Spectrian 30 watt snow flake mod ?

Latest News and Discussion about the use of the DATV transponder on Es'hail-2
G4WIM
Posts: 196
Joined: Thu Jan 29, 2015 8:36 pm

Spectrian 30 watt snow flake mod ?

Post by G4WIM » Tue Apr 16, 2019 8:22 pm

Hi Guys,

some time ago I stumbled across a 'snow flake' mod for the pyrojoe 30 watt Spectrian to lift its power from 25 watts to 30 watts when used for DATV uplink.

Ok, going from 25 to 30 W probably won't make any noticeable difference - but try as I might I can't find this information.

Does anyone have a link ?

73 Tim

g4eml
Posts: 24
Joined: Thu Apr 26, 2018 9:36 am

Re: Spectrian 30 watt snow flake mod ?

Post by g4eml » Wed Apr 17, 2019 8:03 am

I don’t have a link but the point on the amp that responds to snowflaking is on the output of the final FET, where the line takes a 90 degree turn before running down the end of the board. I found a fairly large snowflake (4mm square?) attached to the 45 degree section worked for me. It actually slightly overlaps the adjacent ground plane so I insulated underneath it with kapton tape.

G4WIM
Posts: 196
Joined: Thu Jan 29, 2015 8:36 pm

Re: Spectrian 30 watt snow flake mod ?

Post by G4WIM » Wed Apr 17, 2019 8:24 am

Thanks, once I have the complete unit built up and working I'll check the power as standard then with the snow flake - luckily I have some kapton tape.

Regards Tim

g4eml
Posts: 24
Joined: Thu Apr 26, 2018 9:36 am

Re: Spectrian 30 watt snow flake mod ?

Post by g4eml » Wed Apr 17, 2019 8:46 am

Mine was 21W before and 30W after which is a worthwhile gain for DATV.
I optimised the tuning at reduced power, about 10W output.

g8gtz
Posts: 1107
Joined: Wed Apr 07, 2010 6:26 pm

Re: Spectrian 30 watt snow flake mod ?

Post by g8gtz » Wed Apr 17, 2019 8:54 am

Suggest you take a look at page 15 in the new CQ-TV 263...

73
Noel - G8GTZ

g4eml
Posts: 24
Joined: Thu Apr 26, 2018 9:36 am

Re: Spectrian 30 watt snow flake mod ?

Post by g4eml » Wed Apr 17, 2019 3:16 pm

That article is for the 75W amp Noel. The 30W one is a different beast.

User avatar
G4IUG
Posts: 25
Joined: Fri Nov 23, 2018 6:28 pm

Re: Spectrian 30 watt snow flake mod ?

Post by G4IUG » Wed Apr 17, 2019 10:14 pm

Image

[UKMicrowaves] Spectrian 30W amp problem.
Taken from https://groups.io/g/UKMicrowaves/topics ,
the image above is re-hosted by me The text was :
______________________________________________

Hello Colin and other readers.

I feel that I can't assist your problem any more than the help you've
already received. But I wanted to add that I do have one of these
amplifiers working perfectly well at 2403 MHz, the centre of amateur
activity here in VK.

However, I did go through the whole amplifier chain trying to find
locations for solderable tabs ("snow flaking"), hoping to make it work
better at this further-out-of-band frequency. The interesting thing is
that I did find one sensitive/responsive point and it was between the
final device and the output port, where the microstrip track takes a
left hand turn - see attached '385s image. At 2403 MHz, 10 mW input
delivered 31 Watts output following this small addition.

It was also interesting that there seems to be a layer of some plastic
material everywhere which has to be melted away before the solder will
'take' - it makes the resulting soldered joint less than good looking!

Only for interest's sake, I'm also attaching a general image of the
whole amplifier.

I wish you well with rising to your challenge!

--Doug Friend, VK4OE.
Ex G6ANG/T and G8EAO

G4WIM
Posts: 196
Joined: Thu Jan 29, 2015 8:36 pm

Re: Spectrian 30 watt snow flake mod ?

Post by G4WIM » Thu Apr 18, 2019 7:17 am

Thank guys, just what I was looking for.

Hope yo have my PA up and running under test in a day or so, then I have to make the dual feed and align etc.

All in all it's coming together....

73 Tim

tonyaxn
Posts: 12
Joined: Tue Jun 09, 2015 4:13 pm

Re: Spectrian 30 watt snow flake mod ?

Post by tonyaxn » Thu Apr 18, 2019 8:01 am

Please let us all know how you get on Tim.

I have just purchased one of these from the seller on ebay and have measured 20W out for 10mW in on 2407.750 Mhz.

The photo attached of the PA shows that a snowflake was added at some time either on manufacture or later.

So to optimise do I move it or add another ?

73 Tony G4AXN
Attachments
cu PA stagecrop.jpg
cu PA stagecrop.jpg (215.25 KiB) Viewed 350 times

g4eml
Posts: 24
Joined: Thu Apr 26, 2018 9:36 am

Re: Spectrian 30 watt snow flake mod ?

Post by g4eml » Thu Apr 18, 2019 9:59 am

When you try to add another the original one will probably come off anyway. The exact size and location will be different for each amplifier so it is a trial and error technique.

Post Reply

Return to “Es’hail-2 - DATV Transponder”