In a message dated 11.12.99 07:18:50 Pacific Standard Time, w9ol@dataflo.net
writes:
My exciter is picky about the length of coax between it and my amp.
I had to add coax to allow the exciter to match on 12 meters.
But in doing that I lost the ability to match on 80 meters.
The tuner in the MP just doesn't seem to like the length.
Is there a 'magic' length of coax that will be good for all the HF bands?
It's a pain to switch out lengths when switching bands.
Thanks
"to infinity...and BEYOND"
>>
There is a "Magic Coax Length" of 91' 2" of .66 coax that is a 1/2 WL or
multiple with the least error on all bands 80-10M. It is a 1/2 WL or
multiple at 3.562, 7.125, 10.688, 14.25, 17.812, 21.375, 24.938, 28.5 MHz and
will grid dip very very close. The ham bands are not on harmonic multiples.
This will repeat the Z that is sees with the least change at 1 dB loss on
10M. I don't think this will cure the problem.
The problem is shared grid circuits in the linear. When that is done by
a mfg. it's on a par with tying the DE's of multiband quads together. Your
amplifier is not able to perform properly and a quad is not able to perform
properly. Trying to save a few bucks, the amplifier is degraded as well as a
quad. But they made the sale. They rely on customers who buy on price
mainly. These design practices are detrimental to continued business and
rely on the ignorance of the customer not to notice or realize the
consequences as you have. I have heard there is a special place in hell for
these mfgs.
Certain equipment or antenna designs were slow to catch on due to design
deficiencies. Quads are an example. There was an article in DX Mag on DX
Antennas. He didn't describe the Quad--the best DX Stateside and DX Antenna
there is. I asked him why? He said "they are hard to keep up in the NE in
the winter." So the article was rendered useless by this omission and their
poor designs of the day. Properly built quads are available today that burn
a hole in the ionosphere (well almost) and stay up. Take a look at Antenna
Marts Quads.
In the 30's & 40's, Zenith was the only mfg. that made a good radio, have
become collector items and they still work. It had all the advanced features
also. All the rest of the junk seldom worked right and never as good as the
Zenith.
Would you believe the Zenith designer went to Manufacturers Heaven and
all the rest went to the Cheap Designers Hell. This is an absolutely true
story. I just made it up. They will soon have company. Zenith was behind
Wes Shaums first SSB rig.
The best buys I ever made were for Collins equipment. It worked great, I
got what I paid for it or more if I sold it and it had the only stable VFO's,
I still have a KW-1 and a 75A1 which were given to me. Both work just like
new today. Collins also showed a no-loss Balun in their manuals that you
could make. No one has since. The ones you buy now all have loss and other
limitations as many Posts in TT have shown. Useful ideas like this help
assure their rigs will work better. That desire seems to end for many mfgs.
when they sell their stuff. I have suggested advanced versions of this
customer relation help for their customers to the manufacturers of today and
they can't see the value of it. They can't seem to realize their business
future and the performance of their equipment are at the total mercy of the
ignorance of their customers. They have help lines but there are other
inexpensive areas they could make large signal improving contributions to
their customers.
There is a book called How To Make Life Time Customers by Carl Sewell.
He has a Cadalac and Lexus Agency in Dallas. He started a business attitude
and sales techniques that resulted in his business going from $50M to $250M a
year--totally unprecedented. The first Ham supplier that uses his techniques
will take over Ham Radio. There will be raves on TT instead of requests for
help for deficient equipment. Get the book, follow the guide lines and THEY
WILL COME.
k7gco.
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