I recently moved into a new house which was 7 miles from my previous house. Since I moved, I no longer can receive any of the systems I used to receive at my old location which includes the Indiana Project Safe-T (St. Leon, Guilford and Lawrenceburg towers). Each one of those towers are less than 7 miles away from the new house. I am having this issue on my TRX-1 and also my PSR-800 while my old trusty Pro-96 picks everything up crystal clear. One thing that is different at the new location is I have a cell tower less than a quarter mile from my new house which I am sure is causing the problem but I don't understand why an old Pro-96 isn't affected by this. I have tried low pass filters on the radios having the problem with no luck but I have found that using the attenuator helps a little but everything is still garbled on most transmissions. Any suggestions on how to filter out the interreference from the nearby cell tower or would going to the Uniden SDS series or even a Unication be a better choice?
Reception Issue/Cell Tower Interference
- Thread starter kc8gjh
- Start date
What are you using for an antenna? Also find out what frequency the cellular service is using and have Par Electroncs make you a custom Notch Filter to attempt to block it.
Dale Parrfit
PAR Electronics, Inc.
P.O Box 645
Glenville, NC 28736
Voice: 828-743-1338
Fax: 866-304-8479
EMAIL:
PAR Electronics | Filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave listening enthusiasts
PAR Electronics Inc. Filters for the commercial 2 way market, MATV, FM broadcast, laboratory, marine industry, amateur radio, scanner and short wave
www.parelectronics.com
Dale Parrfit
PAR Electronics, Inc.
P.O Box 645
Glenville, NC 28736
Voice: 828-743-1338
Fax: 866-304-8479
EMAIL:
My guess is that you're now suffering from simulcast distortion in your new location. Map out the three sites of interest using the RR Database to see where your home is in relation to the three towers. I'd bet there's significant overlap in signals from multiple towers at your new QTH.
I wouldn't suspect simulcast distortion in this case. All sites the OP mentioned are single cell
If it is a simulcast issue I doubt his PRO-96 would cope with it.
I wouldn't have thought so either. But simulcast seems to get the blame for everything else here up to and including gout.
I'm using both the stock antenna and also the 800mhz antenna from Whistler. Same results from both antenna. I've moved to different locations in the house with same results. Today I drove about a mile further down the road and everything was back to normal so it is definitely the cell tower. I just need to figure out how to eliminate the interference. There is a tower to my south. I may go with a Yagi and see if that helps.
Ubbe
Member
If you not already have one, get a SDR dongle, the RTL-SDR one are a good working one. Install SDR# in windows and look at the spectrum and you will probably see where any interfering signals have the biggest signal levels. You can also listen to the signal and decode and monitor it using SDR#.
If the monitored systems have a strong signal level and using the attenuater on the scanner helps a bit to fight the interference, then what happens if you unscrew their antennas just far enough where the connection to the scanner just barely breaks and attenuates the signal even more? Maybe you'll need a worse antenna that reduce all signals or a simple 20dB attenuater between antenna and scanner.
Using an external filter from PAR will be some $120 and you then need to use one external antenna, then the filter, then a splitter to be able to feed the signal to several scanners.
/Ubbe
If the monitored systems have a strong signal level and using the attenuater on the scanner helps a bit to fight the interference, then what happens if you unscrew their antennas just far enough where the connection to the scanner just barely breaks and attenuates the signal even more? Maybe you'll need a worse antenna that reduce all signals or a simple 20dB attenuater between antenna and scanner.
Using an external filter from PAR will be some $120 and you then need to use one external antenna, then the filter, then a splitter to be able to feed the signal to several scanners.
/Ubbe
G7RUX
Member
- Joined
- Jul 14, 2021
- Messages
- 408
At the risk of teaching grandma to suck eggs, are you sure that it is the cell site that is causing your problems? I only ask as it is all to easy to asume that the obvious thing is the cause when actually it's something more subtle, or indeed a combination of things.
What frequency(ies) is the cell site using? What sort of levels do you receive them at?
What frequencies are the services you want to listen to using? What levels do they come in at?
What other frequencies are in use in the area? What sort of levels are they arriving at?
It would be unwise to spend money on new radios before understanding where the isue is coming from as you may end up with just more receivers that don't do what you need!
What frequency(ies) is the cell site using? What sort of levels do you receive them at?
What frequencies are the services you want to listen to using? What levels do they come in at?
What other frequencies are in use in the area? What sort of levels are they arriving at?
It would be unwise to spend money on new radios before understanding where the isue is coming from as you may end up with just more receivers that don't do what you need!
tvengr
Well Known Member
Have you updated your profile and are you now in Guilford? Which agencies do you want to monitor? The TRX-1 and PSR-800 will receive only the site with the best signal unless you have a separate system with each site. If you drive down the road and you suddenly start receiving what you want, it sounds like you are switching to the site where the radio traffic you want is affiliating.
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You might try the attenuator function on the scanners if so equipped.
My experience is that when I am near cell sites, the RF renders much of the 7/800 band useless for scanners. I have a site nearby my home and had to resort to yagi antennas rather than omnidirectional antennas to null out the cell site.
If I drive along with DSDPlus/FMP24 running, as I go near any of these sites, the lines go right up to the top of the scale until I am past. I can drop the gain to zero and bring them back down but get no target signal then.
My experience is that when I am near cell sites, the RF renders much of the 7/800 band useless for scanners. I have a site nearby my home and had to resort to yagi antennas rather than omnidirectional antennas to null out the cell site.
If I drive along with DSDPlus/FMP24 running, as I go near any of these sites, the lines go right up to the top of the scale until I am past. I can drop the gain to zero and bring them back down but get no target signal then.
tvengr
Well Known Member
Please attach your TRX-1 programming file. I would like to make a change to it to see if it helps.
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Theres a Verizon site near a whataburger i eat at, at the end of the parking lot and its not very tall. That site kills my G4 till I enter the building. Then signal comes back. So it is plausable that the cell site is interfereing with his reception. But there are still lots of variables.
tvengr
Well Known Member
Interference from cell towers is a possibility. I would like to verify that the scanner is not locked to the wrong site before purchasing filters or directional antennas when a simple programming change could be all that is needed.
I programmed this single site - Indiana Project Hoosier SAFE-T Site: Guilford which is 2.1 miles from my house and my Pro96 picks it up with no problem. I program it into my PRS-800 or TRX-1 and it is nothing but garbled digital. I turned the attenuator on and while it gets better, it is still unreadable. I programed in the other sites (not together) Indiana Project Hoosier SAFE-T Site: St. Leon (5 miles away) and Indiana Project Hoosier SAFE-T Site: Lawrenceburg (4.7 miles away) with same results. If I travel a mile away from this cell tower, everything works as it should no matter which site I choose. I have attached my PRS-800 config file which is exactly the same as my TRX-1 file. To make sure I wasn't going crazy, I pulled out an old Radio Shack Pro 106 and I have the same problem with that radio also. I'm lost on how an old Pro-96 works like a champ and the rest are garbled. Sorry for the late reply and thanks for the suggestions.
tvengr
Well Known Member
I didn't see any problems with your file. This file will scan the Guilford, Lawrenceburg and St Leon sites. There are 3 systems with each using a different site. You will be able to determine which talkgroups are on each site by selecting scan lists. The Guilford site is on scan list 1, the Lawrenceburg site is on scan list 2, and the St Leon site is on scan list 3.
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wtp
Member
this might sound weird.
and i see you are a ham
so,
the antenna on a radio should be pointed up as the 'sides' of it pick signals up the best that way.
but if you rotate it 90 degrees and lay it flat, it becomes directional.
and the worst reception is the way it 'points'.
so try them on a lazy susan and rotate it slowly until you get the best reception.
at that point it should be pointed at the call tower.
good luck hunting.
and i see you are a ham
so,
the antenna on a radio should be pointed up as the 'sides' of it pick signals up the best that way.
but if you rotate it 90 degrees and lay it flat, it becomes directional.
and the worst reception is the way it 'points'.
so try them on a lazy susan and rotate it slowly until you get the best reception.
at that point it should be pointed at the call tower.
good luck hunting.
Thank you. I'll try it out later.
