On 16 Dec 2004 10:26:06 -0500, (Scott Dorsey) wrote:

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

Hi Scott,
The existing circuit simply uses one 1N4007 and a 1N4148 in series
thru a .01 cap to the receiver muting input (it is not THAT simple,
they are across the emitter and collector of the keying transistor; I
tried to draw it in text symbols, but gave up). What I hear in the
phones on keying is a loud "square wave" thump on each character sent.

I bought the Vectronics kits a couple of years ago after a period of
inactivity due to illness, mainly to get engaged and productive on
something.

I'll check out some designs in my 2000 and earlier Handbooks for relay
and/or diode switching better than the current Vectronics QSK design.
I can in fact use a vertical and a dipole, so that is a good
suggestion. Meanwhile, I enjoy QSK with my SW-20+.

Thanks,

Ted KX4OM

TW wrote:

Hi Scott,
The existing circuit simply uses one 1N4007 and a 1N4148 in series
thru a .01 cap to the receiver muting input (it is not THAT simple,
they are across the emitter and collector of the keying transistor; I
tried to draw it in text symbols, but gave up). What I hear in the
phones on keying is a loud "square wave" thump on each character sent.

Try putting a capacitive shunt on the line that is providing the bias
supply to the diodes, so they take a little bit of time to get up to
voltage and back down. That may slow the action up a little bit, but
it will also reduce the clicking. You may have to fiddle around with
values (and you may need a combination of a ceramic and an electrolytic
in parallel), but if the noise is caused by the rapid switching, it will
fix it.

If the noise is caused by DC offset on the output, a .1 uF ceramic in
series with the receiver input will clean that up. This might be the
case in receivers where there is a DC path through a coil winding from
antenna to ground.

I bought the Vectronics kits a couple of years ago after a period of
inactivity due to illness, mainly to get engaged and productive on
something.

I'll check out some designs in my 2000 and earlier Handbooks for relay
and/or diode switching better than the current Vectronics QSK design.
I can in fact use a vertical and a dipole, so that is a good
suggestion. Meanwhile, I enjoy QSK with my SW-20+.

After working at a military installation where the procedure was to disconnect
the UHF connector from the receiver and plug it into the transmitter between
sending and receiving, I am just glad to have anything at all.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Don't be satisfied with a simple arrangement that lets you get by. I worked CW
traffic nets at different level years ago with a thumping, banging system using
headphones and now I wear two hearing aids and regret the nights that I called
myself having a great time. Wish I could do it again and do it better!
(broke=not working, retired=not working, retired=broke)

On Fri, 17 Dec 2004 14:06:57 UTC, (Brokebob) wrote:

Don't be satisfied with a simple arrangement that lets you get by. I worked CW
traffic nets at different level years ago with a thumping, banging system using
headphones and now I wear two hearing aids and regret the nights that I called
myself having a great time. Wish I could do it again and do it better!
(broke=not working, retired=not working, retired=broke)

I copy ya, man.

That's a good reason for me to stay persistant and get the best,
smoothest, real QSK system possible. This stuff about "two
antennas" and let the AGC handle it, isn't right. I'd be trying to
hear an S7 signal through my own S9+40 signal hammering away.

I mentioned putting a pot in the mute line of my old SX-101A. That
worked great.

I was using a dowkey relay but that let me turn down the receiver
gain on transmit. The only problem with that was I was using an
HT-37 with the automatic changeover mod. It, and the dowkey relay
were too slow for QSK.

I know what I want. I've heard it on a Triton IV. Others have
described their Heathkit twins with QSK done right. Signal/One is
pretty good too.

At 57 my hearing is not what it used to be. I'm not on hearing aids
yet so I'm trying to keep every bit of that's left.

I've been mulling over my speaker system. I use cheap hi-fi
speakers with the tweeters disabled. I'm going for smooth, clean,
rich sound.

I'll give the www.radioadv.com bk175 kit a try. The write up on the
site sounds like it does what I want. I hope it'll all fit in the
case I have.



de ah6gi/4 boatanchor qsk here I come.

On Fri, 17 Dec 2004 14:06:57 UTC, (Brokebob) wrote:

Don't be satisfied with a simple arrangement that lets you get by. I worked CW
traffic nets at different level years ago with a thumping, banging system using
headphones and now I wear two hearing aids and regret the nights that I called
myself having a great time. Wish I could do it again and do it better!
(broke=not working, retired=not working, retired=broke)

I copy ya, man.

That's a good reason for me to stay persistant and get the best,
smoothest, real QSK system possible. This stuff about "two
antennas" and let the AGC handle it, isn't right. I'd be trying to
hear an S7 signal through my own S9+40 signal hammering away.

I mentioned putting a pot in the mute line of my old SX-101A. That
worked great.

I was using a dowkey relay but that let me turn down the receiver
gain on transmit. The only problem with that was I was using an
HT-37 with the automatic changeover mod. It, and the dowkey relay
were too slow for QSK.

I know what I want. I've heard it on a Triton IV. Others have
described their Heathkit twins with QSK done right. Signal/One is
pretty good too.

At 57 my hearing is not what it used to be. I'm not on hearing aids
yet so I'm trying to keep every bit of that's left.

I've been mulling over my speaker system. I use cheap hi-fi
speakers with the tweeters disabled. I'm going for smooth, clean,
rich sound.

I'll give the www.radioadv.com bk175 kit a try. The write up on the
site sounds like it does what I want. I hope it'll all fit in the
case I have.



de ah6gi/4 boatanchor qsk here I come.

Don't be satisfied with a simple arrangement that lets you get by. I worked CW
traffic nets at different level years ago with a thumping, banging system using
headphones and now I wear two hearing aids and regret the nights that I called
myself having a great time. Wish I could do it again and do it better!
(broke=not working, retired=not working, retired=broke)

TW wrote:

Hi Scott,
The existing circuit simply uses one 1N4007 and a 1N4148 in series
thru a .01 cap to the receiver muting input (it is not THAT simple,
they are across the emitter and collector of the keying transistor; I
tried to draw it in text symbols, but gave up). What I hear in the
phones on keying is a loud "square wave" thump on each character sent.

Try putting a capacitive shunt on the line that is providing the bias
supply to the diodes, so they take a little bit of time to get up to
voltage and back down. That may slow the action up a little bit, but
it will also reduce the clicking. You may have to fiddle around with
values (and you may need a combination of a ceramic and an electrolytic
in parallel), but if the noise is caused by the rapid switching, it will
fix it.

If the noise is caused by DC offset on the output, a .1 uF ceramic in
series with the receiver input will clean that up. This might be the
case in receivers where there is a DC path through a coil winding from
antenna to ground.

I bought the Vectronics kits a couple of years ago after a period of
inactivity due to illness, mainly to get engaged and productive on
something.

I'll check out some designs in my 2000 and earlier Handbooks for relay
and/or diode switching better than the current Vectronics QSK design.
I can in fact use a vertical and a dipole, so that is a good
suggestion. Meanwhile, I enjoy QSK with my SW-20+.

After working at a military installation where the procedure was to disconnect
the UHF connector from the receiver and plug it into the transmitter between
sending and receiving, I am just glad to have anything at all.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."