SB640 / Split operation

[Stewart D. Lyon]

Hello Randolf,
I tried to do just as you are with a SB-101 / SB-301 and I couldn't make it
work  unless I was willing to modify the -301. I could TX/RX on the SB-102
and the same on the -301 but I could not operate split.

The reason is that there has to be a way to turn off the LMO of the one you
aren't currently using. I seem to remember that the SB-640 gets it's B+ from
the -101 and it's a simple matter to switch off the B+ with a contact on the
T/R relay. I don't remember all the details (it's been a couple of years)
but I wasn't willing to mess up my -301 by switching circuity.

With the switching applied as Heath did on the SB-101/SB-640 you can only
split one way -- you cannot "reverse split". I don't remember which controls
the TX and which controls the RX but they are always that way.

Hope this helps or at least saves some time.

73, Stu W6CUX

----- Original Message -----
From: "R. Schmitz" <HeathlinerSB at AOL.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Wednesday, June 27, 2001 3:55 PM
Subject: SB640 / Split operation


> Hello dear Heathkit OP's!
> Looking for a while for a SB-640 external LMO to make split operation with
my
> SB-102.Was not successful here in DL. The LMO seems to be very rare. Is
> anywhere here on the list a SB-640 for sale ?
>
> May be another possibility for split op. ?
> Sometimes the RX SB-301/303 or the TX SB-400/401 are available on
> flea-markets. Is it possible to wire the seperate RX or TX with the SB-102
> so,that one can use either the SB-102 LMO or the seperate LMO for
transceive
> work and switch to the both LMO's for split operation. It is difficult for
me
> to write exactly what I mean, but I think of an operation like Drake
> R4C/T4XC. With this line You can work with RX or TX VFO in transceive mode
or
> with both in split mode. May be, this is possible even with two times
SB-102?
> Thank You for Your help in advance!
> Randolf,DL6KAI from Cologne,Germany
>

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