This project came about after I repaired a couple of Yaesu amps, and passed them on.

I haven’t used, or wanted to use a linear for at least 17 years, but although once I have finished it, I doubt if I will use it or keep it, I felt like the challenge of building one.

 

What do I want?

If I had all the answers, I think it would be easier, but some starting points, not in ant order!

 

Must be capable of 1kW, even though I will never use it.
Must have a built in auto tuner capable of handling the full power
Must need less than 10W drive for full output
Must have good built in band pass filters
Must have auto band switching for Icom and Yaesu
Must have input and output protection
Must have one button tuning (more on that below)
Must have efficient fan control
Must have correctly designed airflow for cooling
Would be nice if it worked on 6m and 4m
Must have a built in PSU

MUST COST UNDER £1000 !!!

 

Looking at commercial examples, ones that meet few of the above points seem to be selling for around £2000.

Then I saw a video on youtube  https://www.youtube.com/watch?v=-lq0x5cEy_0

and decided that was the way I would try.

 

The same Russian hams also design and sell most of the other modules to put together a complete linear.

The only part that is not available from them is one push tuning. I will improve on a system I designed before, which will set the power and mode of the rig, start the tuning cycle, then change the rig back to the original settings. There is more to do on the linear application, but not complex, although does take time! 

 

So far, I am in the “Getting Things Together” stage, and solidifying the ideas that need to be included.