Building a Field Strength Meter.
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- เผยแพร่เมื่อ 27 ก.ย. 2024
- A field strength meter is a must-have device for anyone building antennas. It is very simple and cheap to build.
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Gil, I am glad you show your successful builds and failures. We learn more sometimes from our failures.
Gil, that's a shame. At least is worked for a little while. Thank you for sharing the things that don't work out 100% - it is how we learn.
When drilling the holes use the end of a block of wood or round dowel behind the plastic where you are drilling. You can also drill from the inside and lay the box on a wooden bowrd.
Loved the video. Cheers
This is one of the best videos I’ve seen. I’ve definitely had projects go this way. Thanks for sharing! Subscribed!
Gil thank you for the video and your honesty!
I enjoy seeing people make the mistakes I would. Gives me hope!
votre honnêteté est merveilleuse, chaque jour j'aime votre chaîne plus
Don't stress! Great job. Cheers from Australia 🙂👍👍👍
Just built it , works well, thanks for the vid , like the way you admit to mistakes , we all make them and learn
Great!
We never know it before we do it ... this meter should not live ... the next will be fine ... and yes ... very useful device ... I can't stress it enough. So, wd are waiting for the perfect second version 😉
Tout a fait d'accord avec toi Gil, j'ai ca depuis peu de temps moi aussi et ca donne un sacre coup de main pour tester et comparer des antennes.
Thanks Gil was looking to buy one, you have encouraged me to build it instead. Keep up the good work.
We all do dumb things sometimes. I’ve lost count of my dumb mistakes, so don’t fret :)
Thanks.
are you SURE that wasn't me you were filming?
the only thing missing was burning a huge hole through my hand.
Gil I lost count of the amount of times something went wrong. But this is how we learn I suppose. 73 Dave M0GGK
Nice project. Thanks!
Gil, the best part of this video is your failures. I do the EXACT same things you do but you don't get as agitated about it. It is nice to see someone make the same mistakes. I look forward to seeing a follow up with a link to the better components.
BTW, the count was 1 pair of jeans, one coffee cup, and 1 complete meter that you lost during this video. MFJ makes the MFJ-801 with no additional losses...
To make holes in plastic use a Dremell type tool with a pointed grinding wheel, it melts it's way through more than drilling it's way through. Interesting project,I will be making one of them. Thanks for making the video.
I could empathise with on the epoxy goofup. Great video and learning indeed!
Sometimes things go sideways. We can learn from that. This seems like a fun and simple project. I should build one. Having seen your experience I think I will try to use a sacrificial backer block of wood when drilling. I might try potting with hot glue rather than epoxy. Thanks for sharing this project with us.
Oh Gil, I was sitting here saying Don't do it!. I would be tempted to drill a small hole into the front of the meter to see if I could free up the needle on the meter with a tooth pick or something. Nothing to lose.
I think I would destroy it...
good one.
At least you proved that it’s easy to build
I find when drilling plastic boxes it helps to warm the box slightly with a hair dryer, then hold the side of the box which you are drilling against a small block of wood to stop the plastic flexing too much. Works every time for me.
Great thanks!
Might have to build one of those Gil, thanks for sharing. 73 G1AW
Upvoting specifically because you did not edit out mistakes. Those are important to see. Much better learning tool than vague admonitions to “be careful about...” that we so often see.
Great video - the mistakes make it all the better! Will have to have a go myself
sometimes mistakes are better than luck! :)
Gil when drilling/repairing cracked boxes.... try glueing thin card behind (don't use superglue, mounting spray is better).
You can cover the holes, and open up with your craft knife/file.
With care you can get an almost invisible repair.
Bon chance 73
de G0EVA.
Thank you!
Welcome to my World Gil! Lol.
We all have days like that. After the first stupid mistake or cock up, I just down tools and come back another day. 👍
Oh, and apart from using better cases, drill from the other side onto scrap wood, so the plastic doesn’t flex under the pressure from the drill.
Gil . Really interesting video will build myself one but no epoxy 👍
a wood block under it/inside the box against the opposite side you are drilling should give you the support you need not to crack it. thanks for sharing.
It was just a 'bad hair day' Gil ...we all have them occasionally;-)
Thanks Gil for the video on the field strength meter today, had a rummage through my junk box and made this one today to your specification,the meter a bit high at 300uA but works ok, de M0XTK
I use my old Heathkit HD-1425 Field Strength meter to indicate RF in the shack. I have a 75m dipole in the attic (it's resonant exactly in the middle of 75m), then use window line down to a Palomar Engineers 4:1 Balun + 1:1 Choke, then coax through a pass-thru and connected to Dentron tuner. I operate from 6m to 160m with it, up to 100W. Some bands have to be operated at much lower power, even with RF chokes on everything, due to the amount of RF that was getting into the shack before I added the Balun and choke (the computer would reset and electronics would go nuts). I have a sheet of paper that reminds me which bands can handle full power. I preset from that and then I adjust output power so the the field strength meter (at maximum) barely indicates. I operte FT8 and CW so I don't often run 100W.
When you said your were going to epoxy the box I said out loud - you're going to f it up :o) Even with tape I'm surprised the pot didn't seize up too.
Interesting use, thanks.
Hi Gil, love your video. Sometimes stuff goes wrong. Don't worry, just start over! :) 73 PA5BAS
Thank you :-)
I myself learned how well epoxy penetrates :-). I potted something and the epoxy leaked out onto the bench, it found a hole in the bench top and leaked down onto a shelf and glued down all of my 1 quart paint cans lol.
LOL.
One way of avoiding epoxy disasters is to mix up some thick epoxy glue and just smear it over all the components - too thick to run inside, it'll cover the holes and cure fast, but still give it a day to cure thoroughly before pouring the bulk epoxy in case they interact chemically.
Hi Gil, I think the problem with your cases breaking is because the material is both brittle and flexing. You can see the flex at 4'14" to 16". Suggest you use a block of scrap wood inside the box to support the plastic and stop it flexing. Then drill through and into the scrap wood. Also if you put some masking tape over the hole you are going to make, it may help stop chipping the hole edge when you drill.
I guess you know all this but if not it may help. 73 G6XIB
Hilarious!....thanks for making my day, Gil!
73.....
Gil, thank you for showing us some of the pitfalls of home built projects - I at least know what to watch for when I build my own FS meter. Liam GM4VYQ
There will be others, LOL.
at least i learn from your mistaken to pour the resin inside the box,, :D
I know I shouldn't have but I did laugh at the end there.... Just when it was almost going to plan too!!!
Please buy a reamer for preparing holes like that. They're cheap enough and much less likely to split the plastic. Plus you can cut those in-between sized holes that the step bit can't do.
Onwards and upwards. 👍👍
Hi Gil
Perhaps you heading for the video should have read "it is fairly simple and cheap to build" bugger looks like you were having one of my shit days when everything that can does go wrong! Never mind I love the fact that you kept persevering where I would have lost my temper and thrown it in the bin. Well done on keeping your cool :)
Cheers 73 vk7ham.
I threw it in the bin, LOL.
I feel for you Gil....we all make mistakes... hope the next one works out fine...
I assume this was tried on 2m but I wondered whether it would be sensitive at UHF- which is what I need. Not sure how it works as there is no inductor or capacitor to form a resonant circuit but if it works - dont knock it! Excellent tutorial. Thank you very much.
It does. I tried at 446MHz.
That is a great project. Very useful and inexpensive. Shame that the thin set epoxy got in the movement but making an omelette requires an broken egg :) Thanks for sharing !
Next one is coming soon :-)
Thanks for showing your failures as well as your successes. You earn a lot of credability that way. 👍🏼
I appreciate that!
Gil great build ! Glad it's just not me that is a bit heavy handed while drilling, etc ! 73's Andy M6APJ
Soviet Meter! ;) CCCP! LOL
When I saw my very first FSM, I thought it was "magic", these are some of the coolest tools for understanding radio waves, and the way energy is transmitted. Have you compared these "real world" measurements to what modeling software predicts?
No.. I haven't used a modeling software either.. Maybe something to look into...
@@RadioPrepper Your project did remind me of one of those days where everything I touch I break.. The days when I think going back to bed and trying the next day may be better. I'd like to see the Military Grade meter you replace the "Prototype" you made, if the cost isn't too crazy I normally try to use them, as I seem to drop everything in water at some point in my ownership.
We all do stupid things sometimes.
I guess the meter was vented to avoid moisture build-up ?
73’s
N7CVG .
Might be.. I sure won't epoxy the next one!
I think you said in the beginning schottky diode is a germanium diode. Actually, it is not, it is based on metal sililicone boundary. It has a lower drop than typical silicon diode like would a germanium diode have too.
Oh noo, I feel pain
sorry, Gil, but .... I caaaaan't stop laughing and rolling on the floor :D :D :D :D :D That ending just killed me :D :D :D
Hello, it was a nice video. Thanks for information.
I was sorry for the epoxy accident. By the way, I wondered why you filled the box with epoxy?
Can you give information about a subject?
Is the shape of the antenna you use in the circuit important? So, is it possible to convert it to a larger, square or circular 30 cm antenna?
Ammeter you use; It measures 250 micro amps. Is it necessary to use a nano-level ammeter for RF power measurement at greater distances than the transmitting antenna?
Thank you in advance for your answers.
I just wanted to make it more durable. Any antenna, small is better; a foot-long wire would do fine. Otherwise no idea..
@@RadioPrepper Thank you so much for answer.
Nice one, thanks for showing the real world where $hit happens and it isn't always a fairy tale happy ending first time! I order some 100uA meters from China last year just so I could do the same and still didn't get around to it. Now I think I better get it done!
Bunu 1hz ila 1mhz arası nasıl yapabilirim
If you want epoxy glue to be black you can mix it with graphite powder. 73 de DL9ZBN - Kurt
At 1:08 I think you meant to say a _forward_ bias voltage drop of 0.2 volts.
Yes thanks!
Hello Gil, thanks for the video, as always! Nice demonstration of how it is done and what to do and not to do! Anyhow, is this meter dependent on a particular frequency or not? Can you use it for fox hunts? Thanks!
I tried it from HF to UHF, and it worked.
Should cover it in Tahoe before drilling to prevent cracks
Tahoe?
Sorry, tape
Ah, poor Gil and his love/hate relationship with epoxy. You love to use it, but hate it when you do. Thanks for the great video. I'm going to have to build me one too, sans epoxy. =) //K6OGR
next time drill it upside down so it won't crack
Hey Gil. This is what I need -- for my Mag Loop Antenna. Can I use it to verify if my antenna is on resonant frequency? Thx fer nfo. 73
Yes.
@@RadioPrepper Wow. That's a lightning fast and short answer 😸. Thx es 73!
sad outcome with the final epoxy pour, I've never been brave enough to pot my work like that at all. Maybe try expanding spray foam? Probably won't get into things the same way, but might provide enough vibration support. That or just a few gobs of type2 silicone.
Might also try drilling from the inside if the box is shallow like this one, would be able to get better support on the back. Or you might drill the table :)
Good advice thanks!
Your not the only one that could break an anvil. Everything I touch explodes, every new pair of pants I buy I catch on fire, every shirt gets ripped. I can't have anything thats nice. It must be written in stone somewhere.
Yep...
Gil, they are a very useful tool indeed. After two lots of encapsulation failures Gil, remember the coupler, I would not do any more. 73 Colin vk2jcc
Annoying and frustrating for you Gil but proof of concept version is in the bag, real one can be built now 👍
Doesn’t matter how long I’m in lockdown, hair days are long gone 🙄😆
I'm a retired electronic technician, designing and building my one and only UFO detector station in Ontario, Canada (that I know of).
Just finished a light spectrometer from publiclab.org and my 5" telescope to take real-time videos and spectrometer readings with a Raspberry Pi3B+ and RaspiCam
I left the most complicated parts for last. A lot of my sensor projects are from this site (techlib.com).
Is there a practical way to listen to and monitor all frequencies from 1Mhz to 5GHz in real time? Can one a HackRF One do it? What kind of weird antenna would I need?
Anything to give me some data, when these things are around, would mean more real-world uncalibrated data.
An SRD receiver would allow you to listen to chunks of it, but not all at once. You would have to write a scanning software to do that, maybe using GNURadio...
@@RadioPrepper Thanks for the reply. My understanding about SDR is the window's BW is 20 MHz on the cheap $10 dongles. Looking at the specs of more expensive units, I don't see any difference. They all seem to be only capable of scanning 20MHz at a time.
That would make it crazy expensive to do in real time. The other way is to scan and move the window to scan the next window, and so on. Then you risk missing bursts of transmissions that could be out of phase with your sampling rate.
Not an easy problem to solve on the cheap.
Olso make sure, that it will not come in to the potentiometer as well.
That I did..
That looks like Peter Parker vk3ye design.
That design, as simple as it is, probably predates most of us alive today...
By showing your mistake you saved dozens of meters from a sticky end. I half expected you to say the control stuck, but no, it was the meter. Only problem I can see is it will measure any RF, so I you are close to an RF source it is also going to indicate it.
I'll check my apartment for bugs ;-)
@@RadioPrepper Need to be a powerful bug! lol
Ohoo, this is no good! Epox no friend this meter. But no problem mr.Gil, try again.
Maybe a simple hot glue have done the job instead of the epoxy ?
hahahahaha the important thing is that you tried :P
Aah ... si seulement c'était en français ! ...
First!!!
Well, at least you didn't cut your finger off or something like that.
Yet ;-)
Gil, face piles of trials with smiles... even NASA has bad days, de VE3KKQ.
True! lol.
Too much time in lockdown perhaps?
Grant VK4JAZ
Cabin fever!
@@RadioPrepper I am going to build one too (without filling the enclosure with epoxy, though!)
Испортил прибор со знаком качества из СССР. Рукожоп.
I never have a problem with these cheap boxes I drill a small whole 1st but from then on I run the drill in reverse at high speed. You end up melting the way through. You will never get a jam and never break a box.
Very nice build (until the epoxy ;-)) everybody need this instrument.
greets Nico PA4NIC
OOPS DO NOT FEEL LIKE THE LONE RANGER 73 jerry kg6mn
has it been 4 hrs ago
I've ruined few things with epoxy too not thinking earlier. Hot glue is your friend :) 73 de s57rw!
Maybe use some Silicone, to seal large gaps, og some Grease if they are small.
yay russian meter !!! even soviet one!!!
I would keep it as a treasure and never use for anything. Simply too precious.
Next meter is Polish military...
Looks like you were having a bad day 😊
Not to laugh at your misfortune, however, this was very intertaining and it did make me both laugh and feel sorry...Live and learn as you say...
Great project and even better video! Just shows us how very much the same we all are!
Oh no, no more epoxy for you.
Shit happens
This is good device for adjusting handmade antenas👍
I don't think my first build of anything goes without mistakes. Thanks for the video Gil. I always enjoy you work,
Really appreciate the honesty of this build. We all learn by doing.
Use a stepped bit to make neat holes in those plastic boxes. You can twist them by hand to avoid cutting too much away.
let's see the new build as well, hair looks good to me not a hair on my head lol