Chinese Amp Kits

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radiogareth
Posts: 505
Joined: Wed Jan 06, 2016 9:46 am

Re: Chinese Amp Kits

Post by radiogareth » Tue Oct 22, 2019 2:33 pm

Could you share the changes you made to use it on 4? Mine delivers about 12 watts of DVB on 2M (biased up to the eyeballs!) but on 4, once filtered, only about 8 watts. The second harmonic (71*2) is bigger than the fundamental!!
Gareth G4XAT

GalmOne
Posts: 5
Joined: Fri Oct 18, 2019 4:07 pm

Re: Chinese Amp Kits

Post by GalmOne » Wed Oct 23, 2019 12:48 pm

Yeah, their quality is all over the place. Sometimes you get something that's fine, and sometimes, well, you get something to show in that thread... I haven't built my own ATV set yet, but I've worked with Chinese radio and video equipment for RC planes and it's always a lottery.

M0YDH
Posts: 195
Joined: Sat Dec 31, 2016 5:59 pm

Re: Chinese Amp Kits

Post by M0YDH » Fri Nov 08, 2019 5:27 pm

Dear Jim
Which value of coupling capacitor did you choose please? What other ingenuity did you apply?
A 70.5 MHz amp for the <10 contacts I'll ever make on TV on this band is OK at this price! :roll:
73
David M0YDH

g7ntg
Posts: 46
Joined: Sat Feb 17, 2018 7:07 pm

Re: Chinese Amp Kits

Post by g7ntg » Mon Jan 13, 2020 2:06 pm

MRFE6S9160 amps no good for DATV I blew 10 devices on 4 different amps at 1255 MHz trying to get them to work reliably - Gone back to MRF286 amps for 23 cms with great success up to 2 transistor amps running 50 watts DATV.
Cheap chinese UHF and VHF kits are great and can be tweaked up to around 130-140 watts saturated output
I agree that parts identification could be much better but great value for money and good for DATV on 4m, 2m and 70cms
input matching has to be twiddled as input SWR can be 3:1!

radiogareth
Posts: 505
Joined: Wed Jan 06, 2016 9:46 am

Re: Chinese Amp Kits

Post by radiogareth » Mon Jan 13, 2020 2:27 pm

These new NXT devices are popping up all over. I'm building this one mainly to go with my FT817, not a lot of frequency sensitive components in the design, maybe it will do a bit on 70 & DATV at least until the ERP limit gets raised a bit. I've ordered what I think is a batch of 10 prototype pcbs from the DIrtyPCB link. These will be available if anyone wants to play. Parts are very little from Mouser. Step up converter from eBay for the PSU under a £5 too. https://sites.google.com/site/rfpowerto ... xp-mrf-101.
ALso building the 300 Watt version that's around although digging the board and parts for that required some 'international cooperation'. Spotted originally on the RF SSPA FB group.
Its good to build :-)
Gareth

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