carbon for transmitters

[bakerbrett741]

there was a decision on carbon for transmitters. I'm not sure if this carbon would work or not.

http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4136+8229&pcatid=8229

[twocvbloke]

I asked about this somewhere here before and I think the conclusion was that aquarium filter carbon is not suitable...

[Bill]

Turns out that aquarium filter carbon is activated charcoal, which is the wrong form of carbon. It is very soft, like a sponge, because it has a very high porosity (makes a good filter). Microphone carbon needs to be in the form of solid granules (like crystals, not a sponge). The hard crystals, getting packed and unpacked, are what are needed for telephone carbon.

Bill

[dpaynter1066]

Way Back in the day, I gained possession of a transmitter from a 3 slot payphone near my school.  I had to trade 3 Bazooka Joe's and a Squirrel nut chew for it!! 

Mr Crummy ran a store right next to  the playground and did a vigorous trade in little brown bags full of sweets.  Little did he realize that Crummy's Store was unwittingly at the heart of the illicit trade in Blood Transmitters.

  After using it for a varied lot of different arcane purposes unrelated to Bell system best practices,  I got bored and cut it open.  As I recall, the carbon granules were about like grits in size and very shiny.

So why not just buy a transmitter capsule and rob, um borrow, the carbon from it?  That should work just fine in a candlestick.  T1 transmitters can be readily had on the cheap nowadays.  maybe for a Clark bar or two at the most, times being what they are.

As time went by, for some reason, at about the same time that payphones suddenly got armored cords on them, the supply of transmitters and receivers abruptly dried up.

Unfazed, the madding crowd merely took up their Magnifying glasses and went to seek out ants guilty of mortal sin and badly in need of moral remonstrance.

As far as making your own goes, The carbon rod from a zinc D battery should be about right once broken up, Ball milled and then screened to the right size.  Dunno how available zinc carbon flashlight cells are these days,  I quit playing with homemade arc lamps a long time ago and havent bothered to open any lately.

[Owain]

These people used to make telephone transmitter carbon

http://www.morganamt.com/gb/Home.htm  ( dead link - 4-28-2020 )

I have emailed them to ask if they still do.

A bottle of fresh clean shiny new carbon granules came up on ebay fairly recently.

[AE_Collector]

Very entertainingly written dpaynter!

As far as making your own goes, The carbon rod from a zinc D battery should be about right once broken up, Ball milled and then screened to the right size. 

Preferably an "expired" D Cell so this would be a good way to "recycle it"! I assume that the cheapest dry cells out there are still zinc carbon, look for an Asian Made brand. I always remember the "Flying Bomb" brand in some stores when I was a kid.

Terry

[twocvbloke]

There's plenty of cheap zinc-carbon batteries out there, though the really cheap ones should be avoided cos they leak more than the british government's secret services...

I use Panasonic Zinc-Carbons for my TMC linesman phone, aswell as a few other things that are low power and don't need anything special...

[rp2813]

@ dp1066:  Great post!

I look forward to hearing more tales of entertainment gained through re-purposing of WECo hardware!

[Owain]

These people used to make telephone transmitter carbon
http://www.morganamt.com/gb/Home.htm

I have emailed them to ask if they still do.

A bottle of fresh clean shiny new carbon granules came up on ebay fairly recently.

They have been kind enough to email back - they don't.

[dpaynter1066]

I think the trend for new telephones is electret mics and an op amp because they use less power.

[Vern P]

I couldn't find this went I was lookng for it, so I made a post in "tech stuff" about this, see my post there.

Vern P