Pro 197 missing P25 transmissions

[KD0TAZ]

I have noticed listening to my feed that my Pro-197 has been missing a significant number of transmissions lately. Many times I will hear a blip in the squelch (like a ker-chunk) and nothing else, then a bit later I will start hearing a conversation in progress. I am relatively close to the tower, but through a lot of googling I have also discovered that my setup is not optimal..

I have the scanner connected to my rooftop omni FM antenna (the crossed-loop Radio Shack one) through a regular 4-way splitter (no amp). This worked great when when the town was on conventional, but last year they switched to P25.. I noticed over the winter that the signal on all of my FM/weather radios would start to fade when it was wet out - and this would also affect the scanner. I figured the lead-in from the antenna was bad at some point, so I replaced the whole thing (regular RG-6). Now the FM radios are crystal clear, but the scanner is missing more than ever.

I originally attributed this to a signal overload (it got worse when the lead-in was replaced), so I put an additional 3dB attenuator inline, and that seems to help - also turned on the scanner's attenuator.. But it is still missing.. So now I am wondering if it is a reflection or simulcast issue? The main KSICS tower for this county (from what I understand) is about 10 miles northeast of me. There are also towers approximately 35 miles to the north, south, east, and west that are for neighboring counties.. I honestly don't know if they are strong enough to cause issues, but being connected to the omni antenna can't be helping things..

I want to try and fix this on the cheap.. So do you think one of the "$5 Yagis" will help? And now I will need to have another lead-in just for the scanner.. Since it will not be used for transmission, and since the signal is strong to the point of NEEDING attenuation, do you think cheapo RG58 will suffice for a ~100ft run? There's no reception in the room where the scanner is located, so the outdoor antenna is a must.

 

[gewecke]

How far is the tower(s) from you? You maybe able to use use a indoor antenna as long as it's tuned for the system you're listening to.
The P25 tower in my city is approx 2 miles and I use a r/s 800mhz duck on the back of a pro-197 with 99% signal on the control channel.

73,
n9zas

 

[KD0TAZ]

No offense, but did you bother to read the original post? I answered both of those questions already..

The main KSICS tower for this county (from what I understand) is about 10 miles northeast of me.

There's no reception in the room where the scanner is located, so the outdoor antenna is a must.

 

[N1BHH]

Are you missing transmissions as it is scanning? That's because it takes a bit of time to recognize what the signal is, be it AM, FM, P-25 or whatever it is. You have to realize you are scanning a number of scan lists and there are quite a few objects in each. P-25 signals do take some time for the scanner to recognize anyway.

You are also running a horizontal antenna, being in close proximity to vertically polarized signals you automatically lose a bit. You may actually take a mag mount, any type or band an stick it on an air conditioner of steel shelving and see what happens then. And also you may want to try per object attenuation. In high RF environments it helps to attenuate.

And take a look at your expert settings having to do with P-25, here they are:

Easier to Read Pro-106/197/PSR500/600 Digital Scanner Manual

 

[gewecke]

No offense, but did you bother to read the original post? I answered both of those questions already..

Sorry, just got up & still on the first cup.
...my bad.

73,
n9zas

 

[KD0TAZ]

Are you missing transmissions as it is scanning? That's because it takes a bit of time to recognize what the signal is, be it AM, FM, P-25 or whatever it is. You have to realize you are scanning a number of scan lists and there are quite a few objects in each. P-25 signals do take some time for the scanner to recognize anyway.

You are also running a horizontal antenna, being in close proximity to vertically polarized signals you automatically lose a bit. You may actually take a mag mount, any type or band an stick it on an air conditioner of steel shelving and see what happens then. And also you may want to try per object attenuation. In high RF environments it helps to attenuate.

And take a look at your expert settings having to do with P-25, here they are:

Easier to Read Pro-106/197/PSR500/600 Digital Scanner Manual

Yeah it's missing entire transmissions/exchanges. As I said I hear a quick blip of sound, then silence, then maybe I'll hear "10-4, 21:40". It's not even like transmissions are tuning late or cutting out early, it's just missing them.

As far as the scan lists, when my county went P25, I wiped all the programming and reprogrammed a single TSYS, with one control channel and just the few talkgroups on my feed. There are no conventional objects in it anymore.

I actually just went through the manual and found out about the Analyze control - the one that opens the squelch on the control channel and sounds like an idling diesel engine.. While listening, it mostly sits at 99%, but every few minutes there are waves of static that fades in and out (the engine noise is very consistent though, it doesn't waver - it almost sounds like the static is 'separate' from the engine), and this corresponds with the % dropping as low as the 20's.. I assume this is the root - or at least a contributing factor - of my problem. Any ideas what it could be? I do not hear it on any of the other radios that feed off that antenna, so whatever it is, it is in the 800MHz band and not VHF..

Would this be caused by the antenna being horizontal (and technically tuned for the wrong band) - even though it's only 3 miles away (I just looked up the tower license and found where it is located) and has 150W?

Sorry, just got up & still on the first cup.
...my bad.

73,
n9zas

It's all good..

 

[N1BHH]

First sentence of the second paragraph from my post prior, you need to go vertical. Horizontal won't work. Try a mag mount for any band, it will work. Find a good hot spot.

 

[Eng74]

Just a thought but do you have it set for Roam or Stationary? If it is set for Roam it might be getting a signal from another site but not enough to decode and then it will switch to the closer site.

 

[lbfd09]

Have you tried the built in attenuator? I use that on an 800 trunking system that's over 30 miles away - now no more missed traffic, unless someone else is talking of course.