Need some help.

[gezafisch]

Here is my analysis of a NA-771 with the center tuned to 466.9875. As is clearly shown, the VSWR at that frequency is infinity... :roll:

In fact, at the actual lowest VSWR of ~3.8:1 is 422.187!!!

I'm not 100% sure what the end result of that test is, as im a complete noob when it comes to radios. Does that mean that the NA-771 will work on 466.9875 or not?

Thanks!
gezafisch

 

[N4GIX]

I'm not 100% sure what the end result of that test is, as im a complete noob when it comes to radios. Does that mean that the NA-771 will work on 466.9875 or not?

See the little green triangle at the lowest peak of the curve? That indicates the frequency of the best VSWR (vertical standing wave ratio) for that range of frequencies.

What that means is that at least for the two NA-771 antennas I have here, neither one of them would work well at your 466.9875 MHz frequency.

 

[toastycookies]

I think there is something wrong with your antenna. Mine looks a lot better, however it is tuned much higher in freq than I thought (and want). I had to piece together a couple adapters and a pigtail so it's probably off a bit anyways. Had to use a SMA to SO-239 to PL-258 to a pigtail with a PL-259 to a SMA male to NA-771.

Anyways, here are my results.

looks like jonwienke is right that they are tuned much closer to GMRS than 70cm ham band.

Unfortunate for me since that's what I use it for.

 

[gezafisch]

Could I just get a replacement antenna for, say, the Motorola CP200 and hook it up to the UV5R with an adapter? Would that give me better reception?

Thanks
gezafisch

 

[toastycookies]

N4GIX - now that I look at your results again scratch that "something wrong with your antenna" I said before.

Why do you have your scan set soooooo wide? makes it a lot harder to see the important part.

Guess I need to get a SMA to SMA connector for this thing to get a more accurate result for mine.




gezafisch : My antenna would actually be perfect for you LOL! Was a huge surprise to me, I thought it was tuned much lower.

 

[gezafisch]

Oh cool!


From the manual of the UV-5R : If you use an external antenna, make sure the SWR is about 1.5:1 or lower to avoid damage to the transceiver.

What does this mean? Is it a setting within the radio or is it a spec on the antenna?

Thanks!
gezafisch

 

[gezafisch]

Sorry for double posting, but are these legit? https://www.amazon.com/NA-771-430Mh...1489872221&sr=8-1-spons&keywords=NA-771&psc=1

 

[N4GIX]

The antenna's performance is best at its resonant frequency. VSWR is a measurement of that resonance. Generally anything less than 2:1 is acceptable, but 2:1 means a 11% loss* of transmitted power.

Nota bene: I corrected the above loss per 'toastycookies' polite note

 

[N4GIX]

N4GIX - now that I look at your results again scratch that "something wrong with your antenna" I said before.

Why do you have your scan set soooooo wide? makes it a lot harder to see the important part.

I've not yet figured out how to set the Span... :lol:

I used two male SMA adapters and a coupling barrel. The are part of a set of adapters I bought to use with my Rigol Spectrum Analyzer.

 

[toastycookies]

The antenna's performance is best at its resonant frequency. VSWR is a measurement of that resonance. Generally anything less than 2:1 is acceptable, but 2:1 means a 50% loss of transmitted power.

2:1 = 11% reflected power not 50%


-------------------------------------------------------------


gezafisch: https://www.amazon.com/gp/product/B00KC4PWQQ/

that is the exact vender I bought mine from.

 

[N4GIX]

Sorry for double posting, but are these legit? https://www.amazon.com/NA-771-430Mh...1489872221&sr=8-1-spons&keywords=NA-771&psc=1

They are the wrong "sex" (male SMA). You need female SMA. :lol:

This one is both "legit" and "female". If you zoom in on the base, you can see that the label is light gray, the A has a tiny triangle for the cross-bar, and the G is stylized with some curvy lines. There are other "markers" but those are sufficient to make the determination between real and fake:

https://www.amazon.com/Authentic-NA...rd_wg=2hSgi&psc=1&refRID=4Y612NKZNMN1XB0CG2VS

 

[jonwienke]

The first link is a fake. HYS in NOT Nagoya. The second link is correct.

 

[jonwienke]

Your analyzer test is probably invalid. Most HT antennas are designed to use the body of the HT as the ground plane. Moving the antenna away from the body of the analyzer with the coax screws that up and you won't get good results from any antenna that needs a ground plane to work properly. Replace the coax with a SMA coupler, or better yet get a single adapter to attach the antenna to the analyzer.

 

[jonwienke]

Also the antenna needs to be in open air, not lying on a table, Even non-conductive things like wood and PVC can alter the resonant freq range if in very close proximity to the antenna.

 

[toastycookies]

Your analyzer test is probably invalid. Most HT antennas are designed to use the body of the HT as the ground plane. Moving the antenna away from the body of the analyzer with the coax screws that up and you won't get good results from any antenna that needs a ground plane to work properly. Replace the coax with a SMA coupler, or better yet get a single adapter to attach the antenna to the analyzer.

It was propped up in open air when tested, not laying down, that was just to show the mess I had to use to connect it.

Would a counterpoise work? I do not have a simple sma coupler unfortunately.

 

[N4GIX]

The first link is a fake. HYS in NOT Nagoya. The second link is correct.

Just for the sake of factual information, HYS is a line produced by the manufacturer "Hypario" who is the OEM supplier to Nagoya and other companies in China.

See: https://www.hypario.com/

 

[jonwienke]

https://www.amazon.com/CESS-Male-Straight-Coupler-Connector/dp/B01FQE4E6U

Try running the test again while holding the coax just below the antenna so that you are the counterpoise.

 

[N4GIX]

It was propped up in open air when tested, not laying down, that was just to show the mess I had to use to connect it.

Would a counterpoise work? I do not have a simple sma coupler unfortunately.

This is what I used for my test:

 

[jonwienke]

Just for the sake of factual information, HYS is a line produced by the manufacturer "Hypario" who is the OEM supplier to Nagoya and other companies in China.

See: https://www.hypario.com/

I don't think so. The base of the Hypario antenna is ribbed, and styled differently than the Nagoya. One of them is a clone of the other, but with Chinese companies, who knows which is which.

I've tried several of the clones and the "Nagoya" antenna worked the best in head-to-head tests.

 

[bama9999]

I looked at the FCC listing for our patrol. It has a part 90 certification. To legally transmit on the patrol's frequencies, do I need a part 90 radio? Also, how does the FCC tell if you are or are not using a part 90 certified radio? Can they tell remotely or would they have to inspect your radio to find out? Also, I was reading on some forums about people who use radios like the UV-5R on MURS and GMRS and FRS. If you were to do this, is there a way for the FCC to know if your radio is part 95 certified or not other than manually inspecting your radio?

Thanks
Gezafisch

Here is a Baofeng that is part 90 certified, and seems to overall be a better radio than the UV-5R, and not a lot more cost. Also, I have the UV82HP, and the antenna that comes with the UV82 line is a much better antenna that what comes on the UV-5R's.

https://www.amazon.com/gp/product/B...Code=as2&tag=v87hh-20&linkId=DKR377YYOVIBVHII