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253Re: Dual Band antenna recommendation?

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  • g4ilo
    Jun 1, 2011
      Wouldn't the connections to the return loss bridge act as a ground? I've done testing using a battery powered AA-200 antenna analyzer but even that is big compared to an HT like the UV-3R and I haven't found adding a 19in counterpoise makes much difference.

      I found the NA-701 performs on a par with the stock rubber duck antennas from Yaesu (and better than Kenwood antennas which seem to resonate aroound 160MHz). I did find the single band 2m antenna that came with the UV-3R performed about 3dB better than the NA-701. I have not found any other antenna that size which performs that well, but it does not seem possible to find a dual band antenna that does not sacrifice performance without gooing for something much bigger.

      Julian, G4ILO

      --- In UV-3R@yahoogroups.com, "andyn1ksn" <acp-smp@...> wrote:
      >
      > Thanks for your interest, Shawn.
      >
      > The return loss bridge is a small square metal case connected to signal ground, and when making the measurements I held it as if it were an HT, close to my head at eye level. The coax cable connections were down somewhat and away from the return loss bridge. That's as close as I think I could come to a real HT situation (using the internal microphone).
      >
      > Nearby objects will have an effect on the match. I'm sure that the manufacturers make sure that the power amplifier can tolerate pretty large mismatches at the antenna.
      >
      > I've built some two meter quarterwave counterpoises (tiger tails) and tested them with a field strength meter, but not in a very controlled situation. I concluded that they generally will help your signal if the rubber duck is equivalent to a quarter wavelength. A speaker mic may accomplish the same thing, since a ground connection is in the wire (but the length is variable since it is coiled).
      >
      > When I built the tiger tails I put a ceramic bead (from a craft store) on the end to keep them somewhat straight. When listening to a weaker signal, the signal strength would change if the tiger tail were swinging back and forth. I tried a 70cm tiger tail, but it didn't help much, probably because it is about as long as the HT body itself.
      >
      > I never tried to use an HT clipped to my belt. I don't even carry them that way, since you are likely to put a permanent bend in the rubber duck. And they would tend to pull my pants down.
      >
      > By the way, I look forward to testing the stock antennas that come with the UV-3R. When I get the results I'll post them in the Files section.
      >
      > 73,
      > Andy N1KSN
      >
      > --- In UV-3R@yahoogroups.com, Shawn Upton <kb1ckt@> wrote:
      > >
      > > Interesting.  Two questions come to mind: first, were you holding somewhere around the base of the antenna when you did this?  So as to simulate the effect of you?  [Obviously, all bets are off for when the HT is clipped to ones belt.  I recall being told once that HT design did, at least at one time, take that into effect.]  Secondly, I wonder what one of those "tiger tails" (as I've heard them referred to) would do for the match.  You know, a 19" length of wire attached to the radio (or 19" minus the length of the radio, if somehow clipped to the bottom of the radio).  I don't know if the match would get better or worse, but I do recall reading that the wire can make a real difference.
      > >
      > > Shawn Upton, KB1CKT
      > >
      > > NAQCC 4723
      > >
      > > --- On Mon, 5/30/11, andyn1ksn <acp-smp@> wrote:
      > >
      > > From: andyn1ksn <acp-smp@>
      > > Subject: [UV-3R] Re: Dual Band antenna recommendation?
      > > To: UV-3R@yahoogroups.com
      > > Date: Monday, May 30, 2011, 5:53 PM
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      > > A few months ago I did a study of several HT antennas, some of them dualbanders. I used a MiniCircuits return loss bridge and an HP E8285A test set with a spectrum analyzer to look at their match to 50 ohms.
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