Vintage Radio & Communications Museum of CT Swap Meet, Sept 6

[EC8010]

"Here's one we prepared earlier" is a common dodge, when demonstrating things where something takes too long to do in the time allotted for the programme, or where something can go wrong. It might be a fiddly set up procedure or having to wait for glue to set.

Fifty years ago I was talking to someone working with photomultipliers which could detect single photons. They said things you'd think would be lightproof, such as folded metal seams and screw threaded fittings, were not; a few photons would always find their way through. Making something light proof was something they found hard. By their standards film cameras were not lightproof.

Indeed, you take your credibility in your very hands when you do a live demonstration, and it takes time, so having a pre-prepared item makes sense. But for exactly that reason, you garner huge respect when you do a genuine live demonstration.

Yes, photomultipliers are capable of detecting single photon events and that's what I was doing, and I found it very hard. I learned that only metals stop light and photons will rattle their way through any gap. Despite having made kit that could observe single photon events with photomultipliers, it still took me four iterations before I had a test jig that was sufficiently light-tight to measure the forward drop of an LED at 3fA. The difficulty was that you happily seal the photomultiplier for good whereas the LED jig needed to be readily openable to change the LED. You need a combination of strategies, but mazes, self-adhesive copper tape over seams, and black felt or rough paper to prevent internal reflections are the main ones.

[tautech]

One of these years I'll cross paths with you at a swap meet, though with my nocturnal inclinations I usually arrive closer to or after the end than the beginning. This is probably a good thing as I have far too much stuff already and really shouldn't be bringing more wayward test gear home...

Take treasures to sell at the swapmeet. After all, if you don't have duplicates, you aren't trying hard enough

With luck and discipline you should have a smaller load on the way back. (And if anyone mentions VNAs, I will go into a corner and sulk)

Go into sulky mode, I have 2 !
A 3.2 GHz combo SA/VNA and a 8.5 GHz 4 port unit.
That's enuf VNA's for now unless something better come out or I win some lottery.......dreams are free.

[tggzzz]

One of these years I'll cross paths with you at a swap meet, though with my nocturnal inclinations I usually arrive closer to or after the end than the beginning. This is probably a good thing as I have far too much stuff already and really shouldn't be bringing more wayward test gear home...

Take treasures to sell at the swapmeet. After all, if you don't have duplicates, you aren't trying hard enough

With luck and discipline you should have a smaller load on the way back. (And if anyone mentions VNAs, I will go into a corner and sulk)

Go into sulky mode, I have 2 !
A 3.2 GHz combo SA/VNA and a 8.5 GHz 4 port unit.
That's enuf VNA's for now unless something better come out or I win some lottery.......dreams are free.

I should have been more specific - my newly acquired boat anchor. Rather nice, pleased with it, except it indicates a lapse in determination ...

(They are fun, aren't they).

[tautech]

Take treasures to sell at the swapmeet. After all, if you don't have duplicates, you aren't trying hard enough

With luck and discipline you should have a smaller load on the way back. (And if anyone mentions VNAs, I will go into a corner and sulk)

Go into sulky mode, I have 2 !
A 3.2 GHz combo SA/VNA and a 8.5 GHz 4 port unit.
That's enuf VNA's for now unless something better come out or I win some lottery.......dreams are free.

I should have been more specific - my newly acquired boat anchor. Rather nice, pleased with it, except it indicates a lapse in determination ...

(They are fun, aren't they).

Yup.
VNA's are a whole nuther rabbit hole !