The time: 1962.
My dad had built a really good Heathkit clock
radio, which was also a portable radio that
ran on batteries. A very good AM DX radio.
The time: 1962.
My dad had built a really good Heathkit clock
radio, which was also a portable radio that
ran on batteries. A very good AM DX radio.
It's gone, but I saw one that looked mint on
E-Bay, not too long ago.
He also built the famous Heathkit CR-1 crystal
radio about the same time. We still have that.
it works very well.
Years later, he built a Heathkit color TV. It worked, too.
It also was a good TV DX TV.
Back to 1962, one day my Dad shows up with a "hand held"
(sort of) metal brick shaped box with a big whip antenna
on the top.
He said it was a Heathkit AM transmitter. The case was metal
and green, with some white stripes on it. On the front near
the top was a red tuning knob. The transmitter's tuning range
was from 1400 to 1600 KHz. You spoke into a white plastic
piece that was sort of a sunken cone in the front of the case
near the bottom. The microphone was in a hole in the middle
of the cone. And the transmitter ran on BATTERIES!
On the left of the transmitter case was a red momentary contact
button, sort of push to talk. It was a very small button, and it
hurt to press it for very long.
This thing used 6 or 8 D batteries - it was a huge thing to hold
in your hand. A lot like a military walkie talkie. And the batteries
ran down very very fast. Of course, batteries weren't all that great
in those days. In order to replace the batteries, you had to unscrew
some screws, and the transmitter sort of opened up. It's something
you would have to see. It's hard to explain.
The range as quoted in the instruction manual was 30 feet. But - this was
a hand held unit. The collapsing whip antenna was HUGE. Maybe 4 or 5
feet high. And the antenna unscrewed. so you could store it.
As far as I remember, this thing only used one or two transistors.
And it was LOUD! Lot's of modulation!
I thought about this transmitter because of the other thread that
was asking about simple AM transmitters.
If this thing went 30 feet holding it in your hand, can you imagine
what it might have done with a ground radial system? I wonder.
It was such a peculiar device. But it did work. Somebody knew
their RF theory.
Am I the only person who remembers this thing?
Maybe Heathkit only made one, and WE got it.
It's gone now. i wish I still had it, just so I could
look at the inside and try to figure out how it worked.
Best Wishes,
Bruce, DRS2
I asked this same question back in 2011.
I don't think there ever was an answer, though.
Best Wishes,
bruce, DRS2
That is a wonderful site!
Thank you very much!
Best Wishes,
Bruce, DRS2
I believe that particular unit had several variants marketed under various manufacturers at one time or another..even as recent as 10 years ago.
They are fun, but if you find one might want to modify it so that it's chassis is not at AC HOT potential by installing an actual power transformer or run the thing through an isolation transformer.
Even with a polarized plug on it, having one side of the chassis tied to either hot or neutral instead of earth ground is asking for trouble..not to mention a nice little jolt to rearrange your hairstyle.
RFB
It was the "SK-10 Transistor Portable Broadcaster", part of the Heathkit "Science Series". I still have mine from when I was a kid. It's blue with white stripes. It had a single 2N1274 transistor, 3 resistors, 2 ceramic capacitors, rf coil, mica trimmer capacitor to tune it and a crystal earphone (the kind you stuck in your ear) used for the mic. Since it was for kids there was no soldering - the whole thing was built on Fahnestock clips! The pushbutton was hard indeed to press. Later I replaced the 6 C-cell batteries with an external power supply, bypassed the pushbutton and replaced the crystal earphone and the plastic cone that held it with a 1/8" jack to turn it into my first low power AM radio station. It worked over the entire AM radio band (530-1800 KHz). The frequency tended to drift over time but it was great fun for a 12 year old kid. The manual even explained how it worked on a child's level with cartoons showing electrons as little circular people with legs that talked. It's now part of my antique radio collection as is the Philco 48-1262 AM radio (with tubes) that I used used to pick up the signal. I still have my other low power AM transmitter: the Bud WO-6A "Phono Oscillator" which used a pair of tubes: 50C5 and 35W4. I played 78 rpm records on my station and used a Western Electric carbon mic from a phone as my microphone. As far as I know my sister was my entire audience. When I became 15 years old my dad gave me an EICO 460 oscilloscope with which I could see my AM signal. I was fortunate to have a dad who nurtured my interest in electronics. Thus began my career as an EE.
Dr. B in St. Louis - you described it
perfectly. That is the very same unit
that I had!
It is great that you were able to modify
the unit to run off of AC and take an
external audio connection. I wish I knew
how to do that in 1962.
Outstanding!
Bruce, The DOGRADIO Group
That 1962 Heathkit handheld
AM broadcaster went
through batteries like crazy.
It would work for an hour
and then the batteries would
be dead. (Of course 1962 C
batteries didn't have the energy
that today's C batteries have.)
It seems like you had to unscrew
a LOT of screws to get into the
battery compartment. I think the
transmitter went about 30 feet,
and I remember it was very loud
through a radio in the same room.
How did they do that with so few
parts? Also from the standpoint of
a 7 year old - even though it was
handheld - it seemed like a shoebox
and weighed a ton. And the whip antenna
was huge. Also, that teeny red round transmit
button put an almost permanent dent in my finger.
I tried to improve it also, but I ended up just
breaking it. What a shame. It would have
been a great keepsake today.
Best Wishes,
Bruce, DOGRADIO
I had one, too. It was my first kit. I remember walking down the street talking into it, asking my friends and neighbors to come out if they heard me. None did.
30 feet was, indeed, about it for range.
It was fun to built, but not what I needed to fulfill my neighborhood radio station fantasy. That would take a rig packing tubes.
I've looked for one for years... even a picture, but no luck. I had more fun with mine. The neighborhood hoodlum lived at the corner, and although he was my "friend", he was a lot bigger and loved to mess with me. One time, along with another guy, we went over to his house, and I hid behind his couch. My friend began saying how he had heard police calls on his little radio.. "Here Chuck, listen!"... Talking into a coffeecan next to the bcstr (to make my voice different), I put out a police call for HIM to be picked up w/address and all. My buddy Roger said he took off like a shot, and hid in the woods, well into dark. We laughed our heads off, and I didn't tell him for years (until after he'd gotten out of prison for robbery!)
I too had one of those - ultimately used the PTT switch to make an upstairs/downstairs buzzer system for Mom to get our attention. Sure wish I still had that thing - it was the FIRST "xmtr" I ever had. There IS a picture on the internet, with correct color, too. My friend and I both had one, and using our pocket transistor radios, had a form of 2-way going. Shoot me a "real" email and I'll send you the picture - tom at daileyservices dot com
Google Heathkit SK-10 and you'll see some pics.