"John Sandin" wrote in message
...

I guess it would have been easier and even cheaper to buy a kit. But
I had fun building this, and I guess I'll have almost as much fun
rebuilding it.

One of the wonderful things about amateur radio is that there are so many
facets to explore. Each of us finds his own favorites, but in my mind,
there are few things in life as fun as building and operating your own
equipment.

Your low pass filter leaps out at me. Typically, the coil windings are
spread out over 80% of the toroid, rather than 20%. If, in fact, this was
the intent of the low pass filter design, then your inductances could be
quite a way off. Not only would this change the cutoff frequency of your
LPF (raising it most probably, so not likely the direct cause of low
output), but it would also change the impedance the transmitter sees. (I'm
leaping to the conclusion here that the LPF is between the transmitter and
the antenna). What this means is that the transmitter isn't seeing 50 ohms
even if your antenna is resonant. This would result in the final heating,
and could also favor the parasitics that I suspect we have going on here.

As you explore what's going on here, keep in mind that these things aren't
magic, what they do is always goverened by the laws of physics. Validate by
measurement that what you think is happening is, in fact, what is going on.
You really don't need a ton of test equipment. Granted, lacking lots of
gear, each measurement can be a bit of a project in itself, but once you
have a DMM and have built an RF probe (about a buck's worth of parts), you
can make pretty much any measurement if you think it through.

...

On Sun, 05 Oct 2003 13:27:59 GMT, "W3JDR" wrote:

John,
Can you post a picture of your unit somewhere(top and bottom views) so we
can see what the PCB & wiring layout looks like?


I want to thank everyone. I never dreamed that I'd get so many great
responses, within a few hours of my original post.

I have put up a website with a link to the web page that inspired me
to do this. Below that are a bunch of pics of my project. Any
comments and advice are welcome.

I guess it would have been easier and even cheaper to buy a kit. But
I had fun building this, and I guess I'll have almost as much fun
rebuilding it.


-John Sandin KC0QWE

Remove the "T" to respond by e-mail

I will try to do that sometime during the next day or so. The author
of the website says that the layout isn't critical, and his version of
the project works great. But when I look at the original QST article
and the photos of how they did it (all direct-wired), I'm amazed at
how simple they were able to keep the assembly. So now I'm wondering
why I bothered to use a printed circuit board in the first place.

On Sun, 05 Oct 2003 13:27:59 GMT, "W3JDR" wrote:

John,
Can you post a picture of your unit somewhere(top and bottom views) so we
can see what the PCB & wiring layout looks like? Many times an improper
layout can lead to parasitic oscillations that will raise DC power
consumption without delivering RF on the proper frequency.

Joe
W3JDR




-John Sandin KC0QWE

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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

John,
Can you post a picture of your unit somewhere(top and bottom views) so we
can see what the PCB & wiring layout looks like? Many times an improper
layout can lead to parasitic oscillations that will raise DC power
consumption without delivering RF on the proper frequency.

Joe
W3JDR


"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

Working people with one watt can be challenging, but certainly not
impossible. In the course of a few years, I worked (and confirmed) all
50 states and 33 countries on 40 meters with about 1.5 watts output.

Your antenna height is a big handicap. 7 feet is severely
low for a 40 meter antenna. While you'll still be able to hear stations
just fine, it'll produce a very weak signal from an already weak
transmitter. If there's any way possible, make the antenna higher. I'd
strive for at least 30 feet if possible; higher than that is better yet.
Another option is to use a vertical. With even a poor to moderate ground
system -- even a couple of ground radials (more would be better) --
it'll do much better than the very low dipole.

A hot transistor combined with low output power makes me suspect that
the transistor is either parasitically oscillating or trying to produce
a lot of harmonic energy. That means that you could be producing only a
tiny amount of power on the desired frequency -- much less than even a
watt. Pull the antenna off your receiver and tune around. Does the
signal from your rig sound hissy or hashy? Are the signals at harmonic
frequencies as strong as or stronger than the signal at the desired
frequency? Set up a sked with a ham that's a few miles away (whom you
can locate through a local club), and have him tell you what your signal
sounds like. Have him listen for harmonics, birdies, or other signs of
instability.

Finally, you need to be aware that a crystal-controlled transmitter can
be a big handicap these days. People don't often tune off their own
frequency to listen, and they're likely to have a pretty narrow filter,
so you're not likely to get a response unless you're lucky enough to be
very close to their frequency. That said, your success rate should be
higher when calling someone than when calling CQ, since people are more
prone to respond to a weak signal calling them than to one calling CQ.
But only if you're on their frequency so they can hear you. I couldn't
get the link to the URL to work, so couldn't look at the transmitter
schematic. However, after you get the other problems fixed, consider
modifying the rig to VXO operation (where you're able to move the
frequency a bit) if it's not already VXO.

There's no reason you can't substitute HC-6 crystals for FT-243 in a rig
like this.

Roy Lewallen, W7EL


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. 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

The fact that the connection between the top of L2 and the base of Q2 is
marked as coax is probably a clue that layout is critical.

...

"Roy Lewallen" wrote in message
...

A hot transistor combined with low output power makes me suspect that
the transistor is either parasitically oscillating or trying to produce
a lot of harmonic energy.

The fact that the connection between the top of L2 and the base of Q2 is
marked as coax is probably a clue that layout is critical.

...

"Roy Lewallen" wrote in message
...

A hot transistor combined with low output power makes me suspect that
the transistor is either parasitically oscillating or trying to produce
a lot of harmonic energy.

Working people with one watt can be challenging, but certainly not
impossible. In the course of a few years, I worked (and confirmed) all
50 states and 33 countries on 40 meters with about 1.5 watts output.

Your antenna height is a big handicap. 7 feet is severely
low for a 40 meter antenna. While you'll still be able to hear stations
just fine, it'll produce a very weak signal from an already weak
transmitter. If there's any way possible, make the antenna higher. I'd
strive for at least 30 feet if possible; higher than that is better yet.
Another option is to use a vertical. With even a poor to moderate ground
system -- even a couple of ground radials (more would be better) --
it'll do much better than the very low dipole.

A hot transistor combined with low output power makes me suspect that
the transistor is either parasitically oscillating or trying to produce
a lot of harmonic energy. That means that you could be producing only a
tiny amount of power on the desired frequency -- much less than even a
watt. Pull the antenna off your receiver and tune around. Does the
signal from your rig sound hissy or hashy? Are the signals at harmonic
frequencies as strong as or stronger than the signal at the desired
frequency? Set up a sked with a ham that's a few miles away (whom you
can locate through a local club), and have him tell you what your signal
sounds like. Have him listen for harmonics, birdies, or other signs of
instability.

Finally, you need to be aware that a crystal-controlled transmitter can
be a big handicap these days. People don't often tune off their own
frequency to listen, and they're likely to have a pretty narrow filter,
so you're not likely to get a response unless you're lucky enough to be
very close to their frequency. That said, your success rate should be
higher when calling someone than when calling CQ, since people are more
prone to respond to a weak signal calling them than to one calling CQ.
But only if you're on their frequency so they can hear you. I couldn't
get the link to the URL to work, so couldn't look at the transmitter
schematic. However, after you get the other problems fixed, consider
modifying the rig to VXO operation (where you're able to move the
frequency a bit) if it's not already VXO.

There's no reason you can't substitute HC-6 crystals for FT-243 in a rig
like this.

Roy Lewallen, W7EL


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. 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 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 think all those wires, and the stray L and C they introduce, is the
heart of your problem with getting it to work right.

I'd try building it as close to the way the original article showed as
possible. An inexpensive bread or cake pan can be a good chassis, and
easy to wrok.

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.

7 feet off the ground is less than 1/16 wavelength on 40 meters.
That's just too low.

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.

That's not right. You may have cooked that transistor.

73 es GL de Jim, N2EY