Topband: BCI filter for MFJ analyzer

[Herbert Schoenbohm]

Guy Olinger K2AV wrote:
> A BC notch filter that works on 160 has two issues, first that it has to
> notch out an interfering station, and second, that at each 160 frequency to
> be measured, the residual reactance of the notch must be tuned out, one
> frequency at a time.  The MFJ design will do this, but if one is being
> bothered by more than one station, a single notch will not work.
>
>   I guess I am lucky.  I have a 5kw day and 1 KW night about 3.5 miles from me.  To verify the 160 meter measurements on the tower I just dial up the transmitter remote contol and reduce the power for a few  minutes.(Its doing maintenence anyway.)  I also have to reduce power of several local FM stations when cell companys and internet providers climb towers to do replacements.  So know the station engineer might be worth more than trying to build a filter.  He might also lend you his Delta OIB in line impedance bridge.One thing I found out about my MFJ is that it makes a great weak signal source for testing antennas. I use it for F/B checks on two wire Beverages rather than drilling down to the BC band.

>  It drifts a bit but you get the drift. right?
>   

Herb Schoenbohm, KV4FZ