You really don't need receiver muting for c.w. QSK,
just a receiver who's AGC can be turned off, or is very fast.

I ran QSK with a crummy Lafayette HE-80 receiver,
a B&W model 380 electronic TR switch, and a Heath Apache transmitter,
all sharing a dipole. No keying relays used at all.
If I zero-beated a station, I could just
monitor my sending with my own receiver. For split frequencies,
turn up the volume on the keying monitor.

The point of the electronic TR switch is that it acts as a preamp
for the receiver, until you transmit. Then, the tube in the TR switch
is cut off due to its high value grid leak resistor, which protects
the receiver's input stage. The signal is still loud, but if you
switch the AGC off, you can hear a breaking station between dits.

If your transmitter final is biased off during key up,
you won't hear the white noise in the receiver. If your transmitter
uses an AB1 or AB2 final for c.w., you may need
to increase the final stage bias a bit in c.w. mode,
to lower the quiescent plate current.

If white noise is still present, you can use a separate antenna
for the receiver/TR switch combination. Don't forget to use
a coax low pass filter between the electronic TR switch
and the antenna, or you will generate TV interference.

73,
Ed Knobloch

I know that I can buy a Century 21, HW-16, or Argonaut and have just
as good a CW QSK experience but I want to use a separate receiver.

Seems that at least one of the QRP CW transmitter kits would include
QSK circuitry to TR and mute a receiver.

de ah6gi/4 I have the receivers, I just need the transmitters.

On 15 Dec 2004 14:19:25 GMT, "No Spam " No wrote:

I've searched the web but haven't found the answer to my
QRP CW question.

I'm looking for a QRP CW transmitter kit that includes QSK and
will mute a boatanchor receiver like an SB-303, SX-101, or 75S-1.

I realize that some receivers might not recover fast enough for
QSK.

I've looked at website ads for Ramsey, Vectronixs, and still
don't have an answer. They might do it out of the box; they
might do it with a mod but I haven't found the answer.

A couple watts of CW and capable of working with the WA6OTP PTO
kit.

Anyone got something like that working?

de ah6gi/4

Quoting from the Vectronics VEC-1220K 20M transmitter kit manual, page
26: "Receiver Hook-up: You may patch most receivers directly into your
VEC QRP-CW Transmitter's receiver jack without risk of damage.
Transmitter output is typically around + 32 dBm and the energy
reaching your receiver through the T/R switch is normally 25 dB lower,
or about +7 dBm. This is a very strong signal, but a high-quality
receiver with a wide AGC range can usually handle it without blasting
out the speaker! If you are able to leave the receiver on during
transmit, you'll enjoy the benefit of full QSK operation."

"This means you'll be able to monitor incoming signals--and listen to
your own outgoing signal--simultaneously. If your receiver has an
attenuator switch, turning it on will help reduce the effects of
overload. By the same token, if your receiver has a pre-amplifier,
you should turn it off. Receivers unable to limit speaker or
headphone volume over a wide range of signal inputs must be turned
down or switched to standby mode while you send."

Enough said?

Ted KX4OM

On 15 Dec 2004 14:19:25 GMT, "No Spam " No wrote:

I've searched the web but haven't found the answer to my
QRP CW question.

I'm looking for a QRP CW transmitter kit that includes QSK and
will mute a boatanchor receiver like an SB-303, SX-101, or 75S-1.

I realize that some receivers might not recover fast enough for
QSK.

I've looked at website ads for Ramsey, Vectronixs, and still
don't have an answer. They might do it out of the box; they
might do it with a mod but I haven't found the answer.

A couple watts of CW and capable of working with the WA6OTP PTO
kit.

Anyone got something like that working?

de ah6gi/4

Quoting from the Vectronics VEC-1220K 20M transmitter kit manual, page
26: "Receiver Hook-up: You may patch most receivers directly into your
VEC QRP-CW Transmitter's receiver jack without risk of damage.
Transmitter output is typically around + 32 dBm and the energy
reaching your receiver through the T/R switch is normally 25 dB lower,
or about +7 dBm. This is a very strong signal, but a high-quality
receiver with a wide AGC range can usually handle it without blasting
out the speaker! If you are able to leave the receiver on during
transmit, you'll enjoy the benefit of full QSK operation."

"This means you'll be able to monitor incoming signals--and listen to
your own outgoing signal--simultaneously. If your receiver has an
attenuator switch, turning it on will help reduce the effects of
overload. By the same token, if your receiver has a pre-amplifier,
you should turn it off. Receivers unable to limit speaker or
headphone volume over a wide range of signal inputs must be turned
down or switched to standby mode while you send."

Enough said?

Ted KX4OM

On Thu, 16 Dec 2004 08:29:16 UTC, TW wrote:

On 15 Dec 2004 14:19:25 GMT, "No Spam " No wrote:

I've searched the web but haven't found the answer to my
QRP CW question.

I'm looking for a QRP CW transmitter kit that includes QSK and
will mute a boatanchor receiver like an SB-303, SX-101, or 75S-1.

I realize that some receivers might not recover fast enough for
QSK.

I've looked at website ads for Ramsey, Vectronixs, and still
don't have an answer. They might do it out of the box; they
might do it with a mod but I haven't found the answer.

A couple watts of CW and capable of working with the WA6OTP PTO
kit.

Anyone got something like that working?

de ah6gi/4

Quoting from the Vectronics VEC-1220K 20M transmitter kit manual, page
26: "Receiver Hook-up: You may patch most receivers directly into your
VEC QRP-CW Transmitter's receiver jack without risk of damage.
Transmitter output is typically around + 32 dBm and the energy
reaching your receiver through the T/R switch is normally 25 dB lower,
or about +7 dBm. This is a very strong signal, but a high-quality
receiver with a wide AGC range can usually handle it without blasting
out the speaker! If you are able to leave the receiver on during
transmit, you'll enjoy the benefit of full QSK operation."

"This means you'll be able to monitor incoming signals--and listen to
your own outgoing signal--simultaneously. If your receiver has an
attenuator switch, turning it on will help reduce the effects of
overload. By the same token, if your receiver has a pre-amplifier,
you should turn it off. Receivers unable to limit speaker or
headphone volume over a wide range of signal inputs must be turned
down or switched to standby mode while you send."

Enough said?

not enough but thanks for the terrific info. I've heard a
Triton IV and Signal/One CX7A's concept of QSK and that's not
exactly their concept.

40 years ago, I put a pot in series with the mute line on my
SX-101A. That gave me an RF gain control that worked on receive and
let me monitor my signal on SSB and CW.

I didn't have break-in but I had the monitoring part. The QSK
experience isn't just, "If I ignore the thumping of the receiver,
clacking of relays, and the excessively loud transmit sidetone, I
can maybe make out a dit between sent characters."

QSK is the change-over happening so smoothly that it sounds like
we're transmitting using code practice oscillators in the same room
and I can control the volume and tone on both oscillators.

Where you helped is this, I can combine that transmitter with the
boatanchor TR-keyer described in the 2004 handbook and sold by
www.radioadv.com to make a device that will mute my boatanchor
receivers.

Should work. Thanks.

de ah6gi/4

--

On Thu, 16 Dec 2004 06:27:16 UTC, Edward Knobloch
wrote:

You really don't need receiver muting for c.w. QSK,
just a receiver who's AGC can be turned off, or is very fast.
...

the receiver's input stage. The signal is still loud, but if you
switch the AGC off, you can hear a breaking station between dits.

Thanks. I'd prefer to something more like Tentec's concept of QSK
and not listen to a thumping receiver or hammer my S-meter against
the pin.

Done right, QSK is a delight.

I think it can be done with off-the-shelf pieces. Looks like the
key is the www.radioadv.com keyer-TR switch and just about any QRP
transmitter kit, or at least that's what folk are telling me.

de ah6gi/4

On Thu, 16 Dec 2004 08:29:16 UTC, TW wrote:

On 15 Dec 2004 14:19:25 GMT, "No Spam " No wrote:

I've searched the web but haven't found the answer to my
QRP CW question.

I'm looking for a QRP CW transmitter kit that includes QSK and
will mute a boatanchor receiver like an SB-303, SX-101, or 75S-1.

I realize that some receivers might not recover fast enough for
QSK.

I've looked at website ads for Ramsey, Vectronixs, and still
don't have an answer. They might do it out of the box; they
might do it with a mod but I haven't found the answer.

A couple watts of CW and capable of working with the WA6OTP PTO
kit.

Anyone got something like that working?

de ah6gi/4

Quoting from the Vectronics VEC-1220K 20M transmitter kit manual, page
26: "Receiver Hook-up: You may patch most receivers directly into your
VEC QRP-CW Transmitter's receiver jack without risk of damage.
Transmitter output is typically around + 32 dBm and the energy
reaching your receiver through the T/R switch is normally 25 dB lower,
or about +7 dBm. This is a very strong signal, but a high-quality
receiver with a wide AGC range can usually handle it without blasting
out the speaker! If you are able to leave the receiver on during
transmit, you'll enjoy the benefit of full QSK operation."

"This means you'll be able to monitor incoming signals--and listen to
your own outgoing signal--simultaneously. If your receiver has an
attenuator switch, turning it on will help reduce the effects of
overload. By the same token, if your receiver has a pre-amplifier,
you should turn it off. Receivers unable to limit speaker or
headphone volume over a wide range of signal inputs must be turned
down or switched to standby mode while you send."

Enough said?

not enough but thanks for the terrific info. I've heard a
Triton IV and Signal/One CX7A's concept of QSK and that's not
exactly their concept.

40 years ago, I put a pot in series with the mute line on my
SX-101A. That gave me an RF gain control that worked on receive and
let me monitor my signal on SSB and CW.

I didn't have break-in but I had the monitoring part. The QSK
experience isn't just, "If I ignore the thumping of the receiver,
clacking of relays, and the excessively loud transmit sidetone, I
can maybe make out a dit between sent characters."

QSK is the change-over happening so smoothly that it sounds like
we're transmitting using code practice oscillators in the same room
and I can control the volume and tone on both oscillators.

Where you helped is this, I can combine that transmitter with the
boatanchor TR-keyer described in the 2004 handbook and sold by
www.radioadv.com to make a device that will mute my boatanchor
receivers.

Should work. Thanks.

de ah6gi/4

--

On Thu, 16 Dec 2004 06:27:16 UTC, Edward Knobloch
wrote:

You really don't need receiver muting for c.w. QSK,
just a receiver who's AGC can be turned off, or is very fast.
...

the receiver's input stage. The signal is still loud, but if you
switch the AGC off, you can hear a breaking station between dits.

Thanks. I'd prefer to something more like Tentec's concept of QSK
and not listen to a thumping receiver or hammer my S-meter against
the pin.

Done right, QSK is a delight.

I think it can be done with off-the-shelf pieces. Looks like the
key is the www.radioadv.com keyer-TR switch and just about any QRP
transmitter kit, or at least that's what folk are telling me.

de ah6gi/4

No Spam wrote:

On Thu, 16 Dec 2004 06:27:16 UTC, Edward Knobloch
wrote:

You really don't need receiver muting for c.w. QSK,
just a receiver who's AGC can be turned off, or is very fast.

..

the receiver's input stage. The signal is still loud, but if you
switch the AGC off, you can hear a breaking station between dits.

Thanks. I'd prefer to something more like Tentec's concept of QSK
and not listen to a thumping receiver or hammer my S-meter against
the pin.

Done right, QSK is a delight.

I think it can be done with off-the-shelf pieces. Looks like the
key is the www.radioadv.com keyer-TR switch and just about any QRP
transmitter kit, or at least that's what folk are telling me.

de ah6gi/4

I fully agree with you that, done right, QSK is a delight. I have been
using a Heathkit HR-1680/HX-1681 combination for over 20 years now.
The QSK works extremely well. It is virtually imperceptible that the
receiver is actually being shut down during my dots and dashes. There
is no thumping or bumping or hammering of the S-Meter, and I can hear
all of the band activity.

IMHO, I think that to have a good QSK setup, you must take the capabilities
of both the receiver and transmitter into account. This Heathkit pair
was designed to work together. There is a keying circuit inside that
controls the timing of the receiver muting, transmitter keying, and
T/R switch operation. No relays are involved at all. The low level
keying and frequency generation is all solid state and the final (tubes)
is run Class AB2, for a nice clean, well shaped, signal.

It may be beneficial to get a copy of the HX-1681 transmitter and
investigate how they implemented it. I haven't looked at the schematic
in a long time but I don't think it was very complicated. It may be
similar to Tentec's concept of QSK.

I also seem to remember that in the ARRL Handbook, 2000 I think,
there was a project for making implementing automatic T/R switching
for vintage transmitters and receivers. I don't remember if they went
into full QSK, or not, but it's another possible resource.

--
Martin E. Meserve - K7MEM
http://www.k7mem.com

No Spam wrote:

On Thu, 16 Dec 2004 06:27:16 UTC, Edward Knobloch
wrote:

You really don't need receiver muting for c.w. QSK,
just a receiver who's AGC can be turned off, or is very fast.

..

the receiver's input stage. The signal is still loud, but if you
switch the AGC off, you can hear a breaking station between dits.

Thanks. I'd prefer to something more like Tentec's concept of QSK
and not listen to a thumping receiver or hammer my S-meter against
the pin.

Done right, QSK is a delight.

I think it can be done with off-the-shelf pieces. Looks like the
key is the www.radioadv.com keyer-TR switch and just about any QRP
transmitter kit, or at least that's what folk are telling me.

de ah6gi/4

I fully agree with you that, done right, QSK is a delight. I have been
using a Heathkit HR-1680/HX-1681 combination for over 20 years now.
The QSK works extremely well. It is virtually imperceptible that the
receiver is actually being shut down during my dots and dashes. There
is no thumping or bumping or hammering of the S-Meter, and I can hear
all of the band activity.

IMHO, I think that to have a good QSK setup, you must take the capabilities
of both the receiver and transmitter into account. This Heathkit pair
was designed to work together. There is a keying circuit inside that
controls the timing of the receiver muting, transmitter keying, and
T/R switch operation. No relays are involved at all. The low level
keying and frequency generation is all solid state and the final (tubes)
is run Class AB2, for a nice clean, well shaped, signal.

It may be beneficial to get a copy of the HX-1681 transmitter and
investigate how they implemented it. I haven't looked at the schematic
in a long time but I don't think it was very complicated. It may be
similar to Tentec's concept of QSK.

I also seem to remember that in the ARRL Handbook, 2000 I think,
there was a project for making implementing automatic T/R switching
for vintage transmitters and receivers. I don't remember if they went
into full QSK, or not, but it's another possible resource.

--
Martin E. Meserve - K7MEM
http://www.k7mem.com

TW wrote:

Quoting from the Vectronics VEC-1220K 20M transmitter kit manual, page
26: "Receiver Hook-up: You may patch most receivers directly into your
VEC QRP-CW Transmitter's receiver jack without risk of damage.
Transmitter output is typically around + 32 dBm and the energy
reaching your receiver through the T/R switch is normally 25 dB lower,
or about +7 dBm. This is a very strong signal, but a high-quality
receiver with a wide AGC range can usually handle it without blasting
out the speaker! If you are able to leave the receiver on during
transmit, you'll enjoy the benefit of full QSK operation."

It would strike me that if you really wanted a full T/R switch, and you
did not want to spend the five dollars or so for a fast relay, you could
probably build an acceptable switch using 1N4007 diodes. I would think
that with these current levels at HF that there would be no need for a
fancy switching PIN diode.

Another alternative, by the way, is just to use a vertical for transmitting
and a horizontal dipole for receive. This also has some major benefits in that
your receiver noise will be lower with the horizontal and your transmitted
signal will be slightly better with the vertical.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."