Strange Uniden 796D 800mhz Reception

[dave7933]

Wondering if any folks out there have experienced what I am hearing. I have owned the 796 for a few weeks now. I'm in the West Palm Beach, FL area monitoring APCO 25 Trunked Palm Beach County frequencies. With the standard antenna (I have tried various lenghts) while I receive the transmissions OK there is some signal degradation every few seconds. The channels do not cut off totally but static comes in and out as the signal strength seems to go from strong to moderately weak. I am on the 2nd floor of a 2 story house and the 796 is near a window. I even bought an 800 mhz antenna with 2.5db boost and that did not help at all.

The strange thing is through some trial and error I hooked up an old GRE 20db Super Amplifier at first with the whip antenna which helped a little but not much. Then I removed the whip so now all I have is the amplifier hooked onto the rear of the 796 with NO antenna attached to it and the reception on 800mhz is excellent! What is going on here? The bad part is I don't think I'll be able to use the scanner for anything but 800mhz in this set up. Thanks in advance for any feedback.

 

[loumaag]

Sounds as if you have something local which is interfering with the signal. In other words in addition to the desired signal, you are picking up something which is either overloading the front end or directly interferring with the frequency you are monitoring. I would guess the latter, based on your rough description. Look, you found the solution, no antenna at all, use it. :lol:

 

[werinshades]

I'm wondering if this is a system problem. Anyone else that monitors the same system expierience the signal degradation as well ? Ever try to leave your house and try it somewhere else?

 

[W4KRR]

Wondering if any folks out there have experienced what I am hearing. I have owned the 796 for a few weeks now. I'm in the West Palm Beach, FL area monitoring APCO 25 Trunked Palm Beach County frequencies. With the standard antenna (I have tried various lenghts) while I receive the transmissions OK there is some signal degradation every few seconds. The channels do not cut off totally but static comes in and out as the signal strength seems to go from strong to moderately weak. I am on the 2nd floor of a 2 story house and the 796 is near a window. I even bought an 800 mhz antenna with 2.5db boost and that did not help at all.

The strange thing is through some trial and error I hooked up an old GRE 20db Super Amplifier at first with the whip antenna which helped a little but not much. Then I removed the whip so now all I have is the amplifier hooked onto the rear of the 796 with NO antenna attached to it and the reception on 800mhz is excellent! What is going on here? The bad part is I don't think I'll be able to use the scanner for anything but 800mhz in this set up. Thanks in advance for any feedback.

Sometimes less is more. I tried a pre-amp years ago. It was worse than having no antenna at all. The reason is that the signal is overloading the scanner, and you get receiver desense. For this reason I have not used a pre-amp since. If you have found a solution that works for you, great. You might want to try experimenting with an outside mounted antenna, such as a discone, and forget about the pre-amp altogether.

 

[dave7933]

Updated Solution!

I played around some more with a few things today and what I have found works best is to back the db about half way down on the GRE Pre-Amp and plug the 800 mhz antenna onto the pre-amp. In addition I had to point the antenna to the right about half way down. Things working great now!

 

[wesct]

Wondering if any folks out there have experienced what I am hearing. I have owned the 796 for a few weeks now. I'm in the West Palm Beach, FL area monitoring APCO 25 Trunked Palm Beach County frequencies. With the standard antenna (I have tried various lenghts) while I receive the transmissions OK there is some signal degradation every few seconds. The channels do not cut off totally but static comes in and out as the signal strength seems to go from strong to moderately weak. I am on the 2nd floor of a 2 story house and the 796 is near a window. I even bought an 800 mhz antenna with 2.5db boost and that did not help at all.

The strange thing is through some trial and error I hooked up an old GRE 20db Super Amplifier at first with the whip antenna which helped a little but not much. Then I removed the whip so now all I have is the amplifier hooked onto the rear of the 796 with NO antenna attached to it and the reception on 800mhz is excellent! What is going on here? The bad part is I don't think I'll be able to use the scanner for anything but 800mhz in this set up. Thanks in advance for any feedback.




i would try updating the firmware for the digital card. this has solved many reception problems on the 800 mhz band.

wesct

 

[dave7933]

I already had upgraded the firmware. Everything is fine now that I have the antenna pointed at the correct angle--always thought straight up was best but know otherwise with receiving digital--and the db backed down about half way on the pre-amp. Hopefully this helps others out there with the same issue.

 

[loumaag]

...Everything is fine now that I have the antenna pointed at the correct angle--always thought straight up was best but know otherwise with receiving digital...

First, digital has nothing to do with it. 800MHz is 800MHz, no matter what the modulation type. As to the vertical vs an angle, when inside, I have never found perfectly vertical to be the right answer. Too many things to bounce the signal around, I have always found (particularly at the higher frequencies) that angling the antenna (indside) produces better results.

 

[Al42]

Everything is fine now that I have the antenna pointed at the correct angle--always thought straight up was best

It usually is - for maximum reception. What you probably want is minimum reception of the interfering signal and whatever you get from the transmitter you want to hear.

Just for kicks, try putting the antenna back on the scanner, but turning the attenuator on for that system. That might be all you need - or that and some antenna aiming.

 

[Voyager]

Wondering if any folks out there have experienced what I am hearing. I have owned the 796 for a few weeks now. I'm in the West Palm Beach, FL area monitoring APCO 25 Trunked Palm Beach County frequencies. With the standard antenna (I have tried various lenghts) while I receive the transmissions OK there is some signal degradation every few seconds. The channels do not cut off totally but static comes in and out as the signal strength seems to go from strong to moderately weak.

Is this a simulcast system? If so, it's likely you are picking up two (or more) sites that are competing with each other and causing mutual interference. Removing the antenna is just enough difference that only one site is coming in, but not both, or three, Etc.

Joe M.