I won't have time to install it
until next week.
That tuning coil is a little shakey,
I hope it tunes down there.
This is another interim channel. It's
better than 1020.
I want to see how different things are
at the low end of the band. Performance
wise.
620 Khz, the ultimate destination, will
happen if I can build an RF generator and
hook it into that 6AL11 RF stage.
So 620 is a ways off.
Bruce, W 60 HZ
I am going to take a wild guess that it's not the crystal that will take a week to slide into it's socket, but the tuning of that LC tank.
Wasn't that 6A TX on a lower frequency to begin with anyway? If it was it should tune up just fine to 550 or 620.
RFB
The transmitter was originally on
640. Then it was on 860. 860 was
a bad channel. 640 has been useless
for decades. I also had an oddball
crystal for 945 kHz, which was lost,
but I did try transmitting there
30 years ago.
Various friends of mine have had the
transmitter. It was in California
a few years ago, and after that, it
was being worked on in New Jersey,
as I'm sure you remember. I've owned
it for more than 30 years. I never
imagined it would become the main transmitter
at this Part 15 station.
I'm worried about the adjustable tuning
coil. My friend in New Jersey said it
looked like part of it is broken. I
can't tell where by looking at it.
But, anyway, this is why I'm not sure
if the unit will go down to 550 kHz.
If the coil has a problem it might not.
We'll see. If that doesn't work, or
if the crystal is bad, I'll just stay
on 1020 for now.
The transmitter is in a physical position
such that it is hard to get to. That's
why I can't get it down to 550 kHz right
away. I have to move a bunch of other
gear to even get to it.
Since the Dog Radio studio was dismantled,
I have just had stacks of equipment that
I have been using and working on. Where
ever we end up, there will be a studio
of some kind.
Best Wishes,
Bruce, W 60 HZ
...but there are interesting problems.
I will be back with a report as
soon as I can.
It's just on a dummy load right now.
Bruce, W 60 HZ and X-13
We all have days when we feel like a dummy load.
550 is a great channel. We have a 5kW station here on 550 that was founded by the St. Louis Post Dispatch in the 1920s, and back then shared their frequency with a Lutheran Church station.
Stations at that low end of the dial seem to have fatter signals than on the upper end, where signals seem very narrow.
I am very curious about your 550 report when it arrives.
Yup. 550s connected to the AC line
now. Night is not a great time
to check telephone poles.
I'll be up early in the morning
trying to look discrete out there.
There is a wonderful station in
Vermont that has great historical
value, and they are on 550 kHz. It's
a real down hometown station called
WDEV. They even have a WDEV truck
from the 1930s that has been restored.
I have read about them in the broadcast
blogs, and you should check out their
website, just to see that truck.
They used to stream SOME shows. I don't
know if they still do. I have
tried with the best phased antenna system
I could build to try to hear them on 550.
I have actually gotten them a few times,
but they are not dominant on the channel.
For years, on Saturday Mornings, they had
a great show called, "Music To Go To The
Dump By." That show is no longer on, but
it was very popular. The GM ran it, I
believe, and he did it with his dog, who
he called, "Butch, the Wonder Dog," if
I remember correctly. He would talk to the
dog and do the show. Somewhere along the
line, the dog passed on, and the GM retired
the show. WDEV is one of a kind. Although,
the station here in CT on 1150 that I have
mentioned - does a very very good job, too.
But I don't think they had some of the humor
that WDEV had in that "Dump" show. I wish 1150
was on FM here. That would be great.
I will have notes probably tomorrow about my
550 venture. As it seems, my LPB RC-6A CC
transmitter was just barely on 1020, but
resonance was good, and the neon light indicator
that shows transmitter resonance glowed brightly.
Now, on 550, I am way on the other end of the
tuning range. As mentioned before, i think
this particular RC-6A goes from 540 to 1000.
That's why I was so lucky to get it working
so well on 1020.
Now, that it's down on 550, it sounds OK, but
not quite as good as it did on 1020. I can
only get 4 watts out, instead of 6. The neon
bulb is dark, so the transmitter is not as
happy as it was before. We'll see.
This is a great experiment as far as I'm concerned.
More to report tomorrow.
Best Wishes,
Bruce, "What are the callsigns I'm using this week...?"
"uhhh..." "...can't remember..."
BIG QUESTION
So far, I cannot get the transmitter
to go into resonance. It is doing
only 4 watts out. I have found that
the right compression trimmer has a
slight problem. I saw the power jump
up to 6 watts once, as I was tuning the
cap, but I couldn't get it to stay there.
I had this problem on 1020, also, but
eventually, it straightened out.
Will this slight detuned condition hurt
the 6AL11 RF tube?
What do you guys think?
Bruce, W 60 HZ, now on 550 kHz CC
"Will this slight detuned condition hurt the 6AL11 RF tube?"
Probably not. However it is probably why the audio is a bit low compared to the previous frequency when the LC tank was at closer resonance.
It's never good to run a TX even slightly off tune. 2 watts off resonance might not sound drastic on the outside but inside that second half of that tube there is high VSWR because the LC isn't quite resonating properly.
Wish I could find my manual to that unit. It was so long ago when I owned a RC-6A. But it sounds like those compression caps are in dire need of replacement.
RFB
Well, those compression caps
are old. I don't even know
if I'm staying on 550. But
I want to see how the signal
goes through the power line
and get some insight on that.
I am very interested in what
the low end of the band can
do under these conditions.
I may go back up to 1020 soon.
Well see.
Here's another question for you.
This 550 rock is teeny. It's
not much bigger than a CB channel
crystal that would go into a
CB walkie talkie. It has wire
leads. Although it seems to be
doing fine and is not physically
warm or hot on the outside, I
know that these little crystals
can shatter just because of the
energy that is going through them.
So far so good, but what do you
think about that?
Bruce, 550 kHz CC Experimental,
and tagging along behind - X-13
on 13.560 MHz
I know you wish you could find
an RC-6A manual around and that's
really a nice gesture.
But that's OK.
You know what's funny - somewhere
around here, I have a schematic
of an LPB RC-5A. I've never heard
of it. It uses only 2 6AL11s,
instead of the 3 that the RC-6A
uses.
I should find it and look at it
just for fun.
Bruce, CC 550
speaking of manuals i am accepting pdf's, or jpg's scans of any manuals, schematics and tech info related to part 15 and/or carrier current. i have had some server space (about 2gb) donated and i will be building a technical archive for part 15 us. looking for manuals for transmitters, studios gear, processors, etc.
Great kc8gpd
When you have a link let us know.
I will link it from my website.
it will be linked to here as a book page
Hi Carl and Robert and the rest
of the gang:
Hmmmmm.
My 550 kHz CC signal
goes nowhere.
I will be doing some
exploring. Perhaps
something is broken
and I don't know it.
It could be something
in my homemade coupler.
Best Wishes,
Bruce 550 kHz zilch radio so far
"I have a schematic of an LPB RC-5A. I've never heard of it. It uses only 2 6AL11s, instead of the 3 that the RC-6A uses.
By all means reference that 5A schematic!!! Same puppy for the oscillator/modulator/final. It should have the same variable compression caps.
RFB