My CK722 Transistor

I’ve acquired an old Ratheon CK722 transistor several years ago. I knew it was a find when I got it, but then it sat, stored away, for many years.  Today I took some pictures of it and here they are.  If you have never seen one of these beauties, they are royal blue with a red dot on them.  It has a date code on it that says “542”  That means it was built in 1955 in the 42nd week.

The inside of the package has the strangest disclaimer.  It reads “The purchaser or lesee of this device shall not be granted by implication, estoppal or otherwise any license under the patent rightsof American Telephoneand Telegraph Company andits subsidiaries for any combination of another element orelements with such device.”

The CK722 started out costing more than $12.00 to purchase and later went down to $7.50.  WOW!  I have no idea what that is at the current rate, but it is expensive.  I could not find the current price of one of these gems.

Click a picture to see a larger view.


The Beautiful Blue Raytheon CK722 Transistor. Package Front Package Back The Inside Of The Package. A Very Interesting Disclaimer.

A Dead Gnat

A week or so ago, I posted a note about the Gnat 1 single transistor QRP transceiver.  I was excited about building this little project.  I gathered up the parts and warmed up the soldering iron.

The project went together easily.  After all, there are only about a dozen parts or so, what could go wrong?  Oh, what a loaded question that was.

I decided to construct the 80 Meter model.  I live about 20 miles out of Helena, MT, and if I was successful in getting this little rig working, I wanted to see if  a fellow Ham in Helena could detect my signal.  After completion, I attached the power, and antenna.  I hooked up the oscilloscope and frequency meter, and powered the rig up.

I was immediately gratified with a signal when I shorted the “key” line.  It looked like I was getting out between 200 and 400 milliwatts, depending on the power supply voltage.  This is where the fun ended.

I was never able to detect any sort of audio out of the little rig.  I followed the tuneup procedure in the instructions to the tee.  The instructions were easy to follow and the results were exactly as written, but through all of the test procedures, I was “NEVER” able to detect any audio.  After several days, I think I am done with it.  Unless something else pops into my mind, I will cut my losses on this one and continue on to the next project that is begging for my attention.

My dead bug Gnat 1.  No audio was ever detected.
My dead bug Gnat 1. No audio was ever detected. Click to see a closer view of the dead Gnat 1.

The Gnat 1

The Gnat One
N7ZWY's prototype of the Gnat 1. About two square inches.

Here is a little project I am excited to build.  The Gnat 1 by Chris Trask – N7ZWY.  It is a ONE transistor CW TRANSCEIVER.  I’ve seen other one transistor transceivers that employ a multi-pole switch or relay to toggle the transistor between the transmitter and receiver, but this one is unique in that it employees neither of those schemes.  The key itself switches it from receive to transmit.  This should be fun.  If I am successful (or not), I will post about the fun time I have with it.

I just received some crystals in the mail today, so my attempt at this little project will be for the 80 meter band.  Check this little project out and warm up your soldering iron and give it a try. It will be FUN!

Here is a six page pdf of the project from N7ZWY: