Topband: Broadcast interfence on a MFJ analyzer

[George (K8GG) & Marijke Guerin]

JIM, W0NFL wrote:

 Sent: Thursday, January 24, 2008 10:39 PM
Subject: Topband: Broadcast interfence on a MFJ analyzer


I was having a awful time trying to work on my 160 vertical  using a MFJ 259
analyzer due to Broadcast interference from a local BC  station.  I had to
wait till the station went to night time low power then  it was getting dark 
and
made it difficult to see what I was doing.  Later I  left the switch on and
ran the battery's down.  With fresh battery's I went  out and had no problem
with tuning the antenna with the MFJ in day  time.  I would think one should
check his battery's if he has problems  with BC interference. I don't know 
for
sure if a low battery  was my problem but if I have problems again I will 
check
my battery's in  the MFJ.  Jim WØNFL


Jim, et. al.,

Sometimes if the BC station is nearby it is impossible to get the AM signal 
out of the antenna analyzer.  For checking receive pennants and beverages I 
have used to methods that track well:

1.    Put only about 2 watts out into the RX antenna from a transceiver with 
a decent internal SWR meter.
I was able to sweep both 160 & 80 meters and get good results.  I tried the 
same thing with a Hi-Pass filter in series and got comparable results.

2.    Put a high-pass filter in series with the analizer.  I did find it 
worked almost equally well as the 2 watts to the RX antenna.  Also it still 
gave me some meaningful reactance readings I could not read with just 2 
watts down the line.  It may take some phase shifting with a smith chart to 
correct them, but the readings helped me.

YMMV        Good luck & 73

George    K8GG