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FGC for tuning antennae?

The world of the domestic radio has now moved far away from the use of tuning condensers (as they were known at the time)with wide-spaced vanes.

Suggesting an old valve radio as a source of such is increasingly not viable. (Mind you, most of those of a CB mentality will be buying auto tuners with their "C"heque "B"ooks)

As they are essentially assemblies of metal, has anybody had a go at manufacturing one?

I perceive the difficulty to be machining the grooves to hold the vanes, which I presume are held in by expanding the shaft under heat and then cooling the whole lot together?

Reply to
Airy R. Bean
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Does it have to be all metal? Some years ago I had the idea of using double-sided copper-clad for the vanes. It never got past the drawing board stage, but I don't see why it wouldn't work.

Reply to
Richard Kaulfuss

If you can avoid being run over by the wheelchairs you complain of, try going to a rally and looking for some.

Or stay at home and study NMR, perhaps.

Reply to
RVMJ 99g

Yep, made several locally for tuning mag loops etc. Used threaded studding and nuts as spacers and a perspex (or similar) chassis. Hardest (ie most tedious) bit is making the vanes. There was a local company who offered to stamp them one FOC but numbers never required it.

Not seem it done like that- more common method is a U shaped notch in the vane, the lower part of the U fitting in the underside of the grove in the spindle and the upper ends of the U being swaged over into the grooves. Heating and cooling wouldn't work- you need to shrink the shaft, assemble, and expand it.

Reply to
Brian Reay

Why did you have to spoil a reasonable post with your silly comments?

Why do you need a wide-spaced cap? No need for on in a rx ATU and you don't have an amateur radio licence.

GW

Reply to
Graham W

It's called 'noblesse oblige'.....

Reply to
RVMJ 99g

I think you are being totally unreasonable.

Airy is the only person who has made a connection, no matter how tentative, between mmw radiation, nuclear emissions, and NMR.

No scientist working in any of the fields mentioned has previously managed to do that.

Reply to
RVMJ 99g

"Airy R. Bean" wrote

I think the vanes are pressed from sheet, assembled on a shaft with removable spacers and then the assembly is soldered together.

-- Jonathan

Barnes's theorem; for every foolproof device there is a fool greater than the proof.

To reply remove AT

Reply to
Jonathan Barnes

You could always go to

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Reply to
Tim Christian

Jonathan Barnes writes .......

Yes, I have seen them like that. Then zink dipped?

Mike

Reply to
Mike Whittome

....... or even zinc. sorry!

Reply to
Mike Whittome

Surely not. Silver plated perhaps but zinc is not a good conductor of RF. The Q would fall quite a lot if you zinc plated/dipped them.

vy 73

Andy, M1EBV

Reply to
Andy Cowley

OK Jonathan, I am sure you are right.

There I go again jumping to conclusions from appearances. I am not in to this radio thingie. :)

Mike

Reply to
Mike Whittome

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