Ham Radio - 2 meter handheld radio performance improvement! Counterpoise.
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- เผยแพร่เมื่อ 7 พ.ค. 2016
- I ran across a video this morning on RadioHamGuy's channel where he talks about adding a counterpoise to your HT. Curious, I duplicated it and did some testing. Here's a quick video showing my tests and results. It really works well!
Here's a link to RadioHamGuy's original video if you want to check it out.
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I had watched the original video on the other channel and commented because I was disappointed there was no testing done. There was just some hand waving and assurance is the the tiger tail works without anything to prove that. I appreciate you doing the testing to verify that it works.
That was great to see, thanks for taking my video to the next level and showing the testing! Thanks for the link back also. I will put a link in my description to this video also. 73...wd0akx
In every single one of these videos I see about making a counterpoise for a handheld radio, the operator is using a SMA to BNC adapter for their antennas. They're trying to improve the performance of an antenna they've already compromised by adding the adapter. These adapters add 3/4 of an inch to the antenna length and introduce additional loss to the RF path with the additional connections. While this might not have an effect when close to the other radio, whether a repeater or another handheld, it could make the difference between a contact or no contact when operating at the limit of the radio's capabilities.
You know what I like best about your channel, Kevin? The work you do to prove ( or disprove) a theory. Thank you, Kevin.
that's a neat trick! Thank you for sharing, really appreciated!
Hi Kevin, It is quite amazing that this is not a tip in the rigs manual. the counterpoise basically gives you 1/2 wave dipole on the handheld and has you proved out by testing it works. 73 de G0WXU (JOHN)
I'm a relative newbee here so please take this with a grain of salt. If any of you old timers have opinions I'll appreciate any corrections to my thinking.
To calculate the wavelength of antenna the formula in inches is:
5905 x A / frequency in MHz where A is a small variable depending on the wire gauge you use to construct the counterpoise. A = either .96 or .98. depends on wire gauge.
So in my case: 5905 X .96 divided by the frequency for a full wave. The frequency would be divided by 2 for half-wave.
After calculations it is approximately 18 and 3/8 inches long for a frequency of 154.570
Where as this works I don't think it is not as good as an extended gain antenna which is designed for the complete frequency range of a radio whereas as the wire length needs to be varied for a specified frequency.
Proof: =(5905*0.96)/(154.57)/2 = 18.3373229
Kevin, I have done this with my own HT and was amazed at the results. I found it to be quite directional in the direction of the counterpoise. Just goes to show the antenna is as important as the radio. David Byrd KN4BHS
Great vid with real world experimentation and feedback!
That’s a creative way to test range without walking too much! Thanks.
Thanks for this video. I found the original RadioHamGuy video unconvincing. When experimenting, I feel there should be some testing to demonstrate benefit. Thanks for doing the tests and sharing the information with us. The counterpoise tail would be inexpensive and portable enough to have when you wanted the performance boost, and it could be omitted for casual use where the inconvenience might not be needed.
Very helpful. will try on my new Bofang UV-5R HT's. Pulled a fairly decent voice signal in simplex mode from a mile away ( my house to the Home Depot parking lot) testing FRS ch. 5 frequency with the standard duck antenna in a heavy residential area, will run a tiger tail and see if the signal gets clearer with the same A to B test locations. Thank you much Sir!
Thank you a great video! So many people ramble on and one, and have audible pauses that I just want to go to something else. You video was interesting and well-made! I did some math, and depending on if you test it at 145 MHz and 146 MHz, it varies from 19.36 to 19.23 inches. I typically use 19.25" to where the end ring touches the antenna. That's such a small difference that 19.5" is fine. I know this might be a bit weird, but for the heck of it, have you ever tried more than one tiger tail? The possibility of interacting with things around the antenna would be higher, but it would be interesting to try it out.
Thanks! And by the way your intro is awesome!
Excellent video about how to use a counterpoise for your 2 Meter rig! 73 Tony Ridlen KC9QVE Gas City,Indiana
Great video thank you. Very informative
Great video , no question a rat tail works and good info on length which makes sense. I have two questions what about orientation of the counterpoise itself ? i.e. if were to be placed vertical in a vertical dipole fashion vs hang any which way or even point directionally any testing on that ? I realize not exactly a ground plane but as you know orientation can have some effect curious if experimented in that regard or anyone else has as well. thx again . Been watching entire antenna series
2 meters is 200 centimeters. divide by 4 for a 1/4 wave is 50cm and 50 cm converted to inches is 19.68504 inches or maybe about 19 and 5/8 might be close to that decimal amount.
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well ham frequency is not exactlly 2meters though
Wish you could test this at the 70cm range, but I know the MFJ you have won't get there. Thanks for the video and thanks to @radiohamguy for the original video
+Kevin Zari Yes, I wish I could have done so. The counterpoise wire might have to be at a different length for UHF.
+Kevin Loughin I wonder if you would have two wires (in parallel), like you would for a fan dipole. Either way, thank you for the video
Excellent video. I had seen the original video as well but wasn't a believer as there was no testing done. A question for you, with the original rubber duck that comes with the UV-5R, what length of wire would you recommend? Thanks for another great video.
The length would certainly be different. I'd have to put that antenna on my analyser and measure it. I can't seem to find the original antenna though. I'll have to dig around for it. If I find it, and an sma to so-239 adapter, I'll let you know.
Kevin Loughin that would be great, thank you. I did buy one better antenna for the UV - 5R but I have a couple of others in emergency kits and I just keep the original stubby antenna with it. Isn't there an equation that will give the correct length? Would that be dependent on the physical length of the antenna or the electrical length of the antenna?
Hard to calculate with rubber ducks. They are helical and no two brands wind them the same way. So each is unique and there's no magic formula that applies in all cases.
thanks for a great video and test.
can you speculate if there would be any difference to your results if the counterpoise was wrapped around the radio (and not hanging)
since i don't have a 2m swr meter, can you please help me ... what wire length should I use for a 6,6" antenna? thanks!
Hello Kristijan,
It would certainly change things if the wire were wrapped around the radio, it would be an inductor.
Each antenna is going to be different. I don't think there's an easy way to calculate a proper length. Most antennas for HT's are helical wound, so you can't rely on the length.
Maybe your local club or another local ham has an anylizer you can borrow and find the right length with.
Thanks for taking the time to make the video! It really seems to work. I will give a go tomorrow.
I did this with my handheld Cb radio. It helps in receiving dx.
Wow, that'd be an 8.6 foot long wire dangling from the radio.
Thank you de David AE4LH
Great tip. Barry, KU3X
I've seen this and I've wondered if the capacitance of a person holding the radio would drop the SWR. Since these antennas are meant for handhelds.
That is a very good point. Might be difficult to measure though. You would need an in line sensor that could sit between the duck and the HT.
Regardless, I did see a marked improvement in receive performance and was full quieting into a local repeater from my porch where I used to be noisy at the same power level.
Can I ask you another question, Instead of having the wire hanging 19 inches straight down can you coil it around a pencil so just Kind on the side of the radio but much shorter, It’s still 19 1/4 inches it’s just coiled up I guess the same way they do with the rubber ducky
Yes, but the wire length would change due to the inductance you create by making a coil out of it. Figuring out the right length would take some experimentation, and an antenna analyzer.
Yes your wire will improve the RX, I also observe that. What will possibly be not improved is your TX, because it all depends on the antenna and also the HT you are using. F.e. I cant observe any improvement in TX when using my nice (and expensive) portable antennas.
The reason for improving RX by rat tail is that the wire becomes in fact a part of the receiving structure of the antenna system.
What about testing with and with out on the air or with a field strength meter? A real test.
1:07 wait, my uv5r antenna connector does not look like that. I have to unscrew mine and inside it looks like a coax connector. Yet yours has like a stud. Am I missing something?
i HAVE A tyt-tH-UV88 hHT.i CANNOT GET INTO ANY LOCAL REPEATER (2-3 MILES MAX). i CANNOT FIND A "GROUND) externally on this mess. My antenna conn is an SMA female on the radio with a rubber washer completely surrounding the thread. I'm afraid to wire onto that so as to make the smoke fly. Any suggestions as I NEED a counter poise. Thanks and I enjoy all of your videos.
The screws that hold the belt clip on or the case together should provide a ground.
Very informative video. Thanks. KI6BNT.
Can you coil or bundle the rat tail to make it tidier or will this drastically affect the performance
That would turn it into an indicator and change its effect.
Ok also did something like that with the family radio are you a prayer hey I put a telescopic antenna on family radio improved the weather grand reception
And when you do this do you have to strip the insulation off the wire
No. It's a magnetic field that's creating an electrical wave. Insulation doesn't matter on antenna wires. Not practically.
what length would you use for a dual band ht?
You would probably want two wires. One for each band. The RF is going to favor the wire that best matches. It really depends on the antenna. For the 440 wire, I'd start around 6 or seven inches and using an anyliser, trim it down until you get the best match.
Probably not coincidence that 19-20" is best, since that's about 500mm which is 1/4 wavelength. I'm sure some boffin can explain that.... Jim ZS6JMB
If you don’t want to do a wire, you can solder it to the connector, or you could hang the wire off a screw on the back of your radio but you have to check it Hass to have Continuity
Yes. A few people use a screw on the case. It's still a ground point.
Is it general rule of thumb to make your counterpoise the same length as your antenna?
No, the rubber duck is usually a helically wound antenna and the physical length doesn't matter. The counterpoise wire should be quarter wave
@@loughkb thanks you Kevin! And for the informative video!
Are you aware that by having that SMA to BNC adapter on your radio, you've affected your antenna's efficiency in two ways? First, there is the loss from the two additional connections between the antenna and the radio. Second, you've essentially lengthened the antenna by an inch, which might be why the antenna by itself is resonant outside the band.
HELP, I hope your still there. I am trying to figure out how long a radial would be for a 7/8 wave 2m/70cm mobile antenna would be. And I am having problems. If your still there, and you know, could you help me out.
I'm pretty sure you're going to have to wind a coil at the base of the antenna. Try different sizes of coils until swr is good on 2m and it should be close on 70cm. Personally, I would use a half wave element for 2m and then it would be great on 70cm. There's no coils to worry about and odd multiples of half of a wave is where the power is. Maximum radiation resistance at the tip means maximum efficiency.
Sorry. I meant a quarter wave element. Your vehicle is the ground plane and represents the other quarter of the wave adding up to half.
@@JoeSmith-po3wy Oops, I forgot to tell you that I am using a Diamond 7900 Super Gainer Dual Band 7/8 wave antenna, and I am using it on a trailer I pull behind my bike. The antenna is 62.5 inches long. And I still need to know how long the radials would have to be, for a proper ground plane. I will be mounting the antenna on a 8 foot tall PVC mast.
I would start with 20 inches. Use at least 3 radials. Install them at 45 degrees to give you a 50 ohm feed point impedance. 90 degrees gives 37 and vertical, like a dipole, has about 75. In the end, SWR is really impedance matching. 20 inches is 1/4 wave at 150 mhz. 450 is an odd multiple of 150, so it should respond well there too. Start with them a little longer and trim them until it's happy.
Does the wire have to be bare?
+Craig Bushby no, not at all.
Kevin Loughin, thanks.
"Ground plane"
Need a real-world test.
For anyone else doing this mod.
DON'T do it this way as you can short out the aerial and burn out your transmitter circuit !
Connect it to another ground point on the belt clip screw, it works exactly the same without the risk !
How? Some magical way the metal of the washer could pass through the metal barrel of the BNC connector? That'd be some star trek stuff. Changing the phase of reality to allow one solid metal to pass through another?
Not going to happen.
But, yes, you could attach the wire to a case screw as long as it goes into the chassis and makes a good ground.
@@loughkb A strand of the wire from the crimp could easily bridge the centre pin you thin skinned Muppet.
You didn't even know the clip screw went to ground eh ?
Uptight much ? lol
So with your video you were just proving that ham radio guy wasn't bullshiting sounds to me like you had doubts So you had to make your own video and tail off his. If someone did that to me I would say he was calling me a liar or a bullshiter.
Actually, it's called peer review. And I'm sure he, just like myself, would appreciate the confirmation through duplication of the experiment. We tend not to have egos that bruise that easily. That's a sign of some degree of insecurity.