[AMRadio] Getting on the Air - May 2008 QST


EP Swynar gswynar at durham.net
Tue Apr 22 06:57:41 EDT 2008


Hi Mark,

Well spoken...

I once had to replace the MRF-422(?) RF power output transistors in my
FT-980 here...for what I paid for these wonderful, low-voltage, SAFE
solidstate devices, I could have purchased a LOT of 12BY7's & 6146's...!

Some of these god-sent transistors cost more --- and are a LOT more rare --- 
than tubes to-day, especially the sand-derived active devices from earlier
no-tube gear (have you priced direct-replacement germanium power transistors
lately, as were employed in the multi-vibrator power supplies of 60's/70's
mobile QRO equipment...?!).

~73~ Eddy VE3CUI - VE3XZ




----- Original Message ----- 
From: "Mark K3MSB" <mark.k3msb at gmail.com>
To: "Discussion of AM Radio in the Amateur Service"
<amradio at mailman.qth.net>
Sent: Monday, April 21, 2008 11:27 PM
Subject: Re: [AMRadio] Getting on the Air - May 2008 QST


> "My first recommendation would be to only consider older vacuum tube
> or hybrid gear (solid state receiver, tubes in part of the
> transmitter) if you have experience working with vacuum tube
> transmitters.  It is too easy to destroy hard to get transmitting
> tubes while you learn".
>
> One of the most common PA line ups of hybrid transmitters is a 12BY7A
> driver and a pair of 6146 finals. Without searching hard, you can get
> all 3 NOS at a fester for $12;  less if you put some effort into it.
>
> 73 Mark K3MSB
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