[HCARC] Baluns, Ununs, Gamma Match, Stubs

[Kerry Sandstrom]

Gary,

The old rigs could match a wider range of impedances then compared to the 
new ones.  The reason the new ones can't match a wide range is because the 
manufacturers have designed them to be broadband /no tune.  Central 
Electronics sold a CE 100V and a 200V in the 50's that were tube rigs but 
broadband/no tune.   They also required a 50 Ohm load and didn't tolerate 
any mismatch.  Now why would you design rigs to require no tuning?  Do you 
think it is because there are no expensive and large variable capacitors and 
large coils wound on ceramic coil forms?  Now the coils are small and wound 
on toroids so they don't have to be spaced from the metal cabinet and the 
capacitors are small fixed values. You bet, radios are smaller and easier 
and cheaper to manufacture now because we don't have large variable 
capacitors and inductors in them.  Do you realize that old tube type radios 
operated at close to 80 % efficiency?  Now it isn't even specified and you 
can't even measure the input power to the final amplifier in a modern radio, 
but the efficiency is at best 50 %.  But the manufacturers have a nice 
profit margin, any body can "operate" the radio, and the FCC even cooperated 
by changing the power from input power to output power.

Impedance matching is a red herring, however.  Most of the baluns that 
provide an impedance transformation are not very well characterized.  If you 
aren't operating at the impedance levels that the broadband 
transformer/balun was designed for, the impedance ratio is unlikely to be 
the 4:1 that is advertised.  The balun  part is just balanced vs. unbalanced 
and I don't think most if not all rigs even care about that.  All these 
limit gimmicks have a grain of truth to them.  What one has to do is take a 
critical look at the conditions required for the grain of truth to be 
significant.  Most manufacturers will never tell you that.  Unfortunately, 
I don't think many of the manufacturers are technically astute enough to 
know.  So what we have is greedy technically unsophisticated manufacturers 
selling whatever they can make the largest profit on to an uncritical and 
equally technically unsophisticated customer.  To make matters worse, we 
have a national organization with a major interest in raising money by 
selling advertising to those manufacturers.  There is no honest broker 
anymore!

So what does one do?  Learn as much as you can about how things really work. 
Ask the guys you know how their stations are set up and why.  Look at every 
claim with a critical eye.  If it sounds to good to be true, it probably 
isn't true.  How many times have you heard that?  If you want to try 
something, try to find it second hand and cheap or try to find a friend who 
will let you try his.  If it seems to make a real difference, then go buy 
the fancy model if you have to have it.

The details for a/c controls are different , but they are really in the same 
boat.

By rthe way, the world isn't going to end on the 21st.  The Mayans have no 
credibility, they were wiped out centuries ago.

Kerry