT,make sure good bonding connection to solder tag\wire .It will act as a ground plane and range will increase easy by about +18dB (3 s points 6dB per S-point)in radiation from telescopic,just be careful dont trip over trailing wire,connect to ground of case only!With old school CB walkies talkies the antenna must be fully extended too as in some higher power ones ull create a mis-match to antenna if not fully extended and could destroy the final RF power transistor-OK Lot to take in ,test kit can be very basic or built if got the skills-internet best friend to find out. Enjoyed watching Glad having fun with retro cb radios,they sometimes work better than modern day equipment lol Xtals ull find on ebay generally a 455khz difference between TX 27.125mhz RX 26.670mhz xtals or try here lots WT spares/xtals like antennas replacements and shop helpful if stuck! Ive order stuff from here and had it shipped to UK here so know they are reliable and helpful www.kenselectronics.com/ have fun and more walkie talkie retro vids please! if you like retro cb and want to know more check out MikesRadioRepair on Utube channel has tonnes of useful info on cb and repairs and can ask questions,mike nice approachable guy. th-cam.com/video/MGykC6dgOzQ/w-d-xo.html Bob in radio shack! 73 from Great Britain!
Neat radios and a fun way to test them. The noisy volume pot can be cleaned with tuner/electronics cleaner. And interference from wallwart power adapters, powerlines, etc. is all part of the fun of AM on 11 meters. Thumbs up!
Nice video exploring how far these can operate. This was amazing technology 40 years ago, especially for someone who grew up 40 years before that when commercial radio was just getting started. Today's increasing rates of change are truly amazing. Now you can get HC-12 modules with a little spring antenna for $4.50 that reliably transmit data over half a mile between Arduino microcontrollers at 433 MHz and at amazingly high baud rates -- your idea of sending digital data over the TRC25A's on steroids.
I would not bother modding these, you would have to go to 1 W to get noticeable difference and tuning the filters is going to be a nightmare without decent equipment and know-how, recent 4 W CB radios and FRS radios will do a lot better, or better still, get a ham licence and interference from other users will not be a problem thanks to the huge spectrum that's available resulting in more usable range, compare it to how you can hear a lot further in a field on a summer evening verses in a bussy city in the middle of the day
I still have my two radios I got from the late 70's. Channel selector #1 usually came with CH14 crystal and #2 was empty. I never could decide on which crystal to get for #2 when I went to Radio Shack.
As a kid I was always disappointed that the Christmas gift walkie-talkies wouldn't reach to the nextdoor neighbor kids' house. Line of site was usually the only way you could use them, and if there were any obstructions (walls, windows, trees, etc.) you just couldn't connect to your buddies.. But nowadays?! Geesh! Could you imagine being 12 and getting a set of Boafeng UV5R's under the Christmas tree?? You'd reach your friends all over the block!! Old walkie-talkies with 100Mw compared to a Boafeng with 5 watts?? No comparison...
Those where built really nicely too bad they did not use the same package for higher power with different batteries Loved the video glad to see people using real walkie talkies
I had one of those way back in 1970s It was during the CB radio craze when just about everyone had CB's in their car and some people had Base stations in their home. Convoy was hit song on the radio that featured renegade truckers driving and talking smack on their CB's about what I don't remember. I remember being impressed with the weight and metal finish! I'm pretty sure I never had one conversation though :( oh well pride of possession was the American way back then. When I think of all the flashy junk I've purchased it kind of makes me ill! ;)
I bought one of these new and tested the range with my dad in the mobile and me in our front yard, he was going to the store and said he'd see how far I got. Well I was able to talk to him in the stores parking lot which was 1.2 miles as the crow flies. We lived in a neighborhood with a lot of trees and houses in the way of my signal, needless to say I was impressed with my trc-25a, I think for 100mw you couldn't get any better.
Neat test. The antennas on those are probably fairly efficient, which would contribute to the range. Most handheld CB radios since the 90s have garbage rubber duck antennas on them, and don't have squat for range, despite being 4 watts. I own a couple of GE 4 watt handhelds from the mid 90s, and they have decent antennas on them. I got a range of about 1 mile between them, through hilly terrain and a bunch of trees. If you try the same test you did here, but at night, you should find that they go a lot farther.
yeah i did this test in town at night and it went a tiny bit further. i find night time is the only time i can ever hope to get TV signals around here since theres less noise then.
Depending on the quality of the radios and the radio conditions, 100mW can go pretty far. On 70cm ham i'm used to 100mW, which gets me repeaters more than 10 miles away. However, between two handheld radios it's a whole different story. It's still enough to cover a large field, say on a music festival or such.
Very interesting Rinoa. I would not suggest a directional areial as you may loose your point of reference if you turn around or twist in differeent directions. If you did use that method, you would need an areail cocking chip and/or rotating mechanism to keep both sets locked onto each other. Another concern is battery life time if accidentaly left on when it is not needed! Which ever way you solve it (and I am sure you will), it was a fun video. Thanks and, Cheers.
Use encryption if you don't want others sniffing the data. Using an uncommon modulation is just security through obscurity that's easily undone with a cheap SDR.
well its not like im really needing to keep my communications secret, its just id like there to be a small barrier to everyone hearing the conversation.
My little $30 Baofeng 2 meter radio can output 8 watts, and if you can see it, you can talk to it. If you have two of them, 1 on 2 meter, and one on 70cm, you can even talk to the space station :-) Although you will need a Technician license to use those bands. My grandfather had a radio similar to that from RS, but his had 5 watt output, and you could add crystals to it. If I remember right, you had to have a license to operate that radio too back in the 70's, b4 the FCC so graciously gave us the citizen band to play with :-) Thanks Ms Genius, really enjoyed this one :-)
I believe you are right, they do put out 5watts , the new ones say 8... But they may be fibbing a little ;-) And chirp is a must for programming along with Repeaterbook here in the US :-) Without those two, it would be almost impossible to program with my large hands... Have you tried the DMR radios? They use 70cm but are digital and can talk around the world via the internet? My call sign is KM4EVI, hope to run across you on the air :-)
Transmit distance depends not only on the transmit power but also on the frequency, the fact that the antenna is long tells us that the frequency is low, probably around 27mhz or so. the newer ones use a much higher frequency and also use FM while the old ones are AM
Rinoa Super-Genius good idea, as for increasing the range, or power it depends on how long your antenna is and also the crystal output, that's what my dad always told me when he was in Nam doing radios back then
lower the freq the longer range on less power or atleast from what i've seen. i wish they would make 900mhz wifi for computers. CB radio is something lost on modern society. they still work really well.
Nice, had a set of Tandy 2 channel 250mW ones, cheap grey and black plastic case by then in 1987 when at Secondary school, 13 year old. Same make as yours, Realistic. With base station CB and another in the friends group had in local village, We here in the the big town, still am!. That worked, another friend had the one working one of my 2, into 1996 by now, even on 250mW got miles out the thing, village to village or into town (me), ok communicating with base stations and antenna on the roof. Any radio is as only as good as what is recieving, as said on a comment, handheld to handheld not do the same as nice roof antenna and 4 W on base staion to 1 handheld, Still those of yours do better is no power line. Find 2 elevated points, bet do a lot more if nothing in the way, 2 higher points. I got 36 miles on 1/2W 70cm band so 430Mhz or so on little 6 inch rubber duck to a repeater (those always favouriable locations and antennas). so 500mW, 37 miles, up high, nothing in between, height is might. 2 photos up from last one on QRZ web site, linked in my profile or banner photo at top.
Had a thought, lower frequency, get more bang for the buck, Why the lower frequency ham, amatuer radio does better for 10W, get to other countries. these being 27Mhz should do well up on high group and piece and nothing in between. Me just only done 2m /70cm amatuer radio, Never goet far, Does me. Little handheld and one in the car.
Fanon Walkie Talkie ----change all the resistors to 1/2 watts instead of 1/4 or 1/8 watts. Larger Capacitors help also ! Tune up radio with a match meter maybe ? Walkie Talkies are awesome COOL Man ! Modifications to the Walkie Talkies are great to do ! I even pick up things like cell phones on a Radio Shack FM walkie Talkies. Power Resistor needs replacing man ! Place or mount a signal meter in side a case of the walkie Talkies !
i like the signal meter idea. and yeah i will most likely be replacing the capacitors so might as well experiment with the resistors as well. i might make an I/O port on the side so i could connect it to a computer or something to send data.
100 mW @ 27 Mhz would travel as FAR as 5 Km away (Omnidirectional) , may be more .. 100 mW should not be (underestimated) ... BUT remember 27 Mhz is very challenging frequency as it needs relatively long Antenna to achieve noticeable Rang. the benefit of Low Power such 100 mW is to use Small/Cheap Battery like regular 9V (Alkaline Battery) which is readily available in any convenient store, besides it let the device to operate for long time without need to worry about Battery Charging Or Replacement. Also Low power doesn't overheat your Radio(means less susceptible to be malfunction) Remember : Loading Coil L1 Before the Antenna (See Schematic Diagram) must be Removed Or Shortened before installing an external Antenna . External Antenna such (Loaded) End Fed Half Wave Antenna would be good choice as it need No Ground Plan and has Low Profile (Shorter) and does offer a Low Radiation Angle. See Procom Model (CT 27 1/2 - BZ -BBMU) Magnetic Loop Antenna (Could be Home Brew) , it is a very Good Antenna and has Very Narrow Band Width yields Extremely Low Noise besides it is Less susceptible to nearby objects Such Human body.. Fulls Size High Quality Antennas could be the best as it has the best performance with Lower Noise Factor (Yet Cheaper) such : Sirio SD-Dipole (with Gamma Match) 10 Meter Tuneable Dipole antenna .. Sirio Gain-Master (doubles your Transmitted/Received Signal). Sirio SY-4 for (Directional) yields extreme Long Range Distance.
Also, even if you could modify the output power you would need to boost the battery capacity. All higher power CB handhelds used 8 AA (12V) batteries to handle the increased draw on the RF stage.
get old terminals, translate the serial to morse code, use call circuit to transmit - welcome to fallout c: i wander what bout rate that could get you xD
They were built at a time with tremendous amounts of interference, this was the early 70's with the cb craze just getting under way with people on every channel. Nowadays it's practically a ghost town and cell phones and the like have no effect on these 27 meg radios.
Try this th-cam.com/video/3-JqK7w_1d8/w-d-xo.html Add a variable capacitor as the tail would be 102". But grounding radials do work as short as 1/6 wavelength chrisD
look it up it's basically a very crude kind of internet done using radios like I have seen it done with those baofeng radios like 4 of them 2 of them for a repeater and 1 at each of the 2 locations i mean of course its gonna be small scale like that it's like dial up
Umm.. What are crystals & why do you need them ? Also why wouldn't it have these "crystals" already ? I know Zero About CB . Just stumbled apon these classics & I'm intrigued !!!!
Not neccesarily "block" but they will definitely attenuate radio signals. Line of sight becomes more important with higher freqs. There is plenty of radio spectrum (~1 GHz and up) that is pretty much line of sight.
skycarl the lower the frequency the less it is disrupted by trees and buildings etc. Mobile phones use into the gigahertz range which is why they are so crap
100mW CB walkie-talkies were popular in the 1970s because at the time, they did not require a license, while higher-powered CB radios did require a license. This web page explains it all: onetuberadio.com/2014/08/30/unlicensed-27-mhz-walkie-talkie-history/
I was given a pair of these for Christmas as a kid and even years after they were dead and gone the nice little battery gauges lived on in other projects. And in 1970 batteries were the weak link at least in my experience it seemed every time you'd let go of the talk button on those walkies that battery meter would be down a bit more even though they were pretty low power. Thinking about a 5 watt unit back then makes me laugh a bit imagining a guy with his cool 5 watt radio but then needs a backpack full of batteries to run it. Thanks for the video it was fun to see something again from so long ago!
collector radios.modify nothing.keep all boxes and manual intact.wait you did not touch these with your bear hands did you.dont forget to remove the batteries when finished.
not sure why that'd make me sound dumb, just a fact. i wouldnt want that much power for walkie talkies though i dont think, my goal with these is to modify them to have a variable amount of power so if im talking in a smaller area i can keep the conversation secret and only broadcast as far as i want.
I love miniature 27Mhz radios. These are wonderful devices.
hardly anyone understands it when it is only a consumer, what else when you are a designer and knows how much effort of the best scientific groups has cost the work of such radio stations. These are the children of military radio stations, the same principles, cheaper parts, weaker enclosures but these are the early models of military radio stations.
Now mobile phones are developing computers, they were developed by real people, the best of the best.
I love mini AM radio stations.
Hello again,
I write from Poland, I am a scientific designer of a portable radio 27hz.
These devices have 100mW of power "Input" meaning they have about 10 to 25 mW of output power.
100mW is a long-established standard for radio stations without permission, in the past it was not possible to measure the output power in a cheap way.
many radio services did not have an output power meter. Therefore, the amount of power consumed by the last transistor power transmitter was measured. So power power, input power (power supply) was measured.
The tapping current of the last stage of the transmitter was measured and the result was multiplied by the power supply voltage. The output power is much lower, usually 3-6 times lower.
These are very delicate and sensitive radio devices, treat them more gently, they can not stand vibrations / shocks, the antenna is delicate and expensive $ 50-100, it should be regularly oiled, and disassembled and assembled after each telescope. Do not move the radio so that there is no strain on the antenna.
Subsequent scientific research has proved that when using a metal housing, the transmitter radiates best at 60-80cm antenna but loses some of the signal during the set because the antenna has lower radiation resistance and is lower than the ground.
When you use BNC sockets and very short helical antennas, the transmission range will be larger but the receiver will lose sensitivity, as a whole the effect will be similar.
Unfortunately, these studies were confirmed only at the end of the eighties.
Clear potentiometers :-), it's amazing that the Japanese have tried this way and these devices still work and the American ones much more expensive do not work anymore.
The Japanese were slaves to the US, but they worked with all their heart, these devices and other electronic devices were their devotion, full dedication and resignation from pleasure / family, their work was worth hundreds of times more.
A long time ago when the CB 27 Mhz radio was to be heard over the band between 40 and 60 Mhz, 54MHz tested, the results were unbelievably good.
However, it was not decided because the portable AM radio at 54 Mhz had better coverage than the portable FM radio at 30-40 Mhz used by the military.
It was not enough for civilians to have such a good radio.
The 27 Mhz band was deliberately designed to significantly reduce the range of portable radios, to require a significant counterweight, a significant antenna length to be clearly visible to the police and other services.
This is in case the CB user can not be anonymous, all for the purpose of national security and public control.
The army got a band of 40-60 Mhz because the human body has a resonance length of around 45 Mhz, at this frequency the antenna receives a high voltage when the counterweight (human body) has a low input resistance, this is a very advantageous distribution in the differential.
In addition, the higher the frequency of the loss of the eddy currents, because the antenna is higher above the ground in relation to the wavelength.
27 Mhz requires a significant amount for effective work.
The reduction of the portable CB range was supposed to be a security guarantee that civilian CB portable radio will not be better than then used by 40Mhz by the military.
Therefore antennas with a central coil are so beneficial for portable devices, initially such antennas were illegal, and their use at 27Mhz could lead to imprisonment.
The antenna with the center coil radiates effectively only from the height of the coil, increasing the height of the radiation, this significantly reduces losses at 27Mhz and lower frequencies.
Test radios after rainfall, as a result of much better ground-level propagation the range will be noticeably better, 27Mhz when carrying out portable work very badly tolerates dry terrain underfoot.
Best wishes.
Arek, thank you so much for your comments!
I recently have gotten into collecting and using 27mhz CB walkie-talkies and I learned a lot just now from you!
@@seanhartman6496 Good health to you :)
If you have a technical question, write to us.
Arek :)
I have two of these and when I was younger modified one with a connector and plugged it into my .64 wave antenna and could talk for miles
have any idea where i could find one?
I love old CB radios !!
I had a TRC25A when I was 12 (1972). Not knowing how antennas worked, I wrapped a wire about 30' feet long around the antenna and ran it on top of my house. It actually worked and I could talk all over town with it. I also hooked two 9-volt batteries in series ( I would NOT recommend this on these old radios) and that worked even better. BTW, it looked like you were about 1/4 mile away when you were at the bridge. Your Ch 2 position is for an optional set of crystals. These radios were way ahead of their time for walkie-talkies.
There was also the TR75 3 channel
Took me 2 years to find ours, Loved the look and assembly of those units, nice collection for your museum.
Here some four years after you posted your video. That was fun. Thanks for posting it. I still have my Radio Shack TRC-74 walkie talkies that I got for Christmas as a kid back in the mid 70's. They don't see much use anymore... just not practical. But now and again I put a battery in each of them and enjoy bringing them to life once again. Be well, and God bless.
Loved the vid. Great little low power radios. In the 70's these were radios I would have given my right arm for. Remember on those frequencies, ANY and ALL obstacles will effect range. VERY COOL VID! Keep it up!
I'm just tryna talk to mike and eleven
My Dad bought me one of these for Christmas 1975. I wanted a Midland 2 watt. But my Dad didn't want to spend that much on a noisy CB walkie talkie! My buddy DID get a Midland. We easily heard him a mile away in the suburbs. Sadly he could not hear me. I never did care for the radio after that. But I tried not show it. Thanks for the look back!😄
Had a pair of these when new.
I had one of these when I was a kid. Saved up and bought it from Radio Shack. I was so happy when I got it.
Had this exact radio. Talked to truckers but mostly listened them. I put a ch.19 crystal in it. Hours of fun.
TR1 2SC645 is the RF final power amplifier transistor ,emitter resistor controls current flow of TR1 and power so be careful changing that value,L1 is used to match antenna and optimize radiation of telescopic antenna,so if say put ch40 xtal in you need a field strength meter or build one very simple.Adjust core L1 with proper trimmer tool (not a metal screw driver) for max defelection of field stregth meter ull see a peak point.I would advise you cover speaker grill as dont want modulation or do it a quiet area,you only want carrier power not modulated power as its Am system.If you want to measure the RF power ull need a 50ohm dummy load,a RF power meter able to read 0 to 1watts and a patch lead in thin 50ohm coax to hook up to walkie talkies -braid of coax goes to ground point and centre of coax goes to the coomon contact of R\T switch just below L1 coil,make sure telescopic is push inside set when making RF power measurements.Also bear in mind this is Am,with AM you have a carrier and a audio modulator TR7,8 and T5.Rule of thumb here is carrier is 4 times less than final output power so say its 100mWatts carrier ull need 4 times more to get 100% moulation and max total power PEP so ie 100mW x4 time power =400mW PEP at 100% modulation .The T5 transformer is used to ramp up the DC voltage 4 times while at same time is modulated by voice. onto the carrier ie 27.125mhz.At T5 point if battery volts are 9V the total when modulated to max voice (say 100%) will be around 9V x 4=36Volts max hence why u must set the carrier power (no voice) at 4 times less again ie 1W carrier (no voice) with voice or tone 1w carrier but 4W PEP (peak envelope power) at 100% modulation .IF modulation say 60% then out pep will drop in value but carrier will not.Hope that makes sense im not the best explaining stuff,better in a workshop to show you.So if you change power transistor TRI and mover carrier from 100mW to say 500mW,ur gonna need more audio power to get get 2W PEP output at 100% modulation ideally.A bit of tinkering prob could get u 100-250mW carrier x4 =400mW PEP to 1W PEP thats assuming can modulate the carrier with TR7,8 T5.Thats all said a good tune and some switch cleaner may help it along,also on old vintage gear electrolytic capacitors do often go bad and have to be swapped out ,dead cheap and easy to do with soldering iron and solder pump.Great vid love the retro USA cb have a few my self work really well crystal controlled stuff!
A little trick i do is add a trailing single core insulated wire 2.75metres in length (about 8-9ft) and use a ring solder tag and screw it onto the metal case of WT,normally a screw on case of WT,make sure good bonding connection to solder tag\wire .It will act as a ground plane and range will increase easy by about +18dB (3 s points 6dB per S-point)in radiation from telescopic,just be careful dont trip over trailing wire,connect to ground of case only!With old school CB walkies talkies the antenna must be fully extended too as in some higher power ones ull create a mis-match to antenna if not fully extended and could destroy the final RF power transistor-OK Lot to take in ,test kit can be very basic or built if got the skills-internet best friend to find out.
Enjoyed watching
Glad having fun with retro cb radios,they sometimes work better than modern day equipment lol
Xtals ull find on ebay generally a 455khz difference between TX 27.125mhz RX 26.670mhz xtals
or try here lots WT spares/xtals like antennas replacements and shop helpful if stuck!
Ive order stuff from here and had it shipped to UK here so know they are reliable and helpful
www.kenselectronics.com/
have fun and more walkie talkie retro vids please!
if you like retro cb and want to know more check out MikesRadioRepair on Utube channel has tonnes of useful info on cb and repairs and can ask questions,mike nice approachable guy.
th-cam.com/video/MGykC6dgOzQ/w-d-xo.html
Bob in radio shack! 73 from Great Britain!
Neat radios and a fun way to test them. The noisy volume pot can be cleaned with tuner/electronics cleaner. And interference from wallwart power adapters, powerlines, etc. is all part of the fun of AM on 11 meters. Thumbs up!
Did this ever take me back to Christmas of 1969 when my parents bought a pair of TrueTone walkie talkies. At age 4, the background static scared me. 😊
Nice video exploring how far these can operate. This was amazing technology 40 years ago, especially for someone who grew up 40 years before that when commercial radio was just getting started. Today's increasing rates of change are truly amazing. Now you can get HC-12 modules with a little spring antenna for $4.50 that reliably transmit data over half a mile between Arduino microcontrollers at 433 MHz and at amazingly high baud rates -- your idea of sending digital data over the TRC25A's on steroids.
very cool old radios. Have a pair of older midlands I bought at a garage estate sale. Fun times.
Cool video. Love vintage cb's for outdoor sport. New subscriber n gamer too. Cheers.
I would not bother modding these, you would have to go to 1 W to get noticeable difference and tuning the filters is going to be a nightmare without decent equipment and know-how, recent 4 W CB radios and FRS radios will do a lot better, or better still, get a ham licence and interference from other users will not be a problem thanks to the huge spectrum that's available resulting in more usable range, compare it to how you can hear a lot further in a field on a summer evening verses in a bussy city in the middle of the day
I remember my dad used one like this on moosehunting when I was a kid. And the call sound, I used to play with that button 😁 nice video👍
Got yourself some nice walkie talkies there! Maybe it was watching back to the future that inspired you to purchase them ha
Great test good old radios.....
I still have my two radios I got from the late 70's. Channel selector #1 usually came with CH14 crystal and #2 was empty. I never could decide on which crystal to get for #2 when I went to Radio Shack.
Kind of an off topic question but do you ever check the dump for electronics? I think it would be a good place to search for parts and old junk
ive never been to the loacl dump. its 12 miles away and im pretty sure they have rigid regulations regarding taking stuff from it.
As a kid I was always disappointed that the Christmas gift walkie-talkies wouldn't reach to the nextdoor neighbor kids' house. Line of site was usually the only way you could use them, and if there were any obstructions (walls, windows, trees, etc.) you just couldn't connect to your buddies.. But nowadays?! Geesh! Could you imagine being 12 and getting a set of Boafeng UV5R's under the Christmas tree?? You'd reach your friends all over the block!! Old walkie-talkies with 100Mw compared to a Boafeng with 5 watts?? No comparison...
Awesome thanks!
Those where built really nicely too bad they did not use the same package for higher power with different batteries
Loved the video glad to see people using real walkie talkies
I had one of those way back in 1970s It was during the CB radio craze when just about everyone had CB's in their car and some people had Base stations in their home. Convoy was hit song on the radio that featured renegade truckers driving and talking smack on their CB's about what I don't remember. I remember being impressed with the weight and metal finish! I'm pretty sure I never had one conversation though :( oh well pride of possession was the American way back then. When I think of all the flashy junk I've purchased it kind of makes me ill! ;)
Id like to see you do a range test with some uniden gmr5089's
I bought one of these new and tested the range with my dad in the mobile and me in our front yard, he was going to the store and said he'd see how far I got. Well I was able to talk to him in the stores parking lot which was 1.2 miles as the crow flies. We lived in a neighborhood with a lot of trees and houses in the way of my signal, needless to say I was impressed with my trc-25a, I think for 100mw you couldn't get any better.
+orange70383 wow, yeah thats pretty good.
I've been going to the De Anza Ham swap for years !!!
Yes, there was very CB HT, 100mW. I had any.
Neat test. The antennas on those are probably fairly efficient, which would contribute to the range. Most handheld CB radios since the 90s have garbage rubber duck antennas on them, and don't have squat for range, despite being 4 watts. I own a couple of GE 4 watt handhelds from the mid 90s, and they have decent antennas on them. I got a range of about 1 mile between them, through hilly terrain and a bunch of trees.
If you try the same test you did here, but at night, you should find that they go a lot farther.
yeah i did this test in town at night and it went a tiny bit further.
i find night time is the only time i can ever hope to get TV signals around here since theres less noise then.
A lower frequency like 27 Mhz, the signal will pass better through trees than those FRS radios at 462 - 467 Mhz.
My dad has one of these for construction sites
Depending on the quality of the radios and the radio conditions, 100mW can go pretty far. On 70cm ham i'm used to 100mW, which gets me repeaters more than 10 miles away. However, between two handheld radios it's a whole different story. It's still enough to cover a large field, say on a music festival or such.
Very interesting Rinoa. I would not suggest a directional areial as you may loose your point of reference if you turn around or twist in differeent directions. If you did use that method, you would need an areail cocking chip and/or rotating mechanism to keep both sets locked onto each other.
Another concern is battery life time if accidentaly left on when it is not needed!
Which ever way you solve it (and I am sure you will), it was a fun video. Thanks and, Cheers.
+The Lamb why would i loose my point of reference when north is the best one?
+Rinoa Super-Genius I was referring to the two of you moving around independtly, in say a forest or in a city/town, that's all! Cheers.
There are lots of digital modes you can use if you want to send some data. You can use any PC with a sound card to send and receive PSK31 or RTTY.
rocketman221projects Hellschreiber is fun, I wonder if I spelt it correctly.
+rocketman221projects if i ever use a digital signal, im not going to use any common standards. i dont want others tuning into my signal.
Use encryption if you don't want others sniffing the data. Using an uncommon modulation is just security through obscurity that's easily undone with a cheap SDR.
well its not like im really needing to keep my communications secret, its just id like there to be a small barrier to everyone hearing the conversation.
Wow you can't beat the good old analogue technology
My little $30 Baofeng 2 meter radio can output 8 watts, and if you can see it, you can talk to it. If you have two of them, 1 on 2 meter, and one on 70cm, you can even talk to the space station :-) Although you will need a Technician license to use those bands. My grandfather had a radio similar to that from RS, but his had 5 watt output, and you could add crystals to it. If I remember right, you had to have a license to operate that radio too back in the 70's, b4 the FCC so graciously gave us the citizen band to play with :-) Thanks Ms Genius, really enjoyed this one :-)
i have 3 of those and 3 of the 5 watts, plus chirp and the uk scanner codes gives me hours of listening.
I believe you are right, they do put out 5watts , the new ones say 8... But they may be fibbing a little ;-) And chirp is a must for programming along with Repeaterbook here in the US :-) Without those two, it would be almost impossible to program with my large hands... Have you tried the DMR radios? They use 70cm but are digital and can talk around the world via the internet? My call sign is KM4EVI, hope to run across you on the air :-)
Transmit distance depends not only on the transmit power but also on the frequency, the fact that the antenna is long tells us that the frequency is low, probably around 27mhz or so.
the newer ones use a much higher frequency and also use FM while the old ones are AM
From my father who would service CB radios like that, I would say adjust your squelch knob for the interference you're getting
its probably a potentiometer inside, i plan to tinker with it and check the capacitors.
Rinoa Super-Genius good idea, as for increasing the range, or power it depends on how long your antenna is and also the crystal output, that's what my dad always told me when he was in Nam doing radios back then
There's no squelch on those transceivers. I owned a pair when I was a kid.
lower the freq the longer range on less power or atleast from what i've seen. i wish they would make 900mhz wifi for computers. CB radio is something lost on modern society. they still work really well.
Hello is that AM or FM CB Walky Talky>
ive got no clue
Nice silent surrounding for test
Nice, had a set of Tandy 2 channel 250mW ones, cheap grey and black plastic case by then in 1987 when at Secondary school, 13 year old. Same make as yours, Realistic. With base station CB and another in the friends group had in local village, We here in the the big town, still am!. That worked, another friend had the one working one of my 2, into 1996 by now, even on 250mW got miles out the thing, village to village or into town (me), ok communicating with base stations and antenna on the roof. Any radio is as only as good as what is recieving, as said on a comment, handheld to handheld not do the same as nice roof antenna and 4 W on base staion to 1 handheld, Still those of yours do better is no power line. Find 2 elevated points, bet do a lot more if nothing in the way, 2 higher points. I got 36 miles on 1/2W 70cm band so 430Mhz or so on little 6 inch rubber duck to a repeater (those always favouriable locations and antennas). so 500mW, 37 miles, up high, nothing in between, height is might. 2 photos up from last one on QRZ web site, linked in my profile or banner photo at top.
Had a thought, lower frequency, get more bang for the buck, Why the lower frequency ham, amatuer radio does better for 10W, get to other countries. these being 27Mhz should do well up on high group and piece and nothing in between. Me just only done 2m /70cm amatuer radio, Never goet far, Does me. Little handheld and one in the car.
I can highly recommend you a Baofeng UV-5R its the best radio i ever had.
My brother, and I have 2 40 channel handhelds.
I have these same radios and channel 1 I hear the same ole ham chatter from CA and Chicago. And I’m in Texas. 🤷🏻♂️
It would be interesting to see if there’s a difference once they cut all the corn and the fields are fallow. Maybe less interference?
Fanon Walkie Talkie ----change all the resistors to 1/2 watts instead of 1/4 or 1/8 watts. Larger Capacitors help also ! Tune up radio with a match meter maybe ? Walkie Talkies are awesome COOL Man ! Modifications to the Walkie Talkies are great to do ! I even pick up things like cell phones on a Radio Shack FM walkie Talkies. Power Resistor needs replacing man ! Place or mount a signal meter in side a case of the walkie Talkies !
i like the signal meter idea. and yeah i will most likely be replacing the capacitors so might as well experiment with the resistors as well. i might make an I/O port on the side so i could connect it to a computer or something to send data.
most real (23 or 40 channel) cb radios, going all the way back to the 60s are 4 watt, which is the highest legal wattage for cb.
Those would have been sweet in the movie Signs.
i think those radios only come with channel 14 installed and you need to buy more crystals to install extra channels
100 mW @ 27 Mhz would travel as FAR as 5 Km away (Omnidirectional) , may be more ..
100 mW should not be (underestimated) ... BUT remember 27 Mhz is very challenging frequency as it needs relatively long Antenna to achieve noticeable Rang.
the benefit of Low Power such 100 mW is to use Small/Cheap Battery like regular 9V (Alkaline Battery) which is readily available in any convenient store, besides it let the device to operate for long time without need to worry about Battery Charging Or Replacement.
Also Low power doesn't overheat your Radio(means less susceptible to be malfunction)
Remember : Loading Coil L1 Before the Antenna (See Schematic Diagram) must be Removed Or Shortened before installing an external Antenna .
External Antenna such (Loaded) End Fed Half Wave Antenna would be good choice as it need No Ground Plan and has Low Profile (Shorter) and does offer a Low Radiation Angle.
See Procom Model (CT 27 1/2 - BZ -BBMU)
Magnetic Loop Antenna (Could be Home Brew) , it is a very Good Antenna and has Very Narrow Band Width yields Extremely Low Noise besides it is Less susceptible to nearby objects Such Human body..
Fulls Size High Quality Antennas could be the best as it has the best performance with Lower Noise Factor (Yet Cheaper) such :
Sirio SD-Dipole (with Gamma Match) 10 Meter Tuneable Dipole antenna ..
Sirio Gain-Master (doubles your Transmitted/Received Signal).
Sirio SY-4 for (Directional) yields extreme Long Range Distance.
Just by looking at that circuit I'd say that there is most likely no way to modify it to transmit more power.
Also, even if you could modify the output power you would need to boost the battery capacity. All higher power CB handhelds used 8 AA (12V) batteries to handle the increased draw on the RF stage.
security camaras definetly affect those radios. most of them are on 27mhz
You should try and do a video on range checking 2 samsung galaxy s8.
you realise cell phones dont directly talk to each other right? they both need to connect to a cell tower
get old terminals, translate the serial to morse code, use call circuit to transmit - welcome to fallout c: i wander what bout rate that could get you xD
Channel 11 was the Calling Channel on CB.
And 9, Emergency.
11 Can you hear me 11 !!!
The trc217 are the stranger things walkies not these
@@jspavlogs9623 I know, I just wondered if anyone got the referance, managed to get the exact radios some time back, good series
Cool mom
Its all about the antenna.
power wont help much.
Just get a base station
Railroad tracks will help!
CQ CQ CQ?
These r a couple of smart elecs just like most of this people. They need to leave the cb s to me and go to ham
that makes no sense
CB, equals Citizen Band.
with my luck , id break the telescoping antennas and i did and do. hem
Thy were built in a time where there weren't to much interference...I wonder how good they were back then?
"Realistic" was shit when it was new. But it was very cheap and it did work.
They were built at a time with tremendous amounts of interference, this was the early 70's with the cb craze just getting under way with people on every channel. Nowadays it's practically a ghost town and cell phones and the like have no effect on these 27 meg radios.
They could save your life
how?
Ch11 the superbowl!
Channel 6
I had a cheaper pair, they had a beep button and the Morse Code alphabet printed on the front.
thats cool, i think i used to play with a similar pair from th 80s that had morse code.
Try this
th-cam.com/video/3-JqK7w_1d8/w-d-xo.html
Add a variable capacitor as the tail would be 102". But grounding radials do work as short as 1/6 wavelength
chrisD
thanks for the tip.
Made in the seventies and still doing what they were made to do
not very well though, their capacitors are going south.
@@RinoaL maybe there is a modern replacement that is durable.
haven't you ever heard of packet radio?
+eddy apple no
look it up it's basically a very crude kind of internet done using radios like I have seen it done with those baofeng radios like 4 of them 2 of them for a repeater and 1 at each of the 2 locations i mean of course its gonna be small scale like that it's like dial up
Why yes. Those are the type of radios that you store in your 'packet'. (I'm SO sorry - that was just ACHING for a pun!)
Would you share the schematic please.
Sorry I moved across the country and dont have access now
@@RinoaL same thing here, if you get access to the schematics again, please post them online?
#2 might not have crystals plugged in.
Umm.. What are crystals & why do you need them ? Also why wouldn't it have these "crystals" already ? I know Zero About CB . Just stumbled apon these classics & I'm intrigued !!!!
crystals would cost more than a used 40 channel walkie
crystals today are only like 5$ for RX/TX (2 Crystals)
What about a Slim Jim for 27.275mhz or an UNUN to match to a long wire. What about a synthesiser based on the MC145151-2
Trees are not going to stop radio waves. You do not need line of sight with those.
+skycarl i find they can. the water in the trees adds up if theres a lot between you
Not neccesarily "block" but they will definitely attenuate radio signals. Line of sight becomes more important with higher freqs. There is plenty of radio spectrum (~1 GHz and up) that is pretty much line of sight.
carl is correct. trees will not stop 27mhz.
skycarl the lower the frequency the less it is disrupted by trees and buildings etc. Mobile phones use into the gigahertz range which is why they are so crap
radios usually have 5watts the store bought ones usually have 500mw, 100mw is very low what the heck would they use them for at that power
i could see it being used for talking between buildings, or like camping.
100mW CB walkie-talkies were popular in the 1970s because at the time, they did not require a license, while higher-powered CB radios did require a license. This web page explains it all: onetuberadio.com/2014/08/30/unlicensed-27-mhz-walkie-talkie-history/
I was given a pair of these for Christmas as a kid and even years after they were dead and gone the nice little battery gauges lived on in other projects. And in 1970 batteries were the weak link at least in my experience it seemed every time you'd let go of the talk button on those walkies that battery meter would be down a bit more even though they were pretty low power. Thinking about a 5 watt unit back then makes me laugh a bit imagining a guy with his cool 5 watt radio but then needs a backpack full of batteries to run it. Thanks for the video it was fun to see something again from so long ago!
collector radios.modify nothing.keep all boxes and manual intact.wait you did not touch these with your bear hands did you.dont forget to remove the batteries when finished.
joke right? ill be modifying these before too long. first thing is to make lithium batteries for them.
Aren't you supposed to say "Over" at the end of everything? Over!
( ･-･ )
Best to recap it.
Use a linear amplifier to boost range
Come on Richard D'Arcy you know linears are illegal! ;-)
Well not to make you sound dumb or anything but standard handheld CBs now do about 3 or 4 Watts
not sure why that'd make me sound dumb, just a fact. i wouldnt want that much power for walkie talkies though i dont think, my goal with these is to modify them to have a variable amount of power so if im talking in a smaller area i can keep the conversation secret and only broadcast as far as i want.
If they get a half mile out of that that's probably the range