This weekends project.

Homebrew equipment discussion, show off your projects.
Sangoma
Posts: 290
Joined: Thu May 28, 2020 4:04 am
Location: Coventry
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This weekends project.

Unread post by Sangoma »

The amp, LPF and tuner is one solid unit
a4.jpg
Not much room in the case
a3.jpg
Not much room for connections either, still have to fit a grommet for the power lead
a2.jpg

And still have to fit the power LED on the front
a1.jpg

All manual at the moment, a board is in progress that will decode and set the band using an IC703, FT817 and X5015.

Manual operation is simpler than normal though, push the tune button, and it disables the PA, and sits and waits for a carrier from the rig, it then starts tuning, and when tuned, re-enables the PA.
Though it works fully automatically with the 703; there was supposed to be an update for the 5105 to work in a similar way to Icom, but I can't find any recent mention of it.

Gives about 50W, capable of 90W, but I changed my mind and decided 50W in a smaller case would be more useful.

Should work on 6m as well, but I will need to make a separate LPF.
G 3 E J S
Sangoma
Posts: 290
Joined: Thu May 28, 2020 4:04 am
Location: Coventry
Contact:

Re: This weekends project.

Unread post by Sangoma »

It has exceeded my expectations, first QSO I had was on 80 to ON6ID, who gave me a 59+10, I listened afterwards and he seemed to be giving honest reports. He was using 400w and me 40W, and I was using a 66' EFLW inverted L which is too short to work properly on 80, he was using a proper antenna.

Other QSOs were also encouraging and the amp works as it should, and doesn't even get warm, let alone switch on the second speed of the fan (it runs slowly and quietly all the time)

I have added one diode, all I have to do to tune is change to FM and press the tune button on the amp.

I have also discovered that it uses Icom CIV commands, with the same address as an IC-7000, so the PIC I intend to add to decode the bands of the three radios will also be able to fully automate the tuning process, so I won't bother decoding the band data, will just read it from the CIV/CAT.

There is a data connection on the 8 pin mini din one the 5105, can't find what that data is, but if it was the CIV (which I have my doubts, as the CIV port is two wire, not single wire like the Icom) it would only need one connection for digital, which would be nice.
G 3 E J S
M0XXQ
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Joined: Thu Sep 27, 2018 10:23 pm
Location: Newcastle upon Tyne
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Re: This weekends project.

Unread post by M0XXQ »

Well Steve, that is some work of engineering and you are no doubt very proud of your effort - Well done!
Why don't you write a Radcom article or maybe even GQRP SPRAT too?
Sangoma
Posts: 290
Joined: Thu May 28, 2020 4:04 am
Location: Coventry
Contact:

Re: This weekends project.

Unread post by Sangoma »

M0XXQ wrote: Tue Jul 07, 2020 9:47 pm Well Steve, that is some work of engineering and you are no doubt very proud of your effort - Well done!
Why don't you write a Radcom article or maybe even GQRP SPRAT too?

Not necessarily proud, but pleased with the result, and in this case quite surprised just how useful it is.
I sold an HF Packer some years ago, didn't enjoy it, and it had no tuner.

I have had no comments about distortion on SSB with this one, in fact quite the opposite, comments have been positive. One day I will put it on the SA and have a look. Will also measure the current draw, and try it on 12V instead of 13.8V, get an idea of the efficiency.

It would no doubt give a cleaner output running on 24V, and would also then give 90W, but there is no room in this case for a DC-DC converter, which was in the original plan.

I don't think the difference between 50W and 90W on the air would make it more useful, however the small size does make it more useful.

If I submit it as an idea to a magazine, it will be to Radio ZS, as most of my previous things have been, there are copyright problems with UK magazines, they insist on holding the copyright, which is completely against what I think amateur radio is about.
I have an idea it might not be what SPRAT is looking for :)

For future larger ones, I have an FT-757 which I started rebuilding and have decided I'm not going to do them any more which I can take the PA and filter board out of, also have a couple of other 100W PAs and filters, and another possibility is an Icom 736 that has a tuner as well, if it does not rely on external processing, that would be ideal, must look in to that.
G 3 E J S
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