[CQ-Contest] Filters

John Laney k4bai at worldnet.att.net
Mon Jun 12 10:37:35 EDT 2006


While the discussion about filters is fresh in memory, let me add a word 
of caution on using Dunestar filters on 75 meters SSB.  Hal, N4GG, is an 
expert on this subject and advised me not to use the stock Dunestar 80 
meter filter above 3890.  He said it would fry above that frequency 
approximately.  Since I have a General class license, that would tend to 
deny to me use of most of the General class SSB band and could be a big 
factor in ARRL SSB SS and a few other contests.  I talked to N7EA at 
Dunestar about it and he advised that it wasn't safe to use their 
80-meter filters above 3850.  That would leave out the entire General 
class band.  However, he specially altered one of their filters for me 
for use on the high end of 75 meter SSB.  I ordered that in addition to 
two six-packs, so I can switch to it as an alternate for 75 M SSB.

Incidentally, I also ordered Dunestar single band filters for the three 
WARC bands to use on contest and DXpedition trips.  I was very impressed 
with Dunestar's service and customer service.  They very quickly 
repaired a couple of their filters that I had burned out components in. 
  Another word to the wise, DO NOT use your ATU to tune an antenna while 
the filter is in the line.  Most of them will put out too much RF at too 
high a SWR and the components will blow.  If you are using an external 
antenna tuner also, do your antenna tuning with the filter out of the 
line and be sure the ATU is turned off when you put the filter in the line.

73,


John, K4BAI.


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