Well,
I've been fiddling some more with my experimental 4M Transverter project.
I've built the RX converter:
This is fairly simple in that it takes the 70MHz signals from the antenna, amplifies them and then mixes them with the 60MHz local oscillator we developed last time:
http://g0mgx.blogspot.co.uk/2014/09/to-transvert-or-not-to-transvert.html
and results in a 10MHz signal at the output. I've done some initial tests on this down converter and it seems to work as expected.
The transmit side is still work in progress:
On the right you can see part of a traditional doubly balanced mixer - I've used BAT85 diodes this time for a change.
The mixer mixes the 10MHz drive signal with the 60MHz local oscillator to make the 70MHz (plus all the harmonics and also the difference). This is fed through a band pass filter, which sweeps like this:
and then amplified and passed through another filter. The second filter is also a band pass at the moment, but I expect I will swap it for an identical low pass filter I made for the RX side - the second band pass filter is no way near as good as the first for some reason.
I then need to make a linear amplifier to increase the output to about 10W to drive my linear.
Good, egh?
I've been fiddling some more with my experimental 4M Transverter project.
I've built the RX converter:
This is fairly simple in that it takes the 70MHz signals from the antenna, amplifies them and then mixes them with the 60MHz local oscillator we developed last time:
http://g0mgx.blogspot.co.uk/2014/09/to-transvert-or-not-to-transvert.html
and results in a 10MHz signal at the output. I've done some initial tests on this down converter and it seems to work as expected.
The transmit side is still work in progress:
On the right you can see part of a traditional doubly balanced mixer - I've used BAT85 diodes this time for a change.
The mixer mixes the 10MHz drive signal with the 60MHz local oscillator to make the 70MHz (plus all the harmonics and also the difference). This is fed through a band pass filter, which sweeps like this:
and then amplified and passed through another filter. The second filter is also a band pass at the moment, but I expect I will swap it for an identical low pass filter I made for the RX side - the second band pass filter is no way near as good as the first for some reason.
I then need to make a linear amplifier to increase the output to about 10W to drive my linear.
Good, egh?
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