---   Today's Status   ---

Regrettably, when beginning the BigRig restoration project, I had torn the speech amp all apart without having photographed its pre-project condition. I had had no thoughts of documenting the project. Over the course of the rebuild, though, several ham friends (?) suggested that the BigRig restoration eventually become the subject of a QST article. I hope those guys all get parasitics in their finals! Iíve strenuously argued no interest in such an undertaking, and right now Iím sticking to my guns. Yet, enough have shown interest in the project to convince me that I should photographically document its progress and post the pictures on the web. Hence this site. Like all similar projects, this one has grown well beyond the plan, and here I sit exercising my word processor instead of exercising my soldering iron.

Well, I did goof by not photographing the speech amp before ripping it apart, but I did photograph it when it was in process and when it was completed. Those pictures are here. I know better now, and Iíll keep an active camera throughout the rest of the project.

I estimate the project will take another year or two to complete, so the BigRig story will remain unfinished until then. Iíll add to things on the site as they develop.

The status on March 07, 2009, is:

1.     The speech amp is complete, tested, and ready to be mounted into the rack.
2.     The rack is being re-worked. It must be shortened and casters added.
3.     The modulator has been disassembled, and the sheet metal is off being powder-coated. Some restoration of the transformers is underway, and new parts are being acquired.
4.     The National CRU-P modulation monitor oscilloscope has been disassembled, and its sheet metal is also out being powder coated. New parts are being acquired here, too. Eureka! Would you believe I was actually able to buy a 50-year-old and unused 2AP1 CRT on eBay?

March 14, 2009:     New picture added to LVPS group, and LVPS schematic updated.

March 15, 2009:      Pictures of Millen-manufactured exciter posted, and the "before" pictures of the final                               amplifier deck were added.

March 17, 2009;      Additional exciter schematics added.

April 04, 2009;      Added a modulator discussion and a couple of new modulator pictures.

April 9, 2009;      Finished the modulator today, added pictures of the newly-finished unit.

April 21, 2009;      The Low Voltage Power Supply is finished, tested, photographed, and ready to go!   Also today, I started looking at the Modulator Power Supply. The "before" pictures have been posted.

June 12, 2009;      The Modulator Power Supply is finished, tested, and it makes lotsa volts! In fact, the open-circuit output is about 2485 volts. One hand in the pocket, please! This finishes the 5th deck of 8 - only three more to go!

June 28, 2009;      Hot Dog! I got the exciter finished today and fired it up. It made RF just as ordered, so I shot a few pictures of it and set it aside. Now, only two more decks to go. The final amplifier power supply, and lastly, the final itself. I'm even beginning to think that I just might get BigRig on the air yet this year! I also added some text to the Exciter page.

July 3, 2009;      I started today on the final power supply. The "before" pictures are posted. Now, it gets torn down, the metal work re-finished, and then re-assembly can begin. Stay tuned for the "after" pictures!

August 30, 2009;      Today is a neat day! I finished up the final power supply. Pictures are posted, and I've added to the Final PS story. Only one more deck to go, then I've gotta work on the rack itself, then I must fabricate a cable fixture to make the inter-deck cabling, and finally, I must find a helper with a strong back to aid me in mounting all the decks into the rack. Also added a picture in the Sundry Stuff folder.

October 20, 2009;      I started today to re-assemble the final! Take a look at the pictures. In an HF RF deck, good grounding practice with short, wide, conductors and interconnects, is essential to proper operation. I've been worried about getting decent grounding in a workmanlike manner, through a steel chassis covered in tough powder coating, and so I elected to use a 0.090" aluminum-plate ground plane arrangement. A tad unconventional to be sure, I've never seen it done this way before, but it should work FB.

December 16, 2009;      Today, I added some text to the "Final Amplifier" page, and added a picture to the "Final" section.

January 2, 2010;      Finished up the antenna-changeover module today. Discussion in the Sundry page, and pictures in the Sundry folder.

January 16, 2010      Today's a red-letter day! Today, I finished up the final amplifier. There's a good deal more to do before BigRig can make an on-the-air contact, but finishing the final is a big leap toward finality (pun intended). There's some text on the "Final Amplifier" page, and some pictures in the "Final" folder.

Now, all that's left is to finish up the mods on the rack, a matter of an hour or so, to fabricate the cable harnesses required to connect BigRig's eight decks to each other, design and build a power supply for modulator bias, and then, finally, I'll try to put it on the air.

Several prominent local radio amateurs have asked to be here when I first turn it on and make the first contact. I've explained that there's little to no likelihood that those two events will happen on the same day. I expect, being a bit of a pessimist, that when first turned on, fuses will blow, wires will smoke, and resistors will pop. The first "turn-on" will actually be a series of turn-ons as the individual decks are powered up, checked out and de-bugged. The transmitter as a whole, will be turned on only eventually. Of course, there will come a day when I'll try to make a contact with it, and on that day, all guests will be welcome.


Here's a list of some of the parts and other help that I need for the project. If you can help with any of these things at a reasonable price, please send an email to me.

1.      An Astatic T3 microphone.

2.      A Teleradio variable capacitor, about 65pf., wide-spaced, 10 rotor plates & 9 stator plates.

3.      A Hammond variable capacitor, split stator, 108 pf/section & 4600 volts.

4.      An "amplifier foundation cabinet," i.e., an old black wrinkle chassis approx. 6" x 9" with a cover largely of expanded metal and having large-radius corners, so named because the expanded metal cover provided ventilation for hot amplifier-tubes!

Click   here   to return to the home page.

Click  here   to return to the Rag Chew links.