Opening The “Catacomb” – National NC-101X Coil Set

I removed the sliding coil assembly, often called a “catacomb coil” for cleaning and service. Needed it too, 80 some years of dirt, and old grease build up make it a mess.

Removed the coil sets, used a sharpie to id the location with small dots, and threw the aluminum housings, top and buttom, in the dishwasher. Worked like a charm, the reassembled, and carefully cleaned each coil set, and wiped down the pins with Deoxit. Lubricated the shaft that it slides on, and cleaned on the old nasty hardened grease out of the gear drive on the front. Tomorrow I have to paint the white band indicating tab, and reassembly. Or, I may go after the recap work first, the old wax paper caps aren’t too bad with the catacomb coil set out. Only a total of 21, should be an afternoon’s worth of work.

Opening The “Catacomb” – National NC-101X Set

Continued on with the restoration of the National NC-101X today. Removed the sheet metal enclosure, which required removal of all knobs again, then carefully undid the front drive gear, part of the rack and pinion gear set that moves the “catacomb” coil holder from band to band.

Once the sheet metal was removed, I could access the two large flat head screws on each side of the case, that held the rod on which the catacomb coil slides on. Both screws came out with minimal effort, but removal of the rod was another story. Two large “dimples” on either side of the case go into the countersunk ends of the rod, effectively locking it in place. The side on the left, receiver front facing me, had an additional star washer on it’s end. I debated using some sort of small jack to move the chassis walls apart enough to get the rod to pop out, but was able to do it with some strong “elbow grease” and a large screwdriver. There is a small braided ground wire on the rod that must be detached as well.

Once the rod was out, it was a simple matter to remove the lower catacomb cover, and then individually remove each coil, which is really a tuned circuit, consisting of an inductor and air variable capacitor. They were held in by two flat head screws and star washers, to avoid mix up during assembly, I sort in the order they came out, and also used a Sharpie to made a line or dot on each coil to indicate it’s position – 1, 2, 3.

Both halves of the catacomb were then put in the dishwasher to remove the decades of hardened grease and grime that had built up. I’ll clean each coil set by hand during assembly.

All About QSL Cards

Ham Radio QSL Cards – In the early days of ham radio, when making shortwave contact with a station across the state was a novelty, across the country was astounding, and transoceanic contacts where nearly unheard of, hams would confirm contact by sending each other QSL, or confirmation of contact, cards. This tradition continues today, but I today’s mass produced cards are often far less interesting than their early counterparts.

Early QSL cards were often handmade, and frequently included a cartoon, photo or information about the ham’s station, or humorous line art sketch. As both a fellow ham, my FCC issued callsign is W1UJR, and a student of history, I find the early cards very interesting, and have posted a short collection of some of my more intriguing cards

I was fascinated with the “Chair Warmers Club” card, a group of early handicapped hams who met regularly on the air. Back in the day, before telephones and the internet, ham radio was the only real contact these folks had with the “outside world”. W1CJD is “Gil” Gildersleeve, and as you might surmise from his card, the famous artist of hundreds of cartoons in radio magazines of the era.

I found the W8CFD card particularly intriguing, for it appears to the photo show a young ham, along with the caption of “”Believe It or Not” — That’s me over there….”. I looked up Wilven Hagerty of Honesdale, PA, not much found using Google, seems the 81 passing years have largely erased the traces of this fellow.

The W8ECA and W3HVD cards are quite interesting, I have soft spot for cards which appear to be homemade. The W8ECA card in particular looks like someone colored it in with crayons! The other cards for areas near where I grew up – Walton and Norwich, NY or cities where I once lived, Buffalo, NY.

National NC-101X – Starting Restoration

The first thing I like to undertake when staring a restoration is to decide if I am restoring or repairing. For me a restoration is to make the unit look, and function as new again, with correct period parts and repair techniques.

A “repair” means that I am going in to do targeted repairs to make the unit work and play correctly, but not necessarily make it look like new again. This involves cleaning cosmetically of dirt, dust, debris, and whatever else as found it’s way into the set over the last 50 years. For me, this set was worthy of a restoration, at least as much possible, some components, like the old chassis mounted electrolytic capacitors are hard to come by now, and any NOS units are likely to be nonfunctional. 

The next step is to document known problems with the set. Fortunately this one played, so that made things easy. Right away I noted the s meter was not operating properly, a common issue with the early National sets, noted some loud 60 cycle hum when the audio was turned down, likely a failed filter cap, and the sensitivity seems low, likely a leaking wax paper cap, and this set has a number of them. So here is where I might differ from the purist. I’ll replace the wax paper caps, and install “orange drops”, without a moments hesitation. While I admire those who will heat the old wax paper caps and hide modern caps inside, I really don’t like to take the time for this, I understand their point, but for me, I’d rather make the set look and play as well as possible. 

Someone had removed, and incorrectly installed the HRO dial, a common finding, and the controls needed a general cleaning and lubrication, not unexpected after 80 years. 

So my restoration plan for this set went something like this:

  1. Remove from cabinet, photo document any wire and components 
  2. Check tube voltages to chart, check caps for leakage, plan on replacing all
  3. Thoroughly clean of the accumulated dust and grime
  4. Remove and test all the tubes
  5. Clean and lubricate the HRO dial and gearbox
  6. Reset the HRO dial properly
  7. Replace all caps needed
  8. Recheck voltages
  9. Check/adjust set alignment
  10. Play outside the cabinet for a few days to test, then reinstall
National NC-101X

National NC-101X – Time Capsule

Fall Project – 1938 National NC-101X Shortwave Receiver

I left Maine last night for a small town in New Hampshire, right near the Vermont border. Purpose of the road trip was to pick up this shortwave set from the grandson of the original purchaser back in 1938. For nearly 80 years this radio was with this family. The original owner Richard W1KEK passed away in 2010 and the radio sat in storage until today. It’s now, along with the original speaker, safely on my workbench. This will be my fall project, to disassemble, clean, test, and repair where needed, with the goal of getting the set on the air sometime this fall. 
The photos are from Richard as a young man, and later in life.

“My Dad (W1KEK) bought this Receiver in 1938. The photos of him are from 1954 and 2010. It was working perfectly when boxed in 2010. Condition is exceptional as he always kept it dry and covered.”

I’ll be sharing the details here as the work progress. I’m not so much an owner as I am a caretaker of these wonderful icons of an age gone by.

– Bruce

W1KEK in 2010, with the same radio.

W1KEK in 1954, with the NC-101X he brought new in 1938.
W1KEK in 2010, with the same radio.