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filters fm

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home121

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Has anyone tried useing 2 of those 88 - 108 fm filters in line with 1 psr 800, and if so how'd it work out ?Thank's in advance...
 

hertzian

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If you are thinking of just stacking two together back to back, you won't get double the notch depth. You would have to separate them by at least a 1/4 wave of coax, taking the velocity factor into account.

PAR Electronics has a good faq about this.

Note that the inexpensive Radio Shack FM traps do not have much of a notch below 100mhz, so rewinding the input coil would help.

The PAR Electronics filters have served me well. Instead of trying to stack two questionable cheap filters, why not just use one quality PAR FM filter?
 

nmelfi

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If you are thinking of just stacking two together back to back, you won't get double the notch depth. You would have to separate them by at least a 1/4 wave of coax, taking the velocity factor into account.

PAR Electronics has a good faq about this.

Note that the inexpensive Radio Shack FM traps do not have much of a notch below 100mhz, so rewinding the input coil would help.

The PAR Electronics filters have served me well. Instead of trying to stack two questionable cheap filters, why not just use one quality PAR FM filter?
I will second that idea.I have a ST2 antenna 30 feet up with a BCT15 and a Pro 106. From 118 up to 350MHZ the 106 worked better turned off and the BCT15 had interference from the FM radio band and the main culprit was my Noaa tower 4 miles from me. I could listen to NOAA on any weak signal up to 350MHZ. I called PAR and got a fm trap and a custom made 162.225 trap for NOAA and what a difference. I can here all communications from GSP including ground from a distance of about 30 miles. I can here Atlanta tower at times and once in a great while even Charolete's tower, that is with me in upstate SC.My airband is alive!The 106 is not as good but a huge improvement. And no I don't work for PAR.
 

home121

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Par it is

If you are thinking of just stacking two together back to back, you won't get double the notch depth. You would have to separate them by at least a 1/4 wave of coax, taking the velocity factor into account.

PAR Electronics has a good faq about this.

Note that the inexpensive Radio Shack FM traps do not have much of a notch below 100mhz, so rewinding the input coil would help.

The PAR Electronics filters have served me well. Instead of trying to stack two questionable cheap filters, why not just use one quality PAR FM filter?
That makes since i'm going to order the par filter, not that the MCM one is bad it works very good. But i'm curious to see what kind of improvement it brings. Thank's
 
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