[ARC5] QST articles.

[k0ng at inebraska.com]

Thank you Dennis !!! In my opinion, working a resonant antenna into the fully
meshed link does not affect the harmonic content to any extent. The  
transmitter
will not load very well but the main harmonic suppression comes from the
parallel tuned tank circuit, much like the old Heathkit AT-1 except that the
AT-1 has more turns so loads better. In fact, the ARC-5 probably has better
suppression than the AT-1 in any case due to the circuit Q being higher.

Any suppression of harmonics in an actual aircraft merely comes about from the
formation of an L network formed by the roller coil and the capacity of the
antenna to the fuselage. Reactance is almost nulled out by the L net itself.
In this regard, the L net resembles the Collins 180 tuner.

Again, in my opinion, the Johnson Matchbox does help a lot in the suppression
area. From my experience, the T net is the worst one as harmonics tend  
to just pass throughthe input and output caps straight to the antenna.

To prove any value of the above, just assume 1000-2000 Ohms plate source and
use on-line computers to show the resonance plot. If you really want to know
and have no spectrum analyzer, terminate the ARC-5 into a 50 Ohm attenuator
and measure the harmonics with any ham receiver with general coverage.
All this can be fun and educational too.

Sorry for the bandwidth and no intent to argue, just my opinion.

73, Charlie,  K0NG.