SB401/301 combo on CW

[Bill Coleman AA4LR]

On 11/3/98 8:20 PM, Stewart Lyon at stu_w6cux at JUNO.COM wrote:

>First, the sidetone setup. The way it is now the speaker line is routed
>through the transmitter where it is switched to a sidetone generator on
>transmit. What happens if you want to use headphones? Joe Lutz found a SB
>on this but he couldn't read it. How do you CW folks do it?

Back when I had a 301/401, I always found the speaker output loud enough
to hear even with the headphones on.

>I prefer to monitor my on-the-air signal rather than use a side tone....

Why?

>have modified by SB301 to add a "key down gain" scheme.  The problem is
>that the SB401 outputs a signal from the carrier generator board when on
>the air in the TRCV mode and all the time in the TRAN mode. Has anyone
>tried to key the carrier generator crystal along with the mixer and 6CL6
>driver? Wonder if it would chirp or be mushy?

My guess it would be very chirpy.

I have heard some 401's on the air that were relatively chirpy, so I'd be
cautious to try and modify any part of this chain. It works well like it
is.

>The third complaint I have that maybe someone has solved is the pulling
>of the -301 LMO whenever the -401 is switched to it (as in the LOCKED
>mode)  The frequency changes about 2 KHz. This because of the additional
>load of the tx mixer. It seems to me the -301 should have another buffer
>for the LMO like there is for the BFO. Maybe I'll add one if I can
>remember how to design tube circuits.

Never used my 301/401 pair in transceive mode. Always used them as
separates.

Are you using the proper RG-62/U cables to interconnect the two radios? I
never had access to this special (93 ohm) cable, so I never tried
transceive mode.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at radio.org
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901

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