14-02-2018, 08:25 AM
(14-02-2018, 05:27 AM)VK2ZIW Wrote: Hi all,
On hols, Diamond Head NSW.
At $12 ea. I bought six MRFE6S9160 LDMOS transistors six months back.
I found plenty of designs for these.
I got the heat spreader from my local metal scrappie (Penrith NSW) two pieces
of 4" copper bus bar 1/4" thick. I was stoked, $40 for six spreaders.
On looking at the designs, I see no reason for PCB. Surely, copper strip laid over
teflon sheet and clamped in place will work.
I'll be able easily to get the stripline impedance down to 5 ohms, then a Pi coupler.
150W per transistor, two will get close to our legal limit.
Power supply: my 24V UPS battery system, now solar charged.
Alan VK2ZIW
Hi Alan, last year I built a few amps using the MRFE6S9160 devices. I used a variation of a European design on Rogers 4003 board and have had
good success with it. 140 to 150 watts out with 1.5 watts of drive at 28 volts, they do like the volts !. I also have a pair coupled together that produces
290 watts and at that level the inter connect coax gets a bit warm. so all in all a good reproducible project.
https://vhfdesign.com/wp-content/uploads...68x353.png.
I changed the bias arrangement on my design.
Ralph VK3WRE