Interference issues

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videobruce

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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.
You are the 1st time I have ever heard/read anyone else mention this. I've had a 2004 for probably almost 30 years.
The 'FM' broadcast problem affected the middle of the VHF high band specifically the railroad allocations (160-161.5) to a point it basically drops the signal levels substantially to a point you either loose reception or it's very weak even from strong signals. A simple 'FM trap solves the problem for me. This didn't seem to affect any other part of the VHF high band..
 

Ubbe

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I have a Pro2006 and it's unaffected by any broadcast or other strong transmitters, like a professional 2-way radio, when practically all other scanners loose sensitivity and needs a FM trap filter or other filters. It is the sum of all signals that matter so if getting rid of one of them could help to not make them reach the scanners overload level. I guess Pro2004 isn't of the same quality as a Pro2006.

The Pro2006 isn't as sensitive as most other scanners, at 0,5uV when others are at 0,25uV, so it depends of the interference level from the antenna which scanner that will work best. No interference and most other scanners receive better but close to a high power transmit tower and the Pro2006 will be superior in reception.

/Ubbe
 

videobruce

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I have both a 2004 & a 2006 and both need FM traps. I have two FM stations 1 mile away 180 degrees away from one another. Between the two, I don't really see/hear much difference as far as reception thou I've never did a side by side. ;)
 

G7RUX

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Try an attenuator or two to see if the problem reduces…strong signal intermods tend to be third order effects so reducing the incoming by 10dB say should reduce such an effect by much more than 10dB.
 

videobruce

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Those 2004's & 2006's have a built-in switchable attenuator that I have tried. Yes, it helps but at too high a cost to weaker desired signals making it a non starter.
When I first got this activity on the UHF band was no way near the extent it is now. That and the opening up of the lower 420 & up portion made matters much worse. The saturation of these new 'digital' systems has done a number on UHF. I have added a tunable trap in that range that has helped.
The VHF Hi band doesn't have the problem back in the 80's or so of 'Pagers' which blasted that band. They are gone, that problem isn't anymore.
 

Ubbe

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I have two FM stations 1 mile away 180 degrees away from one another.
That close to a couple of kW transmitters are a real issue for both scanner and any amplifiers and multicouplers and needs FM trap filters, probably the ones that do 60dB and takes away some of the VHF AIR band.

/Ubbe
 
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