[Fourlanders] Fwd: [VHF] A Different 1kW SSPA FOR 144 MHZ

[whensley11 at comcast.net]

----- Forwarded Message ----- 
From: "Fred" <n1dpm at verizon.net> 
To: moon-net at list-serv.davidv.net, microwave at lists.valinet.com, newsvhf at mailman.qth.net, vhf at w6yx.stanford.edu 
Cc: n1jez at burlingtontelecom.net, stanka1ze at aol.com 
Sent: Friday, February 4, 2011 9:08:59 PM 
Subject: [VHF] A Different 1kW SSPA FOR 144 MHZ 

Hello all, OK It's time to let the cat out of the bag. I have a new SSPA 
(1kW) up and running well on 2 meter EME. It is based on the NXP part 
BLF578 with the circuit that is published in the NXP app note AN10800. 
Mike N1JEZ has duplicated my efforts and results by starting with the FM 
broadcast module that is available from a RF pallet manufacturer here in 
the USA (built on a copper spreader) with repeatable results. These 
results and construction details can be seen on the VK4DD forum site 
http://www.vk4dd.com/forum/index.php?sid=c40f4da137bcaa73fe3da6 
3952373f6a I have seen over 1kW out of this amplifier and the 2 tone 
measurements excellent. I feel there may be more power to be had, I have 
simply not had the time to play with it more to see what can be 
"squeezed" from it. At 1kW output the amplifier draws less than 30 
amperes at 48VDC. This was a nice jump in power for my EME station from 
the 350 watt level. I have made ~40 EME QSO's with this amplifier on 
WSJT and with the cooling and heatsinking as described on the VK4DD site 
it barely gets warm. This amplifier also has a temperature compensated / 
regulated bias network on the board. Now for letting the cat out of the 
bag.... I have worked with the folks at NXP who originally got me going 
on this amplifier to secure enough boards and transistors, along with 
Stan, KA1ZE, and Mike N1JEZ to put together 8 pallet kits each 
with 2 FETs (in case there is an "oops"...btw...I burned up a number of 
parts in tuning but not an FET!) that will be DONATED to a number of VHF 
conferences to auction off with the proceeds going to help defray 
conference costs. We did not want these to go as simple free door prizes 
and end up sitting on a shelf or in a box and we felt that if they were 
auctioned as other items have been at conferences like microwave update 
that the chances were good these would get in the hands of folks that 
would actually put them to use. Mike, N1JEZ is currently gathering the 
components and Stan, KA1ZE has the 1/2" (13cm) copper spreaders on order 
and in line for machining. I'm gathering the the coaxial components and 
have all the the boards and FETs. We will bond / solder the boards to 
the spreaders and kit up the rest of the parts for the pallets as 
complete kits. Our current time schedule (as this is a hobby and were 
"squeezing it in" to our schedules) is to complete these 
kits approximately in May or June. There will be at least a few of them 
at Microwave Update in Enfield CT, USA in the fall and I will 
be contacting folks who are in charge of running other confereces to get 
them in the right hands to pass them onto the VHF amateur 
community. So...if you have some patience and want to support one of 
your VHF conferences you could "score" one or more of these kits for I'm 
sure a reasonable price. Also this kit with some changing of the coaxial 
components and chip caps can also be "re-worked" to easily operate on 
50MHz or 70MHz, or potentially 222MHz. I don't believe the coaxial 
transformer matching method is suitable for use at 432 MHz but the FET is 
good to 500MHz and I have seen test data for it there in a circuit. 
Once I contact the folks at various conferences I will release a list of 
where these are going. I would ask for some feedback of a contact person 
or two to be able to get 2 or 3 of them over to a large European 
conference, or outside the USA as I am not familiar with ones held there. 
So...Be paitent and stay tuned for further announcements.... Best 73 FredN1DPM 
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