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Reviews Categories | Transverters | Microwave Modules MMT 432/28S Help


Reviews Summary for Microwave Modules MMT 432/28S
Microwave Modules MMT 432/28S Reviews: 2 Average rating: 4.0/5 MSRP: $Out of production as of the mid
Description: Transverter: 28MHz IF, up to 500mW input, 432-436MHz operating frequency
Product is in production.
More info: http://
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W5FH Rating: 4/5 Jan 4, 2014 08:20 Send this review to a friend
Good Old Transverter  Time owned: more than 12 months
In the early 1970's a friend and I ordered a pair of these directly from Liverpool, England and then he went on to become a US importer (Texas RF Distributors). I made many 432 contacts using one of these with a TS-520S IF rig. I enjoy working with these units for 144, 222 and 432 Mhz. The MMT432-28 can be improved a little by substituting a better front end transistor. The stock BFR-34A first RF amp is OK for casual use, but substituting a better bipolar device such as the MRF951 will really make a difference. There are a number of low noise bipolar devices that can be used but you may need to adjust the Vcc voltage and biasing. I prefer to not use the internal PIN diode T/R switching and use an external coaxial antenna relay, and it is easy to use a transistor switch, tied to the transverter +12 VDC TX bus, to operate the relay.All in all, these units are still very usable.
 
KM3F Rating: 4/5 Dec 12, 2011 15:13 Send this review to a friend
First testing  Time owned: 0 to 3 months
....This unit has been out of production for quite a number of years. I found one in very good condition to begin a 432 station.
....I have the schematic and operation info.
....Has reasonable sensitivty and NF rated at 3db.
....Seperate 28 mhz input and outputs.
....Seperate 432 output/input options.
....Case is cast alum at 7.25L x 4.58W x 2H inches.
....Built a transfer switch for the 28 mhz input side for single T/R cable use at 28 mhz.
....Removed the seperate 432 receive 'option'.
....The T/R in/out switch has an 15 db attenuator pad installed in the transmitt side to reduce to drive power to the transmitt side from the 4 watt level of the driver radio.
....Output power is a solid 10 watts, the rated.
....It is possible to install optional crystals to move to the desired frequency range.
....I use this transverter to drive a MIRAGE D1010 solid state amplifier with rating of 10 in-100 watts out. The power out is a solid 110 watts as measured on my watt meter into a flat load. A great match of equipment.
....Other features are auto internal keyup 'RF sensing'. External key up. Pin diode switching.
....The unit is very well engineered and built using seperate componants on the PC board. The power output section is in it's own enclosed metal box with feedthough terminals.
....In and out connectors are N type.
....Main power and control is a 6 pin DIN connector.
....While long out of production it is worth a look at if you find one said to be working and at a low cost.
Since there was no write up, I provide this for those who may have a chance to work with the unit.
Good luck.
 


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