[Heathkit] SB-610 scope to SB-303 receiver

[Kenneth G. Gordon]

On 11 Dec 2007 at 15:46, Dan Pividal wrote:

> the Heathkit SB-610 assembly manual says to use a 1.0mmf.

That should be about right.

> Also says,
> they supplied the 1.0mmf as well as a 2.2mmf and a 12mmf capacitor in
> the original kit. I believe that long ago mmf meant Picofared.

Yes. mmfd means pfd today. However mf still means mf.

> That
> would make a big difference. Tech notes I have from Heathkit says to
> use a 1.0mf coupling cap to the 3rd IF via a RG174 coax to a spare RCA
> plug in the back of the receiver.

WRONG! Either that is a typo or you need better glasses! :-)

Should be as SMALL as will give you good results.

> To which document do I pay heed.

The one that says mmf...

BTW, as someone else pointed out, RG-174 has pretty high capacitance 
per foot, like 22 pfd/foot, so it, in combination with the coupling capacitor, 
forms a capacitive-voltage divider.

Ken Gordon W7EKB