modulation of low power rigs like DX-60

[Brian Carling]

On 15 Nov 97 at 7:38, Joel wrote:


> The popular low-power phone/cw rigs of DX-60 / Knight T-60 (etc.) vinage
> were AFAIK not plate-modulated.  I was wondering -- what was/is the
> advantage to the modulation methods used in rigs of that genre, opposed to
> plate modulation??

1) They are cheaper... no expensive/large/heavy mod transformer.
2) Purported to sounds just as good (doubt!)
3) Easier to lift rig into trunk at hamfest.

> Was there some preferred aspect to the screen modulation (or whatever it
> was)...?  Is it not as "good" as plate modulation, and if so, why not?

I think good quality 100% plate-modulated AM is hard to beat for
sound quality. However, the intelligibility on these screen-modulated
and clamp-modulated rigs may be just as good in marginal conditions.
Say you have a guy on the other end who is coming in RS 4-7 with you.
Can you REALLY tell whether or not he is using plate modulation?
Perhaps not! Can you copy him through the QRM and mush on 40m?
Then it doesn't matter!

>Was
> the modulator-circuit more or less just thrown into a basically cw-novice
> transmitter, to allow for merely adequate voice capability (for novices
> eventually upgrading to general class)?

In some cases, yes.  There are some good write-ups about this in ARRL
Handbooks, and you can pick one up at a hamfest for $5-8 and it makes
for some great reading on such topics!

Perhaps some of the other chaps on here can refer you to some good
magazine articles too.

See you on good old AM soon!!!!

Bry, AF4K

****************************************************
*** 73 from Radio AF4K/G3XLQ Gaithersburg, MD USA  *
**  E-mail to:  bry at mnsinc.com                     *
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**  http://www.mnsinc.com/bry/                     *
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AM International #1024, TENTEN #13582. GRID FM19. Using a SWAN 250 on 6m,
Other rigs: Valiant, DX-60/HG-10, FT-840, TM-261, Ameco TX-62, Gonset Communicator III
HTX-202...TEN-TEN #13582, DXCC #17,763 Bicentennial WAS

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