AVQ 47 Weather Radar Unit Help

[Dodger57]

Hello all!

I recently came into possession of a AVQ 47 Weather Radar Unit (links to pics below) - I imagine it was a pull from a craft many years ago, shelved and forgotten about until a recent clean out. It's of no use to me but I thought it would be fun to see if I could get it "working" - or lit up as an interesting office item.

There is a connection labeled J101 - I've googled around but there doesn't appear to be a surplus of that particular connector - or old harnesses. I thought I could rig up a power supply to one and use it to at least the screen.

Any thoughts on this project - or got a line of a J101 connector source?

Thanks!
Daffydd

I would think J101 was the designation of the connector, not a part number.

[Dodger57]

Thank you, sir. You must be right as I've had no luck with that as a part number. One of our engineers mentioned that he's seen that type of connector with RF components - tho this one appears to be keyed so that may make it harder to locate.
Thanks again!

That looks like a 62GB connector, one of the favoured military jobs 38999 is the other common one.

[Dodger57]

Yes, the 62GB looks spot on! Thank you!

I'd like to rig up a bit of power to light the screen. It looks like a CRT screen - might take 110v? I've seen some manuals for the unit on the net - but damn expensive for this lark.

[majoconz]

That bit is only the display - usually fitted in the centre of the cockpit instrument panel. There would have been a large receiver/power supply box somewhere in the avionics bay and the scanner behind the nosecone.

[Dodger57]

Hey thanks, majoconz - I figured there was at least a dish or scanner somewhere.

[Graham G3ZVT]

What I, and I think the OP would like to know, is how would one go about powering the display and emulating a target blip on the screen?
I know these are not designed to display a scanned raster like a TV. I used to think that the circular axis was done with magnets and a motor, but I remember reading it can be done none-mechanically.

[TonyDuell]

Driving the 2 deflection axes with sine waves of the same amplitude in quadrature (90 degrees out of phase) will produce a circle. Changing the amplidute of them (both together) will of course change the size of the circle.

So I guess if you have relatively slow sine waves for the 2 axes and control their ampltiude with a much faster ramp you will get the rotating line display.

I have a TDMS5 (Telegraph distortion measuring set) which displays a single circular trace on a CRT screen. This is generated electronically, not by rotating deflection cols. I think the manual, including the circuit is on Sam Hallas's telephone web site.

[G6Tanuki]

The usual 'timebase' on those displays was a vertical line which appeared with the bottom end anchored at the 'pointy' part of the display and which then swept from side to side to create a fan-shaped display. The 'straight up' position of the line represented the aircraft's heading and the sides of the fan showed what weather was at different angles either side of the current heading; recreating this electronically could be a fun exercise!

The distance 'up' the line from the base indicates how far ahead the particular weather events are.

[Dodger57]

Originally Posted by rambo1152

What I, and I think the OP would like to know, is how would one go about powering the display and emulating a target blip on the screen?

Yes, please!
Glad to see more activity on this thread - I think getting this unit lit up, and moving, would be so cool!

Thanks everyone!
Daffydd

[Graham G3ZVT]

Originally Posted by TonyDuell

Driving the 2 deflection axes with sine waves of the same amplitude in quadrature (90 degrees out of phase) will produce a circle. Changing the amplitude of them (both together) will of course change the size of the circle.

Of course, a 1:1 Lissajous figure! I should have known that.

Originally Posted by TonyDuell

So I guess if you have relatively slow sine waves for the 2 axes and control their amplitude with a much faster ramp you will get the rotating line display.

Sounds easy enough to do on any scope then.
It's then a matter of synchronising your servomotor to it and applying the returns to the "Z" axis.

Are RADAR experiments allowed in appropriate amateur bands? In the 50 odd years that I have been licenced I've never been aware of any.

[Julesomega]

Originally Posted by rambo1152

Are RADAR experiments allowed in appropriate amateur bands?

Only communication with other licensed amateurs is allowed. 'Broadcasting' in the literal sense of the word is specifically forbidden, so spraying RF around is not allowed

Only communication with other licensed amateurs is allowed.

Or putting out a call. Or use one of the "licence free" bands, I there are radar slots available.

[Graham G3ZVT]

Originally Posted by Julesomega

Only communication with other licensed amateurs is allowed. 'Broadcasting' in the literal sense of the word is specifically forbidden, so spraying RF around is not allowed

I'm not so sure.
FT8 is little more than secondary RADAR

[Radio Wrangler]

Originally Posted by merlinmaxwell

Or putting out a call. Or use one of the "licence free" bands, I there are radar slots available.

Licence free radar means motion detectors for burglar alarms and automatic doors. The equipment has to be type approved to be legal and is required to be low power CW doppler in the mW power category.

The power limit dramatically limits range, and this means the time scales are dramatically shortened, so the sweep time the CRT deflectors are built for will be out by orders of magnitude. So even the display unit is specific to high powered radar. Power levels unsafe for anyone to enter the beam near the dish.

David

[joebog1]

I would have thought a circuit diagram of the display is the place to start. Inventing a B52 simulator to light a screen is outside the scope of the ORIGINAL question. "CAN I MAKE IT WORK", as I remember.

I "suspect" it's just the screen and associated controls, don't think it has scanning motors, OR transmitters, or transponders as may be appropriate.

IMHO it's just the EHT, brightness, focus anti-stigmatism controls. The rest would be in the receiver/power supply, transmitter and radar control. That display is "most likely" DC which means JUST the display part. It would have horizontal and vertical amps, perhaps a power supply. Its almost most likely to be 400Hz or even 1Khz supply if it does contain transformers.

Joe

[majoconz]

Here's a quick pic of a typical medium light aircraft installation - it looks like all the gyros are in there too.... I don't think you'll need to duplicate all this Here's everything you really wanted to know...... quite interesting for nerds like us!
http://aea.net/AvionicsNews/ANArchiv...borneRadar.pdf

[joebog1]

I must say its nice to see someone who knows the Beechcraft King Air aircraft. The RFDS has hundreds of them. ( RFDS = Royal Flying Doctor Service ). I am still asking for a circuit diagram of the said
" Display Unit".
I would think that Dodger57 also needs such an article.

with respect to all,

Joe

[SiriusHardware]

the time scales are dramatically shortened, so the sweep time the CRT deflectors are built for will be out by orders of magnitude. So even the display unit is specific to high powered radar. Power levels unsafe for anyone to enter the beam near the dish.

Getting ahead a bit, but how about making a 'model radar' to drive this using ultrasound instead of RF? Could just be a distance indicating display to start with, like early chain home radar displays (but with the line going up the screen rather than across).

That would give the needed relatively long interval between TX pulse and RX return.

Of course you need to get the display unit itself powered up and working first, if only with a 'dot' in the middle of the screen to begin with.