Have You Ever Seen What's Inside a D-104 Crystal Element?

I had not seen this  I must say, I am disappointed.  I had visions a circular collection of shiny Rochelle salt crystals.  But look at this thing.  It is quite flimsy -- not at all what you'd expect from the sturdy D-104 exterior.  It has kind of a "Wizard of Oz" behind-the-curtain feel to it.  Yuck. If I can't find a D-104 element in good shape, I might reach for a dynamic element or -- gasp -- an electret.

Stop Me Before I Commit an Electronic Atrocity!

Sadly, not mine

I like the D-104 mic.  I bought one from Astatic shortly before they went under and it has provided good service with many different rigs for a long time.

I wanted another one, primarily for my DX-100/HQ-100 station.  I saw one on e-bay and a few days later it was here.  Unfortunately the seller was correct when they warned that it showed no output.  I had hoped it was a problem with the amp in the base, but no, it seems that the crystal element is quite dead.  It is an MC320 cartridge marked 7-77.  There is an aluminum sheet at the front that is apparently supposed to be riding atop a center support that connects mechanically with the magic crystals.  But it looks like a circular tent that has poked through the center support and collapsed around it.

Just a few years ago there were some options for replacement elements, but it seems that most of these are gone.  Bob Heil does have a dynamic element replacement kit for about 68 bucks. 

There are many schemes for putting electret elements in the old D-104 head...  I was reaching for the junk box but I stopped myself.  NO!  I will try not to commit this kind of electronic barbarity. (I have already sinned by killing several QF-1 Q multipliers and a couple of Benton Harbor lunch boxes.)  I will instead turn to the SolderSmoke brother/sisterhood and ask if anyone out there has a crystal element that could bring this old mic back to life.  My DX-100 deserves nothing less. 

Anyone have a D-104 crystal element in their junk box? 

Steve N8NM Gets Modular -- With Both Hardware and Software

Steve N8NM has an excellent article on his blog about the benefits of modularity.  He breaks new ground by extending the concept into the software realm.  Check it out:

https://n8nmsteve.blogspot.com/2017/07/sr-16-lets-get-modular.html 

Subscribe to Steve's blog, or link to it.  Hopefully this will encourage him to post more great things like this.

Another LM373 Rig - Pete Is Not Alone!

Bill,

Thanks for coming back to my call. It was a thrill to finally catch you on the air.Like I said my Soldersmoke marathon was amusing and kept me in great company on my round trip drive from Murphy NC to Chicago. While I was in Chicago I emptied my storage garage of goodies that have been there for 12 years, it was like Christmas in June. I uncovered treasures I didn't know I even had and yes I found the box of project boards that kind of or didn't work at all. I now have these treasures to play with and see with renewed eyes what I may have done wrong, or burned up. It looks like a few of these modules can be made into rigs.

I also found a couple of antennas that I traded for that never made it up.

Also the bigger surprise was how many parts I had kept especially the ICs that were intended to beused in rigs like the LM373's that Pete has talked about. I have one test circuit board to test the LM373 that just needed the oscillators so with my SI5351 breadboards I have what I need to get this going.

Now that I'm settled into my new QTH in the wilds of western NC I will noodling and tinkering moreto get my little DSB rig on the air and an LM373 based SSB rig too,  using mostly or all obsolete/vintage parts. This is something I have been noodling about for sometime now.

I also will get my MMM finished.

Thanks again for the QSO and I look forward to working you again. Now to melt some solder.

73,

Skip Davis. NC9O

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Pete's LM373 page: http://www.n6qw.com/LM373.html

The Radio Laboratory at Bandung, Java -- SSB in 1927

Anton PA0AST alerted me to this important piece of radio history:

The first phone radio between Indonesia , the city of Bandung ( Dayeuh Kolot, Jalan Radio 1 ),  and Holland , Radio Kootwijk  were made  in SSB already in 1927... Before that time they had only a CW  1 Mega Watt spark transmitter in Malabar.
One of the receivers still exists in a museum in Amsterdam (cdvandt ). It is 3 meters in length and 2 meter in  height....  All made with plug-able units with 1 tube inside .

The transmitter was 10 kW. Ua was 6kV was made by dynamotors. Transmitting Tubes locally made by craftsman in a workshop.  Both  buildings as well  in Bandung and in Kootwijk still exists .

Anton

The old images come from:
http://www.cdvandt.org/bandung-lab-kwk.htm

At the other end was Radio Kootwijk in Holland. 

Before you jump to the English version of the page, be sure to check out the Drone video of the site, and the audio file of the Morse transmissions: 

http://radiokootwijk.nu/     Thanks to PA0JWU for the wonderful site.

Quite an impressive shack!  My favorite part is the note indicating that local residents cleaned out the cooling pool and used it for swimming each summer.