Sudden Loss of Reception
- Thread starter emsflyer84
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| 155.640 | KRC763 | RM | 817 NAC | Conway PD | Police Operations | P25 | Law Dispatch |
So, a bit of history, I used to pick this up fine from my house. When I realized I wasn't getting it anymore (sometimes broken) I went and shortened my coax run and bought new cable and connectors thinking I had an issue with my feed line. No improvement. I thought maybe I had an antenna issue. Put a new antenna up, no improvement. I opened the squelch all the way on my scanner on that frequency and saw like 3-5 bars of signal, telling me it's picking up interference. I haven't tried on other frequencies because everything else I scan is strong enough that it's still coming through fine. This particular frequency is on the edge of my reception range, but again I was picking it up fine previously. Unfortunately I don't know exactly when this started happening so I don't know what might have changed at my house. We've bought some random electronics, who knows what it could be.... Pretty much everything I scan is in that public safety VHF range.
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Did you do any of the suggestions in the other thread?
Yes, I was about to start with that, just checking to see if there are any other ideas as well. I can start throwing breakers room by room, I just have to figure out what to do when I get to the room where the scanner is, etc. I suppose I'll connect a handheld direct to the antenna line when I do that...
Run the scanner off a battery then turn power off to the whole house. That will instantly tell you if it’s within your house and under your control without wasting time with individual breakers. If you find your house is making noise then go room by room shutting off breakers to narrow things down.
RFI-EMI-GUY
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- Dec 22, 2013
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Many if not most VHF scanners get wiped out from high power paging and/or NOAA VHF weather transmitters. A third problem is FM broadcast interference. The reason is that the receivers are rather broad band and all this other stuff saturates the "front end" of the receiver, the RF preamp, the mixer, sometimes first IF. You can get notch filters from PAR specific to your intereference. You can also get band stop filters from Mini Circuits. With one high pass filter and one low pass filter, you can create a window or band pass to block broadcast or other out of band. However with VHF paging and NOAA , you pretty much need to notch them out.
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MTS2000des
5B2_BEE00 Czar
Also a good idea to check the noise floor. VHF in particular, is full of hash and trash thanks to Chinaturd unintentional radiators. Back when the FCC cared, part 15 used to mean something. That being said, the idea of getting a baseline for what the noise floor is on that desired frequency with everything on, then turned off, should be a starting point.
Quick update. Shut all the breakers off in my house yesterday and ran a handheld scanner on batteries. No real improvement! Now I’m at a loss. Maybe there is outside interference that is being picked up by my roof antenna and not the small mobile antenna on my car? Can’t really figure it out. Next step will be to take the handheld up on the roof and plug directly into my roof antenna and rule out any antenna feed line issues.
Hey all, I’ve posted before about a loss in reception I’m experiencing at my house with my BCD996P2 connected to my Diamond X50 on my roof. Been experimenting for a while to try and track it down. I’ve ruled out interference from something in my house. I did a test where I opened the squelch all the way and saw 3-5 signal bars on the scanner when tuned to one frequency. In the static I could hear a digital noise in the static, like a pager or something. This all went away when I disconnected my antenna. I did some VHF scanning and found this on two frequencies.
I’m thinking this signal is strong enough to interfere with the distance frequencies I’m now having trouble getting. I’m in Wolfeboro, NH and can’t find anything local registered to these frequencies. I know some paging systems are very high power so not really sure how far out this could be coming from. Anywhere, that’s where I stand in my hunt for interference.
Next I’ll take my handheld up on the roof and see if I pick it up. If I do I’ll head back to the ground and drive around to see if I can pinpoint it. But I’m guessing I won’t pick this up with the handheld. We’ll see.
I’m thinking this signal is strong enough to interfere with the distance frequencies I’m now having trouble getting. I’m in Wolfeboro, NH and can’t find anything local registered to these frequencies. I know some paging systems are very high power so not really sure how far out this could be coming from. Anywhere, that’s where I stand in my hunt for interference.
Next I’ll take my handheld up on the roof and see if I pick it up. If I do I’ll head back to the ground and drive around to see if I can pinpoint it. But I’m guessing I won’t pick this up with the handheld. We’ll see.
Thanks for this. Coincidence that location 6 is Conway, NH and that’s also where the signal is that I’m trying to pick up and isn’t coming in?
This all for the input here. Is there such a thing as a notch filter ti trap specific frequencies?
tvengr
Well Known Member
I had to put a notch filter in the antenna line for our newsroom scanners which were being wiped out by a paging transmitter. Luckily, I had professional equipment for tuning the 2-stage filter. You can listen to the offending frequency on a scanner and tune the filter to minimize the signal.
Just for fun I sat in my car in the driveway with my handheld scanner and stubby antenna. Both these frequencies came in good. Just based on signal strength, it seems like 152.6000 is closer, or stronger anyway.
Not strong enough to effect reception. I think the only reason I’m being effected on my base station is because of the height / gain of the antenna so it’s really receiving the pager signals strong.
Might seem crazy but maybe I need to downgrade my roof antenna….
Not strong enough to effect reception. I think the only reason I’m being effected on my base station is because of the height / gain of the antenna so it’s really receiving the pager signals strong.
Might seem crazy but maybe I need to downgrade my roof antenna….
kayn1n32008
ØÆSØ Say it, say 'ENCRYPTION'
Yup. The drawback of barn door(wide band) receivers. Zero selectivity, and susceptible to front end overload.
Hey all, been fighting with a couple very strong pager sites that seem to be overloading my BCD996P2 and wiping out some of the more distant frequencies I used to get with no problem. One or both pager transmitters must be new. Anyway, I’ve changed out my roof antenna for one with less gain, still having issues. Would this be a situation where I could try the attenuator in the scanner? I see online that you can turn on global attenuation so it’s already on, or turn it on by specific site, etc. But I can’t seem to figure out how to do that. I can turr r n on the global, but if I manually tune to one of the pager frequencies, is there a way to turn on att for just that frequency if it’s not a frequency that’s stored in the scanner? Do I have to store the frequency first to be able to turn on the att? Can’t find any info on this in the manual. Thanks!
wtp
Member
you would have to store it to attenuate it.
and you probably don't want it stored anyway.
do you really NEED an outside antenna ?
and you probably don't want it stored anyway.
do you really NEED an outside antenna ?
Scannermaster used to sell filters for paging and you ordered and tuned the one you needed.
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