Fringe monitoring with multiple scanners

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Muskratt

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I was trying to monitor a sheriff frequency about 60 miles away and wasn't receiving it so well - was cutting in and out on my 996xt. So I decided to monitor it at the same time on my 346xt. What surprised me was that both radios didn't receive the same parts of the transmissions. They would both cut in and out at different times. I was then able to better copy more fully what was being said. Both radios are using 2m whip antennas and are about 15 feet apart. Looking into this a bit further, I found this interesting post from Exsmokey here:

http://forums.radioreference.com/general-scanning-forum/78622-simple-question-ppl-multiple-scanners.html#post586921

My question is this - is there some magical number of scanners (handheld) that could be used with different spacing or antenna orientation (I have noticed some fringe frequencies come in better with the radio and antenna horizontal rather than vertical and pointed in different directions) that could be used to successfully monitor frequencies on the fringe? I'm primarily interested in the 150MHz range and also some 450MHz.

Muskratt
 

kd7rto

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Bountiful, Ut
I'd bet if you were to try a high grade communications receiver (AOR AR5000 or ICOM R8500), an older scanner from back in the days when they had to build them with a strong front end, because clearing the intermod by setting a PL was not an option (PRO-2006), or a Motorola or Kenwood programmed rx only, it would make a world of difference.
 

gmclam

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Try a different brand of scanner

I've had Unidens sitting next to my GREs all connected to the same antenna and the Unidens just are not as sensitive. For 800 MHz I like my PRO-95s, and overall I like my PSR-300. I monitor a huge area with great success.
 

kskarma

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Topeka, KS
A ShortWave Listening technique.....

Quite a few shortwave listeners used to employ a technique called "Diversity Monitoring" when attempting to follow a program on shortwave. The idea behind this was to use two radios and two antennas tuned to the same frequency.. The goal was to have the antennas separated by as much distance as possilble so that the 'fades' in the signal would sort of 'average out'.. Most of the time it worked very well, giving sort of a "stereo effect" when both radios and antennas were getting a strong signal...and at least improving the audio quality perceived when one side dropped out a bit.

At one time...about 1938, Hallicrafters even built a special radio called the Diversity Radio, the DD-1. This was super expensive and NOT a big seller, but it did what it was designed for, and is currently VERY rare.
Here is a link... Dual Diversity Receiver DD-1

Some of the radios, or people,... that employ this technique also use a 'voter'...this device switches either the input from...or the output of the combo that has the best quality reception to the speaker...
 

Muskratt

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May 9, 2009
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Eagle, WI
Thanks for the information kskarma. I did not know about the DD-1 or the voter and it was interesting to learn about them. Those were the kind of ideas I was thinking of. And kd7rto and gmclam, I appreciate the information about the different receivers and scanners. But what I should of said in my original post was the I was purposely trying to find fringe frequencies to monitor. When there is very little or no tropo going on in the middle of winter, it is a good time for me to experiment with antennas and radios to see what really helps with reception. I'm limited to indoor antennas only, on the ground floor, so that makes it even more challenging.

Around that time, I purchased a 2m/440 portable beam antenna to use for satellite work on ao51.

Elk 2m 440 Dual Band Antenna

I mounted it on an old camera tri-pod, and just for the heck of it tried it on the 996xt to see how well it worked as a scanner antenna. All I can say is WOW. Not only was I receiving that fringe frequency much better, but everything improved. I used to need 3 different scanners with 3 different antennas to monitor the different things I wanted to monitor. I have since consolidated everything from the 3 scanners into the 996xt with the elk antenna. And to top it off, I've added several new frequencies of towns that I've never been able to successfully monitor consistently with any of my other antennas/scanners. This antenna has pretty much filled in every gap of coverage that I had with my previous setup. Even an 800mhz system off the side of the antenna comes in consistently now on the 996xt that the pro-197 with the radio shack 800mhz antenna couldn't receive. I really never expected a beam antenna to work well indoors as a scanner antenna since I thought I would lose reception off the sides of the antenna compared to using my 2m whip antennas. Boy was I wrong.

I have so many conventional frequencies on 150/460 that I receive consistently now, that in order to keep up with the local action on the local 800mhz trs, I had to split all the conventional frequencies into 5 separate groups so the scanner wouldn't spend too much time at once with all the conventional frequencies. The scanner monitors the local trs, then one group of conventional frequencies, then back to the local trs, then the next group of conv. freqs etc...

This elk antenna is now a dedicated scanner antenna. It hasn't moved since the day I tried it on the 996xt. For coax I am using a 25ft cable with pl259's from cable experts CXP1318FX.

Coax Cable assemblies |RF 50 OHM| RFID Cables | Custom coax assemblies

Muskratt
 
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