[HBR] Link to pix of HBR16 and HB SSB transmitter LINK

[waltah at ntelos.net]

John wrote:
> I've upped some pictures of the "New" HBR16 and Homebrew SSB transmitter 
> I've recently acquired. I wonder if anyone recognizes the 
> transmitter?  I've uploaded some pictures as requested by several.\
> 
> http://www.k5mo.com/Temporary/HBGear.htm

How COOL!

The 75-20M combination was most often done by 'band imaging' 
with a 9 Mcs IF.   I see the 455 kcs IFT in one of your pictures so 
this could be one that generates the SSB at that frequency, 
hetrodynes it up to 9 mcs (filtering could be done at either 
frequency but most likely at 455) and then mixes with a 5-5.350 
Mcs VFO.   That suggests an earlier -- say 1960 +/- -- design.   
Tidier ideas -- fewer conversions -- were more common later.  

Upconverting from 455 kcs to those two bands to 75-20 will 
generate some spurs.   8 x 455 = 3640, 9 x 455 = 4095.   And 
others, too, depending on details of the conversion scheme.   

I can't think of a way to make that conversion work without having 
to generate both sidebands.   The nicer band imaging designs give 
you LSB on 75 and USB on 20 without having to do that.   For 
example, generate USB at ~5 Mcs and either add that to or 
subtract it from a ~9 Mcs VFO.   Stability is a challenge with that 
one, but it can be done, and it's trivial for VXO-type designs.   

(Anyone here ever build the 'Imp'?   Three tube VXO SSB 
transmitter found in one or two of the SSB For the Radio Amateur 
books?   Someday I'm going to do that with 150 mA tubes, say 
with a 70L7 rectifier/PA or a pair of 35GL6's, and two 17H3's or 
35W4's in a doubler.

(Definitely regressing in my old age.   I use fewer and fewer solid 
state diodes, more and more glass ...)

I'm just nitpicking about the TX design.   This was done at a time 
when ham SSB gear didn't come in a four-color box with a plastic 
handle on the top from Japan and it represents some serious ham 
skills.   Congratulations!

One you get the circuit diagram up we should be able to figure it 
out.

Walt 
KJ4KV