what do with MRF148A transistors?

[ssbothwell KJ6RSG]

i bought some weird unlabeled device at the scrapyard because it has a giant heatsink (10x4.5x2). when i ripped open the device i discovered it has two MRF148A transistors, an MWA130, two Anaren 10262-3, a minicircuits pscq-2-250, and a some other goodies. whatever this thing was, it must have been expensive when  it was new. i paid $12 for it.

could the mrf148A transistors be used for an HF amplifier?

also, how the heck do i desolder them? they are 'case 211-07' packages and have tons of solder holding them down. i tried using solder wick but it just pushed the solder around on the board.

[kb3ouk]

here's the data sheet for the MRF148A. going by what the sheet says they are used for, i'd say that what you pulled them out of was some kind of amplifier. the sheet says they are good up to 175 mhz.

http://www.macomtech.com/datasheets/MRF148A.pdf

shelby

[w3jn]

Don't unslobber 'em, use em in the existing board and heatsink.  If it was a VHF amplifier it might have stripline combiners which you can re-do by making binocular combiners and transformers.  If it has a pair of 'em that's a 60W amp and it should work at HF after re-doing the output and/or input combiners/splitters.

[ssbothwell KJ6RSG]

hmm. i think its a bit too late for the board. i stripped everything else off it already.

do you guys know what  Anaren 10262-3 hybdrid couplers are for? do they just act like a balanced transformer and split the signal at 90 degrees?

[WA1GFZ]

MRF148 is a great device. MY modified MRI final uses a pair as drivers for the MRF150s
an XACTO blade is great for lifting tab leads. Just heat up the solder and slide the blade under the lead. Remove the screws first.
Gates are static sensitive so wrap some solder around all four leads to short them to sources and drain. 
MRF130 is a BB amplifier about 14 dB of gain and will do about 16 dBM out.

[N4LTA]

You found a possible treasure. Those RF FETs don't come cheap. I wish I had a junk yard like that one close by.

Pat

[ssbothwell KJ6RSG]

i'm glad to hear these transistors are so great. for $12 i was happy just to get the heatsink. all this other stuff in addition is really amazing. i saw a couple more of these amp units at the yard, i should go back and grab them.

any ideas what i could do with the Anaren 10262-3 hybrid couplers?
http://www.anaren.com/Content/File/Product/10262-3.pdf

[WA1GFZ]

The quad hybrids don't work below 125MHz so not useful for HF applications.
I'm using the MRF148s 160 through 6 meters. So they will make a good low power linear or final. You will not need source resistors with these FETs but you can apply everything you learned so far with the IRF FETs.

[N4LTA]

I had a 6 meter amp project in QST in 1990 that used a MRF 140 at 28 volts. I suspect that this transistor would work in it at 50 volts with minor chages. The MRF 140 cost over $100 back then if I remember correctly. Helge Granburg at Motorola sampled me a couple for the project. The 12 volt version of the amp put out about 100 watts with a MRF 492 bipolar transistor and a MRF140 dropped in and worked with no change in the matching circuit. I ran one at 160 watts out for several years and used it swamp down to drive a 4CX1500 amp. I haven't worked 6 meters in years. ( I did work one QSO last year with my 10 watt K3 running into my 80 meter dipole)

Pat