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National NC-2-40D




 
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N0WVA
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« on: June 11, 2010, 10:34:43 PM »

Theres one for sale here locally with matching speaker. Never knew this receiver existed, but since seeing it, cant stop thinking about it. Anyone here have any experience about how well or poorly they work for AM? Not many reviews on the net.
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David, K3TUE
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« Reply #1 on: June 11, 2010, 10:49:00 PM »

Frank, KB3AHE has one in his basement.
I am not sure if he has gotten around to placing it in the guest position since I last saw him.
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David, K3TUE
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« Reply #2 on: June 11, 2010, 10:52:58 PM »

Very cool receiver, grab it! Smiley

Performs well, looks great.
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Rodger WQ9E
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Don
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« Reply #3 on: June 11, 2010, 11:47:37 PM »

It's basically a bandswitching HRO minus one of the rf stages. It uses the same type of IF cans as the HRO.  It takes a while  for the massive coil catacomb assembly to come temperature from a cold start, but once it reaches equilibrium after about 45 minutes, the thing is rock stable both mechanically and electrically.

I had one  for a short while and I loved it.  Unfortunately, I traded it off for something else.  I should have kept it.  It was actually more stable than the HRO because you don't have to wait for the cold plug-in coil to come to temperature after changing bands.
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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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KC4VWU
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« Reply #4 on: June 12, 2010, 08:29:07 AM »

I have 3 and all are in need of attention of maintenance and cleaning /re-finish. I've ran one for about 6 months before I got a 75A2, and it did a great job. Also have a NC-101X with the PW dial.

Phil
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W9GT
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« Reply #5 on: June 12, 2010, 09:56:43 AM »

I have one and they are great!  Their art decco styling with the metal feet and all is so ugly its cool.  Shocked Grin  I have found that mine works very well on AM and is an all-around good performer.  Great audio and good sensitivity.  Pretty stable, as well after initial warm-up.  Highly recommend them....lots of receiver for the money!

73,  Jack, W9GT
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Carl WA1KPD
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« Reply #6 on: June 12, 2010, 01:39:36 PM »

I had one for a few years and I really liked it.
Would buy another without much of a hesitation
Carl
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"Okay, gang are you ready to play radio? Are you ready to shuffle off the mortal coil of mediocrity? I am if you are." Shepherd
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« Reply #7 on: June 12, 2010, 07:45:29 PM »

Im another fan, I have 4 but only 2 have been restored; Ive also done 2 last month for a customer as well as several over the years as well as working on them while at National in the 60's.

There are 2 versions. The early is about 50% NC-200 and uses its dial and catacomb drive assembly as well as the dial scale which is quite different than the later.

The primary overhaul effort will be the coil contacts being dirty after 60 or more years. Use plenty of Q tips as you will need to remove every coil assembly and degrease. The fixed ones dont have to be removed but you have to get deep between the sections. Then go thru them all again with diluted TarnX to remove the oxidation, and flush off any residue. DO NOT use DeWrexIt. The process is actually easy, just takes time.

All together, recapped (dont even bother trying to save the electrolytics, you will just fry the transformer later than sooner. Replace the electrolytics and all audio stage caps before even attempting to power up), and aligned it will be a mechanically and electrically stable radio quite capable of good SSB even on the higher bands. Ive had very few out of tolerance resistors in these. If you select the best 6SK7 and 6K8 front end tubes from several it will be quite sensitive even on 10M. Bill Orr had an excellent article on adapting a 6SB7Y mixer which works well and I also used a 6SG7 RF in one of them here. Really picks up 10M and even will be an improvement on 20. I used it on 10M a lot before getting a HRO-60.

It has Nationals famous 1/2 turn alignment loop in the coils for the low end of the dial alignment. This may take some getting used to for a first timer but there is no tuneable slug to cause drift or age and really screw things up.

Carl
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sndtubes
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« Reply #8 on: June 13, 2010, 06:02:33 PM »

I have one that I took to Dayton to sell.  It's been rebuilt, but I decided to sell it because I didn't have the room for it.  I really hadn't tried using it.  So, at Dayton, I hooked it up so people could see it work.  It worked so well, I decided to keep it!  I'm working it into my vintage setup and hope to have it incorporated in my RX lineup soon.  Very cool, great sounding RX.
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« Reply #9 on: June 13, 2010, 06:50:31 PM »

Good thing you tried it out Smiley 

I put out a want for one on the old boatanchors list and got it about 12 years ago.  Since then I have added some earlier family members, a NC-100X, NC-101X, and a Wells Gardner produced RAO-7 built using mostly National components and including the additional RF stage of the RAO series.  I am sure that National was the inspiration for Karl Pierson when he produced his KP-81 moving coil catacomb receiver.

The only problem with that half turn coil tuning loop is when a previous owner over adjusts and breaks it.  I had to repair a couple of NC-300 coils that suffered this fate.  But it is still easier to repair that than deal with a stuck/fractured ferrite core.

I have one that I took to Dayton to sell.  It's been rebuilt, but I decided to sell it because I didn't have the room for it.  I really hadn't tried using it.  So, at Dayton, I hooked it up so people could see it work.  It worked so well, I decided to keep it!  I'm working it into my vintage setup and hope to have it incorporated in my RX lineup soon.  Very cool, great sounding RX.
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Rodger WQ9E
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« Reply #10 on: June 13, 2010, 08:46:50 PM »

If it is in the Kenosha area it may have been the one I had. It was recapped, has a new dial cover and works FB. Send E-mail about current owner and I will confirm. It worked very well if it is the one I had.
K7YOO
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N0WVA
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« Reply #11 on: June 13, 2010, 10:11:34 PM »

Its on craigslist. A little more than Id want to pay for a boatanchor. but I guess thats what they go for these days.

http://stlouis.craigslist.org/ele/1785928024.html

Ive always like the National rigs, they seemed to have the right combination of electrical/mechanical quality that went well together, much more so than say most Hallicrafters stuff. And it was mostly textbook circuitry. Kind of like Millen equipment.
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k4kyv
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Don
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« Reply #12 on: June 13, 2010, 10:21:18 PM »


Since then I have added some earlier family members, a NC-100X, NC-101X, and a Wells Gardner produced RAO-7 built using mostly National components and including the additional RF stage of the RAO series.  I am sure that National was the inspiration for Karl Pierson when he produced his KP-81 moving coil catacomb receiver.

James Millen built a prototype moving coil catacomb receiver right after he parted from National and started his own company, just before or just after WW2.  It was supposed to incorporate the best of the National design plus some refinements.  He had planned for it to be the very best amateur receiver ever. It was never put into production probably because the cost would have  been prohibitive for the amateur market, and perhaps he saw the competition coming from Collins.
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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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« Reply #13 on: June 13, 2010, 10:32:48 PM »

Its on craigslist. A little more than Id want to pay for a boatanchor. but I guess thats what they go for these days.

http://stlouis.craigslist.org/ele/1785928024.html

Ive always like the National rigs, they seemed to have the right combination of electrical/mechanical quality that went well together, much more so than say most Hallicrafters stuff. And it was mostly textbook circuitry. Kind of like Millen equipment.

A lot more than I'd want to pay for one that didn't work.

And the guys attitude, well......

--Shane

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WQ9E
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« Reply #14 on: June 13, 2010, 10:50:07 PM »

At that price it should be recapped, aligned, and working properly.  This is a good but far from rare receiver. 

I love the ebay comparisons that show up in ads.  Sometimes you will find units sell for a high price on ebay because:

a.  It truly is a perfect example.
b.  Two or more bidders "just got to have it" and bid it to stupid amounts.
c.  Somebody just got there tax return/pony came in first/won the little lotto and has money burning a hole in his pocket and pays a ridiculous BIN price

Those examples do not represent what you can expect to sell for at a hamfest, garage sale, or classified listing service. 

I have seen NC-2-40D receivers with speakers at 2 hamfests so far this year and both examples were nice and had listing prices of $200 and $250 and I bet either could have been obtained for less than the marked price.  My second NC-2-40D with speaker cost me $60 because someone painted the middle panel section gold; I guess they wanted their own "golden anniversary edition".  It would be easy to paint back to National Gray since there are no markings to worry about but I haven't bothered yet.
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Rodger WQ9E
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« Reply #15 on: June 13, 2010, 11:33:44 PM »

I'm in 100% agreement with Rodger (I bet Carl too) on this: it really is a neat radio, but for $500 it had better be completely done, plug-n-play, near perfect shape. There are just too many of them around to pay a lot then have to put a lot into it. $200-$300 seems to be the going price for a decent set. I paid $175 for mine with the matching speaker, in nice cosmetic shape but needing the usual cap replacements. It actually worked fine, but the 3rd or 4th time I turned it on, I was greeted by HUMMMMMMM. So when you do get one, do as Carl suggests and swap out those electrolytics pronto. Also the caps associated with the audio section to prevent frying the output transformer.

One thing to keep in mind: it's mainly an entertainment receiver, not a communications receiver. As such there are trade offs like lacking proper band spread or the dial resolution and resettable accuracy of a Collins PTO, for example. In exchange you get wonderful push-pull audio output, general coverage from the low end of AM Broadcast to over 30 mcs, and the aforementioned Art Deco styling. It also has a nifty tuning knob that does double duty for band switching by pulling it out. The solid metal dial skirt gives it a nice flywheel effect for tuning.

Definitely a rig worth having, and one of the keepers here as well.
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K8WBL
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« Reply #16 on: June 13, 2010, 11:43:41 PM »

Beautiful rig and very different band changing.. I have a 240-C - very similar but round meter and I have a RAO-7 which is also simlilar but military.. the bottom of the receiver has a sliding catacomb tray that contains all the tuned IF circuits and it slides left and right to make connections, depending on the band.  Better construction than old Hallys and a shade better than Hammarlunds in my opinion .. will always be collectable, just not many of them aruond...never seen a 240C like mine before..the 240D was a later variation and more popular.

73, tim K8Wbl
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W9GT
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« Reply #17 on: June 14, 2010, 08:50:21 AM »


One thing to keep in mind: it's mainly an entertainment receiver, not a communications receiver. As such there are trade offs like lacking proper band spread or the dial resolution and resettable accuracy of a Collins PTO, for example. In exchange you get wonderful push-pull audio output, general coverage from the low end of AM Broadcast to over 30 mcs, and the aforementioned Art Deco styling. It also has a nifty tuning knob that does double duty for band switching by pulling it out. The solid metal dial skirt gives it a nice flywheel effect for tuning.


Sorry Todd, but I gotta disagree with your statement about bandspread!  I have an NC2-40D that has tremendous bandspread and slow tuning rate for the ham bands.  Granted, the dial space doesn't take up the whole scale for the hambands, but the tuning rate is such that it works extremely well for ham use and you get the bonus of general coverage.  Of course that push-pull audio is wonderful for AM and the big matching speaker sounds great.  The only real criticism that I would have is that it is somewhat hard to read the dial scale under low-light conditions.  The dial light is insufficient for my requirements.  I have contemplated either adding an additional lamp or somehow enhancing the existing dial lighting. (maybe use LEDs?)

I believe that the NC2-40C and D models were used by the airlines in the 40's for point to point communications.  I specifically recall seeing ads for Pan American Airways utilizing the National receivers in their stations.

I have had my 2-40D for many years.... got it at Dayton several years ago and was told that it came from a National engineer.  Some of the documentation that I got along with it supports that claim.  I also got several spare parts along with it, including IF cans and even a spare dial scale.  I have a matching speaker, but it was lacking the metal feet.  (might have come from an NC-200)  Thanks to Don, K4KYV, I later found a set of feet for the speaker.  All-in-all the NC2-40D is an outstanding bargain.  It seems that prices are very low, considering the overall performance of this jewel.  It will remain a fixture in my shack for some time to come, that is for sure.

73,  Jack, W9GT
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Todd, KA1KAQ
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« Reply #18 on: June 14, 2010, 11:39:54 AM »

I don't disagree with that, Jack. But slow tuning rate vs a calibrated band spread are two different things. Not terribly critical to AM work if the main tuning is fine enough, but without proper dial resolution, it's still a crap shoot. OTOH, you have rigs like the Halli S-40 with its separate "band spread" dial which is nothing more than a logging scale when combined with the main tuning scale. Without the resolution to start with, it's not much good. My favorite is still the pre-war Super Pro. The SP-100 I got from Buddly is spot on, and amazingly resettable.

Back lighting the dial on the NC-240-D would've been cool, and made reading much easier. But considering how badly the old translucent dials have darkened with age, it's probably just as well they went with a durable painted dial. Maybe you can get a small lamp to mount above it and angle out over the radio, facing in towards the dial.

  I have a matching speaker, but it was lacking the metal feet.  (might have come from an NC-200) 

IIRC, the 200s were two-tone paint jobs using light and dark grays. Maybe that was just the early versions? Carl would know. If your speaker is all one color (original paint), it's probably the correct one. Even if it's from a late model 200, I'd think it would be electrically as well as visually identical.

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« Reply #19 on: June 14, 2010, 05:49:33 PM »

Ive paid up to $100 for a mint 200 or 240 speaker but only $50-75 for radios with excellent cosmetics. The plastic dial face for the 240 and late 200's is $18 on Fleabay.

While they dont have frequency meter readout they have loads of reduction driven bandspread, especially the later models where the BS follows each GC range rather than all bunched at the bottom as in the early and NC-200. Get a digital readout if your fussy Grin but it tunes 20M SSB very easy where the 10kc calibration marks are about a 1/2" apart.

I also have a NC-240CS (Commercial Special) which is a rack mount with the lower BC band changed to 200-400kc. The NC-240C (Commercial) has the normal BCB and GC SW to 30mc as do all catalog models. Ive seen another commercial/government variant with a oversize doghouse PS and single ended audio. I believe the 240D is the only one with BS aka Dual Range for the D in the model. One of them here is serial 61 from the first run in 3/46 and is the one I mentioned earlier that is 50% a NC-200.

All 200's are two tone, some are brown & tan (or light brown) and mid production was the Anniversary model with the special diamond. Early ones had a flat glass dial cover, later was a formed plastic as on the 240.

Any 200/240 is a real easy recap, the complete bottom is wide open as the rack is moved to either extreme. Just remember to keep the replacements close to the deck so they dont get run down by the rack Huh

I would not be at all surprised to hear of other variants, if you had the money National would customize a standard version of most of their products. I even built a few military and embassy NCL-2000's for foreign customers.

Carl


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David, K3TUE
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« Reply #20 on: June 15, 2010, 07:52:15 PM »

I had no idea the NC-240D was so well regarded.
I have been all considerin an SX-28 for some time,
but now I'm thinkin I should keep my eyes open for one of these.

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David, K3TUE
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« Reply #21 on: June 15, 2010, 07:59:33 PM »

Now, hold up a minute. The SX-28 ani't no slouch either. It's definately one of Halli's superior rigs! But I love the NATIONALS!

Phil
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KM1H
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« Reply #22 on: June 15, 2010, 08:08:09 PM »

There is no reason you cant have both Grin I do  Cool My only serious complaint about a stock SX-28 is that it overloads easy on 80/40M where it doesnt need all the gain

I cycle my preferred receivers thru an operating position on a fairly regular basis to keep them happy and dry. 

Carl
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The Slab Bacon
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« Reply #23 on: June 16, 2010, 08:42:29 AM »

I just dont know, I love the 28 so much that I just cant leave it away from the operating position for long. I am so impressed with the S/N ratio of that old receiver!! (Especially if you swap the 2nd IF 6SK7 to a 6AB7) The signals just seem to leap out of the background noise.

I have a recapped 2-40D that I bought a few years ago, and I have never put power to it!!

My 28 is one of those pieces that they will have to pry out of my cold, dead hands after I crap out!!
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« Reply #24 on: June 16, 2010, 11:31:45 PM »

My thoughts exactly. I have an SX28 with ALL caps and resistors changed. Its a masterpiece. I really enjoy it. Its so damn noisless!  Then someone keys up and pins the meter.  It also has wonderfull audio from the push pull output. Its one of my favorites for sure. 

That guy selling the National is probably on meds.  Thats way to much money for a 240D. 

C
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