UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Graham G3ZVT · 17th Jul 2017, 7:01 pm

I had two of those handsets complete with the 4 pin plugs when I was a youngster.
I bought them from Globe Radio in Manchester.

I made a pair of light-beam telephones with them.
The transmitter was carbon, the receiver was balanced armature, I remember the resistance was much less than the similar inserts in a pair of headphones, but I still think they were around the 1000 ohm mark, so I was surprised at the readings taken above.

The PTT switch was either N/O and in series with the mic or N/C and across the mic I can't remember which.

17th Jul 2017, 7:01 pm	#7
Graham G3ZVT Dekatron Join Date: May 2010 Location: Greater Manchester, UK. Posts: 18,715	Re: Telephone Set H Mk III I had two of those handsets complete with the 4 pin plugs when I was a youngster. I bought them from Globe Radio in Manchester. I made a pair of light-beam telephones with them. The transmitter was carbon, the receiver was balanced armature, I remember the resistance was much less than the similar inserts in a pair of headphones, but I still think they were around the 1000 ohm mark, so I was surprised at the readings taken above. The PTT switch was either N/O and in series with the mic or N/C and across the mic I can't remember which.