antennna identification

[WRPQ991]

Over the years I have acquired a few antennas, Is there any way to identify which would do UHF Gmrs, which are 10/11 meter, which are 2M ? I was goofing around on a Ham equipment site last night after a few adult beverages. I saw a antenna matcher,  supposedly whatever freq you transmit on it matches it for optimum SWR and impedance. It wasn't cheap, but with all the multi band, or any band radios, with on heck of a frequency range... I guess you could do it all with one antenna?

If I used the wrong terminology or misspelled anything, I'm not a Ham operator. I spent years OTR using CB everything from "converted 10M" to Pres. Bill, alot of Cobra and Unidens. Yes I've played in the "prepper bands" or "free bands"   Retired now with too much free time on my hands. LOL

[Borage257]

If you have an antenna analyzer or NanoVNA you can 'sweep' the antennas and see where they are resonant. Some antennas may have a stamped or printed mark near the base with a part number or frequency range. 

[KAF6045]

1 hour ago, WRPQ991 said:

Over the years I have acquired a few antennas, Is there any way to identify which would do UHF Gmrs, which are 10/11 meter, which are 2M ? I was goofing around on a Ham equipment site last night after a few adult beverages. I saw a antenna matcher,  supposedly whatever freq you transmit on it matches it for optimum SWR and impedance. It wasn't cheap, but with all the multi band, or any band radios, with on heck of a frequency range... I guess you could do it all

Antenna "tuners" (matchboxes) only adjust the impedance on the transmitter side, to make the transmitter output transistors happy (most decent radios "roll back" the output power if the SWR is too high. The SWR on the antenna side of the tuner is not changed -- and if you are using coax, excessive SWR with high power [at the worst, you have nearly all the power bouncing back down from the antenna, so the cable and tuner are seeing 2X power on the antenna side] can result in cable warming and possible melting of the insulator. They may be optimized for ladder-line/window-line rather than coax (such lines need to be kept away from metal surfaces as the signal is not confined within the line)

Many are also only rated for HF bands, maybe including 6m. None of mine handle VHF or above. The smaller auto-tuners may only be rated to match SWR up to around 3:1; the better ones go to 10:1.

As mentioned, the best method is to use an antenna analyzer or vna and sweep through the various bands to see where the SWR is lowest (may be multiple places).

 

ADDENDUM: unless you explicitly purchased commercial/GMRS band antennas, the odds are good none of the ones you have will cover GMRS. Not even a dual band 2m/70cm antenna (most 70cm repeaters span the 446MHz area, which is 20MHz below GMRS; the usable bandwidth of a 70cm antenna may span 430-450MHz).

[WRPQ991]

I'll be doing 100% coax I have a Surecom SW 102and Surecom SW 33 mark II. to check SWR and power. I was certainly disappointed to learn all my CB test equipment SWR/Power wouldn't work on GMRS.  I do have dedicated GMRS antennas but they look just like the ones that come with the little CBs that are on the market. Fit in the palm of your hand, some dead key around 6 Watts and swing 10-15Watts I run a President Bill in my Ford Ranger but have it on a 5 Ft firestick, SWR is 1.5/1 to 2.1/1 from 25.615 to 29.205. If I'm on a longer trip I'll put in a RM AM/SSB KL23P 100W linear. On a good day it will talk across the grass median.

Ran a Midland MXT500 for awhile, with the included antenna, I was not at all impressed. Nobody out there. Of course alot of places I go there is NO cell service, NO FM radio, and AM is the boarder blaster Mexican stations.

So, I was thinking of running the Midland as a base station, and as long as I have the pole down put up a good CB Base as well. That's another story on a different forum..

Guess I'll go looking for an antenna analyzer. And see if I can figure out how to use it.

Rules can be broken, Laws cannot (should not). So don't lecture me on power and frequencies, I know the rules. 

[Borage257]

1 minute ago, WRPQ991 said:

Guess I'll go looking for an antenna analyzer. And see if I can figure out how to use it.

The NanoVNA is good for the money, about $60. There is tons of documentation and easy startup guides on youtube. Lots of guys here have one and can attest to its value.

[MarkInTampa]

1 hour ago, Borage257 said:

The NanoVNA is good for the money, about $60. There is tons of documentation and easy startup guides on youtube. Lots of guys here have one and can attest to its value.

I picked up a NanoVNA a few weeks ago to test my antennas. With a quick 10-15 minute YouTube tutorial on using NanoVNA with NanoVNA Saver (free software) I had my antenna tested in minutes. I find it much easier to use the computer interface than a 2 or 4 inch touch screen. It's also nice to be able to save or screenshot the results.

 

[Borage257]

7 minutes ago, markskjerve said:

I had my antenna tested in minutes.

What antenna is that?

[MarkInTampa]

2 minutes ago, Borage257 said:

What antenna is that?

Comet GP-6NC

Much better than my other two antennas tested...