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Author Topic: National Radio R-1490/GRR-17  (Read 7510 times)
K6EID
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Posts: 8




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« on: September 03, 2011, 09:24:04 AM »

I have a neighbor who has two of these units. They look to be in excellent physical shape. Anyone have any info on value of same?

Thanks

Phil K6EID
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AC5UP
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Posts: 4413




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« Reply #1 on: September 03, 2011, 10:34:16 AM »

BAMA has pics and docs on this one in case anyone is interested: http://bama.edebris.com/manuals/military/r1490/

Best bet to establish a baseline price is to search eBay for previous auctions, although I have a hunch the examples will be limited. Fair Radio Sales (which IMHO is overpriced) would likely try selling them for $495 to $695 each. Maybe less because they don't have the cult-like following the R-390A has developed. Priced one of those lately?

On the plus side the radio is built fully mil-spec, documented on BAMA and self contained with an internal 117 vac power supply. The drift spec is one part in 10 to the 7th per day which translates to " No Drift ". Would make an excellent RTTY monitoring receiver since that's exactly what the Jarheads used them for.

On the down side it is not a convenient SWL receiver and even worse for casual Ham use. Flipping the decade counter knobs gets real old real quick, for casual listening a VFO is the much better choice. Tuning increment is 100 Hz with a vernier. If you rarely QSY this isn't an issue, otherwise it's clumsy for SSB. Tuning range is 2 - 30 MHz which means no Rehab Rush on this radio, but you can listen to Alex Jones do his nightly meltdown on 4840 kHz or Dr euGene Scott preach from the grave on 5935 and 6090 kHz. Scott's lectures have a certain crusty, crunchy texture that I find entertaining. Dual conversion superhet and all solid state which I'm putting on the down side... In 1968 solid state receivers were on the path to getting good. IMHO the silicon of that day was marginally worse than hollow state and not nearly as rugged. Longer lived and lower maintenance for sure, but for HF receiver performance I think a good tube set had the edge up through the early 80's.

Opinions will vary on that last point.  Wink

Greatest determinant for price will be the operating condition and cosmetic appearance of these particular radios. I hope they come with power cords as the connector could be an oddball. I'd be reluctant to go over $200 even if they were super nice, but remember that I have more radios than I'll ever need. To someone who's obsessed with OD electronics three or four times that might be reasonable.........................?

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K6EID
Member

Posts: 8




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« Reply #2 on: September 03, 2011, 11:35:13 AM »

Thanks. I think the one we opened had a power card. I'll borrow one and fire it up and get some photos.

Tnx

Phil
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AC5UP
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Posts: 4413




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« Reply #3 on: September 03, 2011, 06:33:11 PM »

Just for grins I took a quick tour of the service manual and two things jumped out at me:

1) It's an early example (possibly the first ?) of a receiver that up converts to the 1st IF. IF frequencies are 112 and 5.xx MHz and in the 80's that was considered the hot ticket in receiver design. Allegedly minimized birdies and PLL noise from a synthesized VFO by putting the first conversion several octaves above the received frequency.

2) The front end has a range type preselector with a fine tune adjustment. Modern synthesized rigs are broadband no-tune and suffer somewhat in the presence of strong out of band signals because of that. While the preselector is two more knobs to tweak when selecting a frequency, the benefit should be a near-bulletproof front end.

3) The rig is loaded with 2N709, 2N2222 transistors and 1N914 diodes which are extremely common part numbers... Aside from the usual custom pieces like the crystal filters, it's very off-the-shelf friendly should it ever need repair. I wish more radios were like that.

Yeah, that's three observations, but I'm feeling generous tonight.  Grin
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K6EID
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Posts: 8




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« Reply #4 on: September 04, 2011, 11:13:14 AM »

Thanks for the FB observations.
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K6EID
Member

Posts: 8




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« Reply #5 on: December 03, 2011, 12:22:57 PM »

I have them both to check out. They only have the DC power cord and I don't have a 24 VDC supply. The AC 115V cable model is C44486-G1. Any one have any idea where I can purchase one of these or the plug that fits the three prong male receptacle on the receiver?

Tnx
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K6EID
Member

Posts: 8




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« Reply #6 on: October 14, 2017, 10:47:58 AM »

Finally got around to this (it's only been 6 years!. Have photos and info posted at http://k6eid.com/R-1490.htm
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KM1H
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Posts: 2499




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« Reply #7 on: October 23, 2017, 05:38:16 PM »

National was way ahead of others for build quality and technical advances such as the 1964 HRO-500 from the amateur/commercial division. A lot of their mil spec stuff will never see the light of day as it was custom built for a purpose and was destroyed when surplused.

Carl
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