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I ordered a UHF amp and when it arrived I thought great 28 quid what could go wrong.
Well, just about everything, it was the wrong kit, it was a VHF board, half the bits were missing, none of the SMD parts were identifiable, the MRF186 was attached to a bit of secondhand pcb, they did put it an anti static bag bless em, no circuit and no instructions.
After about 20 emails backwards and forwards no chance of making them understand they had supplied the wrong bits, so I gave up.
Be aware if you buy these kits be prepared for a bit of work.
Some pics for reference.
Postman Pat's missing head is nothing to do with me
I bought one of those kits (VHF version). I have not had time to put it together but a BATC member emailed
(Dave G0MXW) me the instructions on how to build it. If I ever get around to building it I will let you know how I got on.
The transistor supplied MRF186 is not really suitable for VHF operation so I expect it to be either be very lively
of not work at all. I was planning on substituting a different device in it.
144 / 220 / 430 MHz amps so maybe there is hope
http://k5tra.net/TechFiles/VHF-UHF%20Re ... 20LNAs.pdf
After seeing these and reading the info at:
(and the 2mtr kit write upon that sit too.)
I brought some of these kits for 2 and 70.
The 2mtr kits worked pretty much first time. An easy 100watts and even got towards 150watts with 28V and darving hard. But that is getting silly given the ratings of the device.
So I am going to combine 4 of these to get 400watts. (And poss 40watts on DATV.)
I'm trying out the 70cm version and not having as much success.
I am seeing a poor input match, even using the longer phasing line lengths, in the above link. And only about 45watts out. With a bit more drive, because of the poor match.
Anyone had any joy with these?
But, assuming there is a need for 250W modules I am wondering if anyone has tried using pairs of 900MHz transistors on 70cm. The MRFE6S9160 which was available for 10 Euro that DF9IC was using to produce over 150W on 23cm for example. http://www.df9ic.de/doc/2015/mmrt_2015/ ... Hz_PAs.pdf
I agree, not the simplest route. But I brought a couple to tat with, and the idea grew from there. And I was already half way.
Probably similar to the story of the yocal sat on the village wall, when a townie pulls up to ask for directions. The reply being "well if I were trying to get where you're goin', I wouldn't start from 'ere !"