[Drake] Drake B-Line - 600 Hz off

[ed.brooks]

The Drake B Twins, used in transceive, should result in the TX being dead on
frequency with the RX.   If in transceive mode, there is no "spotting" possible, as
spotting is accomplished with the TX VFO.

If, in transceive mode, the TX is off frequency from the RX (as mine was, enough to
cause people to comment, or even to miss my calling them!) then an alignment is
necessary.

On CW, the TX is shifted automatically by about 1 KHZ during key-down from the
receive frequency.  This means if the rig is aligned properly, and you use it on
transceive CW, the transmitter will be one KHZ below the receiver.  So if the other
guy zero beats your TX signal, you will hear his signal as a one KHZ tone.  For
most of us, that is not a comfortable pitch CW tone - we prefer lower, like 600
Hertz.   What happens then, is when the other guy transmits, you tune your receiver
to get that one KHZ tone, but that moves your TX as well, and he retunes - this is
called leapfrogging.   For that reason, the B-Twins do not work well for CW
transceive.   This was true of the Collins S-line as well, until they put in the
BFO on the 75S3B which allowed the BFO to take care of the 1.2 KHZ offset in the
S-Line.  But with no BFO on the R4B that method won't work.

You should not, neither on CW nor on SSB, see  the transmitter as 600 Hertz off
freq from the receiver.  On SSB it should appear dead on frequency.  On CW , it
should appear 1 KHZ off.   To check it on SSB, use a dummy load.  Put the Twins in
RX control transceive. Use headphones.  Switch the receiver to ON, instead of MUTE,
and turn the RF gain down very low.  Now press the PTT switch and talk into the
microphone.  Raise the RF gain until you can hear your own signal.  You should hear
your natural-sounding voice.   If you do not, then the units are not properly
aligned.

To call another station on CW first zero beat his signal in your receiver, then use
the spot switch and zero your transmitter.  You will be right on his frequency.

In SEPARATE mode, you can "talk on" frequency by using the "spot' position.  Switch
the TX to SPOT, and start talking into the microphone.  It's that simple!  You will
hear your TX audio in the receiver speaker.  Move the TX VFO until the voice sounds
natural, and you have it.

If it is really 600 cycles off, you need an alignment, per the manual.  It isn't
difficult, and if you have access to a scope with RF probes, or even a DVM with RF
probes, it's really pretty easy.  Lacking those, you can use another transceiver
with a digital readout.  I used my Icom 706 for much of the alignment.    This goes
all the way back to the carrier oscillator and the xtal filters, and it requires
the RX and TX be hooked up with the transceive cables you will be using all the
time.

My guess is you need the alignment.  It can't hurt, and it can help.  Aside from
that, it creates a familiarity with the equipment you will find in few other ways.
It "gets your hands dirty."   And it just plain feels good to know you did it.


73
Ed, W5HTW





> ******************************************************************************
> > > I sent a previous post about my b line not xmiting on
> > > the same freq as receiving. Several replied and told me
> > > where to find it in the manual. But this just covers the
> > > procedure for the "spot" position. Remember i am using
> > > the receiver not only to receive but also to xmit. Since
> > > the xmitr is 600 cycles high how do i get it on the
> > > correct freq?
>
> =====
> May your days be full of sunshine and good thoughts fill your head.
> From: Larry Knapp, KC8JX, St. Joseph, Mi  49085
>   Best 73's
>
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