"Pete KE9OA" wrote in message
...
One more thing I forgot to mention............I am also adept at aligning
all Drake receivers, up to the '7 line.
Thanks!

Pete

"Pete KE9OA" wrote in message
...
Hi folks,
My job at at my present employer is winding down, so it
might be time to market some of my other products and services.
Would there be interest in.............................
1. a DDS based AM signal generator, tuning steps down to 10Hz, coverage
from 10Hz to 30MHz. This could go all the way up to 60MHz.
2. A DDS based VFO that has programmable offset for the displayed
frequency............good for an LO for your receiver experiments.
3. A DDS based replacement for the Drake FS-4 synthesizer, that has a
projected price of about 130 dollars. Some of you Drake list folks may
have seen this inquiry posted by Dan.
4. Receiver mods, such as attenuator removal, etc. I could do audio mods
to receivers, but since Craig, over at Kiwa is already doing this, I
don't want to encroach into his territory. I have spoken to him in the
past, and he is a good guy, as well as being a straight shooter.
5. Receiver characterizations, such as sensitivity, overload point,
distortion measurements. I have all of the equipment necessary to do
these characterizations. Price for this service would be 30 dollars, plus
shipping.

There are quite a few ideas that I have, but if there is some kind of
service you are looking for, please e-mail me directly and let me know. I
can do some receiver repairs, including the Lowe HF-150, and I can align
just about any receiver, including the old tube boatanchors. I have
restored and aligned: all Hammarlund receivers, most of the Hallicrafters
and National receivers, Collins receivers.
I am also set up to do stereo FM tuner alignments. I can verify stereo
separation up to at least 65dB, and distortion measurements down to
0.0015%.
Before I started designing radios, I used to design and build custom
audio equipment for folks.
Thanks for looking at this post................once again, it would be
good to contact me directly so that I don't end up starting a long
thread, but I will check this one from time to time.

Pete

I think there is actually a market for all of the above, Pete.

73,

Steve Lawrence
Burnsville, MN

BTW - I saw your post about the Cedar Rapids Hamfest. We probably walked
right past each other a dozen times or so, but didn't know it. (I lived in
Dubuque
a few years ago)

That could very well be.....................I used to set up at those
hamfests with one of my plexiglass receivers. Nice hamfest. I never saw so
many honest people in my life. I have a friend from Dubuque; his name is
John Richardson. He would always set up a long tent over several tables. He
looked like an American Indian with that long ponytail, and he always would
have some cool stuff, like those old RCA navy receivers, R390s, R338s, and
other super cool stuff. Last time I ran into him was at Radio Expo last
September.

Pete

"Stephen M.H. Lawrence" wrote in message
news

"Pete KE9OA" wrote in message
...
One more thing I forgot to mention............I am also adept at aligning
all Drake receivers, up to the '7 line.
Thanks!

Pete

"Pete KE9OA" wrote in message
...
Hi folks,
My job at at my present employer is winding down, so it
might be time to market some of my other products and services.
Would there be interest in.............................
1. a DDS based AM signal generator, tuning steps down to 10Hz, coverage
from 10Hz to 30MHz. This could go all the way up to 60MHz.
2. A DDS based VFO that has programmable offset for the displayed
frequency............good for an LO for your receiver experiments.
3. A DDS based replacement for the Drake FS-4 synthesizer, that has a
projected price of about 130 dollars. Some of you Drake list folks may
have seen this inquiry posted by Dan.
4. Receiver mods, such as attenuator removal, etc. I could do audio mods
to receivers, but since Craig, over at Kiwa is already doing this, I
don't want to encroach into his territory. I have spoken to him in the
past, and he is a good guy, as well as being a straight shooter.
5. Receiver characterizations, such as sensitivity, overload point,
distortion measurements. I have all of the equipment necessary to do
these characterizations. Price for this service would be 30 dollars,
plus shipping.

There are quite a few ideas that I have, but if there is some kind of
service you are looking for, please e-mail me directly and let me know.
I can do some receiver repairs, including the Lowe HF-150, and I can
align just about any receiver, including the old tube boatanchors. I
have restored and aligned: all Hammarlund receivers, most of the
Hallicrafters and National receivers, Collins receivers.
I am also set up to do stereo FM tuner alignments. I can verify stereo
separation up to at least 65dB, and distortion measurements down to
0.0015%.
Before I started designing radios, I used to design and build custom
audio equipment for folks.
Thanks for looking at this post................once again, it would be
good to contact me directly so that I don't end up starting a long
thread, but I will check this one from time to time.

Pete

I think there is actually a market for all of the above, Pete.

73,

Steve Lawrence
Burnsville, MN

BTW - I saw your post about the Cedar Rapids Hamfest. We probably walked
right past each other a dozen times or so, but didn't know it. (I lived
in Dubuque
a few years ago)

I am using a modulator circuit that I found on the web. An Exar function
generator chip provides the modulation. I will probably go with a Twin T
oscillator for the final product. I am using an AD9851 for the RF source.
I had actually thought about some sort of loop antenna. The Wellbrook design
looks pretty interesting. It appears to use a diff amp as the input stage
for their RF amplifier, probably using some sort of CATV transistor for the
final amp. If there is a good market for something like this amplifier, I
could probably develop it. Last year, I did some experiments with a
regenerative RF amplifier but ran into a brick wall trying to find those
linear optoisolators. Maybe I will give that another try.
An interesting about receivers that use those 50 ohm Mini-Circuits
doubly-balanced ring mixers............you can connect an 8 foot diameter
untuned loop directly to the antenna input of a receiver, closing the loop
at the ground connection on the receiver. LW/MW performance is astonishing,
even with no preamplification. As an example, I can tune to 524kHz and hear
the Iowa City beacon up her in northeast Illinois.

Pete

wrote in message
oups.com...
When you say DDS based generators, how do you propose doing the
modulation? I understand how you can get a carrier from DDS, but do
these chips have digital modulation as well? In the dark ages, I did
DDS (very low frequency) using coordics. This was prior to DDSs being
on the market.

Personally, I'd like to see someone compete with Wellbrook on their
loop antennas. The damn George Bush weak dollar policy really sucks
when you buy stuff from the UK. Hell, it sucks just buying gasoline.
Even making the amplifier such as the Wellbrook ALA 100 would be a nice
product.

Hi Pete. I got my freq converter working. Thanks for your help.

73 and good DXing.
Brian
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A lot of radios and 100' of rusty wire!
Zumbrota, Southern MN
Brian's Radio Universe
http://webpages.charter.net/brianhill/

EMAIL-
(Hide the $100 to reply!)

Pete:
I have seen very linear opto-isolators in a end, custom made
AD converter. Sadly I couldn't get a diagram or even pop the
cover to study the magic. A Advark like USB audio capture
device that had the audio input completly isolated for hum/noise
control. It used 6 "D" cells that where supposed to run it for at
least a year. It was very clean, 24 bits. I hoped we would buy
several. Too pricy for our budget.

I will check around and see if any one remembers the make.

Terry

Another dumb question from me.What are Signal Generators and how do they
work? Are they external devices.I don't know unless I ask? I own one or
two old Signal Tracers,I don't know anything about them or how they are
suppose to be used.
cuhulin

The problem with delivering something that appears to be a bit of test
equipment, is you are competing with used test equipment. When it comes
to test equipment, 20 year old HP wins over brand spanking new brand X
every time. Most of the used gear I've bought over the years is still
used in real labs. I could get it calibrated if I had the need. I have
to think really hard if I ever bought any new test equipment.

If your box was digital through and through, then maybe you might get
some sales. I'm not sure which Exar chip you are using (BTW, I used to
work there), but the Twin-T is an analog topology and thus has all the
bad features of analog as well as the good. It should be possible to
make a completely digital AM or sideband modulator with a DSP chip and
high speed DAC. The coordic is how the sine wave is computed, though at
the time nobody really talked about it since there were still patents
on coordic processors from the scientific calculator manufacturers. One
of the best books I've seen on the subject was a masters or PHD thesis
by a Stanford grad whose full name escapes me. First name Ahmend, which
might as well be Joe or Bill nowadays.

A coordic is a lookup table technique that converges on the the sin and
cos. You make a sine wave generator by accumulating phase, then taking
the sin/cos of this phase value. If the phase accumulator were 8 bits,
you would use a scale where 256 is one revolution. This way as you
accumulate phase, the sine function automatically wraps around after
reaching one revolution. You control the amplitude of the sine wave by
the initial value of the coordic. It's really much easier than it
sounds, at least the algorithm, Programming the DSP is another story.

I suspect the Wellbrook has a jfet amp because of the positive ground.
I think today most CATV circuits are bipolar to simplify the biasing.
For certain frequency ranges JFET has lower noise.You can parallel them
up for lower noise. There are a few companies still serious about
Jfets, but they are becoming less and less since the money is in high
bandwidth.
http://www.calogic.com/ comes to mind as a jfet company

Another idea would be to make VHF/UHF amplifiers using SiGe.

Anytime Brian. There were a few folks who had this kind of project. Are you
the one who was trying to do a frequency translation of I.F. output for a
panadaptor that was designed for another intermediate frequency?

Pete

"Brian Hill" wrote in message
ups.com...

Hi Pete. I got my freq converter working. Thanks for your help.

73 and good DXing.
Brian
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A lot of radios and 100' of rusty wire!
Zumbrota, Southern MN
Brian's Radio Universe
http://webpages.charter.net/brianhill/

EMAIL-
(Hide the $100 to reply!)

Thanks, I appreciate that!
I have some devices laying around that were used in the Boonton modulation
meters, and I also have some that Krohn-Hite used in some of their audio
oscillators. These were Wien Bridge designs that used these devices instead
of the old light bulb in the feedback network. I guess I could do it with an
FET. I do have a schematic for a regenerative preamplifier laying around,
but I haven't put much effort into it. I also have a schematic for the
Quantum Loop preamplifier, but I consider it the designer's intellectual
property; henceforth, I need to come up with my own design as a matter of
ethics.

Pete

wrote in message
oups.com...
Pete:
I have seen very linear opto-isolators in a end, custom made
AD converter. Sadly I couldn't get a diagram or even pop the
cover to study the magic. A Advark like USB audio capture
device that had the audio input completly isolated for hum/noise
control. It used 6 "D" cells that where supposed to run it for at
least a year. It was very clean, 24 bits. I hoped we would buy
several. Too pricy for our budget.

I will check around and see if any one remembers the make.

Terry

The Signal Tracers I own are old and large.As large as some table model
radios or larger.I bought them at a thrift store years ago and I also
own some radio and tv tube testers.About twenty years ago,I read
somewhere that most of those tube testers such as the kind we used to
see in the stores,food stores,drug stores,hardware stores and the
like,are not accurate so as to fool people into buying some new tubes.
cuhulin