Improving 436/SDS100 Reception

[KI5IRE]

I noticed I am able to receive several somewhat distant 700/800 MHz P25 systems near me on my Unication G4 with no external antenna, however I am not able recieve them on my 436 or SDS100 with or without an external antenna.

I understand my Unication is a commercial grade radio and is tuned for 700/800 MHz only and my Unidens are tuned for a wide spectrum, but I was curious if anyone has any tips to potentially increase my reception?

I have tried turning my squelch all the way down with no luck and a few other things like that.

I was just curious if anyone has had any luck solving a similar issue with the settings in the radio and without buying pre-amps and stuff like that since I use these radios while mobile frequently.

 

[hiegtx]

I'm not using any pre-amps. When mobile, with either SDS100 or 436HP, I'm not having problems picking up systems that I know are in range. I'm using one of the Remtronics antennas on both scanners. The 436 has one of the BNC versions, and I'm using the SMA to BNC adapter that came with the scanner. For the SDS100, I'm using the specific Remtronics antenna made to attach correctly to the SDS, and maintain the water resistance. I don't have a Unication pager to compare them to.

I've seen a number of comments about using the Wide-Invert filter helps on the SDS for 700/800MHz systems, but I have not found a need to experiment with the filters.

 

[jonwienke]

The factory antenna is crap on 7/800MHz. The Remtronix 800 is your best option for a ducky/whip antenna.

 

[n1chu]

Everyone knows a commercial radio (or a radio that is tuned to receive just one particular band (or frequency) can run circles around a multi-band scanner. There is a trade-off. ALL of my VHF/UHF amateur gear hears better compared to my scanners when I take advantage of their ability to listen to other services on the same band. It’s just the nature of the beast.

On a related matter, I was always critical of why it was a commercial repeaterized system didn’t have the “ears”, it’s ability to receive weak signals when I knew the equipment was so much better than scanners and even better than ham gear. Then I was enlightened to the fact it all had to do with the “noise floor” at the repeater’s antenna site. Basically, and simplistically, the commercial professional gear was “dummied down”. The squelch would be turned up to a point just above the noise floor. Because the antenna site is probably shared with other services which increase the noise floor. True, there are filtering and isolation techniques used but they run into money, whereas a simple squelch adjustment cost nothing. Today, most all of those tools available are used to create that compromise of signal strength over interference. (I’ve been to repeater sites that have so much equipment mounted on the towers that the RF level (noise floor) is so high the florecesant tube lights in the shack are glowing without any power! The switch is off!)