[Johnson] Johnson Adventurer/122 VFO power question

[Carl]

The 122 and Viking 1 came out in 1946. The Adventurer was much later.

Carl
KM1H


----- Original Message ----- 
From: "SX-25" <telegrapher at hotmail.com>
To: <johnson at mailman.qth.net>
Sent: Wednesday, December 31, 2008 8:56 AM
Subject: [Johnson] Johnson Adventurer/122 VFO power question


     I just recently added a Johnson 122 VFO to my Adventurer. I am 
curious if anyone can weigh in with their speculation on what the 
original intent of Johnson was by introducing the 122 to its product 
line? Although I do not own a Viking I,  I am wondering if the 122 was 
designed as an adjunct more for the Viking I than as an upgrade for 
Adventurer users? Not having a Viking I schematic I have no idea of 
whether it was more readily suited to adding the VFO.

     My first discovery was that the  octal socket on the back of an 
Adventurer does not supply the necessary voltages. The 122 requires 
250-300 VDC for B+ and my Adventurer only supplies plate voltage for the 
807 at around 550 VDC. Obviously I could have added dropping resistors 
but  then throw off the parameters of the plate supply. Since I wanted 
the 122 also useable with several other 50s/60s vintage transmitters I 
own,  I built a separate power supply to fix the voltage problem and it 
works very well.

     But I am wondering about this. Why wouldJohnson sell a VFO that was 
incompatible with its Adventurer? Surely bucket loads of novices 
advancing to their general class license in the Korean War era stayed 
with their li'l Adventurers (at least for a while) and added the VFO 
pursuant to their new privileges and were looking for that correct B+ 
voltage by way of the Adventurer octal socket. After all, Johnson 
provided everything else needed in the octal socket, filament voltage 
and keying  circuit. Also, most external VFOs of the era required that 
same voltage for B+; they pretty much all need 300 VDC and 6.3 VAC.

     Quite frankly, in spite of Johnson equipment being top of the line, 
I feel their instruction manuals are terrible and in many ways are too 
nebulous to be of much help. In concert with this, my Adventurer does 
not have its original transformer, so quite possible there was some 
scheme that precludes direct use of MY Adventurer with a 122 VFO.

     Thoughts?

     73 and Happy New Year to all. Keep 'em glowing. They make the 
nicest sounding CW on the air today!

     Vern WA9VLK




--------------------------------------------------------------------------------


> Johnson mailing list
> Home: http://mailman.qth.net/mailman/listinfo/johnson
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Johnson at mailman.qth.net
>