Polish 13cm PAs

[G8DKC]

Mike, I'm interested about your comment.

"Failing that, just wire it up as a regular PA and bypass all the digital stuff."

Maybe not run at full power, more power consumption, not such good linearity?

But you do have a brick or working amp

See you on the io.group.

Peter

[DG8KD]

Hi Rainer,

Thank you for the pin out, apparently each PA requires individual settings on 4 transistors.

Together, the settings require 10 parameters.

So looks like some study in Digital PreDistortion (DPD) measurements etc so a big ask and long study.

The guy who did the original mods started his journey about 3 months ago with the help of an Arduino expert.

But not giving much away, which I have views on...

https://www.youtube.com/watch?v=LPpyAkAD27s

73

Peter

I have a bunch of numbers (parameters) for my PA.
I will count them and give you the total number.

Maybe someone from the UK can contact the original supplier and ask for some more docs, maybe there is a radio amateur working who can give us a helping hand...

www.aceaxis.co.uk


EDIT 22.02.19: 10 parameters on my sheet

[g0mjw]

I have one on order - but all this modification is doing is setting the bias and possibly the protection. At the end of the day the transistor needs a certain bias voltage and that can be supplied by analogue as well as digital means. What analogue will not do is dynamic bias to linearise or protect the devices, nor will it do temperature compensation. Nominal Idq is 900mA according to the data sheet and the output 14W in CDMA service. Presumably a lot more output can be had in CW but we don't know what the rest of the circuits would think of that - e.g. Dolphin PAs. 4x14W when combined is probably nearly 50W which should be more than enough already.

Mike

[DG8KD]

Some more infos that I got:

Input Output
0.05 mW bei 10 W out
0.1 mW bei 20W out
0.15 mW bei 30 W out
0.3 mW bei 50W out and current of 11 A (maximum possible with internal PSU)
0.65 mW bei 100W out and current of 16A (too much for internal PSU (48V)).


When you get +6V to PA, the Arduino module starts,
it activates them. When you switch on + 28V, each PA has standby currents and is ready for operation.
This time, the output should be 50 Ohm loaded (or an antenna).
When you use the built-in 48V inverter, both voltages will be delivered together and PA's are on Tx modus.
To switch the PA to receive, cut both two-colored wires - then both PA's on Rx modus and it get possibility to use PTT,

Connectors MCX J4 i J8 near to the output connector SMA, can be use to monitor the output power and have couplings -38 to -39 dB.

[g8gtz]

Excellent - thanks for the info.

Hopefully we will get them working.

Noel

[G8DKC]

Thanks from me also Rainer.

Peter

[G8PEF]

We have started a separate io.group for this topic.

Let me know if anyone wants to join.

And yes, agreed this hobby would be a lot poorer if we all charged for everything we do rather than share it for the good of the community.

73
Noel

Hi, Noel - I have one of these lumps, which I bought a while ago, so would be interested in any info on getting it working - how do I join the group?
John

[YL3AKC]

We have started a separate io.group for this topic.

Let me know if anyone wants to join.

And yes, agreed this hobby would be a lot poorer if we all charged for everything we do rather than share it for the good of the community.

73
Noel

Hello! I am also lucky owner of polish PA. PA is on the way right now. I want to join that special io.group if possible.

YL3AKC, Janis

[g8gtz]

Sent you both invites...

[DG8KD]

I am interested too!
Cheers
Rainer