Newbie seeks help to improve reception

[JamesO]

I use a rule of thumb that you should be able to easily receive a site that is 15-20 miles from your location depending on elevation and other attenuation.

So look closely and determine where the transmit sites are as compared to your location.

Then program in the transmit site(s) within a 15-20 mile crow distance and see what happens.

If you cannot receive them, then take the scanner and drive 3-4 miles to a high area near you and see what happens.

At the end of the day you may find out that you live in an RF hole and you may have a challenge based on your home location.

 

[ofd8001]

JamesO- Maybe you can help me understand something:

This is a simulcast system consisting, apparently, of seven sites (three licensed under WQPX838 and four licensed under WQPX837) all of which are using the same frequencies.

How can someone program a single site for a simulcast system? If you program one, I was thinking you are also getting the others because they use the same frequencies at the same time?

 

[LIScanner101]

Unless I'm missing something, it seems impossible to program in a system and expect the scanner to "listen" to"Tower 1" and NOT "Tower 2" if they both transmit the same exact frequencies and they are both within reception range of your scanner. How would any scanner differentiate between them?

 

[DickH]

When I got back inside, I tried straightening out a paper clip guess what... It seems to deliver as good performance as any of the 4 antennas I've plugged into it. Still seeming the alert lights and 5 bars with choppy reception or no audio at all. Hmmm.

Bill

From your description, it sounds as if there may be a cell phone antenna site nearby. They raise havoc, even with my Motorola on our trunked system. At certain spots around the city, there is noisy reception and it even cuts out in some very bad spots. If your scanner has an attenuator try turning it on.

 

[SCPD]

Unless I'm missing something, it seems impossible to program in a system and expect the scanner to "listen" to"Tower 1" and NOT "Tower 2" if they both transmit the same exact frequencies and they are both within reception range of your scanner. How would any scanner differentiate between them?

BY not programing Tower 1 Frequency in 2 or Tower Frequency in Tower 1 and setting them up in the same List.
In the New Scanner it seams "Uniden" somehow worked it out

This is for a 396xt not new x36

 

[JamesO]

JamesO- Maybe you can help me understand something:

This is a simulcast system consisting, apparently, of seven sites (three licensed under WQPX838 and four licensed under WQPX837) all of which are using the same frequencies.

How can someone program a single site for a simulcast system? If you program one, I was thinking you are also getting the others because they use the same frequencies at the same time?

If the OP is dealing with a simulcast system, regardless of the number of sites, the scanner may be picking up more than a single site. It would be unlikely that the scanner would be picking up more than probably 3 sites depending on his location and even then there should be a significant signal level difference so likely there is a primary location and maybe a secondary location that the scanner may need to deal with?

I went back and reread the OP original post again and what is strange is the fact that at times he has 4-5 bars and is not receiving anything. This means either he has few, if any talk groups programmed and all he is seeing is the control channel showing or likely there is some other configuration problem.

If the OP can see LNK and DAT toggling back and forth on the display, then this is an indication that the Control Channel is being tracked. Given his comment about the paper clip and close to full signal bars or no difference between the antennas, this is telling me that the problem may be less about a signal problem and more about the scanner programming??

So rather than worrying about the local system he is wrestling with, this is why I said get the scanner back to a factory default configuration and focus on the basics, putting a toe in the water before diving in.

I am finding there tends to be a steep learning curve with these newer scanners and trunked systems, so the basics need to be covered and then recovered.

I may be wrong, but I think this is mostly a pilot error issue, there would be simulcast issues added on top of that, but at least in my specific case, simulcast issues are not constant and continuous, but intermittent depending on local weather conditions and possibly trunked system loading and activity.

 

[ofd8001]

I went back and reread the OP original post again and what is strange is the fact that at times he has 4-5 bars and is not receiving anything. This means either he has few, if any talk groups programmed and all he is seeing is the control channel showing or likely there is some other configuration problem.

My local system is a P25 simulcast system having 13 sites. I've repeatedly seen this same thing - there are multiple bars indicating the scanner is receiving something, but no audio is heard or the audio is garbled.

(I knew the system was transmitting as I was in my fire department vehicle and heard transmissions on the mobile radio, but nothing came over the scanner).

I could move 100 yards down the road and get clear reception.

I'm reasonably certain that the scanner receives fine. I don't think it is a programming issue or something the user has done.

Rather the "innards" of the scanner are having difficulty with transforming what it receives into intelligible audio. In other words: Good reception, bad audio/voice decode.

The "real" radios on the system probably have a lot more costly decoding chips than do scanners.

About the only thing the OP can do to improve this is lessen the incoming signal so he isn't being bombarded with multiple towers and tinker with the P25 Adjust Mode and P25 Adjust Level. It's also be said that opening the squelch may help, but that didn't do much for me.

 

[wakker200]

Update....

I am very thankful for the discussion that's happening in this thread. I feel like I'm getting a lot of informed opinions and they are appreciated!

I have done a bit of research and what I'm going to do next is build an 800 MHz Yagi out of a few bits of yarn and twigs I have laying around the place. ;-)

I'll post back and let you know what that does for me, if anything.

Thanks to all,

Bill

PS The nearest tower is about 3 km from my house.

 

[SCPD]

Thanks for the replies.

First off, JamesO... the firmware is up to date. It shipped with the newest firmware in it. Do you think the RS antenna is better than the one I bought (Diamond RH77CA)? It was recommended in another thread. The same company also makes one that provides a 2.5 db gain...

teufler... I have seen the single beam antenna. We live in a single story home but I could get on the roof with the scanner and see if things improve. (I would think that reception would have to improve with height). I would be willing to put an antenna either on the roof or inside the attic if that's what it's going to take to fix this.

I will try your file and let you know how it works out. I'm east of CR in the Mt. Vernon-Lisbon area.

Thanks again!

Bill

I use both depending on what I monitor... the RH77ca is great for vhf/uhf but lacks the gain that you would get in the 800 mhz...
so depending on what you intend to monitor the rs model is great for 700 and 800 because of its gain in those bands...
however if monitoring VHF/UHF then the RH77ca is the antenna for you

 

[JamesO]

My local system is a P25 simulcast system having 13 sites. I've repeatedly seen this same thing - there are multiple bars indicating the scanner is receiving something, but no audio is heard or the audio is garbled.

(I knew the system was transmitting as I was in my fire department vehicle and heard transmissions on the mobile radio, but nothing came over the scanner).

I could move 100 yards down the road and get clear reception.

I'm reasonably certain that the scanner receives fine. I don't think it is a programming issue or something the user has done.

Rather the "innards" of the scanner are having difficulty with transforming what it receives into intelligible audio. In other words: Good reception, bad audio/voice decode.

The "real" radios on the system probably have a lot more costly decoding chips than do scanners.

About the only thing the OP can do to improve this is lessen the incoming signal so he isn't being bombarded with multiple towers and tinker with the P25 Adjust Mode and P25 Adjust Level. It's also be said that opening the squelch may help, but that didn't do much for me.

13 simulcast sites is a bit crazy, however, I doubt you have the ability to be in an area where more than 3-4 sites would be strong enough to be received at a single location at the same time. There may in fact be a number of places where there are touch spots as you stated, but also what model number radio are you currently running?

I have seem my 536HP stop on a Talk Group, but not get any audio. My 396/996XT's all seems to play much nicer, but again, I have need to swap the 536HP and 996XT location in the house and see what happens when I have more time on the 536HP.

If the OP has an issue which may be multipath, he should try the attenuator or keep the RH77 antenna on the radio, it does have crappy 800 MHz performance.

There are SO many variables to include terrain and system layout it is hard from behind a keyboard to fully understand what is going on. So I start with the assumption that things should work as expected, start simple and learn the radio. I am seeing A LOT of folks transitioning to the x96/x36 radios and they have a STEEP learning curve and then add the system issues on top of these as well as the possibility of encryption or scrambling.

So for someone that has been out of the scanner world for a number of years is in for a whole new set of issues once they return to P25 Trunking and the more complex radios.

Time is needed to figure out how to program and operate the device, then figure out the issues with the system(s) that are trying to be monitored.

Then you do have a few small tweaks you can make in the radios that may help the issues slightly, but these should come toward the end of the programming and learning curve.

 

[ofd8001]

JamesO-

Our system covers a fairly large county and is radio challenging. There's the basic downtown area with tall buildings, suburban areas with very large concrete warehouses and lots of hills and valleys. Initially we had 12 sites, but one part of the county had some dead zones so an additional site was contructed. The system was designed to be a "portable" system meaning that the system would work anywhere using portable radios only. (We also have three additional sites in adjacent counties for roaming purposes, but last I heard they were not fully configured.)

I'm reasonably sure I'm in the coverage footprint of at least three towers. I can remove the antenna from a handheld scanner and receive the system because of the saturation at my home.

I have 396T, 996T, 396XT, 996XT and two 536s. My 396T is probably the best scanner I had for this system until I got the 536s. Before I retired from the fire service, the radios assigned to me were an XTL 2500 mobile and an XTS5000 portable. While not stellar, I found that on the XT scanners I could reduce the "no audio decode or when it did, it was garbled" problem with turning the attenuator on, and setting my P25 Adjust Mode/Level to 13/175. (My son also has a 996XT and where he lives, the best settings are 11/181 for the Louisville MetroSafe System)

 

[wakker200]

OK, I haven't forgotten about this thread

It's been a while since I posted to this thread but I have been busy, some of it working on solving this problem.

First off, thanks to a file sent to me it's clear that there's nothing wrong with my radio. I have been trying copy the Linn County Iowa P25 system from the Mount Vernon area and struggling with what I believe is a phase cancellation problem. I found out from the file sent to me that I can hear Johnson County's P25 system just great. (They're just to the south of us). It's the Linn County system that's the problem. There is a very long thread on this forum discussing this system, which apparently is giving others a bit of heartburn, too.

So, I built a 3 element 800 MHz Yagi and gave that a try. No good. I suppose it may not be directional enough with only 3 elements. Anyway, it didn't work any better than the duckies I have.

Next, I bought a Ramsey 400-1000 MHz LPDA... the one built on a printed circuit board. This antenna actually works the best of any that I've tried. I'd say it's approaching usable at times, although at other times it doesn't do much at all. But in the documentation that came with the Ramsey, they talk about building a corner reflector for their antenna. I wanted to test the concept, so I lined part of a cardboard box with aluminum foil and suspended it and the antenna from the boom on a mic stand from the studio.

Guess what? This actually more or less works! It works enough for a proof of concept that I've decided to build a "real" version of a corner reflector to use with the Ramsey LPDA. I went to the hardware store today and bought all the materials I need EXCEPT that I couldn't find the two aluminum cookie sheets that I wanted that were plain flat ones with a 45 degree bend on one end. (Guess where I'm going to rivet them together?) I had to order the cookie sheets and they should be here sometime this week. When I finish, I'll have a tunable system. I will slot out the end of a piece of 1" PVC electrical conduit to mount the LPDA in. I bought a PVC coupling that I can install a threaded set screw on, so I can pull the LPDA in and out of the reflector to tune it.

I'm probably going to put this in the attic, possibly with a rotator. I do have a question... assuming all of this works well, is there any way I can avoid having to run a long feed wire to the scanner? I'm thinking of something like possibly a repeater....? I'm not necessarily averse to running the cable, but my wife is no fan of wires in the house. She almost never comes into the recording studio because the wires put her into a fugue state, kicking up a mess of OCD impulses that I'd rather not deal with.

Is there a practical and affordable solution to putting something electronic in between the antenna and the scanner to avoid having to run a cable?

Thanks for everyone's help, PMs, emails, and so forth. I'm not there yet but you have helped me get closer. I will post some pictures of everything when it gets built.

Cheers,
Bill

 

[kd7mxi]

place powerfull freqs such as radio stations , pagers, digitals, dead key sounding signals, birdies , known users also into global filter ,,, i find this helps

 

[kd7mxi]

place unlistened to stuff into the globals also ,,, there are 2 global filters