HP signal reception question.

[airems]

Just a question for all the HP experts. I have a new HP with the extreme upgrade. I've got a question about the signal reception of the unit. I'm listening to a P25 Simulcast system with 3 different sites. I've got all the control channels programmed into one single site favorite system. When watching the HP screen the signal meter in the top right hand corner will be full scale for a few seconds then completely go blank as if there is no received signal. About 2-3 seconds later the full scale will return lasting a few seconds. This cycle repeats itself. Upon looking at it under the system analyze feature on the HP it is very similar on the signal strength scale. The quality scale remains high as well as the activity scale. This particular system is very busy so I know there is a lot of traffic on it. I frequently do not hear the expected amount of traffic. I have all the usual agency types selected to receive. I'm geographically in the center of all 3 system tower sites. I have listened to it both on the database side and on the favorite system I built with similar results. I actually programmed all the control channels off a code plug from an active radio on the system itself. I'm just curious if this is normal for the HP? I'm guessing the loss of signal meter times is the unit just searching for another control channel? Is it better to build a system site for each tower site on the system. The HP is attached to an external NMO 800 MHz commercial antenna on the vehicle so I don't think the antenna is the issue. I have other systems that seem to work just fine. The HP has 2.0.4 firmware. I've tried downgrading the firmware with same if not worse reception quality. Any thoughts would be appreciated. Thanks!!

 

[danham]

I'm more of an HP-1 newbie than expert, but two observations that may help...

First, my BC 895 XLT does the same thing when monitoring our local trunk system, at least as far as signal bars go. The amount of traffic I hear (vs. my HP-1 and BC 235 XLT) does not seem to be affected.

Second, to diagnose whether the radio is at fault, see if you get similar "dropouts" on a conventional 800 mHz signal.

-dan

 

[airems]

Thanks for the ideas Dan. I tried both. Just seems to be the P25 system thats mainly effected. More trial and error I guess.

 

[TedRHayes]

I don't consider myself an expert, but I think I might be able to shed some light.

You said your monitoring a system with three sites. Are all three sites within reception range of your physical location? If they are not, the HP-1 will cycle through each of the sites looking for a signal on the frequency for the control channel(s) defined for each site. When a control channel signal is found that will be displayed in the strength meter. I think it will stay on that for about 1 second waiting for activity (ie. the assigning of a TGID to a given channel). After that, it will move on to the next site.

This could explain why you see the signal meter dropping out.

You can "avoid" sites that are out of range, or you can use the "Location" based scanning features of the HP-1 (i.e, zip code, city, gps, etc.) which should automatically avoid sites that are out of range.

 

[scosgt]

I would program in the sites into three different favorites, then enable the one I am near, or as stated, use located based scanning. I saw similar problems with a 396T when traveling through CT. My 296D was chattering away, the 396 got nothing.

 

[airems]

Thanks for the ideas. I will try them all. I usually have the most problem when I'm geographically in the center of reception for all three sites. That's when it seems to be the worst at reception. When I'm in an area covered by one tower the reception issue seems to go away. I'm guessing as stated its trying to search out the different control channels and causing the delay. Thanks again gents!!

 

[airems]

Update

I followed scosgt advise. I took all 3 tower site and programmed into separate systems (favorites). This made a drastic improvement in traffic reception. The received signal strength remain almost full scale for a longer period of time with only 1-2 second drop out. I guess packing all 12 control channels into one system causes too much delay when scanning to hear all traffic consistently. Thanks for all the ideas and suggestions everyone.

 

[UPMan]

If they were all in one site, then the scanner would have only ever seen the first (not necessarily the strongest) frequency that it was able to receive as a control channel. Assuming this was a tower with a weak signal at your location, that would explain the poor reception.

 

[scosgt]

I followed scosgt advise. I took all 3 tower site and programmed into separate systems (favorites). This made a drastic improvement in traffic reception. The received signal strength remain almost full scale for a longer period of time with only 1-2 second drop out. I guess packing all 12 control channels into one system causes too much delay when scanning to hear all traffic consistently. Thanks for all the ideas and suggestions everyone.

I am new to this radio, but the nicest thing about it so far is the ability to quick and easily alter the programming with a few mouse clicks. And to troubleshoot issues with the extreme upgrade.

I think if you plugged the system into the trunk analyzer, it would allow you to see the relative signal strengths of the towers and figure out the best scheme to monitor.

 

[airems]

Does the HP always check the first control channel programmed in the list every time?

 

[KM4WLV]

Glad you got it figured out. When you said 3 sites that were simulcast along with being P25 the first thing I thought about was multipath distortion which can cause the scanner to "wig out" so to speak, but looks like that may not have been the case since you're getting better performance.

I had issues with multipath distortion with one of our local P25 systems on my 396XT but when Uniden put out the last f/w update it pretty much cleared it up along with adjusting some settings on the radio.