Pro-106 deaf on FRS/GMRS

Status
Not open for further replies.

hertzian

Member
Joined
May 28, 2009
Messages
2,605
My 106 seems to be somewhat deaf on FRS/GMRS freqs as compared to a $20 bubblepack radio.

While monitoring a very weak GMRS repeater on the bubblepack, I tried the 106. Nothing heard. Switched to the Diamond RH-77CA antenna. Still nothing, even with the squelch open and blowing noise. No PL/DPL used.

Instead of searching, I tried programming the freqs into a scanlist, using narrowband, and applied the 6db audio boost - still nothing heard - unless I went to my roof.

I tried a Uniden 396XT with a comet HT-55 antenna - and the sensitivity is back. In fact, the bubblepack is just a tad more sensitive than the 396!

I'm surprised by this large difference in sensitivity, and that a $20 frs/grmrs radio with it's 3-inch built-in antenna is doing better. It almost makes me think that there is a built-in attenuation on FRS/GMRS to perhaps protect the front-end of the 106. :)

I'll have to dig around my UHF stuff other than FRS and see if the sensitivity is down on other uhf bands...
 

62Truck

Member
Joined
Aug 13, 2005
Messages
1,464
Location
Uranus
Make sure you don't have the ATT on...The gmrs/frs radio might have better sensitivity then the scanner since the radio is tuned for one band. Hopefully your 106 is still under warranty.
 

KC5EIB

Member
Joined
Mar 24, 2002
Messages
1,479
Location
Flower Mound, TX
A radio designed to work on any very narrow band of frequencies will have much better sensitivity than a broad band receiver. One reason is front end overload protection from other frequencies around the target frequency. The FRS radios can be built, for very little cost, with very sharp filters to block any close by frequencies.
 

hertzian

Member
Joined
May 28, 2009
Messages
2,605
Thanks guys - I checked the attenuation but that was ok. I was probably being dramatic when I said "deaf". That was harsh, since I was comparing a very, very weak UHF gmrs repeater that barely broke squelch on the bubblepack.

I did some more testing and the end result seems to just be that my Pro106 is ok, but is not "hot" on UHF. The sensitivity on UHF compares to my less expensive Uniden 95xlt.

And, while the Uniden 396XT was able to break squelch when set at level 1, even with the squelch wide open, no recoverable audio was able to be discerned. Only a slight change in noise as the repeater carrier dropped and came back up. I tried using NFM and even FM just to see if a change in recoverable audio would be noted, but nope. And no attenuator. Unlike the 106, the 396 knew that something was there, but couldn't do anything with it.

The only thing that was 100 percent copy, albeit weakly, was the Midland LTX490 bubblepack. KC5EIB is right - these things have very sensitive receivers, and possibly narrow bandpass filtering - I didn't expect that for $20 each. :)

It isn't a deal-breaker since I don't listen to super-weak signals all the time, but it was an interesting experiment.
 
Joined
Dec 5, 2009
Messages
382
Location
Michigan
Thanks guys - I checked the attenuation but that was ok. I was probably being dramatic when I said "deaf". That was harsh, since I was comparing a very, very weak UHF gmrs repeater that barely broke squelch on the bubblepack.

I did some more testing and the end result seems to just be that my Pro106 is ok, but is not "hot" on UHF. The sensitivity on UHF compares to my less expensive Uniden 95xlt.

And, while the Uniden 396XT was able to break squelch when set at level 1, even with the squelch wide open, no recoverable audio was able to be discerned. Only a slight change in noise as the repeater carrier dropped and came back up. I tried using NFM and even FM just to see if a change in recoverable audio would be noted, but nope. And no attenuator. Unlike the 106, the 396 knew that something was there, but couldn't do anything with it.

The only thing that was 100 percent copy, albeit weakly, was the Midland LTX490 bubblepack. KC5EIB is right - these things have very sensitive receivers, and possibly narrow bandpass filtering - I didn't expect that for $20 each. :)

It isn't a deal-breaker since I don't listen to super-weak signals all the time, but it was an interesting experiment.
Hmmm yeah. I learned a llittle bit in this post. I am curious as to what the 106 would be more sensitive in frequency wise. I would guess 800 mhz since the radio is or big designed to work with newer digital trunking radio systems in the 700mhz, 800mhz, 900mhz frequency range. But that would be interesting to find out.
 
Status
Not open for further replies.
Top