Multipath and noise on Eastern KY FM's

[kayman]

You hear noise and multipath on a lot of stations in the mountain area and I know that it's impossible to filter it all out. However, do any of you know any processing hints or any other tips to minimize it. It's especially rough on smaller Class A stations.

 

[KR4BD]

It can be "minimized" by transmitting in MONO. That's why WSGS-101.1 in Hazard killed their STEREO years ago. The MONO signal is much less "swishy" in mountainous environments.

 

[radiorob2.0]

KR4BD mentions the only full proof solution. WSGS has tried stereo only to kill the pilot due to multipath issues. Antenna height helps but those hollers are still a challenge. Something that might help is avoiding any stereo enhancement as too much increases multipath.

Slightly off topic, WIFX Jenkins promotes on their website they are using IBOC. I wonder how that works in those hollers?

 

[greg.hahn]

It helps to keep the AM noise level low on your transmitter. For solid state transmitters that's usually not much of an issue.

But for tube type transmitters it can be. After tuning the transmitter the usual way you need to tweak each control (tune and load) slightly to minimize AM noise. (Efficiency may suffer a little.)

You need an AM noise monitor to do this. And it's far easier to do it while transmitting a test tone than it is with a Beatles record. So this is best done late at night, though it doesn't take very long to do.

This will make some improvement, but the mountains are the big problem and those aren't going away.