Microwave Modules T432/144R transverter


g3zqu
 

Hi all.
I picked up at a rally - remember those! - last year a MM 432/144MHz transverter at a very cheap price!
It has two xtals in it, one at 101MHz and one at 101.4MHz (along with a 116MHz one as well). These will obviously give the needed 1.6MHz shift for repeater operation. Problem is how do you select the appropriate xtal as there are not the usual two toggle switches on the rear over the power DIN socket. However the two DIN pins 2 & 4, normally a "not connected".  are connected to the pcb and I suspect that the repeater shift can be remotely set. The two pins in question have zero volts on one and 8volts on the other.
Question is does anybody know how these pins are connected to remotely control the repeater shift.  As the unit stands with no external connections to either pin,. 144.2MHz in gives 432.2MHz out
Hopefully somebody might know or even have a circuit/manual for this version.

Martin G3ZQU


Chris Ruddy MM0KOS
 

Hopefully this will help you.... http://www.g4kfk.co.uk/html/microwave_modules.html

 

 

Chris MM0KOS

 

Sent from Mail for Windows 10

 


Alan Beard
 

Our Mike G4KFK missed one very important Microwave Modules version:

Back in 1977 I had a Yaesu FT-620 6m transceiver, they covered 50 to 54 MHz.
And a Yaesu FT-221.

(Us "Z" call limited licencees had only 50 MHz and up.)

Well, ham satellites were going to use 432 and 435 MHz so I needed a transverter
system that would cover 432 to 436 MHz.

I wrote to Microwave Modules, they responded so I bought their 432 to 50MHz version. 

An FT-620 is extremely easy to hookup to the MMT432-28 (now on 50MHz). In the 620 there's a short
coax from the exciter to the RF PA, route that to a socket on the rear of the radio to feed
the Tx signal to the MMT432. I still have the combo today and it still works.

Thanks MMT.

Alan VK2ZIW


On Fri, 22 May 2020 22:08:11 +0100, chris ruddy via groups.io wrote
> Hopefully this will help you.... http://www.g4kfk.co.uk/html/microwave_modules.html
>  
>  
> Chris MM0KOS
>  
> Sent from Mail for Windows 10
>  

---------------------------------------------------
Alan Beard

OpenWebMail 2.53


G8DQX list
 

Martin,

there were at least two variants of that transverter. A PW review (http://www.g4kfk.co.uk/MMT432-144_70cm_Transverter_PW_198111.pdf) indicates that there was the arrangement you noted, to offer double conversion operation. As memory recalls, there was a switch to set 1.6MHz offset operation when required. [My unit was the earlier version that required 1.6MHz offset at 2m, generating RF outside the UK 2m band.]

There was the 432-144R variant, with the 1.6MHz shift, and another 432-144 variant which covered 432-434, plus 432-436. See http://www.wirralcam.org/wadarc/Technical_Topics/MMT432_144.pdf. It is highly likely that other variants exist.

There is a circuit at http://g4fre.com/MM.htm, but it is shows an unswitched LO version. This inside view might also be helpful: http://www.retro.co.za/zs1ke/MMT432-Transverter/index.html.

HTH, 73, Stay Safe,

Robin, G8DQX

PS: Happy days of working PA novices on 70cms FM, sea path!

On 22/05/2020 21:35, g3zqu via groups.io wrote:
Hi all.
I picked up at a rally - remember those! - last year a MM 432/144MHz transverter at a very cheap price!
It has two xtals in it, one at 101MHz and one at 101.4MHz (along with a 116MHz one as well). These will obviously give the needed 1.6MHz shift for repeater operation. Problem is how do you select the appropriate xtal as there are not the usual two toggle switches on the rear over the power DIN socket. However the two DIN pins 2 & 4, normally a "not connected".  are connected to the pcb and I suspect that the repeater shift can be remotely set. The two pins in question have zero volts on one and 8volts on the other.
Question is does anybody know how these pins are connected to remotely control the repeater shift.  As the unit stands with no external connections to either pin,. 144.2MHz in gives 432.2MHz out
Hopefully somebody might know or even have a circuit/manual for this version.

Martin G3ZQU


Mike GD6ICR
 

I have one of these units if Anyone is interested 
--
Mike GD6ICR IO74PF73TW


John E. Beech
 

Hi Chris,
There seems to be one missing from that list 1296 - 28 MHz Rx Converter - I know they exist Ive got one! No paperwork though.

de John G8SEQ

Hopefully this will help you....
http://www.g4kfk.co.uk/html/microwave_modules.html

Chris MM0KOS


John Fell
 

I thought the PW review link looked interesting .... I wrote that back in 1981 and the R variant in question sits 200mm from my left hand as I write .
I use it with my ELAD FDM DUO to drive an SG labs TVTR for QO100 use .
The only issue I have had was the trimmers used in the RF filter - these were replaced with Tetfer type and have remained stable for the last 30 + years .
For many years it sat in the boot of my car as the 70cm device for Repeater operation /M .
Classic British kit .

73
John
G0API

On Sat, 23 May 2020 at 01:26, G8DQX list <list@...> wrote:

Martin,

there were at least two variants of that transverter. A PW review (http://www.g4kfk.co.uk/MMT432-144_70cm_Transverter_PW_198111.pdf) indicates that there was the arrangement you noted, to offer double conversion operation. As memory recalls, there was a switch to set 1.6MHz offset operation when required. [My unit was the earlier version that required 1.6MHz offset at 2m, generating RF outside the UK 2m band.]

There was the 432-144R variant, with the 1.6MHz shift, and another 432-144 variant which covered 432-434, plus 432-436. See http://www.wirralcam.org/wadarc/Technical_Topics/MMT432_144.pdf. It is highly likely that other variants exist.

There is a circuit at http://g4fre.com/MM.htm, but it is shows an unswitched LO version. This inside view might also be helpful: http://www.retro.co.za/zs1ke/MMT432-Transverter/index.html.

HTH, 73, Stay Safe,

Robin, G8DQX

PS: Happy days of working PA novices on 70cms FM, sea path!

On 22/05/2020 21:35, g3zqu via groups.io wrote:
Hi all.
I picked up at a rally - remember those! - last year a MM 432/144MHz transverter at a very cheap price!
It has two xtals in it, one at 101MHz and one at 101.4MHz (along with a 116MHz one as well). These will obviously give the needed 1.6MHz shift for repeater operation. Problem is how do you select the appropriate xtal as there are not the usual two toggle switches on the rear over the power DIN socket. However the two DIN pins 2 & 4, normally a "not connected".  are connected to the pcb and I suspect that the repeater shift can be remotely set. The two pins in question have zero volts on one and 8volts on the other.
Question is does anybody know how these pins are connected to remotely control the repeater shift.  As the unit stands with no external connections to either pin,. 144.2MHz in gives 432.2MHz out
Hopefully somebody might know or even have a circuit/manual for this version.

Martin G3ZQU