Some miscellaneous gear including Pye MX294. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Jon_G4MDC · 3rd Jan 2023, 8:51 pm

We can do it! Unless it's a weird export set most likely no need but it's good to check.

The 6m conversion needed care here. It's 10kHz channel spacing.

sentinel040 · 6th Jan 2023, 1:27 pm

Sorry I am rather late to the party.

Regarding the MX series, I have become a bit of a fan of these,over the years having modified many and still have a reasonable 'stash' of them. Generally I have buit a small adaptor board to carry a UV erasable EPROM and programmed it with 32 channels. The two banks of 16 being accessed either by an additional small togle switch fitted to the front panel or via a modified TEDX board, more of that in a bit. If it works I shall add some images of some EPROM boards.

I can also programme a EPROM if all else fails (you would have to make your own adaptor board though) or can provide a calculating spreadsheet for a DiY job.

If you can obtain a TEDX board with a full complement of push buttons (four large plus two small) and the LCD display there is an EPROM listing that lets the TEDX board generate all the relevant CTCSS tones, have CTCSS on/off, have a squelch override and then with a handful of extra components you can then also use one of the push large puttons to select between two 16 channel banks of stored frequencies.

The Holy Grail would be one with the G8UJS PIC modified TEDX board, which unfortunately is no longer available. This adds scanning, CTCSS, squelch override and 64 channels.

That is part of the attraction of these radios, they are so adaptable, easy to use and reliable. Well, in my experience anyway.

Cheers

Ian (G8KSZ)

Jon_G4MDC · 6th Jan 2023, 5:23 pm

Hello Ian nice to hear from you. That's the kind of thing and I still have some too.
Very nice sets. I would still like to try one with an alternative programmable divider to NF8813 + SP8906 that does not need 4 sequential 4bit nibbles to program.

I tried an ADF4111 which should have a mode where the phase detector is disabled and divide by N is output instead. I was quite new to I2C in those days and I think I just made a mess of it.

Now I have had some better success with Si5351s etc I might go back to it. There is also the possibility that my chips were duds.

3rd Jan 2023, 8:51 pm	#21
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Some miscellaneous gear including Pye MX294. We can do it! Unless it's a weird export set most likely no need but it's good to check. The 6m conversion needed care here. It's 10kHz channel spacing.

6th Jan 2023, 1:27 pm	#22
sentinel040 Hexode Join Date: Feb 2007 Location: Near Lichfield, Staffordshire, UK, most of the time and Crystal Palace, S London, some of the time.. Posts: 330	Re: Some miscellaneous gear including Pye MX294. Sorry I am rather late to the party. Regarding the MX series, I have become a bit of a fan of these,over the years having modified many and still have a reasonable 'stash' of them. Generally I have buit a small adaptor board to carry a UV erasable EPROM and programmed it with 32 channels. The two banks of 16 being accessed either by an additional small togle switch fitted to the front panel or via a modified TEDX board, more of that in a bit. If it works I shall add some images of some EPROM boards. I can also programme a EPROM if all else fails (you would have to make your own adaptor board though) or can provide a calculating spreadsheet for a DiY job. If you can obtain a TEDX board with a full complement of push buttons (four large plus two small) and the LCD display there is an EPROM listing that lets the TEDX board generate all the relevant CTCSS tones, have CTCSS on/off, have a squelch override and then with a handful of extra components you can then also use one of the push large puttons to select between two 16 channel banks of stored frequencies. The Holy Grail would be one with the G8UJS PIC modified TEDX board, which unfortunately is no longer available. This adds scanning, CTCSS, squelch override and 64 channels. That is part of the attraction of these radios, they are so adaptable, easy to use and reliable. Well, in my experience anyway. Cheers Ian (G8KSZ) Attached Thumbnails

6th Jan 2023, 5:23 pm	#23
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: Some miscellaneous gear including Pye MX294. Hello Ian nice to hear from you. That's the kind of thing and I still have some too. Very nice sets. I would still like to try one with an alternative programmable divider to NF8813 + SP8906 that does not need 4 sequential 4bit nibbles to program. I tried an ADF4111 which should have a mode where the phase detector is disabled and divide by N is output instead. I was quite new to I2C in those days and I think I just made a mess of it. Now I have had some better success with Si5351s etc I might go back to it. There is also the possibility that my chips were duds.