Interference issues

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SA_tx_88116

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I think I’m getting interference while listening to my radio especially on VHF frequencies the thing I could be listening to can be very far away but the radio still says I have good signal. I live right by a 4G cell tower and some other tower not to far away with orange and white panels sticking out of it. Is there anything I can do to help?IMG_1096.jpeg
 

mmckenna

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Unlikely a cell tower is upsetting your VHF reception.
A photo of "orange and white panels sticking out " would be useful.

Would help to have some more details about the issue:
- Is this a repeated system you are listening to?
- Is there a pattern to the weak signal? Certain users? Certain locations?

Details are super helpful when asking others to remotely diagnose this sort of issues. Without the details, like frequencies, agencies, etc. anyone who answers will be just making a guess based of very limited information.
 

Ubbe

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I once where on a roof with a basestation that had extreamly good bandpass filters for its 420MHz receiver and when having its antenna 5 meters from a cellular antenna and its microwave link my coverage test showed to be about 1/10 of the predicted one. I moved my antenna 10 meters from the cellular site and sensitivity where fully restored. There was something in that cellular installation that emitted RF in the 400MHz band.

At another time a whole sites VHF systems suddenly got its coverage reduced to 1/4 and it turned out to be a new digital DAB 220MHz Italien made transmitter 500 meters away that spew out RFI over the whole VHF band.

What scanner model is it and what does the signal strength show if you tune to an unused frequency and open squelch? Test both VHF and UHF. You do not have any other scanner to compare to?

/Ubbe
 

SA_tx_88116

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I once where on a roof with a basestation that had extreamly good bandpass filters for its 420MHz receiver and when having its antenna 5 meters from a cellular antenna and its microwave link my coverage test showed to be about 1/10 of the predicted one. I moved my antenna 10 meters from the cellular site and sensitivity where fully restored. There was something in that cellular installation that emitted RF in the 400MHz band.

At another time a whole sites VHF systems suddenly got its coverage reduced to 1/4 and it turned out to be a new digital DAB 220MHz Italien made transmitter 500 meters away that spew out RFI over the whole VHF band.

What scanner model is it and what does the signal strength show if you tune to an unused frequency and open squelch? Test both VHF and UHF. You do not have any other scanner to compare to?

/Ubbe
It’s a pro 197 with a stock antenna and if a program a vhf frequency not used in my area I always have close to full signal
 

SA_tx_88116

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You're probably suffering from overload from a FM broadcast station as the GRE-based scanners are very prone to this. A FM notch filter would probably help you considerably.
So you mentioned a fm broadcast station and 0.72 miles away is what looks like some radio tower any idea?IMG_1114.jpeg
 

SA_tx_88116

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I Believe the interference May be caused by my local school districts antennas that they use for busses although those are in NFM
 

n0xvz

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I Believe the interference May be caused by my local school districts antennas that they use for busses although those are in NFM
Just curious, why do you think it's another transmitter in your area? Have you already ruled out any RFI from other sources in your dwelling?
 

KevinC

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Full signal bars all the time on VHF with a GRE-based scanner is a classic sign of overload from a FM broadcast station.

A good test is pick a NWR station and switch the attenuator on and off, I'd bet it sounds better with the attenuator on.
 

SA_tx_88116

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Full signal bars all the time on VHF with a GRE-based scanner is a classic sign of overload from a FM broadcast station.

A good test is pick a NWR station and switch the attenuator on and off, I'd bet it sounds better with the attenuator on.
NWR?
 

SA_tx_88116

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Just curious, why do you think it's another transmitter in your area? Have you already ruled out any RFI from other sources in your dwelling?
I think it’s another transmitter because even when everything in my house is turned off I still get interference
 
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