[Central-Electronics] Correction: PS-2 or PS-1

[Jim Candela]

Tony,

The PS1 in a 20A can be adjusted with a dual trace scope, two identical 10X 
probes, and a low distortion audio generator (sine wave).

Use X:Y mode for Lissajous pattern where you get a perfect circle when the two 
signals are equal in amplitude, distortion free, and 90 degrees phase shifted. 

I have done this a few times, and while at it I modified the PS-1 to perform 
better such that frequencies beyond 4 Khz had proper phase shift. Here is a link 
to that:
http://mailman.qth.net/pipermail/central-electronics/2006-January/000489.html

Also, if you stabilize your BC-458 with a Huff & Puff, remember the signal level 
will be too high for the LED that comes with the kit. I used dual 1N4007's as 
varactor diodes. Here are two cases where I did this:

1 IC chip H&P for BC-458 (touchy circuit):
http://pages.prodigy.net/jcandela/Huff%20and%20Puff%20VFO/

PIC stabilized H&P for Lakeshore Bandhopper VFO:
http://pages.prodigy.net/jcandela/Band%20Hopper/

After installing the Cumbria Pic circuit (http://www.cumbriadesigns.co.uk/), the 
dominant drift comes from the 9 Mhz crystal in the 20A. Some of these crystals 
move 200Hz or more in the 1st hour of warm up. A PTC thermistor (maybe 50C) 
heater on the crystal should help.

Jim
WD5JKO




----- Original Message ----
From: k6jek <k6jek at comcast.net>
To: central-electronics at mailman.qth.net
Sent: Tue, December 21, 2010 3:54:02 PM
Subject: Re: [Central-Electronics] Correction: PS-2 or PS-1

For the experiments I want to do, A PS-2 would be better.  A PS-1 would be OK, 
however.

On Dec 21, 2010, at 12:57 PM, k6jek wrote:

> Anyone have a PS-1 from a parts rig?  Also, tips ad pointers on the 20A info 
>would be most appreciated.  
>
> 
> My 100V is now just so wonderful I decided to step back in time and get a 20A 
>which I'll be picking up in January.  "It needs work." says Brian.  Perfect.  
>
> 
> I fully expect to be fighting sideband suppression issues with the 20A.  It 
>sure would be grand if I had an extra PS-1 to goof around with.   Has anyone 
>broken the code on "adjusted at the factory" don't touch them variable caps in 
>the PS-1?  
>
> 
> Incidentally, I could not get  decent the sideband suppression on the 100V 
>until I rebuilt the PS-2.  I got my hands on a just calibrated very high 
>precision LCR meter, a Stanford Research SR720.  None of the bridged parts were 
>in spec which is .1%.  Some were out 4%.  This was not a project for the meek or 
>hurried, but I did manage to get it rebuilt in spec and then was able to get  
>satisfactory opposite sideband suppression.  But that's a longer story ...
> 
> Can't wait to get the 20A and 458.  I even have a huff and puff kit lying 
>around somewhere.  
>
> 
> 
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