On Sun, 4 Apr 1999 18:38:42 EDT, w7ntf@... wrote:
took about 10 minutes and all I had to carry with me was the MFJ SWR analyzer
and a pair of pliars to loosen and tighten the set nuts on the plungers...
I just finished installing the 6 meter machine at a temporary
site, and tried to use the MFJ to tune the antenna. Boy, was
I surprised to find that the MFJ was "going nuts"! At times
the SWR meter was going from 1.2, all the way up to infinity.
The only thing I could think of is that this site has 3, medium
to high power FM and TV transmitters (2 FM and one TV), all putting
out about 100K watts ERP, PLUS about 70 other commercial transmitters,
and they were overloading the MFJ. I took out a Daiwa HF to 6 SWR
meter, and it showed a consistent 1.2.
Lesson(?): Always have a backup, hi!
Another topic for discussion might be the difference between tuning for
minumim SWR and tuning for a peak & notch or bandpass and bandreject with a
spectrum analyzer...... I know that the reflected power is quite high on my
Wacom WP-639 BP/BR duplexer when tuned with a spectrum analyzer, as opposed
to the SWR method. Can anyone shed some light on this?
This was the main problem with my 4032 DB duplexer. I could get
real good isolation, but lousy SWR or great SWR and lousy isolation.
Thanks to everyone on this list, I started playing with stub
lengths and harness lengths and now, I got the isolation to about
80 db, and SWR is LESS than 1.2, on both the RX and TX!
Again, I really appreciate everyones help getting my 6 meter
machine working. With a quarter wave ground plane about 30
feet off the ground, and 1320 feet ASL, I had a check in from
75 miles away! The machine is throttled back to about 45 watts,
and I'm really excited about it's performance. Can wait to
get it up another 150 feet to it's final resting place.
Hope everyone had a Happy Easter!
Tedd Doda CET CEO
Lazer Audio and Electronics
packet ve3tjd@va3sed
e-mail lazer@...
