Old tech I’ve never heard of

MaxHeadRoom

Joined Jul 18, 2013
25,230
I worked in industrial electronics where Decatrons, Thyratrons, and Ignitrons were used. :cool:
Also a transmitting Valves (tube) used in HF heating unit, it had a 3kw cathode heater element!!
 

ApacheKid

Joined Jan 12, 2015
688
I'd like to post a picture of an old RAF "air position indicator" these were mechanical devices with embedded gryoscopes that used a bearing rolling on a rotating disk that was able to track position LAT/LONG.

I bought two of these from a surplus store in the mid 70s, took them apart and then lost all trace, these were truly remarkable device.

The core was a cylinder that rolled against a bearing and the bearing in turn touched a smooth steel disc (about 2" diameter).

Hard to explain operation but there were two disc/roller assemblies, the gyro must have controlled the rate of rotation of the cylinder (or disc) so heading due north the latitude roller would turn fast but the longitude was still and if heading east the latitude roller was still and the longitude roller was fast, at flight directions anywhere in between the rollers would turn at some intermediate speed (so heading northwest they'd rotate at the same rate).

The assembly clearly could (small mechanical decade counters) track position using this design, I think they were from old WW2 bombers.
 

ApacheKid

Joined Jan 12, 2015
688
I think this is close to what I'm trying to describe:

1638721641845.png

This might even be one of these very units, this pic is very reminiscent:

1638721773416.png

One the left is a roller (sitting horizontally in this image) and visually beneath the roller you can see a disc, to the right of the disc, on its edge you can see a bearing, this is almost certainly the device I had.

From close inspection it seems it was the bearing that was movable, perhaps on some separate slide rail, the disc and roller were fixed relative to each other. As the bearing moved across the disc the relative speed between roller and disc would change - I don't know if it was the disc or roller that rotated at a speed proportional to air speed but one of them did.

Looking at this closely I think the disc rotated and "drove" the cylinder at a speed that depended on where the bearing was positioned, if center the cylinder would not rotate at all, if slid one way he roller would turn one way and if slid the other way the cylinder would rotate in the opposite direction.

So Im thinking the two discs were drive at a speed related to one's direction...
 
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KeithWalker

Joined Jul 10, 2017
2,357
I worked on Marconi SWB-8 HF radio transmitters when I was in the Royal Air Force (1957-1960). They were used at RAF bases around the world as teletype transmitters. The power supply was 3-phase AC rectified with mercury vapour rectifiers.

SPECIFICATIONS:

Power: 2 to 3.5 kilowatts
Frequency Range: 3 to 22.2 MHz
Frequency control: Used a two valve Franklin oscillator which was mounted right at the bottom of the transmitter, on the floor, where temperature change was minimal. This was particularly important.
Power input - ?
Weight - ?
Dimensions - ?
Tube (Valve) types: Output stage- ACT9
Intermediate stages- 807, KTW61, ML6
Power supply- G020 (mercury vapour)


SWB_8.jpg
 
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MaxHeadRoom

Joined Jul 18, 2013
25,230
I worked on Marconi SWB-8 HF radio transmitters when I was in the Royal Air Force (1957-1960). They were used at RAF bases around the world as teletype transmitters.
I recall our instructor stressing the need to remove power before working on those,
Anyone caught not observing said instruction would be placed on a charge.
One week later he came in with all the ends of his finger tips taped,
Guess How that happened? :oops:
 

KeithWalker

Joined Jul 10, 2017
2,357
I recall our instructor stressing the need to remove power before working on those,
Anyone caught not observing said instruction would be placed on a charge.
One week later he came in with all the ends of his finger tips taped,
Guess How that happened? :oops:
Yes, we had to work with one hand in our back pocket until we had switched off and discharged the power supplies.
 

MaxHeadRoom

Joined Jul 18, 2013
25,230
This is the decatron tube I mentioned earlier, it is used for counting pulses, or as we used it for firing ignitrons, counting so many cycles on, so many off.
It operates very similar to a stepper motor principle in operation.

1638908425494.png
 
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boostbuck

Joined Oct 5, 2017
184
Many years ago I disassembled the video terminal from an old ICL System 4 and within it was a monoscope. It took me a while to work out what it was and how it functioned - a very bulky non-digital character ROM complete with heaters and HT. I still have it. Also the video frame memory, which was a torsion-wire delay line. I had the complete circuits within the maintenance manual and unravelling the design was fascinating.

The monoscope I have is the upper one:

BrimarMonoscope.jpg

The delay line is similar to this:

Torsion_wire_delay_line.jpg
 

dendad

Joined Feb 20, 2016
4,142
When I was first at Radio Australia, the 100KW AM transmitters used those Mercury vapor rectifiers. Then they were replaced with a stack of Silicon rectifier diodes.



I my "treasures" somewhere I have a traveling wave tube. Are they still in use?
Something like this one....
1638918793462.png

But, one of my favorite bits of old tech is this VSWR meter that I rescued from the trash when almost all the Radio Australia Shepparton transmitter site was sent to scrap.
(I won't start on what a crime I think that was)

RA_SWR_meter3.jpg
RA_SWR_meter2.jpg
RA_SWR_meter4.jpg
This was lifted up to run on the top of the 600ohm 4 wire feeder and pulled along with the rope to measure the VSWR.
This is well worth saving and I hope the radio Australia main building will be turned into a tech museum and if so, a short length of feeder installed in the transmitter hall and this fun device set up on it to show how we did it years ago.

FYI....
We had some access there for a ham radio event a couple of years ago...
http://www.sadarc.org/xenforo/upload/index.php?forums/vi3ra-radio-australia-weekend.9/

EDIT: Oops, I had 2 bottom views but now it has the top that shows the shielded pickup loop.
 
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Delta Prime

Joined Nov 15, 2019
1,326
I my "treasures" somewhere I have a traveling wave tube. Are they still in use?
Something like this one..
1638918793462.png
Very much so.they're still used today. They are a key element of
satellite transponders.
2 years ago at JPL( Jet Propulsion Laboratories) here in California, I was part of a team of technicians charged with the responsibility of
optimizing the RF output power and
heat dissipation of TWTA's.
 

nsaspook

Joined Aug 27, 2009
9,751
Very much so.they're still used today. They are a key element of
satellite transponders.
2 years ago at JPL( Jet Propulsion Laboratories) here in California, I was part of a team of technicians charged with the responsibility of
optimizing the RF output power and
heat dissipation of TWTA's.
TWT's make excellent countermeasure amplifier systems.
https://www.dvidshub.net/image/4130473/slq-32-maintenance-course
https://slideplayer.com/slide/7876793/
Afloat EW SystemsThe AN/SLQ-32(V) shipboard EW system provides electronic support and countermeasure protection for U.S. and international navies. It is the primary EW system carried by major US Navy surface ships, with more than 450 systems produced to date. The (V)1 and (V)2 suites are passive, providing early warning, identification and direction finding capability for simultaneous multiple threats. The (V)3 suite provides an additional active response for simultaneous electronic jamming and deception of multiple threats. The (V)4, an expanded version of the (V)3, is used on aircraft carriers. The (V)5, used on destroyers and frigates, integrates a passive (V)2 with active equipment called “Sidekick.” The SLQ-32(V) system has been in operation since the 1970s and ongoing efforts to restore and upgrade older systems will extend the life of the SLQ-32(V) well into the 21st century.The system achieves EW objectives by providing full threat band frequency coverage, instantaneous azimuth coverage, 100 percent probability of intercept and simultaneous response to multiple threats. It can detect aircraft search and target radars well before they detect the ship. The system’s rapid response time ensures that jamming protection is enabled to prevent long range targeting of the ship and to deceive missiles launched against the ship. The system has an on-line library of emitter types for rapid identification.
http://www.teledynedefenseelectronics.com/mec/Pages/Home.aspx
 

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