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Argus25 · 22nd Nov 2017, 1:33 pm

A while back I restored a ZC1 MK2.

I got it out again tonight. It has to be one of the best radios ever made. It TX/RX's 2-4 MHz and 4-8 MHz. Maybe this post will inspire others to fire up their vintage military radios.

I made some modifications to it (without drilling any holes). I noticed that the connector on the front panel, which was designed to feed a small lamp via a resistor, could be used to couple out a very tiny amount of the set's local oscillator or the TX oscillator signal. That way I could run my homebrew frequency counter (using TIL311 displays) which has an IF offset, to display the tuned (or transmitted frequency) the counter detects the level and switches out the IF frequency offset on transmit

Also I made a high impedance speaker to replace the headphones.

There are quite a few good stations still on shortwave in the 4 to 8 MHz zone. But I have a pantry transmitter with a variable RF output so I transmitted to the ZC1 at just under 2MHz tonight. The radio sounds great. I listened to a few song's such as Mr Hendrix's version of All Along the Watchtower.

I also managed to find a vintage pocket watch to fit in the watch carrier (photos attached)

This set is very reliable now, it runs a simple electronic plug in replacement for the original electromechanical split reed synchronous vibrator which I designed using germanium transistors and a coupling transformer which forces the main transformer into oscillation. I wrote an article on these power supplies and also how to get the most RF power out of a standard ZC1 on transmit into a 50R load and how to extract the L/O signal. etc.

I posted this article once before but it may be of use to others with the same or a similar radio:

http://worldphaco.com/uploads/ZC1_MK...R_SUPPLIES.pdf

22nd Nov 2017, 1:33 pm	#1
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	NZ made ZC1 MK2 Radio. A while back I restored a ZC1 MK2. I got it out again tonight. It has to be one of the best radios ever made. It TX/RX's 2-4 MHz and 4-8 MHz. Maybe this post will inspire others to fire up their vintage military radios. I made some modifications to it (without drilling any holes). I noticed that the connector on the front panel, which was designed to feed a small lamp via a resistor, could be used to couple out a very tiny amount of the set's local oscillator or the TX oscillator signal. That way I could run my homebrew frequency counter (using TIL311 displays) which has an IF offset, to display the tuned (or transmitted frequency) the counter detects the level and switches out the IF frequency offset on transmit Also I made a high impedance speaker to replace the headphones. There are quite a few good stations still on shortwave in the 4 to 8 MHz zone. But I have a pantry transmitter with a variable RF output so I transmitted to the ZC1 at just under 2MHz tonight. The radio sounds great. I listened to a few song's such as Mr Hendrix's version of All Along the Watchtower. I also managed to find a vintage pocket watch to fit in the watch carrier (photos attached) This set is very reliable now, it runs a simple electronic plug in replacement for the original electromechanical split reed synchronous vibrator which I designed using germanium transistors and a coupling transformer which forces the main transformer into oscillation. I wrote an article on these power supplies and also how to get the most RF power out of a standard ZC1 on transmit into a 50R load and how to extract the L/O signal. etc. I posted this article once before but it may be of use to others with the same or a similar radio: http://worldphaco.com/uploads/ZC1_MK...R_SUPPLIES.pdf Attached Thumbnails