Something I cooked up

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nursepen

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I've seen the post where people were asking what was the best antenna to use with the gre 800, this is something I put together.
 

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gewecke

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With both antennas being so close together, I would be hesitant to think it would work that well.

73,
n9zas
 

W2PMX

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All it does is make the calculations of what it actually does more complex. The impedance is way off, you're receiving 2 signals of different phase (and the phase difference varies by frequency) so I don't want to be the one who has to model what you did.

"The best antenna" depends on use. For portability, the RS 800 MHz antenna is probably the best. Only 7" total length, but it receives pretty well. For best reception? A 128 element bedspring isn't that large on 800MHz.
 

nursepen

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I'm not much on the engineering side,but it does work,it appears to me that this setup has cleaned up the reception of some of my channels
 

KE4RWS

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I guess it *looks* neat, but I don't see how it would actually receive any better than a single 800MHz antenna, taking into account the added connections the adapter results in. But hey, if you think it works better I guess that's all that matters . . .
 

Ed_Seedhouse

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Maybe it's just attenuating the signal for the sensitive receiver. Sometimes that can give the effect of "cleaning up" a signal.
Unless there is a balun between the two antennae and the input, then the impedance at any frequency will be changed. I was going to say "halved" but my knowledge of rf is insufficient for me to be sure. If you put two resistors in parallel then the total resistance is halved, but inductance involves more complicated math. This suggests that at any given frequency whatever the impedance of a single antenna is will be halved when they are in parallel. They are too close together to be a phased pair but likely the directivity at any given frequency will be likely changed at least slightly. Also if they are wired out of phase then the antenna will act like a transmission line and the sensitivity will drop way down unless they are at resonance for the distance between them.

In any case "it seems to work better" is an anecdote, not a measurement. The 800 is designed for a 50 ohm impedance but that would only occur at the quarter wavelength resonance. If you want more signal (which you don't, necessarily) then a longer single wire will do it better. If you think the antenna works better then don't worry, be happy. But if you want to know for sure you have to measure or know how to do the math for the given parameters.
 

rcool101

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I have one of those someone gave me along time ago. They are called.......... Double Duck...... and I still have the original rubber generic antennas that it came with.
 

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BeerNutz

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Jumpin' jingle bells. I've been drinking so much egg nog, I'm seeing two antennas.

Well, time to head back to detox. Thanks a lot. What's next, pink elephants?
 
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c5corvette

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I'm not much on the engineering side,but it does work,it appears to me that this setup has cleaned up the reception of some of my channels
It would be interesting to note what systems you thing this made a difference on???

I believe that it could make a difference on some simulcast systems by countering the phase issues that are common reception problems.
 

KE4RWS

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I don't think any of us have really questioned this. However, in reality many of us don't see how this configuration would provide any better reception than a single tuned antenna. I think that's all some of us here are merely pointing out. Personally I doubt this little setup does anything at all beyond a good, single 800 MHz antenna. But again, that's just me.

I guess when someone shows a picture of an antenna setup it's just natural for folks to offer constructive information or at least their own experiences with a similar setup or how or why this could possibly be self-defeating. That's just what normally follows when you show people what you're using. However, it doesn't mean people are doing anything wrong by offering their information provided they aren't being nasty or rude about it which I certainly haven't not seen here.

Honestly speaking, an old coat hangar stuck in the BNC connector would work, but does it really work better than the stock antenna, or a dedicated antenna? This isn't so much people questioning it but rather whether or not you really get any benefit from it. It's honestly nothing more than that. But when someone shows an antenna setup normally folks will always at least try to help them with the logistics of *why* it may not be beneficial to use a particular configuration by offering reasons that could explain their thinking. But again, if they think it works better then go for it. Ultimately one never knows what might work better unless you try it.
 
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ratboy

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Worrying about impedance on a receive only antenna is like worrying about the Klingons attacking tomorrow morning.
 

Ed_Seedhouse

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It works, so why question it? I do it with different antennas, no problem.
Well from what I've seen so far you don't have a basis for making that claim. It is clear that you yourself honestly think it works, but you have shown no actual evidence that it does. And you have cited no theoretical argument for why it would work.

But if you think it works keep using it and enjoying it. But don't expect others to believe it just because you do.
 
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