Blimey, those didn't last long!

Hi, Has anyone tried using 22mm copper pipe endcaps as a PCB mount filter for 13cm, with the usual tuning screw and pair of probes'? Just curious if there is any data/experience on this. I've used 15m

Excellent, I was going to try a pin spacing of 16.5mm (centre to centre) ... does that sound about right? I assume it is not particularly critical, that would put the pins roughly 2.5mm from the cavit

Many thanks for that, excellent work. It looks like a somewhere between 3/16" and 1/4" probe length should be about right at 13cm then. That helps a lot. Many years ago, inspired by WDG, I built a 5.7

Making brass filters and silver plating them would not be an issue if the 22mm copper caps are not going to work ... I have a lathe, and spare time! Knowing the ideal dimensions or indeed a method of

That's fine ... I'll stick with the 22mm ones for 13cm then (I think the Americans call them 3/4" ... we refer to the OD of the pipe, I think Americans refer to the ID, but I suspect they are the same

We used to have a fishtank full of silver plating solution, but the idea of moving it again convinced us to plate out the silver and dispose of the remaining cyanide. It was very useful for plating st

Andy, I think these days, with cheap and easy gain, they make a useful and easy to implement inter-stage filter. They also take up minimal board space. Printed filters would be interesting, but withou

I would not put one ahead of the LNA, but beyond there, I really don't see the problem. There are gain device available with 24dB of gain at 13cm, costing less then £1 ... I estimate the insertion los

That is a fair point, filter shape is non ideal, but as ever it is a trade off between simplicity/availability of parts and performance.In the more bizarre moments that pass for sanity around here, I

I can probably get on 23cm, but will be QRP, as the poxy Mitsubishi driver module is not playing ball ...

About 30 years ago when I bought it, we powered it up on +15V and it drew no current and produced no power. I tossed it in a box. Recently I pulled it out and played again ... there is an interlock on

I meant "powered it up on + and - 15V and got no results" ...

A section of the 2" stuff would be great, I don't need a lot, 4" or something like that. If you get a bar of 1" I'll take a foot of that as well, happy to pay. I can make the tapered section in the wa

I have some suitable -20 couplers .. somewhere ...

The final device is marked "NEC 9004-13" so I assume it is internally matched to some degree.

1W would be worth having ... it probably just needs a little "snowflaking" then to get the best out of it, although, with 6 stages, I suspect I might have more than enough drive power from the WG unit

it looks like the amp is at best 1 watt out ... I suspect you are OK.

Well, a bit of messing around with some copper foil and it's doing a bit more than it did before ... some more playing needed, and I need to find my input attenuators, as I am fairly sure I am over-dr

Looks like copper on the ceramic to me. Even the gold flashed PCBs are just a few microns of electroless gold on top of copper ...