All in the days work for a Part 15
operation.
Hi Guys!
One of my audio processors decided not
to process audio anymore. Now it boils
eggs, but I'm not hungry.
All in the days work for a Part 15
operation.
Hi Guys!
One of my audio processors decided not
to process audio anymore. Now it boils
eggs, but I'm not hungry.
My DBX 160X processor (from an old radio
station equipment pile) looks great and
all of the wonderful LED bargraphs are
all pretty with bright LED orange and red.
Nothing is coming out the back output jacks,
though. Oh well. I've got other processors
on the big pile. This had been a really good
processor for AM transmitters. It's mono. Well,
actually... now it's not anything.
So be it.
The MPX-96 workhorse FM transmitter got unstable
and is putting out weird stuff. I noticed it right
away. In my opinion, that's why it's important
to comply with Part 15.239 - at least in this
particular case. The MPX-96 only sent RF around the
house, so nobody got interfered with. I believe
I know what's wrong. There is an important coil
in there that might need adjusting. Still, this
workhorse will only be "horsing around" around the
property, if I can fix it. We'll leave the attempts
at a little more signal coverage to the certified
FM transmitters. The C Crane is lent out to a friend.
That just leaves the $11 Maxell P-13. It's chugging
away on 88.3 this morning. Mot going too far, either,
but I sure like the thing, for what it is. Too bad
it only operates on 88.1, 88.3, 88.5, and 88.7.
"Crazy ideas dept" I was thinking of combining the output
of the Maxell P-13 with another oscillator to mix up to
another part of the FM band. Yeah, that will be the day.
Still, it's cool for a science experiment. I'll probably
never do it.
Weird AC line impedance changes here at "W 60 HZ." I don't
have any equipment to measure this. I can just tell
from observing everything involved with this experiment.
RFB was and is right about his CC stuff.
A friend of mine who knows a guy who knows another guy
has located another stash of AM BCB crystals. I might
be changing channels from 1020 kHz (for the CC operation)
to something lower on the band. I also might get a crystal
and grind it to get onto 620 kHz, my channel of choice.
These are all long term projects, but they are part of
the fun. Work on the CC coupler continues. I'm going to
build a wide range tunable coupler someday. I'm learning
more and more about how to do it.
Odd audio recorder discovery:
I went out and brought an audio recorder - like
a micro cassette recorder - except that it's
completely solid state. This thing is a Sony
- um - I'll have to get the model number later.
This teeny and very elegant little device works
great for my job, where I make notes of what I'm
doing - so I don't have to write them down.
Then I realized how great the fidelity is on this
little unit. Then I saw it was sampling at 192 kbits/sec.
It has jacks for an external mike and external earphones.
So I built an audio attenuator and fed in music. It sounded
great through the little speaker. Then I hooked it up
to the home audio system for playback. Oh man - great HIFI!
Was I surprised.
And then, after a great many experiments, I realized that this
little recorder records in STEREO! There is nothing on the
box that even mentions stereo.
I have no computer here, so this thing just became a music
recorder. What a deal for $40! I rigged up an external power
connection so it does not have to work on batteries. It
also has a very good audio limiter, in case the audio into
it gets to be too great.
I'll check on the model number. More advanced units have
SD cards and USB ports.
As is, at 192 kB/sec, it get 21 hours of great HIFI stereo.
You can lower the sampling rate. I am going to try this.
The amount of music stored on there could be very great.
Are there limitations with this little jewel? Sure.
But, for what it is, I'm really happy.
Will, that's it at lake Wobegon. I hope I spelled
it right.
Bruce, "W 60 HZ" - AM 1020 "The best hum on your radio dial"
Bruce,
It appears that your equipment situation may be a blessing or a curse depending on your perspective. On the one hand it is a nuisance to have things break but if you enjoy fixing things it can be a bit of a perverse blessing. You won't become bored since there will always be something to do. That's the way it is around here with something always needing attention.
It would be great if you can snag some more BCB crystals but failing that would you want the schematic of a PLL that I just put together? It runs on a cheap but really stable crystal available from Mouser for about $1.35 and produces a 5 V logic level square wave out from 40 kHz. to 2.5 MHz. I built it as a spare for my AM txmtrs and am planning to try it as the frequency element of my old Knight Kit broadcaster just for fun. I haven't worked out how to suppress the harmonics so it will feed a tube input but a simple LC filter should work. The voltage level, if shifted with a capacitor, matches the input at the grid of the KK final so it is close to working.
Those pocket solid state voice recorders are neat and I might put one on my Christmas covet list. I have learned that some of them use proprietary file structures requiring the manufacturer's software to download but it sounds as if yours is MP3.
Neil
Neil, the circuit you have might be what I'm waiting for to complete the Deep Voice LW transmitter.
I have a PLL circuit, but am lacking an oscillator to connect it with for long wave use.
Can the oscillator section of your invention be applied to another PLL circuit (the one I already have)?
This one is DATAKit P.L.L. Experimenter Kit No. 80-035
Carl,
"Can the oscillator section of your invention be applied to another PLL circuit (the one I already have)?"
No, but doesn't the one you have cover the long wave band?
I designed this one to cover the BCB but it covers from 40 kHz to 2.56 MHz in 10 kHz steps. This is a wider frequency range than predicted by theory.
Maybe it could be modified. What frequency range and steps would be needed?
Neil
The range is based on 15.217 -- Operation In the Band 160 - 190kHz
Here in the Introduction to PLL-Experimentor's Package it says, "Although the PLL-EXP1 is not a "complete kit" ... the prototyping area is large enough to accommodate both an oscillator circuit and RF amplifier stages."
The literature gives some general oscillator circuits, but leaves it to the experimenter to build in the features that define the operating frequency range.
Based on previous discussion in the LW Deep Voice Transmitter thread, the buffer of the Big Talker SW transmitter we designed will be used, together with the special LW final stage you yourself submitted.
This PLL states that it is keypad controlled in 10kHz steps, but RFB indicated that it will actually provide 1kHz steps in the LW band.
The exact target frequencies being sought are 162 and 180kHz, suggested by The Crow for our LW Radio Network being discussed at that time.
I would love to feed the transmitter
with that solid state digital "VFO."
That would put me on 620 kHz, where
I want to be.
But one of my engineer friends told me
that the 6AL11 RF section (osc and power amp)
has to be modified to be fed by another
oscillator. In other words, you can't
just feed the circuit into the crystal
socket - it won't work.
I'm going to have to go in a minute. But thank
you for the comments, this makes me think
about this stuff more. And I will.
I actually like it when things are broken. I have
a lot of old equipment and there is a lot of
redundancy here. When something breaks I can
usually piece something else together.
The Dogradio studio/1690/1700/W 60 HZ is a
wonderful wonderful experiment.
And this digital recorder - what a find. This
one cannot connect to a computer.
(Which is fine - the set-up has no computer) -
but there are other units that can. I couldn't
believe it when I realized it could do stereo.
I was super happy just to store tons of mono
music for the AM transmitter. And then I find
it's stereo. Yikes.
Maybe RFB would have a way to feed the 6AL11
osc. section on the CC transmitter with an external
RF drive source. If he does, I will start
saving up for one of the versions that you
guys have described.
Very best wishes,
Bruce, W60HZ - - AM 1020 CC
P.S. Carl - I'm glad you are still doing the
LW work. I will be following you, eventually.
I think you guys are right, either
Neil's circuit, or the one RFB has
described, could drive my CC transmitter.
I wonder if it would need a buffer stage
to drive the 6AL11 RF section?
The other way, which would be fun too -
in MY opinion, would be to get a lower
frequency rock and grind it up to
channel. I actually know a guy who
is my age (58) who is really good
at grinding crystals. He could show me how.
Back to the programmable osc. circuit, could
it be phased locked to make an FM transmitter
(I mean easily for a guy like me) or is this
too much of an open ended question?
Best Wishes,
Bruce, W 60 HZ - - AM 1020 CC
"Listened to - next to telephone poles, everywhere"
P.S. I'm raising power for a brief test tonight.
This is for the carrier current set-up. I'm going
up to 6 watts into the neutral, at the advice
of a local BC engineer, who has been working
with me on this.
KABLAMM!! (Hope not) Very very brief.
OK. Looking back - I see Neil,
that your circuit only goes up
to 2.5 MHz. That would be fine for the
CC transmitter.
Best Wishes,
Bruce, W 60 HZ - - 1020 AM CC
P.S.
Any future CC reports I have will go in
the CC thread. But I guess talk about
programmable osc. circuits will stay here?
Somehow I opened this thread
twice at the same time and lost
a couple of comments.
My fault - not yours.
that's OK.'ll be back.
Bruce, W 60 HZ - - 1020 AM CC
"Listened to - next to telephone poles
everywhere"
Sorry about that, and
you guys are very good at what you do.
Eyes are going. Must take a rest.
Bruce, W 60 HZ - - 1020 CC AM
"It really DOES hum, but doesn't
know the words"
Carl,
I can't tell from the description on the website much about the PLL "Kit" you have so I am going to let it be for now. I did some checking and the PLL circuit I designed can be easily modified to work from 160 to 190 kHz in 1 kHz steps using a 58 cent crystal available from Mouser. Here's a LINK to the schematic so you can see what's involved and if you are interested in building this I will work out the details on the modifications for operation in the LW band. It involves changing the crystal, one wire connection, and one or two of the resistors/capacitors. I built mine using the "dead bug" method and it wasn't too difficult.
Bruce,
"But one of my engineer friends told me
that the 6AL11 RF section (osc and power amp)
has to be modified to be fed by another
oscillator. In other words, you can't
just feed the circuit into the crystal
socket - it won't work. "
I do not have a copy of the schematic for your unit but I have plugged VFOs into crystal sockets with success. It depends on where in the circuit the crystal is connected and the biasing would have to be checked but it can work, Your consultant is correct in that it may take a bit more than just plugging into the crystal socket but there is most likely a way to make it work. What I am going to try with my Knight Kit is to couple the PLL output through a transformer with a low Q tuned secondary right into the crystal socket.
There is also the possibility of pulling the oscillator tube and connecting the PLL output to the next stage grid circuit. The signal level out should be adequate to drive a tube stage but some filtering may be needed to provide a sine wave. It depends on the tube circuitry involved but it most likely can be done.
By the way, a reminder to be careful working with tube circuits. Last night I received a strong reminder of this when I got across a 1000 VDC source. My arm is still sore. What happened is I turned off the HV supply with the switch on a power strip on the workbench but a clipboard I had placed nearby bumped the switch and turned it on as I was moving things around. I didn't notice this and picked up the tube socket and got zapped from finger to thumb which made the muscles in my arm contract. Fortunately, with DC you can usually pull away which is what I did. Many years ago I took a 1200 VDC jolt arm to arm and for a week it felt like a horse had kicked me in the chest.
Neil
The DataKit unit will work fine just needs an oscillator. It's instruction manual has great oscillator examples.
But if you need something easier, and just needs dip switches added or jumpers, then try THIS.
RFB
The oscillator examples printed in the DATAKit PLL papers are not specific for long wave, they show sample inductor and varactor values required for operation in the FM frequency region.
In essence they need to be design engineered to become able to provide long wave output.
I am looking for an oscillator that is already designed for long wave and compatible with this PLL.
Thanks for the info on the freq.
generators and thoughts on how to
hook them to the my transmitter.
I really appreciate the interest.
STORIES YOU MAY HAVE HEARD BEFORE DEPT.
I got across a 150 DC volt supply bus
on an old radio teletype machine
30 years ago. The muscle contraction
smashed my arm into the inside of an
equipment rack and I got a little
cut up.
CC experiments continue. I will have
more on that thread soon.
Thank you, my friends,
Bruce,
W 60 HZ - - "1020 AM CC"
"Coming to a telephone pole near you!"
"I am looking for an oscillator that is already designed for long wave and compatible with this PLL."
Actually those oscillator examples in the PLL manual are NOT specific to just FM. More accurately stated they are shown with parameters to work in VHF. But that does not mean any of them cannot be changed to work in LW. Taking ANY one of those example circuits and building them around LW is doable. All your looking for is a CW signal, thus you don't need to be concerned about modulating that oscillator, so leave out the section for modulating.
At some point, one has to go beyond the "plug and play" and get their feet wet, or hands dirty, or break out the "Electronics 101" book and start building and experimenting.
I sent you an excellent candidate oscillator schematic some months ago which is basically a design stolen from an old 6 transistor AM radio (yeah those old Japan made 9 volt jobbers). I even added the circuit for the varactor and oscillator "tin can" inductor (red). You should have that in your arsenal files somewhere. That oscillator is built around working in the LW band too. All you need to do is simply round up the junk parts and build it. Be done in less than an hour if even that long.
But if plug and play is what you want, then try that PLL/Oscillator I linked to before (THIS ONE) and add the jumpers or dip switch banks and set for a LW frequency. It spits out the actual frequency you want to operate on. Feed it's output into the final stage of that LW thing and your done.
I find building and experimenting far more pleasing and rewarding than finding something pre-built and plug and play. Learn more and retain more by doing.
RFB