Antenna Problem

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bensrudy

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I have a Outdoor VHF-Hi/UHF Scanner Antenna Model: 20-176 from Radio Shack mounted on a 2x4 set about 5' above the eave of my house. I have a metal roof, so I know it can cause interference. I can receive our local weather net frequency using a rubber duck or a telescopic antenna on the scanner. When I switch to the outdoor antenna I can take the squelch completely off and hear the transmissions through static, if I switch to the indoor antenna's they come in loud and clear. What can I do to improve the outdoor antenna's reception?
 

737mech

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20-176

I have a Outdoor VHF-Hi/UHF Scanner Antenna Model: 20-176 from Radio Shack mounted on a 2x4 set about 5' above the eave of my house. I have a metal roof, so I know it can cause interference. I can receive our local weather net frequency using a rubber duck or a telescopic antenna on the scanner. When I switch to the outdoor antenna I can take the squelch completely off and hear the transmissions through static, if I switch to the indoor antenna's they come in loud and clear. What can I do to improve the outdoor antenna's reception?
First check the 20-176 connections, make sure the coax is ok (no kinks/holes/frays/shorting to shield/etc) and also make sure the radials that screw into the bottom and form the ground are not all the way in. Too far in is bad. Use the lock nuts to hold them out. One last thing try to use very few adaptors, one clean run of coax. If that doesn't work maybe try a different location a few feet away. If that fails then it might be time for a better antenna.
 

jackj

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The first thing to do would be to fine out what is wrong with it. It sounds to me like you have a problem with the coax. Us an ohm meter and check for either an open center conductor or a short.
 
K

kb0nly

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Not to mention that Rat Shack antenna ain't that great to begin with.. I have one up on the tower, not hooked to anything anymore, gave up on it. One of these days i will tear it down.
 

bensrudy

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I have checked my patch cable that has the bnc and it has a short. I will pickup some ends tomorrow at RS and see if that fixes it.
 

Alliance01TX

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Antenna Issue ?

Howdy

Are you showing the 'short' between the ground & center conductor or ground-to-ground or center-to-center conductor? It was unclear on your last post....?

If you tested the two conductors separately you should have a 'short' (low ohms reading) on each and when testing between ground & center conductor you should have an Open....

The metal roof will could attenuate (drop the signal level) some amount I would guess... but the coax/connectors sound like a high possibility.

Also, I had a like antenna the actual antenna connector on the antenna itself (SQ-259 type) had 'corrosion' inside the center feed area.

So you might also (after the coax/connector) look at taking a look for corrosion inside the antenna connect point from your coax & clean it up & apply some 3M or like 'liquid electrical tape' that you can get at a Lowe's or Home Depot in the electrical area of the stores. It's a thick (think tar) that you can brush-on thickly at the coax point to antenna....it's a bit messy to work with, but I use on my antenna's and it last for a couple years in the Texas heat....

Best of luck and let us know what you find.....

Thx

Bill
 

bensrudy

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I was showing a short between the ground and the center. Thanks for the tip about the liquid elec. tape.
 

eaf1956

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Yep

I was showing a short between the ground and the center. Thanks for the tip about the liquid elec. tape.
Yep, a short from center to ground would be a problem...You also may want to use a GOOD Quality coax depending on the FREQ you listen to. I use BURY FLEX on 2m 440 Mhz and also on that same type antenna to one of my 996's. LMR 400 is also usable, I like to use COAX with lower losses on the higher FREQ cause I listen to 900 Mhz Trunked Systems.

KC9LVX
 
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