Dave Richards AA7EE

July 27, 2014

My $10 Fleamarket Find!

Filed under: Amateur Radio,Ham Radio — AA7EE @ 12:29 am
Tags: ,

I usually roll out of bed anywhere between 6 and 7:30 in the morning, prompted by cats who want to be fed. The last couple of mornings, after feeding them, I have gone back to bed and napped for a few more hours. This is not normal for me, but probably has a lot to do with the very warm weather we’ve been having recently. So it was this morning, and was the reason that by the time I got a message on Facebook from my old neighbor Sue that the California Historical Radio Society was holding an auction and fleamarket in the city of Alameda today, the event was already underway. I rushed in the shower and hoofed it to the bus stop as soon as I could. I didn’t even have time to stop off at the ATM so when I got there, I only had $22 in my pocket. $5 paid my admission, leaving me with just $17 to score a cool deal. There were some lovely old vintage pieces in the auction but like all good cheapskates, the piles of “junk” in the fleamarket at the back were what drew me in. This is what I found -

My $10 fleamarket find. The marks on the front panel and on top of the cans were just dust and dirt, and cleaned up nicely with a damp rag.

What attracted me was the National ACN dial, fitted with a “Velver Vernier” drive. They were in good shape and the reduction drive operated smoothly. The drive and dial alone were well worth the $10. The dial is marked “Frequency cut-off in KC” and calibrated from 1.8 to 25. On the back, there are 2 1/4″ jacks, marked “In” and “Out”. The rectifier tube is a 6X5GT and the other one is a dual-triode 12AU7. This looks to be a tunable audio low-pass filter. I was hoping that the wiring on this homebrew project would be done poorly, so I could easily justify cannibalizing it for parts. Sadly, this was not the case. This is what it looks like without the bottom cover -

I already have a National ACN Dial like this one, and several National “Velvet Vernier” reduction drives, but this one has the smoothest action of them all. If I wanted to restore this audio filter, I’d need to at least recap it but as nice as it is, I’m thinking that the same function can now be attained more easily with solid state devices (so why would I want this one?) The front panel is thick, and the chassis stout and solid. If I were to cut out the top of the chassis and replace it with a new aluminum plate, there are any number of projects that could be built around the dial, vernier and that 3 gang variable capacitor. The variable capacitor wouldn’t be ideal for a high stability VFO, but it might work well for a preselector for MF thru’ HF, for example -

Sitting on the bus on the way back home, as I clutched this on my lap, the guy sitting next to me asked, “Is that a flux capacitor?”

So what would you do this with this if it was sitting in your shack?

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5 Comments »

  1. Dave. I am a retired 65 year old fart. I enjoy my amateur radio hobby of 50 plus years. I love to build QRP equipment and I am presently collecting parts to build the 40 meter DSB transceiver that you published several months ago. You probably have forgotten but you sent me info on microphone preamps during the past year. I treasure my vacuum tube gear from my youth. I hope you keep your beautiful new find as is; perhaps change the caps to keep it operational. There is no such thing as ancient, old or boat anchors. It is all science and physics,  both of which are timeless and beautiful. Chet. Armellino KF6WND Tracy, CA

    Sent via the Samsung Galaxy S™ II Skyrocket™, an AT&T 4G LTE smartphone.

    Comment by Carmelli — July 27, 2014 @ 4:44 am | Reply

  2. I would restore it for no other reason but to honor the Ham who built this beautiful piece of gear! But that’s just me. It is yours and I suppose it would honor the builder just as much to have you perform your beautiful work on it. Either way, it was a nice find and I am certain it will turn out to be a wonderful addition to your homebrew collection.

    73 — de Mick, WB4LSS

    Comment by Mick Bradford — July 27, 2014 @ 4:24 pm | Reply

  3. Chet and Mick – I think you are right -it would be a shame to dismantle this well-made homebrew project. I am leaning towards reverse-engineering it, drawing a schematic and figuring out how it works (perhaps there was even a published article on it), then recapping it and getting it working again. In the meantime, it will sit here on a shelf, safe from the ravages of time.

    On the other hand, the dial and capacitor in that case would make a great foundation for an HF preselector…………!

    Dave
    AA7EE

    Comment by AA7EE — July 27, 2014 @ 8:52 pm | Reply

  4. Hi Dave,
    Darwin here! (W9HZC) Now that I’m ‘retired’ and mostly just play golf, play with radios and teach part time at a local community college, I got a little fed up with too much free time. So – I got a part time job repairing old radios. Working on a Zenith right now that is 4 months older than me! (June 1942). At the work ’20’ we normally replace nearly all the old Cap’s just as normal procedure. Then replace any of the old wire that is falling apart. It seems to me that not restoring any of these would be a crime. We have a ball trying to put these back on the air and the look of delight of the Old Timers who brought them in is well worth all the effort.
    Of course, you could just take out all the insides and replace the insides with a Raspberry-Pi and make it an Internet radio. Check the Make home page where someone did that to an old 5 tube kitchen radio. clever, but still……..
    Dar…

    Comment by Darwin — July 29, 2014 @ 2:04 pm | Reply

  5. Hi Dave
    What a wonderful find…and at 10 bucks its a real steal… if your looking as to what to do with regards to your new find.. you have just got to go down the road of restoration…yeah you can “adapt” a few things to get it up and running but to break up such a work of art would in my opinion be just so wrong…. its all too easy to canabalise radios and finds from yesteryear, but if by restoring it to the best of your ability, which I am sure would make the item a success then that surely has to be the way to go….not everything has to be “up to date”
    Rgds

    Lyndon g7imo

    Comment by lyndon handley — August 4, 2014 @ 8:08 pm | Reply


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