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THE AM BULLETIN BOARD => Military Amateur Radio Section => Topic started by: Todd, KA1KAQ on March 16, 2019, 05:02:34 PM



Title: Aircraft Radio Corporation Type K - Where it all Started
Post by: Todd, KA1KAQ on March 16, 2019, 05:02:34 PM
Some years ago Mike Hanz/KC4TOS of aafradio.org and other fame spent some time helping to restore this big ol' airplane called the Enola Gay at the new Air & Space Udvar-Hazy annex just up the road a piece. At some point during this time he was able to gain access to a very important piece of history in their possession: the ARC Type K, prototype and basis for the later ARA/ATA, ARC-5, and SCR-274N Command sets. He took excellent photos and posted them on his page along with the story behind them. Have a look when you get a chance (WARNING: Mike has a LOT of great stuff on his site, it is easy to spend hours there):

  http://aafradio.org/flightdeck/ARC_Type_K.html

If you ever saw Raiders of the Lost Ark, there is a scene at the end with a worker placing a crated artifact into storage in a large warehouse. The first photo on Mike's Type K page is eerily similar!

Anyhow....those of us who are interested in this stuff just ate this all up and remain very thankful to Mike for providing us with a look at something not accessible to the general radio public. I recall thinking 'This is the closest I'll ever get to seeing the Type K in my lifetime' or something like that.

Fathers Day 2018 rolls around. For my big day, Jen and Caitlin took me back to Udvar-Hazy where we had visited once before in 2016. It was a fun weekend with a lot going on at the museum.

As we came in through a back door from the air strip, we passed by a row of display cases lining the back wall. Approaching the second case, I was stunned and actually froze in front of it for several minutes. There, right before my eyes, no further away than the thickness of the glass, sat the Type K, along with a nice ART-13 and several other items. Whoa!

Made two more trips up last summer, in July and August, and it was still there (I checked each time, of course).

This is my favorite museum, easy to spend an entire day there. If you are in the MD/northern VA/DC area, it's truly a must see. Be sure to check out the Type K, on the back-right wall behind the F-15 and Vietnam-era aircraft.



Title: Re: Aircraft Radio Corporation Type K - Where it all Started
Post by: Todd, KA1KAQ on March 16, 2019, 05:04:00 PM
A few more...


Title: Re: Aircraft Radio Corporation Type K - Where it all Started
Post by: KE5YTV on March 16, 2019, 05:56:50 PM
Todd, thanks for the pix. Very cool! The Air and Space Museum is the best thing to see in Washington.


Title: Re: Aircraft Radio Corporation Type K - Where it all Started
Post by: AJ1G on March 16, 2019, 10:46:16 PM
Always try to get over there when I am in the area. Just a heads up- admission is free but IIRC they whack you something like 20 bucks for parking.


Title: Re: Aircraft Radio Corporation Type K - Where it all Started
Post by: KB2WIG on March 17, 2019, 07:25:07 AM

Take the Metro to  L'Enfant Plaza........

The museum is the cats butical area.

KLC



Title: Re: Aircraft Radio Corporation Type K - Where it all Started
Post by: Todd, KA1KAQ on March 17, 2019, 01:48:49 PM
Actually, that's the original Air & Space museum in downtown DC. The Udvar-Hazy Annex is over in northern VA, Chantilly I think. It's right next to Dulles Airport. In fact, they have their own taxiway over to the Annex so they can bring in aircraft for display or special events. For Fathers Day Weekend they had a 767 out back along with an array of warbirds, antique cars, re-enactors, airport equipment, and military transport aircraft available for perusal.

And unlike the downtown museum, they have a lot of space, including a large restoration facility where Flak Bait has been sitting. In 2016 they had the Horton 'Flying Wing' jet in there, currently moved out onto the main floor until they can get back to it.

When you think about having the Boeing DASH 80/707 prototype in there along with the Enola Gay, a Concorde, SR-71, Ju-52, Super Connie, Space shuttle and much, much more, well....downtown is clearly dated in comparison. Think they're doing renovations in DC right now.

Chris, you're right - admission is free, though parking is $15 which is truly a bargain when you consider how much it costs to go to a movie these days or such. And there's no time limit - you can get there when it opens and stay until it closes, which I've come close to doing. There's just so much to see, history all around you.

In summer they also have free parking after 4 or 4:30PM until closing which is 6PM I think. Not all day, but it's great for getting your feet wet.

And they have a nice ART-13 in display along with everything else. Need to get a working station set up....


Title: Re: Aircraft Radio Corporation Type K - Where it all Started
Post by: Todd, KA1KAQ on March 17, 2019, 01:54:31 PM
Here are a couple shots from out back, along with a shot from the Air & Space page showing the DASH 80 landing at Dulles in 2003 when it was donated to the museum by Boeing after restoration. You can see the Annex in the background including the large observation tower.

The day I was there in June they had some WWII re-enactors out back with an airfield set up of sorts. Part of this included a nearly complete SCR-274N Command set station with a J-37 key hooked to an oscillator. After I tapped out a CQ with my call a couple times several of the crew came over and invited me to join. Seems they have no real radio guys involved.


Title: Re: Aircraft Radio Corporation Type K - Where it all Started
Post by: Opcom on March 19, 2019, 11:03:39 PM
On the 4th shelf from the botton, note the small CRT radar display there.
I have the 3DP7 and 3DP1 CRTs for that.
Those CRT are special having a rod type electrode protruding from the front of the tube face.
The sweep is circular, 360 degrees.
The unit measures distance, is called a J-scope, and is effectively an A-scope trace wrapped in a circle.
The A-scope used the H axis for distance and V axis for return strength.
The J-scope there uses an electronically created circle trace (H and V plates driven 90 degrees out of phase) and signals applied to the rod electrode changes the size of the trace according to return echo strength.
Other J scopes, German for example, modulate the circular trace size rather than using a special electrode in the face of the tube.
http://www.radartutorial.eu/12.scopes/sc09.en.html

The CRT is still very interesting in that you can put a circular trace on it and use the center screen electrode as a extremely hi-Z electroscope.

Recall also the novel "circular modulation scope" article.
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands