MMDS Converter on ATV
So, you have seen these on ebay for 10-15 quid:
MMDS Converter
Now you would like to use them on 13cm ATV or for receiving the ISS when HAM-TV is switched on...
Some simple mods make this possible and the units seem to be fairly sensitive too, i can receive GB3KM at 30km away quite well with one of these indoors!
All you need to get going is:
MMDS units as seen above, other maybe similar to mod
SUP-2400 Up-Converter (available on batc shop) - or buy one off ebay and modify yourself here
10pf cap
8MHz crystal
The internal mods are shown below, this moves the IF up to around 400MHz from ~120MHz so that we can up-convert it to a standard satellite receiver.
The SUP-2400 up-converter is used to convert the MMDS IF back up within the range of a modern satellite tuner, they have a 2.4GHz LO, so we need at least a 300MHz IF from the MMDS converter to get within the sat receiver IF at around max 2.1GHz.
MMDS Converter mods
For example to receive GB3KM at 2.440GHz the IF from the MMDS unit is now 392MHz, we then mix this with the LO in the SUP-2400 converter (2400MHz - 392MHz) which equals 2008MHz to tune the satellite receiver to.
You could probably drop the LO even further but it found the LO level drops off too much when you get below 2GHz.
