How the heck is this working?

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BCasto

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I have a BCD996XT, frustrated by the poor reception and decoding of a digital trunking system about 15 miles away (Durham City NC). Tonight, out of desperation I tried something new. How the heck is this working? I hope it isn't a fluke and will continue to work all day, different weather, etc.

I took a t-splitter (https://www.radioshack.com/products/bnc-t-adapter-1), attached 2 telecscoping antennas, and attached it to the scanner. The results are shocking, reception is now consistently 4-5 bars, voice decoding vastly improved (fewer error rates), the scanner holds on the control channel, and the voice transmissions are not breaking up.

I have tried the RS 800MHZ antenna (https://www.radioshack.com/products/radioshack-800mhz-scanner-antenna), the telescoping antenna that came with the scanner, a discone antenna in the attic, and the loaded RS antenna (https://www.radioshack.com/products/radioshack-center-loaded-telescoping-whip-antenna) and none worked. The reception bounced around between 1 bar and 3 bars, sometimes with no bars, the scanner wouldn't lock onto the control channel, there were TG displayed but no voice, etc.

The scanner is located on the second floor of my brick house. I have 3 other scanners in the same shack.
 

marksmith

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If it works now, it likely will continue to work.

Usually what happens is the two antennas partially cancel each other out, or the loss involved with two antennas offsets any gain.

You must have hit the right situation in terms of where the radio is sitting, the orientation of the two antennas to the source being monitored, length of the antennas as telescoped, etc.

I have played around with this but never was able to improve over the stock antenna.

Note: leaves are coming off the trees and generally improving reception on trunked 700-800mz systems.

Mark
WS1095/536/436/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652
 

BCasto

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Thanks Mark

Mark, thank you. I am a neophyte when it comes to radio theory etc. So, are you suggestion the signal was too strong for the scanner? I did try attenuating it and the signal was lost completely. I tried the Low Pass filter too with no effect. I just remember seeing parallel antennas used in the CB world and thought "what the heck". Truly, leaves impact reception??
 

marksmith

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Mark, thank you. I am a neophyte when it comes to radio theory etc. So, are you suggestion the signal was too strong for the scanner? I did try attenuating it and the signal was lost completely. I tried the Low Pass filter too with no effect. I just remember seeing parallel antennas used in the CB world and thought "what the heck". Truly, leaves impact reception??
Leaves on trees absolutely impact reception. You will find reception to improve in the fall and decline in the spring in general, with FM signals, as they are line of sight.

Was not suggesting that the signal was too strong. It was whatever your s-meter says it was. From your description, it sounds like you went from 1-3 bars, to 5 bars. Unless you are dealing with a simulcast distortion sysyem, that should be a substantial improvement.

What I was suggesting is changing the length of the telescoped a tennis or the orientation of either the radio or antennas could dramatically change the signal received.

Mark
WS1095/536/436/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652
 

BCasto

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Mark, thanks for the extra information. Perhaps the darn site is just too far away to get reliable reception.
 
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