A Good Day in the Shack -- 2B Fixed, SPRAT Arrives

The temperature has dropped to around 10 C today. Fall is in the air. So it was appropriate for me to do some work on an old tube radio. (Several of our correspondents have reported similar seasonal urges to melt solder and to heat filaments.) This week my trusty Drake 2-B was giving me trouble on 17 meters. It was working on all other bands, but not on 17. Today I put it on the bench, pulled out the schematic and started troubleshooting. I quickly determined that the problem was, in fact, with the 22 MHz crystal. The 2-B has a 24.5 MHz rock for tuning the lower portion of the ten meter band. When I put that crystal in the "E" socket (where the 22 MHz crystal normally sits), the local oscillator worked just fine. Putting the 22 MHz rock back in the E socket resulted in no oscillation. And when I tried to the 22 MHz crystal in the 10 Meter socket normally used by the 24.5 MHz rock... nothing. What causes a perfectly good crystal to go bad like this?

Consulting the 2-B manual, I saw that I could also tune the 17 meter band by using (in socket D) a 14.21 MHz crystal from my junk box (it had been used in my 20 meter NE-602 DSB. transceiver). It works great. I'm listening to DK9KW calling CQ on 17 right now. Makes me want to fix up my homebrew 17 meter transmitter. (I need a final for it, and am thinking of using Farhan's JBOT circuit). I may even buy some telescoping fishing poles and rebuild my Azorean rotate-able dipole (I have the mast and the wooden center support for the fishing poles). This magnificent antenna is shown above, spreading its wings above Sao Miguel island in the Azores (our home from 2000--2003).

Icing on the cake: I went out to the mailbox, and, instead of the usual pile of bills, there was a SPRAT 148 and the G-QRP Club's Members Handbook.

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Oscillating Light Bulbs

Oh man, this is some fascinating stuff: old light bulbs found to be oscillating at VHF! Wayne, VA7AT, stumbled upon this phenomenon at age 13 while engaged in Knack activities. Now Joe Sousa explains the physics behind the emissions that caused Wayne's light bulb to interfere with the broadcast of baseball games. How long until AA1TJ has one of these bulbs on the air, making contacts? There is much in this that would appeal to Michael: light bulbs, weird physics, translations from German... You gotta love the BNC connector plugged directly into the bulb. Check it out the radio museum article here.

Hi Bill

There was a question posted on Antennex E-mail discussion group talking about how a vacuum type light bulb will oscillate and radiate RF at about 100MHZ. This answered the question I had since I was a boy of 13 experimenting with a light bulb in series with an electrolysis bath (aluminum electrodes with table salt dissolved in water) and 117vac. The bulb dimmed with the electrodes apart and at a certain position the radio I had on blanked out with fissing sound. I had to shut down the experiment quickly because the neighbors were listening on their favorite baseball game and cussed loudly .

I now know what happened on that fateful day. Here is a site I found about the oscillating light bulb http://www.radiomuseum.org/forum/rustika_lightbulb_fm_measurements.html

Wayne VA7AT

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Sputnik Rigs Cross the Pond, Cambridge to Cambridge

The Chief Designer, Michael, AA1TJ, alerted us to this wonderful post on Roger, G3XBM's blog:
http://g3xbm-qrp.blogspot.com/2011/09/sputnik-across-atlantic-today.html
We clearly see the spirit of the International Brotherhood of Electronic Wizards in Roger's comment: "Nice to think that valves used in missiles aimed at each other in the Cold War end in bringing friendship and joy. CW is a wonderful mode if you want simple equipment capable of DX." Indeed. Well done!

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Google, Supernovas... and DRAKES

I liked this ad for Google, but I now have the urge to decapitate my garden shed. Check out dad's Drake gear. Late in the clip you can see some beam antennas on a tower near the house.

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ALL the Bell System Tech Journals -- FREE!

Thanks to Dave, N8SBE, for alerting us to yet another tech treasure trove:

http://www.alcatel-lucent.com/bstj/

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Earthquake Video -- From Atop the Washington Monument

Check it out. This gives you an idea of what the August quake was like (albeit from a perhaps the scariest location):

http://youtu.be/BgHC2qREslw

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2-B Trouble Continues

Thanks for all the suggestions and encouragement. I agree with WA6ARA that the bandswitch is a likely suspect. For the E socket on the Drake 2-B (that's where my 22 MHz rock goes) the bandswitch switches in not just the crystal, but also a slug-tuned coil. It is presumed to be an overtone crystal.

The receiver works fine on all other bands.

I've already hit the wafer switch with several shots of RadioShack Contact Cleaner (I'm out of De-Ox-It). And I've given position E a good work out. No joy.

I will dig deeper this week.

It may be the crystal. It looks like I got it from Drake -- it is marked "22 MHz 2C" so it may be for the 2C receiver. It has a sort of worrisome dent in the side. I may build the test oscillator that Steve recommends.

Of course, as soon as I get this fixed the sunspots will disappear and 17 will become a white noise generator.

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