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eHam Forums => Misc => Topic started by: ND9B on February 25, 2013, 09:12:38 PM



Title: AM Broadcast Filter Needed
Post by: ND9B on February 25, 2013, 09:12:38 PM
I live close to an AM station on 1350 KHz. My Kenwood TS-570 can handle it WITH the attenuator turned on, but my old Kenwood R-599 is severely overloaded even with the RF gain turned down.  I think a notch filter tuned to 1350 KHz would be just what I need. Are there any commercially available units that would fit the bill?

Bobby Dipole ND9B



Title: RE: AM Broadcast Filter Needed
Post by: TANAKASAN on February 26, 2013, 04:34:25 AM
Grab a copy of July/August 2008 QEX and you'll find an article by Wes Hayward W7ZOI on building crystal notch filters. 1.35 MHz crystals will have to be ordered but with one of these filters plus some decent screened cables you should be sorted.

Tanakasan


Title: RE: AM Broadcast Filter Needed
Post by: KE3WD on February 26, 2013, 05:54:00 AM
http://dlwc.com/ (http://dlwc.com/)

http://www.universal-radio.com/catalog/filters/4426.html (http://www.universal-radio.com/catalog/filters/4426.html)

73


Title: RE: AM Broadcast Filter Needed
Post by: AD5X on February 26, 2013, 02:02:07 PM
I don't know how much help your receiver needs, but here are a couple of choices that work very well:

www.arraysolutions.com/Products/BCB%20RF%20Filters.htm

Phil - AD5X


Title: RE: AM Broadcast Filter Needed
Post by: G3RZP on February 27, 2013, 03:09:44 AM
With just one BC station, a 365 pF variable cap from an old BC radio, and coil will make a fine wavetrap: just need a small metal box to put it in and a couple of connectors. Depending how the radio is configured, you may not even need any switching on transmit.


Title: RE: AM Broadcast Filter Needed
Post by: ND9B on March 13, 2013, 06:43:41 PM
Problem solved :) A crude homemade notch filter was all my Kenwood R599 receiver needed. For my transceiver I bought a Morgan Manufacturing model M-402X BCB filter. You can transmit through this filter without any TX/RX switching. Works great.

Bobby Dipole ND9B