Reducing interference from nearby transmitter

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ch40n1k

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I'm not really sure which forum to put this in ... so I'll start here.

I live about 2 miles from a local EDACS transmitter site. (http://www.radioreference.com/apps/db/?action=siteInfo&siteId=10237)

According to the license, the site puts out 48 Watts and uses these frequencies:
851.2500, 851.7125, 851.2250, 852.6875, 852.9125, 853.3000, 853.5375 and 853.7500

I am getting walked all over by this site when tuning the control channels of several local P25 sites. One site in particular uses a frequency of 853.31250. I know the nearby tower to be the offender as I can hear their traffic on the P25 control channel. (Albeit noisily)

My question is, is there anyway to reduce the amount of interference I'm getting from the nearby EDACS transmitter? When the interference occurs, I completely lose my link to the P25 site.

I currently have a Log Periodic antenna that is pointed away from the offending transmitter and is pointed towards the P25 site.
 
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zz0468

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Feb 6, 2007
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Looks like you're trying to listen to a system only 12.5 KHz away from the offending EDACS site. Can we presume the site you WANT to listen to is further away?

About the only thing you can try is a directional antenna pointed in whatever direction gives you the LEAST signal from the offending transmitter. There's no RF filter made that will get rid of something 12.5 KHz away.
 

ch40n1k

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Sep 29, 2006
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Location
Lakewood, Colorado
Looks like you're trying to listen to a system only 12.5 KHz away from the offending EDACS site. Can we presume the site you WANT to listen to is further away?

About the only thing you can try is a directional antenna pointed in whatever direction gives you the LEAST signal from the offending transmitter. There's no RF filter made that will get rid of something 12.5 KHz away.
Yes, much farther away. 70 Miles to be exact. I'm frustrated because with my setup, I can easily listen to systems that are far away, but I'm constantly experiencing interference from the close site. I know that the ultimate solution is to MOVE, ;) but that's not an option at this time.
 

Zack08

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Get a yagi with as many elements as possible, and it *should* block the interference.


It may be expensive to get a band reject filter with a sharp enough cutoff so as not to disturb the signals that are 12.5 KHz away.


There is always a plan d.... It involves a pair of bolt cutters and the coax at the offending site. JK, this is NOT an option :cool:
 
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zz0468

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It may be expensive to get a band reject filter with a sharp enough cutoff so as not to disturb the signals that are 12.5 KHz away.
You CAN'T get a band reject 800 MHz filter that will reject a signal 12.5 KHz away at any price.

To the OP - Your best bet, as previously suggested, is a yagi, but the effectiveness is going to be doubtful. The interfering site is only 2 miles away, so that's going to be hard to reject. Even worse, the system you want to hear is 70 miles away. That's an awful long haul at 800 MHz, and probably well outside the intended service area. There simply may be nothing you can do to help THAT particular situation.
 
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