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What channel is the FM station on that is interfering with you, how much power is it running, and how close is it? Is the audio coming through it distorted or understandable? What repeater are you using? Does the interference come through only when the transmitter is keyed? FM stations will generate odd harmonics if their final is tube and even if it is transistor. So the 4th harmonic has been known to land on the Local Oscillator frequency of the receiver, like 442.075 - 21.4 / 4 = 101.418, which could get interfernce from 101.3 or 101.5, Even so the harmonics a station generates have to be at least 60db below the carrier in order to be legal. Another thing that is more common to happen is if 2 FM stations are 5MHz apart, that will mix when your transmitter is keyed and put garbage 5 MHz up and down from your TX carrier. About the only thing you can do in that case is switch to an odd-ball split like 6 or 3MHz. This was the case with a battery chargers 600kHz switch mode supply in close proximity to a 2M repeater. The garbage only apeared when the TX was keyed + and - 600kHz from the TX frequency, so it was a perfect jamming source. A dead giveaway is you can get an audio feedback squeal. On 3/15/06, Jay Urish <[EMAIL PROTECTED]> wrote: > Actually that is 442.075 > > > dallasreact112 wrote: > > Every once in a while we get FM broadcast interference on our DCR > > 442.425 uhf repeater here in Dallas Texas. It apparently bothers other > > 440 ham repeaters in the area as well. Seeing how the broadcast FM is > > 250mhz+ away from our input, and a DCI bandpass filter is inline with > > our rx, could this be the famous "rusty bolt" as a mixer intermod > > problem? Any input is appreciated. > > > > Thanks > > > > Bernie Parker > > > > K5BP > > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > -- > Jay Urish Network Administrator > Unixwolf Enterprises LLC. > http://www.unixwolf.net > 972.691.0125 972.965.6229 > > > > > > Yahoo! Groups Links > > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
