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 Post subject: National NC 270
PostPosted: Jun Sun 29, 2008 1:12 am 
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Location: Clinton Twp. Mi.
Might have a chance to pick one of these up. I would like opinions about this receiver.
Stan Ski


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 Post subject:
PostPosted: Jun Sun 29, 2008 1:32 am 
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Location: Monterey California USA
Electric Radio for January 2008 has a fairly comprehensive article about this receiver.


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 Post subject:
PostPosted: Jun Sun 29, 2008 1:49 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Utica, NY 13502 (USA)
Here is what some others have to say about it:

http://www.eham.net/reviews/detail/1711

Dave


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 Post subject:
PostPosted: Jun Sun 29, 2008 2:16 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20548
Location: Sandpoint, IDAHO 83864
I saw an NC-270 at the last hamfest for sale. But the seller did not have a price on it and when I asked him what he was asking for it, all I got was a smartass answer, so I told him he could keep it. When I asked, all he could tell me is that it has been completely gone thru (by whom, may I ask?).

I told him that I was perfectly capable of doing that myself and how much do you want for it. He went on to tell me more about it, which I could not have cared less about, and after the third time I asked him how much, all he could say was to make an offer.

If those stupid sellers don't know what to ask pricewise for what they are trying to sell, I don't have the time or patience to deal with them. They can either tell me a price, and if it is suitable, out comes the wallet, if I think it is too high, then I start dickering on the price.

But after three times asking the price and not getting a definate answer, I told him he could keep it, and I am sure he packed it back home with him.

Yeah, it was in pretty good cosmetic shape, and I would not have minded getting it, but I don't care if it is the Queen's Crown, I do not have patience with such stupid sellers.
Curt

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Curt, N7AH
(Connoisseur of the cold 807) CW forever!


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 Post subject:
PostPosted: Jun Sun 29, 2008 5:26 pm 
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Joined: May Thu 22, 2008 5:27 pm
Posts: 26
Location: MO Ozarks
Be very wary of eham reviews. I glanced at the first in line and the NC-270 does NOT have an AGC on CW/SSB!

The radio does not measure up to it's advertised claims. Light construction, drifty, poor dial spread, cheap meter and controls and selectivity nowhere near as good as indicated on the panel.

All that being said, it is different and cute. Mine is the only one on my road! If you can get it cheap enough, it is a conversation piece.

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DNichols, N0DBX


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 Post subject:
PostPosted: Jun Sun 29, 2008 6:46 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Monterey California USA
I'll second that. Unfortunately eHam seems to be a magnet for the mentally disturbed and some of that spills over onto the equipment reviews. Some of the reviews are quite accurate and a few even written by degreed engineers, while others are written by people with an obviously weak grasp of the subject matter. A critical review of some item is usually met with an attack by someone else who thinks the gear is just the greatest.


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 Post subject:
PostPosted: Jun Sun 29, 2008 10:04 pm 
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Joined: May Thu 22, 2008 5:27 pm
Posts: 26
Location: MO Ozarks
Geoff Fors wrote:
........ met with an attack by someone else who thinks the gear is just the greatest.


OR has one to sell on the bay!

TNX. Love having my prejudices reinforced!

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DNichols, N0DBX


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 Post subject:
PostPosted: Jun Sun 29, 2008 10:19 pm 
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Location: Utica, NY 13502 (USA)
I don't necessarily have anything good or bad to say about the reviews but the way I read it, the author of the first review is saying this set does not have AVC for the SSB mode:

"There was a major revolution in receivers in the 1960 era... AGC on CW/SSB, crystal controlled, PTO design, bandpass filters. This is BEFORE the revolution. Tuning on SSB is a chore, and you have to ride the RF gain control all the time or you get audible distortion of the SSB."

He said this (set) is BEFORE the revolution and tuning SSB is a chore...

Dave


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 Post subject:
PostPosted: Jun Sun 29, 2008 11:13 pm 
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Hey Stan,
I've operated with a 270 before and I'm on the fence for an opinions. A lot depends on what you are wanting to compare it to. Its no HQ-180 but its no Hallicrafters S-120 either. And lots of fellas think the S-120 "works great" and lots of fellas will trash a 180 :) Go figure.

I think the radio is typical of others that were in the same price range at the time. I'm scratching my head to imagine what would be a good comparison but then you may not be familiar with that rig either!

Geoff, I tend to agree with you. Many of the eHam postings are guys suffering from nostalgia and the euphoria that their hamfest find has come to life. Thats ok, I guess, but thats also why I make the point of putting it into some sort of perspective compared to other rigs. The old receivers of this era don't necessarily line up dollar wise as much as they price because of nostalgic reasons and/or particularly good physical condition.

That said - I'm surprised to read that this radio cost $295 in 1960.


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 Post subject:
PostPosted: Jun Mon 30, 2008 1:10 am 
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Location: Utica, NY 13502 (USA)
Stan - I assume you know that this is a ham-band receiver and will not receive international shortwave like a general coverage radio does. It does have a few things going for it like double conversion and a product detector.

Dave


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 Post subject:
PostPosted: Jun Mon 30, 2008 1:16 am 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20548
Location: Sandpoint, IDAHO 83864
What? A product detector and no AGC on CW or SSB? Small miracles never cease to amaze me.
Curt

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(Connoisseur of the cold 807) CW forever!


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 Post subject:
PostPosted: Jun Mon 30, 2008 5:13 am 
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Joined: Aug Tue 28, 2007 6:44 pm
Posts: 462
Location: Tustin,CA
Hi Stan,

I have owned FIVE NC-270's Since Oct.'07 and wrote an article for the Jan.'08 Electric Radio. I would read that article before buying one. A follow-up article is in the works as a result of restoring, repairing, and aligning five of them.

Personally, I like the radio - after it has been aligned. All five, as received were STINKO performers and behaved like pre-SSB designs in spite of their product detector. One acted DOA because a previous owner had "mucked" with every thing he could turn - including the ferrite filter!!! This radio must be precisely aligned to be anywhere close to its published specs, and even after alignment, will probably not meet those specs - especially the 5 KHz selectivity position.

My recommendation for the casual boatanchor collector is to steer clear of it unless you're going to use it as a bookend or doorstop and my follow-up article says as much. The heart of the NC-270's 230 KHz IF filter is its "patented" ferrite filter. It appears that the ferrite filter has "aged" over time and typically, you will not be able to align it to 230 KHz - you have to find a "new" IF freq that the filter will adjust to. That hasn't proven to be a problem with all five - it just takes some work.

Finally, read my comments on eBay regarding my last two auctions. That should give you a hint. If you need more info, send me an email and we can discuss the NC-270 a bit more off-line.

Dave - WA6VVL


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 Post subject:
PostPosted: Jun Mon 30, 2008 8:03 am 
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Posts: 364
Location: Washington Crossing, Pa. USA
Hello Stan,
I've owned a NC-270 for about 10 years now, and concur with WA6VVL's statement. They're not bad receivers once you replace the caps and do an alignment, etc to them. The NC-270 wasn't at the topof Nationals' rx line for it's time, it was meant to compete with other mid-priced receivers.

My only "beef" is that they don't include the 160M Amateur band, of which I do most of my transmitting-receiving on. I used my NC-270 with my Heathkit Apache, and found it to be quite adequate on 75 and 40 Meters.

GL and Best Regards,
Joe Cro N3IBX


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 Post subject:
PostPosted: Jun Mon 30, 2008 11:53 am 
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Location: Utica, NY 13502 (USA)
Curt Reed wrote:
What? A product detector and no AGC on CW or SSB? Small miracles never cease to amaze me.
Curt


Same with the Hammarlund HQ-160. AGC on SSB would be a great mod for the 160 (and I'm not a person who thinks much of modding a vintage radio). At least I wouldn't need to drill holes in the front panel.

Dave


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 Post subject:
PostPosted: Jun Mon 30, 2008 3:14 pm 
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Joined: May Thu 22, 2008 5:27 pm
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Location: MO Ozarks
Dave Doughty wrote:
I don't necessarily have anything good or bad to say about the reviews but the way I read it, the author of the first review is saying this set does not have AVC for the SSB mode:

Dave


I made my first jump to a conclusion of the year! Somewhere down the list from years ago a 270 is proclaimed the best receiver ever.

My favorite eham review is the HRO-500 guy who said something to the effect that "...the chase was more rewarding than the aquisition." I've had that experience (not on a 500. YET!)

I have poorly performing radios that money could not buy. Any vintage RX has something to offer.

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 Post subject:
PostPosted: Jun Mon 30, 2008 3:29 pm 
Silent Key

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20548
Location: Sandpoint, IDAHO 83864
The only reason I showed any interest in the NC-270 was strictly for nostalgia reasons. I have never really operated one myself and was only exposed to one in operation one time and that was back in June of 1963.

Our local ham radio club was holding Field Day and we ran a single station with an old PE-75 generator providing the power. The Field Day setup consisted of a DX-100 transmitter and an NC-270 receiver. I don't recall what members owned the equipment, but since I had not got my license yet, I was one of the loggers who logged the contacts.

It was all AM operation back then and I always got a kick out of hearing the grunt from the DX-100 plate transformer every time the switch was thrown and that loud relay that switched the antenna clacking behind the operating position.

So, that, in a nutshell, is my experience with the NC-270. Never operated one, but was present while one was used. So it is just the nostalgia factor that perked my interest when one was mentioned.
Curt

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(Connoisseur of the cold 807) CW forever!


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 Post subject:
PostPosted: Jun Mon 30, 2008 3:29 pm 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: Irving, Texas USA EM 12
Joe Cro N3IBX wrote:

My only "beef" is that they don't include the 160M Amateur band, of which I do most of my transmitting-receiving on.
Joe Cro N3IBX





I've had a 270 since about 1973. I built a crystal controlled converter with a 6BA6 and 6U8 to use ahead of the 270 for 160 metres.

It converts the 1.8 - 2.0 mc. band to 7000 - 7200 kc. on the 40 metre position of the RX. Works FB.

Mine is far from stock. Added audio deriven AGC for CW & SSSC, a real product detector, Handbook "S" meter circuit, and various other changes.

And, it looks like no other. Gone is the Cosmic Blue color and "Flip Foot". The panel is black crackle with black National knobs, and it sports a 3" rectangular 'S' meter.

Presently mated with a 1961 Johnson Valiant, which looks stock, but isn't.

John

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Philmore "Little Wonder" crystal set and Trimm headphones in 1950


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 Post subject:
PostPosted: Jul Tue 01, 2008 5:34 am 
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There's one on ebay right now.

Mike


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 Post subject:
PostPosted: Jul Tue 01, 2008 3:23 pm 
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Joined: Oct Sat 20, 2007 3:36 am
Posts: 11481
Location: Southern NH, 03076
National went thru several management changes after WW2 and each one wandered off in a different direction.

The 270 was not one of their better ideas especially since the Drake 2A/2B were already showing the future direction for design. Im actually suprised it sold so well and so many survive.

Even when almost new it was a PITA to work on and that ferrite glob was forever problematic.

Someone with an experimental bent might consider a few options.

- Use the 230 IF section from a junker NC-300/303

- Use multiple 262 Kc auto radio IF's padded down plus selectivity switching as well as IF offset

- Skip the above and go right to 50 Kc from a junker Drake.

- Build a CE Slicer or Hammarlund HC-10 clone to work at 230 Kc.

- Put it on a shelf and get another radio :lol:

Carl
National Radio 1963-69


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 Post subject:
PostPosted: Jul Tue 01, 2008 4:39 pm 
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Joined: Aug Tue 28, 2007 6:44 pm
Posts: 462
Location: Tustin,CA
Hi Carl,

While the NC-270's ferrite filter is a real PITA to work on, all five of the NC-270's were successfully aligned. A couple of points:
1. The IF adjustment at 230.00 KHz most likely isn't going to happen. You can, however, find a new IF frequency in the range of 226 - 234 KHz where both sections FL1 and FL2 will peak together. The frequency range of the BFO and notch frequency adjustments will tolerate that range of IF's.
2. The discrete components that switch selectivity will also accommodate that new range of IF's.
3. After adjusting the IF to it's new frequency and peaking IF xfmrs T12 -T14 and adjusting the BFO and notch frequency, the radio will work quite well and "instant selection" of USB/LSB signals will work with the BFO knob in its 12 o'clock position as designed.
4. The kicker is that the 0.6 KHz position will probably be wider, ranging from 0.5 - 1.0 KHz and averaging 0.73 KHz. The 2.5U, 2.5L, and 3 positions will be close enough, but also wider than spec. The 5 position may be useless - only one of five NC-270's had a truly spectacular 5 KHz position. You really don't have a clue about the filter response until you've completely aligned the radio. If you can't live with the wider bandpass, the radio can't be "repaired".
5. I ran an experiment that should be of interest. I aligned a unit, manually scanned the positions and recorded the data. I then removed and replaced the ferrite filter with one I had just "rebuilt". After finding the "new" IF frequency and aligning the radio, I manually scanned the positions and recorded the data. Even though those two filters had two different, unique IF frequencies separated by 2 KHz, the characteristics of the IF were virtually identical which implies that with a "good" filter, the characteristics of the 230 KHz bandpass was dictated by components external to the filter.

At the end of the day, I enjoy using the NC-270, and I think for a mid-priced radio, it does the job it was designed for. It compares well with the HQ-110/110A and other mid-priced radios of that era.. The Drake 2A/2B?? Now there's an exceptional radio.

One last comment concerns the lack of AGC in CW/SSB. When you start life as a Novice using a BC-454 and other hand-me-down radios, using a radio like the NC-270 is a "dream", with or without AGC.

Dave - WA6VVL


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