Band pass filter isn't working?

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ScanMaine

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SO I got one of the band fliters and its connected to my 4 mutliy coupler direct from my antenna and the only time i pick up tons of pagers and loud bleed over nosie is when I do a manuel search from 150 to 174 even with the filter.. Any ony Ideas. Still picks of tones of noise and Im not sure what to do .. I think I wasted 50 bucks
 

ecps92

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You still have not take the time to identify the offending Frequency
Just moved way up to our new house on a huge hill - Page 2

SO I got one of the band fliters and its connected to my 4 mutliy coupler direct from my antenna and the only time i pick up tons of pagers and loud bleed over nosie is when I do a manuel search from 150 to 174 even with the filter.. Any ony Ideas. Still picks of tones of noise and Im not sure what to do .. I think I wasted 50 bucks
 

ScanMaine

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A friend on a another message board hit the light and Now I know how it works and I am gonna send her back.. Thanks all
 

teufler

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you can get filters that block certain portions, like the pager frequencies. PAR has those. Several hams have them nstalled to block pagers out.
 

ScanMaine

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Well I have not the first idea where to look. Lol. I have no ham shops around me

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UPMan

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If the signal you want to receive is also within the band of the filter, the signals you want to receive will also be cut in strength, relative to the cut of the unwanted signals. Net effect is that everything in the band would be harder to receive and offending signals will still be receivable. You could have turned on Attenuation in the scanner and gotten about the same effect.
 

ScanMaine

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Right but if I'm searching and the ATT button on its not gonna search for new freqs unless close bye right

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KevinC

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any recommendations or ideas.. im looking on some sites right now
I know you weren't asking me, but you first have to identify the source(s).

One problem may be your multi-coupler. Is it the kind used for cable TV? If so the 4-Way ones usually have a lot of gain and that may be causing or compounding your problem. Have you tried not using the multi-coupler to see if you still have the issue?
 

ecps92

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(One Example) He is complaining of Paging interference (Intermod) on atleast one Frequency 154.xxxx which is the Primary FD channel for his area

He also lives within a stones throw (electronically) of a nice Mountain that sprouted (Long Long ago - not new) many towers (likely the source)

He needs to sit back and (as told on the SNE forum) identify what Freq are causing the interference FIRST. Not just what freq is being interfered with. He was told to lock on the Freq and take a second scanner and find the offending Freq by using search when it occurs. Yes it can be a LONG process, but is needed to determine the FIX, and then Repeat the procedure until all Possible sources are identified.

Note he has conflicting posts as to the Freqs. He claims when in Search of 150-160 he keeps getting noise. Well, Yea. That band is filled with Paging, Data, Telem, and now DMR, however he does have 1-5 Freqs that will require WEEKS of his spending time SEEKing out the offending source.


I know you weren't asking me, but you first have to identify the source(s).

One problem may be your multi-coupler. Is it the kind used for cable TV? If so the 4-Way ones usually have a lot of gain and that may be causing or compounding your problem. Have you tried not using the multi-coupler to see if you still have the issue?
 

ScanMaine

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I know you weren't asking me, but you first have to identify the source(s).

One problem may be your multi-coupler. Is it the kind used for cable TV? If so the 4-Way ones usually have a lot of gain and that may be causing or compounding your problem. Have you tried not using the multi-coupler to see if you still have the issue?

Yes it still does it!!!
 

prcguy

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In my opinion, buying a random filter to cure the problem described is like buying random parts at the auto parts store to fix a noise under the hood. As others have mentioned the problem may be high power paging transmitters in the 152-153MHz range and the filter purchased will have no effect in that case.

Just like diagnosing a car or anything else you need the proper tools and unfortunately the tool you would use for this problem is a spectrum analyzer. And I don't mean a USB dongle receiver with spectrum analyzer software that would get overloaded like your scanner, I mean an actual spectrum analyzer. A few minutes of monitoring your system with a spectrum analyzer will tell you what the offending frequency is and if your active splitter is being overloaded and creating IMD. Any other method would be very time consuming and probably inaccurate in finding the problem.

You might look for places that ham radio people gather for meetings and see if you can find a sympathetic hamster that owns a spectrum analyzer that could drop by your house and take a look.
prcguy
 

wtp

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antenna

take off the antenna and do a scan and see if it still happens.
if it is really strong you might have to turn up the squelch and maybe turn the attenuation on.
don't forget it could be from the 930 range of pagers and getting in the radio.
 

ScanMaine

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In my opinion, buying a random filter to cure the problem described is like buying random parts at the auto parts store to fix a noise under the hood. As others have mentioned the problem may be high power paging transmitters in the 152-153MHz range and the filter purchased will have no effect in that case.

Just like diagnosing a car or anything else you need the proper tools and unfortunately the tool you would use for this problem is a spectrum analyzer. And I don't mean a USB dongle receiver with spectrum analyzer software that would get overloaded like your scanner, I mean an actual spectrum analyzer. A few minutes of monitoring your system with a spectrum analyzer will tell you what the offending frequency is and if your active splitter is being overloaded and creating IMD. Any other method would be very time consuming and probably inaccurate in finding the problem.

You might look for places that ham radio people gather for meetings and see if you can find a sympathetic hamster that owns a spectrum analyzer that could drop by your house and take a look.
prcguy

This is what Im gonna do.. Thanks
 

mancow

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In my opinion, buying a random filter to cure the problem described is like buying random parts at the auto parts store to fix a noise under the hood. As others have mentioned the problem may be high power paging transmitters in the 152-153MHz range and the filter purchased will have no effect in that case.

Just like diagnosing a car or anything else you need the proper tools and unfortunately the tool you would use for this problem is a spectrum analyzer. And I don't mean a USB dongle receiver with spectrum analyzer software that would get overloaded like your scanner, I mean an actual spectrum analyzer. A few minutes of monitoring your system with a spectrum analyzer will tell you what the offending frequency is and if your active splitter is being overloaded and creating IMD. Any other method would be very time consuming and probably inaccurate in finding the problem.

You might look for places that ham radio people gather for meetings and see if you can find a sympathetic hamster that owns a spectrum analyzer that could drop by your house and take a look.
prcguy
A cheap RTL dongle would probably work well too.
 
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