[Heathkit] Heathkit Digest, Vol 87, Issue 5 - Re-engineering an SB610

[G3OOU at aol.com]

Hi Dave
 
I am in the process of re-engineering an SB-101 at the moment and the  
SB-601 and 620 are in the pipeline to do. The 610 was not a bad design but I  
have never been impressed with the 620 as it was too limited and not very  
stable.
 
For a good starting point you could look at the X and Y amplifiers and  
timebase from the SB-614.
 
I plan to do the same as you and convert to solid state which also makes  
more room available and less heat. However, I intend to use a Y bandwidth 
only  up to about 150KHz and put RF directly onto the vertical deflection 
electrodes  for trapezium and AM testing. As my new SB-101 will properly cater 
for FM and AM  as well as the other usual modes I am going to add a simple 
receiver to the 610  to convert from 3.395MHz to 100KHz and include an AM 
detector, FM pulse  counting discriminator and a 100KHz feed to the Y amp so that 
I can look at  incoming signals in more detail and measure their deviation 
on FM as well as my  own outgoing signal on all modes. I have arranged for 
an interface on the SB-101  to feed Rx and Tx audio, Rx and Tx IF and the PTT 
line to the revised 610.
 
I would be interested in swapping notes in due course.
 
73

Bob

Bob F Burns
C Eng,  FIET, MSE
Amateur Radio Callsign: G3OOU
Registered RSGB  Instructor
G-QRP Member No: 6907; Zone: 14, QRA: IO91WH; WAB:  TQ25
Secretary of Crystal Palace Radio & Electronics Club: _www.g3oou.co.uk_ 
(http://www.g3oou.co.uk/) 
Technical web site: _www.qsl.net/g3oou_ (http://www.qsl.net/g3oou)