Sunday, July 22, 2012


She was torpedoed in the Pacific 30 July, 1945, after delivering an atom bomb to Tinian. Of 1,196 crew, some 900 made it into the shark-infested water. Despite sending a distress call, the sinking went unnoticed for five days. Only 317 men survived. It remains one of the worst U. S. naval disasters.

The USS Indianapolis Memorial is here in Indianapolis, and a room of the Indiana War Memorial Museum is dedicated to the ship. Just around the corner in the War Memorial, volunteers have recreated the ship's "Radio Central," piece by piece.

11 of the 41 radiomen were among the survivors.

The original installation is gone with the ship, but the equipment was quite standardized. "Was" being the operational word, as much of it has become quite scarce. The old receivers were uncommonly good -- and uncommonly heavy; the transmitters were even more so, on both counts.

So simply collecting the equipment is a huge accomplishment. But the volunteers are committed to more than mere static display -- they're getting the old gear running!

Entry is very much like stepping into a busy radio room -- CW in the background (including "SOS SOS de NABD...") and recorded talk about the gear plays at several positions. Visitors walk down a narrow aisle between transmitters and the test bench before coming to the row of operating positions. Left: Center: Right: Ship's radio rooms are a pretty fair match for the ideal ham shack, too, though I don't suppose very many of the guys copy traffic on a "mill" these days. (And I wonder if there might not be a few southpaws on the crew -- or did the Navy train ops to send left-handed?)

The transmitters cover from low frequencies all the way into VHF, with "big rigs" into the upper HF range.The big transmitters are right there where you can get a good look. The TBS low VHF transmitter-receiver they've been getting into operating condition is kept far enough away to keep curious fingers safe. You can just see the side of it in the right-side image of the operating positions -- the acronym for this is sometimes (and unofficially) translated "Talk Between Ships" and sure enough, my Dad's 1946 Introduction to Radio Equipment, NAVPERS 10172* says it was "designed to provide short-range communications between surface craft such as task forces or convoys." Interestingly, the book covers operation of just about every receiver and transmitter in the USS Indianapolis Radio Room exhibit.

It's a fascinating installation. It includes a couple of Amateur Radio operating positions, at the Supervisor and Test desks, operating as WW2IND: The more modern ham gear is kept out of sight when not in use, but pipe that shiny green SP-600! I'll be back -- the museum is not very far from where I work and they tell me volunteers are present many mornings and all day most Thursdays.
* This book was my first exposure to the technical side of radio, and does a pretty good job of covering basic theory before moving on to specific equipment. The Naval Reserve, when they learned my father worked for RCA, was determined to make him a radioman...until realizing he didn't know International Morse code. Rather than run a reservist through radio-op school, they set him to toting bags of powder in a gun turret. Which is, if you ask me, one more reason to learn CW! Why'd they think Dad would be a radioman? Have a close look at the photos and you'll see a discreet RCA "meatball" on an awful lot of Navy comms gear; RCA and radio were just about synonyms, as far as the Navy was concerned. There are only two non-RCA receivers on the entire NABD operating bench shown above, in fact -- can you ID them?


  1. Thanks for the wonderful tour.

    I've known a few WW II radio operators (sadly, all are SKs now) and was told they were trained to send left handed so they could use their right hands for writing if a mill wasn't available.

    Haven't been active on the ham bands for some years and my CW skills are rusted away. Need to get them back. I like QRP operating and that really calls for CW.

    Jeff The Bear (N1SN)

  2. can you ID them?

    Well, you gave away the Hammerlund SP-600 and I think I see, in the picture above the SP-600, a Collins ART-13 trying to slip out the right side of the picture.

  3. By the Cold War years, the "TBS" designation had been dropped. Four short-range links were used for routine operations:

    --PriTac (Primary Tactical). The work-horse channel for bridge-to-bridge communications and most often used to direct ship movements. It was controlled by ships' captains.

    --SecTac (Secondary Tactical). A backup for PriTac.

    --PriCI (Primary Combat Information). An intelligence channel controlled by the senior man on watch in CIC, Combat Information Center -- the radar shack. It served to exchange information on radar contacts

    --SecCI (Secondary Combat Information). Backup for above.

    In the early '60s, CW was still going strong for long range, and our radio men took pride in speed-key competence. Loose talk held that single side band advances were making Morse less important. Some dreamers were saying the U.S. would get its own Sputnik some day so we could bounce voice radio signals world-wide, making CW obsolete. We paid little attention to such fools.

  4. Off-topic:

    A new Hamster

  5. Added to my "Must see" list. Thank you!

  6. Homebru, that's on the Test & Repair bench. Still two non-RCA receivers....

  7. Roberta

    its easy to learn Morse if you do it by cipher all dit E I S H 5
    all dah T M O CH 0
    dit first A U V 4
    dah first N D B 6

    and so on on a very good day i could copy traffic @ 16 wpm
    mostly it was blinker @ 5 wpm it is still required for a deck license
    I learned it when i was in the scouts its a perishable skill
    but about 15-20 years ago they did away with CW and Sparks saving voice
    and teletype for use aboard ship i was sorry to see them go
    amongst others im available as a tour guide thanks for the tour of CA-35

    best wishes to you and Tam


  8. You'd like the piece that occasionally shared traffic with TBS.. The TBY, otherwise know as the code talker radio. It was a portable VHF (25-80mhz) of about 30 pounds and featured a regen RX and a Pushpull modulated osc TX of about .5W using acorn tubes. typically used for beach to close in ship for command traffic, spotting, logistics. I have one and it's even functional though the TX has as much FM as AM and the RX is wide. Still a tBY-8 is a part of WWII history and 1950s ham portable gear for 10M and 5M later 6M back then.


  9. Navigator: I'm a 20-wpm Extra...though not at the same time; I took the faster code test when I upgraded to Advanced and by the time I went for Extra, they'd dropped the CW requirement. But I still have my certificate of successful completion!

    To this day, I have never had a voice QSO below 142 MHz. Maybe someday, when I get an AM rig going.

    (As I recall, the guy who taught the Novice class I took as a High Schooler went in EATOIN SHRRLU... order, but it's been a few years.)

  10. That sounds like the old Codemaster tape. That's what they taught us with when I took my Novice classes.

  11. Stuff like this... it's why I love this blog.

  12. Aww, NJT, you and youre Remintion Noiselesses are makin' me blush!

    (On close inspection, there are at least hree non-RCA receivers on the operating bench: a .mil version of the Hallicrafters S-27 VHF rig atop the right end, a National (or Wells-Gardener) RAO or RBH -- MF through HF -- below and to the right of it, and the receiver of the Collins TCS -- RX and TX -- setup in the shelves at far right.)

  13. My father was a radioman on the USS Portland, sister ship of the Indianapolis. He spent much of his time copying 25 WPM CW from radio station NSS in Annapolis, MD. The traffic was all five letter code groups which meant nothing to him since they had to be sent to another room for decoding. He said that they only rarely transmitted any traffic, most of their work was receive only. (The ship may have been operating under radio silence to avoid giving away their position.) The radiomen could copy CW and type without thinking about it at all, the code just flowed from their ears to their fingers without stopping at the brain, they sometimes would read a magazine while they were typing the five letter groups. All the ships in the fleet copied all of the messages, if they needed a fill on something they would ask another ship by blinker light to fill in the missing traffic. Late at night the navy sometimes sent family welfare information in clear text, and they also copied Associated Press news transmissions for the ship's newspaper. He took radio training at the Great Lakes center north of Chicago, the code class started out slow and increased the speed by a couple of wpm every week, the people who could not keep up with the class were sent on to other navy duties. After the war he gave up radio and went to college on the GI bill, he was never a ham but when I became interested in ham radio as a young kid, he tried to help me learn CW but I could never copy as well as he could, and he had trouble copying anything slower than 25 wpm because that was what he was used to during the war.

    Dan Schultz N8FGV

  14. Robert Tevault KC9TRVAugust 9, 2014 at 9:20 AM

    The TBS at the Indy Radio Room now operates on 50.4 Mhz. AM. That was a fun project.

    Robert Tevault KC9TRV

  15. An E.H. Scott Model RCK is on it's way to the U.S.S. Indianapolis radio Room as I write. I understand that it is the only Receiver that they (Radio Room) has been missing and will complete a long awaited project which is only possible from the ongoing relentless efforts of the volunteers. The "RCK" was an upgrade as President Eisenhower considered this ship his favorite and thus had to have had the better quality (Carrier type) radio equipment installed. This radio is a 2 meter receiver (and from my understanding) used for high frequency communications between ships and aircraft. In those days operating at this "Very High Frequency" (VHF) was surely a Tactical advantage as the enemy could not listen in that high up the frequency...yet. This RCK Receiver has not been tested, however it's seems to be in pristine shape inside & fair condition externally. Who knows how much work it will require, but it will be the hands of the Radio Room Exhibit Crew very soon. Though no current U.S.S. Indy Radio Operators are still with us, repairs and upkeep are still an ongoing mission. Donations are always being accepted for the U.S.S. Indianapolis Radio Room.

    Doug Christensen