I am a new technician with code privileges. I built the following CW
transmitter for 40 meters:

http://cs.okanagan.bc.ca/ve7ouc/eng/...nsmitter2.html

It's a solid state 3-watter, based on an article in QST in June 1967.
I used a printed circuit board instead of wiring everything together
directly, as the QST article suggests. So, there are many wires
running from various parts mounted on the chassis to the circuit
board.

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less. I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground. I'm using fundamental frequency HC6/U crystals for 7110 and
7125 kHz. I've been trying for 2 weeks, at all hours of the day and
night, and have had no indication that anyone hears me. I've called
CQ, and I've attempted to answer CQ's. Nothing, after about 100
tries.

I know it's impossible for any of you to know exactly what's wrong,
but I'd like to see what opinions I can glean here.

Is there any reason why I should use FT-243 crystals, as specified in
the article and on the website? I used HC6/U crystals because they
were easy to get.

One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Also, the transmitter chirps a bit at the beginning of each
transmission, but settles down after a few strokes of the key.

Many thanks for any help you can give.


-John Sandin KC0QWE

Remove the "T" to respond by e-mail

Several comments ....

When your output is a LOT different than you expect, likely there is
something wrong. Worse, there's a good chance that a lot of your energy is
being transmitted where you don't expect.

One thing that I found helpful on my first homebrew adventure was to model
any circuits that didn't seem to be quite right in PSpice. It's tedious,
but it helped me immensely in understanding what's going on.

Secondly, a 40 meter antenna 7 feet off the ground is going to radiate
pretty much straight up. That means that the only time any of your energy
will get back to the ground is when the flux is very high, something that is
happening less and less often. Worse, 40 meters is pretty noisy, and the
old novice segments really not all that heavily occupied, so not getting a
response right away isn't all that surprising.

If your output transistor is getting really hot you probably want to revisit
your heat sink. If you have, or can borrow, a scope, take a look around and
make sure that circuit is doing what you want. The heat could be telling
you that a lot of your energy is being spent in parasitics. Presuming you
have filtering after this transistor, that could be related to your low
output, as well.

If you have, or can borrow, a general coverage receiver, listen for your
transmitter on your fundamental, and on the harmonic frequencies, especially
the odd harmonics. You probably will be able to hear your transmitter on
21.330, but it should be a LOT weaker. If it isn't, you have a problem.

Finally, I would try to find someone local (line of sight, say 10-20 miles
if it's reasonably flat) and arrange a schedule. This won't take any
propagation and it will give you some idea that your transmitter is working.
Recognize that locals are often a lot weaker on 40 than stations more
distant, but if there are huge issues then perhaps this will uncover them.

Finally the chirp - get a fat wire from your power supply to the radio.
Also, make sure that the power path to the oscillator is very low
resistance. It doesn't take much voltage change to shift the oscillator
frequency, and there is a huge inrush of current on key down, so good old
E=IR tells you that with a big I it doesn't take much R!

Hope this helps...

...

"John Sandin" wrote in message
...

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less. I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground. I'm using fundamental frequency HC6/U crystals for 7110 and
7125 kHz. I've been trying for 2 weeks, at all hours of the day and
night, and have had no indication that anyone hears me. I've called
CQ, and I've attempted to answer CQ's. Nothing, after about 100
tries.

I know it's impossible for any of you to know exactly what's wrong,
but I'd like to see what opinions I can glean here.

Is there any reason why I should use FT-243 crystals, as specified in
the article and on the website? I used HC6/U crystals because they
were easy to get.

One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Also, the transmitter chirps a bit at the beginning of each
transmission, but settles down after a few strokes of the key.

Many thanks for any help you can give.


-John Sandin KC0QWE

Remove the "T" to respond by e-mail

On Sun, 05 Oct 2003 04:42:11 GMT,
(John Sandin) wrote:

I am a new technician with code privileges. I built the following CW
transmitter for 40 meters:

http://cs.okanagan.bc.ca/ve7ouc/eng/...nsmitter2.html

It's a solid state 3-watter, based on an article in QST in June 1967.
I used a printed circuit board instead of wiring everything together
directly, as the QST article suggests. So, there are many wires
running from various parts mounted on the chassis to the circuit
board.

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less.

How is this figure arrived at? How are you measuring it? 1W doesn't
sound much, but it can go a long way on 40M., given an efficient
antenna system with short, low-loss feeder and matched radiation
resistance.

I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground.

That's *way* too low! As you must know for any ariel, you gotta get
that thing up as high off the ground as you can and that's even more
important at low frequencies like 7Mhz.

I'm using fundamental frequency HC6/U crystals for 7110 and
7125 kHz. I've been trying for 2 weeks, at all hours of the day and
night, and have had no indication that anyone hears me. I've called
CQ, and I've attempted to answer CQ's. Nothing, after about 100
tries.

I know it's impossible for any of you to know exactly what's wrong,
but I'd like to see what opinions I can glean here.

Is there any reason why I should use FT-243 crystals, as specified in
the article and on the website? I used HC6/U crystals because they
were easy to get.

One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Something's wrong, then. The heat dissipated in your final transistor
should equate to the output power at the antenna if the system is
matched properly. Sounds like your tranny's trying to dissipate rather
more than a Watt. Are you sure you don't have a feeder/matching
problem somewhere? Have you cut the ariel to the right length? Are you
using a balun? Have you tried a substitute balun?

Also, the transmitter chirps a bit at the beginning of each
transmission, but settles down after a few strokes of the key.

Many thanks for any help you can give.

Get another ham a couple of miles away from you to give you a signal
report. It might show up something useful.
--

"Windows [n.], A thirty-two bit extension and GUI shell to a sixteen bit patch
to an eight bit operating system originally coded for a four bit
microprocessor and produced by a two bit company."

On Sun, 05 Oct 2003 13:50:43 +0100, Paul Burridge
wrote:

snip

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less.

How is this figure arrived at? How are you measuring it? 1W doesn't
sound much, but it can go a long way on 40M., given an efficient
antenna system with short, low-loss feeder and matched radiation
resistance.

Voltage is measured across my 50 ohm dummy load and rectified using a
..05 mfd ceramic disc cap and a 1N34A diode. Then I'm calculating
thusly:

Power = (Voltage x Voltage) / 50

I'm taking the author's word that this works for a ballpark estimate.
I'm measuring 7 volts across the load, maximum, which works out to 1
watt or less. I've verified that my meter is accurate.


I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground.

That's *way* too low! As you must know for any ariel, you gotta get
that thing up as high off the ground as you can and that's even more
important at low frequencies like 7Mhz.

We have a mess of power lines around the house, so it's hard to find a
spot to even get it 7 feet high in a straight line. I'm thinking
about trying it on the roof, which is about 20 feet high at the
highest point, and mabye angling it in the center.


One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Something's wrong, then. The heat dissipated in your final transistor
should equate to the output power at the antenna if the system is
matched properly. Sounds like your tranny's trying to dissipate rather
more than a Watt. Are you sure you don't have a feeder/matching
problem somewhere? Have you cut the ariel to the right length? Are you
using a balun? Have you tried a substitute balun?

The length of each element is 32' 11", which I calculated for use at
7110 kHz. There's no balun; I'm using coax, the shield is connected
to one element and the center conductor is connected to the other.
The coax might be 75 ohm. Pretty soon I'll have RG-58 for the entire
run, but right now it's a mix of RG-6/U and RG-59/U.


Get another ham a couple of miles away from you to give you a signal
report. It might show up something useful.

I will do that. Thanks.
--


-John Sandin KC0QWE

Remove the "T" to respond by e-mail

The circuit you describe should be delivering approximately the peak
voltage, not RMS, so the formula is more like V X V / 100. At 7 volts
peak, that means you're putting out around 1/2 watt. That's a lot below
the 3 watt figure you mentioned, so you should track down why it's so
much lower. Pay special care to the circuit components in the final
transistor output (collector) circuit, and make sure the inductors are
built as described and the components are connected correctly.

Roy Lewallen, W7EL

John Sandin wrote:
. . .
Voltage is measured across my 50 ohm dummy load and rectified using a
.05 mfd ceramic disc cap and a 1N34A diode. Then I'm calculating
thusly:

Power = (Voltage x Voltage) / 50

I'm taking the author's word that this works for a ballpark estimate.
I'm measuring 7 volts across the load, maximum, which works out to 1
watt or less. I've verified that my meter is accurate.
. . .

The circuit you describe should be delivering approximately the peak
voltage, not RMS, so the formula is more like V X V / 100. At 7 volts
peak, that means you're putting out around 1/2 watt. That's a lot below
the 3 watt figure you mentioned, so you should track down why it's so
much lower. Pay special care to the circuit components in the final
transistor output (collector) circuit, and make sure the inductors are
built as described and the components are connected correctly.

Roy Lewallen, W7EL

John Sandin wrote:
. . .
Voltage is measured across my 50 ohm dummy load and rectified using a
.05 mfd ceramic disc cap and a 1N34A diode. Then I'm calculating
thusly:

Power = (Voltage x Voltage) / 50

I'm taking the author's word that this works for a ballpark estimate.
I'm measuring 7 volts across the load, maximum, which works out to 1
watt or less. I've verified that my meter is accurate.
. . .

On Sun, 05 Oct 2003 13:50:43 +0100, Paul Burridge
wrote:

snip

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less.

How is this figure arrived at? How are you measuring it? 1W doesn't
sound much, but it can go a long way on 40M., given an efficient
antenna system with short, low-loss feeder and matched radiation
resistance.

Voltage is measured across my 50 ohm dummy load and rectified using a
..05 mfd ceramic disc cap and a 1N34A diode. Then I'm calculating
thusly:

Power = (Voltage x Voltage) / 50

I'm taking the author's word that this works for a ballpark estimate.
I'm measuring 7 volts across the load, maximum, which works out to 1
watt or less. I've verified that my meter is accurate.


I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground.

That's *way* too low! As you must know for any ariel, you gotta get
that thing up as high off the ground as you can and that's even more
important at low frequencies like 7Mhz.

We have a mess of power lines around the house, so it's hard to find a
spot to even get it 7 feet high in a straight line. I'm thinking
about trying it on the roof, which is about 20 feet high at the
highest point, and mabye angling it in the center.


One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Something's wrong, then. The heat dissipated in your final transistor
should equate to the output power at the antenna if the system is
matched properly. Sounds like your tranny's trying to dissipate rather
more than a Watt. Are you sure you don't have a feeder/matching
problem somewhere? Have you cut the ariel to the right length? Are you
using a balun? Have you tried a substitute balun?

The length of each element is 32' 11", which I calculated for use at
7110 kHz. There's no balun; I'm using coax, the shield is connected
to one element and the center conductor is connected to the other.
The coax might be 75 ohm. Pretty soon I'll have RG-58 for the entire
run, but right now it's a mix of RG-6/U and RG-59/U.


Get another ham a couple of miles away from you to give you a signal
report. It might show up something useful.

I will do that. Thanks.
--


-John Sandin KC0QWE

Remove the "T" to respond by e-mail

Several comments ....

When your output is a LOT different than you expect, likely there is
something wrong. Worse, there's a good chance that a lot of your energy is
being transmitted where you don't expect.

One thing that I found helpful on my first homebrew adventure was to model
any circuits that didn't seem to be quite right in PSpice. It's tedious,
but it helped me immensely in understanding what's going on.

Secondly, a 40 meter antenna 7 feet off the ground is going to radiate
pretty much straight up. That means that the only time any of your energy
will get back to the ground is when the flux is very high, something that is
happening less and less often. Worse, 40 meters is pretty noisy, and the
old novice segments really not all that heavily occupied, so not getting a
response right away isn't all that surprising.

If your output transistor is getting really hot you probably want to revisit
your heat sink. If you have, or can borrow, a scope, take a look around and
make sure that circuit is doing what you want. The heat could be telling
you that a lot of your energy is being spent in parasitics. Presuming you
have filtering after this transistor, that could be related to your low
output, as well.

If you have, or can borrow, a general coverage receiver, listen for your
transmitter on your fundamental, and on the harmonic frequencies, especially
the odd harmonics. You probably will be able to hear your transmitter on
21.330, but it should be a LOT weaker. If it isn't, you have a problem.

Finally, I would try to find someone local (line of sight, say 10-20 miles
if it's reasonably flat) and arrange a schedule. This won't take any
propagation and it will give you some idea that your transmitter is working.
Recognize that locals are often a lot weaker on 40 than stations more
distant, but if there are huge issues then perhaps this will uncover them.

Finally the chirp - get a fat wire from your power supply to the radio.
Also, make sure that the power path to the oscillator is very low
resistance. It doesn't take much voltage change to shift the oscillator
frequency, and there is a huge inrush of current on key down, so good old
E=IR tells you that with a big I it doesn't take much R!

Hope this helps...

...

"John Sandin" wrote in message
...

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less. I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground. I'm using fundamental frequency HC6/U crystals for 7110 and
7125 kHz. I've been trying for 2 weeks, at all hours of the day and
night, and have had no indication that anyone hears me. I've called
CQ, and I've attempted to answer CQ's. Nothing, after about 100
tries.

I know it's impossible for any of you to know exactly what's wrong,
but I'd like to see what opinions I can glean here.

Is there any reason why I should use FT-243 crystals, as specified in
the article and on the website? I used HC6/U crystals because they
were easy to get.

One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Also, the transmitter chirps a bit at the beginning of each
transmission, but settles down after a few strokes of the key.

Many thanks for any help you can give.


-John Sandin KC0QWE

Remove the "T" to respond by e-mail

John,

I can't get your URL to bring anything up in my browser.

If your final Q is getting REAL hot upon keydown in a very short period of
time, I'm guessing you have some circuit issues there.

I had a similar problem with a little Tuna Tin transmitter I built a couple
years ago, my problem was my antenna was broken. It was not resonant on
7040, which was the crystal I had in the transmitter. It was way off.
After I replaced the final a couple of times, I broke out a SWR meter and
noticed the mismatch. A new dipole 15 minutes later did the trick.

I run a 40m 1/2 wave dipoe in the very top of my attic peak, so it's about
30 feet off the ground...which is pretty low for 40m anyway but I get out
pretty well.

If you do not subscribe to QRP-L I suggest you try there for some answers.
Some of the brightest low power folks in the world are there.

See: http://qrp.lehigh.edu/lists/qrp-l/

73

"John Sandin" wrote in message
...
I am a new technician with code privileges. I built the following CW
transmitter for 40 meters:

http://cs.okanagan.bc.ca/ve7ouc/eng/...nsmitter2.html

It's a solid state 3-watter, based on an article in QST in June 1967.
I used a printed circuit board instead of wiring everything together
directly, as the QST article suggests. So, there are many wires
running from various parts mounted on the chassis to the circuit
board.

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less. I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground. I'm using fundamental frequency HC6/U crystals for 7110 and
7125 kHz. I've been trying for 2 weeks, at all hours of the day and
night, and have had no indication that anyone hears me. I've called
CQ, and I've attempted to answer CQ's. Nothing, after about 100
tries.

I know it's impossible for any of you to know exactly what's wrong,
but I'd like to see what opinions I can glean here.

Is there any reason why I should use FT-243 crystals, as specified in
the article and on the website? I used HC6/U crystals because they
were easy to get.

One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Also, the transmitter chirps a bit at the beginning of each
transmission, but settles down after a few strokes of the key.

Many thanks for any help you can give.


-John Sandin KC0QWE

Remove the "T" to respond by e-mail

On Sun, 05 Oct 2003 04:42:11 GMT,
(John Sandin) wrote:

I am a new technician with code privileges. I built the following CW
transmitter for 40 meters:

http://cs.okanagan.bc.ca/ve7ouc/eng/...nsmitter2.html

It's a solid state 3-watter, based on an article in QST in June 1967.
I used a printed circuit board instead of wiring everything together
directly, as the QST article suggests. So, there are many wires
running from various parts mounted on the chassis to the circuit
board.

I'm getting very little output. After tuning the transmitter, per the
specs, and measuring the output using the method suggested by the
author of the web page, I figure I'm getting 1 watt or less.

How is this figure arrived at? How are you measuring it? 1W doesn't
sound much, but it can go a long way on 40M., given an efficient
antenna system with short, low-loss feeder and matched radiation
resistance.

I am
running this into a dipole cut for 40 meters, which is 7 feet off the
ground.

That's *way* too low! As you must know for any ariel, you gotta get
that thing up as high off the ground as you can and that's even more
important at low frequencies like 7Mhz.

I'm using fundamental frequency HC6/U crystals for 7110 and
7125 kHz. I've been trying for 2 weeks, at all hours of the day and
night, and have had no indication that anyone hears me. I've called
CQ, and I've attempted to answer CQ's. Nothing, after about 100
tries.

I know it's impossible for any of you to know exactly what's wrong,
but I'd like to see what opinions I can glean here.

Is there any reason why I should use FT-243 crystals, as specified in
the article and on the website? I used HC6/U crystals because they
were easy to get.

One of the transistors (Q2) is supposed to be heat sinked. I have put
a large homemeade heat sink on this, using plenty of heat sink grease,
and it gets so hot I can barely touch it.

Something's wrong, then. The heat dissipated in your final transistor
should equate to the output power at the antenna if the system is
matched properly. Sounds like your tranny's trying to dissipate rather
more than a Watt. Are you sure you don't have a feeder/matching
problem somewhere? Have you cut the ariel to the right length? Are you
using a balun? Have you tried a substitute balun?

Also, the transmitter chirps a bit at the beginning of each
transmission, but settles down after a few strokes of the key.

Many thanks for any help you can give.

Get another ham a couple of miles away from you to give you a signal
report. It might show up something useful.
--

"Windows [n.], A thirty-two bit extension and GUI shell to a sixteen bit patch
to an eight bit operating system originally coded for a four bit
microprocessor and produced by a two bit company."