"Nordic Breeds WA4VZQ" wrote in message
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"Edmund H. Ramm" wrote in message
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In "Nordic Breeds WA4VZQ"
writes:

[...]
Neutralization becomes more of an issue the higher you go in frequency.
Most simple entry level transmitters using a single 6146 in the 1950's
and 1960's were not neutralized as the 6146 was only used "straight
through" on 80 or 40 meters. On higher bands it was used as a frequency
multiplier/power stage. The Eico 730, the Elmac AF67, the Heath DX-20,
DX-35, and DX-40, and the Knight T60 used no neutralization.

Nor does the E.F. Johnson Viking Ranger. But it's CW-only variant,
named "Navigator" IIRC, does.

The Eico 723, the Heath DX-60 and the Drake 2NT. however, did.

The Drake 2-NT has a 6HF5 line output valve in the PA stage.

Several of the transmitters I named also used TV sweep tubes. In general,
all of the higher power TV sweep tubes have a higher perveance than does a
6146. In the case of the 6HF5, the transconductance (plate amps/grid
volts) is 1.6 times that of the 6146. My point was that with reasonable
layout, neutralization would not be required. All of these transmitters
multiplied in the final above 40 meters. If the plate is tuned to a
harmonic while the grid is tuned to the fundamental, there is far less
need to neutralize.

73, Barry WA4VZQ

You are surely correct there, Barry. I guess my homebuilt rigs never
multiplied in the final stage. I did try multiplying with a 211 (VT-4C)
triode in the final (read BC-375), but the power output instrument (75 watt
light bulb) was not impressed. (it did, of course have elegant Hammarland
neutralizing condensers in the plug-in tuning units)

Old Chief Lynn, W7LTQ