Tag Archives: Hammarlund

WWII Machine Shop Supervision film includes the Hammarlund Super Pro

Many thanks to SWLing Post contributor, Colin Snow (KM6NTW), who notes that the following 1944 film “Maintaining Workers’ Interest” from the US Office of Education, features the Hammarlund Super Pro.

The video starts at the point in the film where the Super Pro is featured. To view the film from the beginning, click here.

Click here to view on YouTube.

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Dan spots the ultra rare Hammarlund SP-600 JX21A on eBay

Many thanks to SWLing Post contributor, Dan Robinson, who discovered a very rareHammarlund SP-600 JX21A on eBay. Dan writes:

Collectors of classic boatanchor gear know what has been probably the rarest of tube sets year after year, decade after decade. That set is the Hammarlund SP-600 JX21A.

While there have been numerous JX21s on eBay, there has not been, to my memory, a single JX21A appearing. This particular model was a version of the SP-600 that was produced in small quantities in the 1960’s, and according to one writeup was the only one with a product detector and switchable sidebands. According to Radiomuseum it was the last model in the SP-600 series, and was recognizable for its knobs which were different because the silkscreen information was printed directly on the front panel rather than on the edge of the knob skirts.

According to Les Locklear’s excellent history of SP-600 models, the JX21A was produced between 1969 and 1972.

Now, an ultra-rare SP-600 JX21A has appeared on eBay. Like other models in the series, this would likely require replacement of numerous capacitors and a thorough refurbishment. The seller in this case has started bidding at a very low level, but if history is any guide, a rare model like this one may indeed go for thousands of dollars when all is said and done at the end of the auction.

Click here to view the Hammarlund SP-600 JX21A on eBay.

Amazing!  Thank you for sharing, Dan! What a gorgeous set. Though the seller states it’s in need of restoration, I’m pretty sure this one will get snagged up at end of auction. I’m very curious where the final price will land.

Are there any SWLing Post readers who own an SP-600 model–or the JX21A?  Please comment!

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Dan sheds light on various Hammarlund SP-600 models

Many thanks to SWLing Post contributor, Daniel Hawkins, who leaves the following comment in reply to our previous post about the Northern Radio SP-600 and discussion about diversity operation. Dan writes:

Diversity operation: two or more receivers and antennas used to copy CW or RTTY from one or more transmitters.

Most of the Hammarlund SP-600s were models built for diversity use including the well-known JX-17, the most common SP-600. Diversity models can be used as single receivers. In this eBay example Northern Radio has modified a SP-600 J-11 for diversity use.

SP-600 nomenclature: J means joint army/navy (JAN) mil-spec components. L means low frequency. X means crystal frequency control in addition to VFO. My SP-600 is a JX-21, which is not a diversity model. Higher model numbers do not necessarily mean later production dates. All SP-600s use the same serial number sequence regardless of model. Somewhere between serial numbers 15,000 and 17,000 (mid 1950’s) Hammarlund stopped using molded black beauty capacitors and switched to installing ceramic capacitors.

The two-digit model numbers indicate model types. JX-1, 7, 10 and 21 were similar non-diversity receivers. SP-600s built for military contracts will have an additional tag showing the military model number(s).

Here is a great page showing Northern Radio modified SP-600s in action with accompanying Northern Radio RTTY gear.

http://www.navy-radio.com/rcvrs/frr28.htm

Thanks for the primer, Dan! I believe I have one of the X models with crystal control, but I’ll need to verify once back home. Any other SP-600 owners out there in the Post readership?

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Exceedingly rare Northern Radio modified SP-600

Many thanks to SWLing Post contributor, Dan Robinson, who writes:

Those of us who still use SP-600s, and those of us who once did but can’t deal with them in retirement, lust after some of the rarer versions of the radio. This is one of them, the Northern Radio modified SP-600.

Click here to view on eBay.

Wow! Many thanks for the tip, Dan!

I must say that when Dan finds these rare treasures on eBay, they usually carry a very hefty price.  In my opinion, this is a good deal for a rare SP-600. Best of all, it has a BuyItNow price, so first-come, first serve and no bidding up the amount.  The shipping price is a bargain considering this radio probably weights upwards of 80 lbs.

This SP-600 may need some electrical restoration and possible re-capping. It’s listed as: “For parts or not working.” If you’ve been looking for an SP-600 to restore, this might be worth consideration. Thanks again, Dan.

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Colin’s Hammarlund HQ-120X restoration

Hammarlund-HQ120X

Many thanks to Colin Snow for sharing the following photos and commenting on his Hammarlund HQ-120X restoration. I originally noticed his photos in the Extreme Shortwave Listening group on Facebook and he kindly wrote up descriptions for each image to be published here on the SWLing Post:


Hammarlund HQ-120X restoration

by Colin Snow

Hammarlund HQ-120X

Purchased on eBay March, 2016. Hammarlund HQ-120X (1939 restored) and PSC/10 speaker (1939 original). The radio was frist restored by KE7RD, the collector who owned this unit for years. This was a late production version. It has 6K7’s instead of 6S7’s (good). The O/P TRANS has been replaced and an SO-239 added. It was recapped and aligned both IF + RF and works well on all bands.”

Hammarlund-HQ120X-2

I had the cabinet repainted locally at NRI Sandblasting and Coating with a black semi-gloss crinkle powder coat paint. I cleaned the chrome part of the handles with Quick Glo and stripped and painted the two shoulders with black gloss enamel.

Hammarlund-HQ120X-3

I had the speaker enclosure stripped and painted at the same time as the cabinet with the same black semi-gloss crinkle powder coat.

Hammarlund-HQ120X-5

The original 1939 speaker was a 10″ Jensen. It worked, but I wanted the best possible sound. This current production model Jensen fit exactly.

HAmmarlund-HQ120X 6

White lines for the knobs were done using white out. The lines are grooved so I just gobbed it on and wiped off the excess.

Hammarlund-HQ120X-Faceplate

I had the faceplate rescreened by Adam’s Precision Screen Printing, Inc. San Leandro, CA. They created a film positive first, then a negative screen.

Hammarlund-HQ120X-9

It was a perfect job. The color and sheen matched original. This should last longer because it is an epoxy ink that has been baked to harden.

Hammarlund-HQ120X-knobs

The lettering came out clean. Even though they made a 1.5X negative they still had to create artwork for the fonts. The original letters were just etched into to aluminum. It looked like it was done by hand.

Hammarlund-HQ120X-8

Funny how words change. We now say “megahertz”, not “megacycles.”

Hammarlund-HQ-120X-DialLight

I refurbished the dial windows myself. They were easy to strip and I used a flat black enamel spray. The S-meter glass was dirty so I disassembled it and cleaned with Quick Glo.

Hammarlund-HQ120X-10

Still works after all that!

Hammarlund-HQ120X-12

Its final resting place is my office and looks pretty good next to an original Tiffany’s lamp. I have a second listening post.


Colin, I can see that you spared no expense to restore this Hammarlund HQ-120X and it has paid off–an absolutely gorgeous job! I love how its “final resting place” is in a part of your office that gives it an appropriate amount of space–a place to be admired and, more importantly, enjoyed.  I bet the 120 sounds simply amazing!

Thanks again for sharing these photos and your commentary, Colin!

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Hammarlund HQ series: A digital display modification

HQ-DisplayMany thanks to SWLing Post reader, Jeff (KB7AIL), who shares the following:

Saw the article on the DC meter in a Hammerlund HQ180.

Another mod I have seen is replacing the meter with a digital display.

http://www.electronicspecialtyproducts.com/dd101.html

It integrates with the HQ180 nicely.

They also have digi-displays in cases or use with other receivers/transceivers.

Very cool, Jeff. While I know a digital display might kill the vintage look for some enthusiasts, I have to admire such a useful modification to replace a broken Hammarlund clock/meter.

As Jeff mentions, Electronic Specialty Products has a number of external digital display boxes as well. Check out their full line of products on the ESP website.

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Dan notes a unique modification on this Hammarlund HQ-180A

Hammarlund-HQ-180A

Many thanks to SWLing Post contributor, Dan Robinson, who shares a link to this eBay listing of a Hammarlund HQ-180A and notes:

Whoever owned this Hammarlund HQ-180A installed a DC meter where the clock or crystal unit usually is.

Hammarlund-HQ-180A-Mod

s-l1600 (1)

And the screws on the top of the hatch seem to indicate installation of a DC supply perhaps?

Click here to view on eBay.

Like you, I’ve never seen this particular mod to the HQ-180A, Dan.

I’m curious if the owner installed the DC meter to replace a broken or missing clock?  Though I’ve never searched for one, I suspect those Hammarlund clocks are getting more difficult to find on the used market.

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