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Author Topic: Multi directional antenna modification  (Read 33779 times)

dave w

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Re: Multi directional antenna modification
« Reply #30 on: January 21, 2011, 09:13:05 AM »

I can't remember when  Dennis Weaver [playing Chester Goode] finally decided to leave the show. But I may have graduated high school by then. Festus was Chesters replacement.
Give the man a Kewpie Doll! (nobody will get that - I don't know why I said it.)  rofl
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mike

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Re: Multi directional antenna modification
« Reply #31 on: January 21, 2011, 07:07:54 PM »

If both camera and receiver paddles were aimed exactly at each other, then I would think the paddles would produce a slightly stronger picture than the "Omni" stick antenna.....

I don't think so;  for instance, the cheap collinear omni directional 2.4ghz antennas can reach 18db (sorta fake - compared to 1/4 wave not dipole).  For instance:

http://cgi.ebay.com/18db-2-4Hz-WiFi-Router-Antenna-Booster-WLAN-NEW-20-1642-/120603909930?pt=LH_DefaultDomain_0&hash=item1c148d9f2a

The x10 paddle is probably 1.1 - just a tad better, if at all, than a 1/4 wave antenna would be....

When you put sma or rp-sma connector on the receiver, you can try different gain antennas and see the improvement in the video.  w/o my approx 20" long 18db antenna, i would have no hope getting the video from thru 4 walls 100' away as i do.
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dave w

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Re: Multi directional antenna modification
« Reply #32 on: January 21, 2011, 08:23:26 PM »

I don't think so;  for instance, the cheap collinear omni directional 2.4ghz antennas can reach 18db (sorta fake - compared to 1/4 wave not dipole). 
Exactly. It is fake. Passive antennas can not amplify RF. A directional antenna will have more "gain" than a 1/4 or 1/2 and likely a omni, but only in a specific direction.  An omni's "gain" is still from it's donut pattern instead of a dome pattern.
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mike

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Re: Multi directional antenna modification
« Reply #33 on: January 22, 2011, 07:34:22 AM »

yepper.  and taking that 1/4wave antenna's round basketball shaped radiation pattern and squishing it down - like putting your hand on top of it and pushing down - of course does increase the radiation distance horizontally in an omni directional way, so the net effect is the same as a directional gain antenna - it goes further horizontally, so the effect is the same - it works farther.  The 18db based on 1/4 wavelength and length of my 18db antenna is probably only 15db gain in reality.  I think our amateur radio mfgrs are the only ones still rating db gain on dipole as it should be, and even a lot of them are now comparing to 1/4wave too for sales propaganda instead. But this beats the flat thing shipped on the receiver hands down. 

AC8V
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troll334

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Re: Multi directional antenna modification
« Reply #34 on: January 24, 2011, 08:53:09 AM »

Excellent assessment gentlemen,
I like it !
wd4fqk
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