The MicroPa50 Plus is a completely crap amp .? It has had very bad reviews many have blow up under very little stress .? the Old versions has Zero low pass filters in them so you? ?will l get? please explains from the FCC if you use one of those. THat all explains why Kaching? - cheep .? That might be before? the Plus. version it comes from a bad pedigree .
The MX-P50M? uses an MRF 186 Gemini pair RF Mosfet? which is second hand - almost for sure second hand from the Sino telecoms industry boards. It is one of the higher priced? tin shed amps and it is hard to burn out.
Look at the specs on the? MRF 186 .It? is a very inefficient part so the amp will run hot.? It needs a Full 7W to drive it to full power in semi linear mode.? The Old Radio Guy? Kevin a VE has done some reviews on THe? Ytube.? He comes to the conclusion that if you want say 35 W out you need to be providing it with 18 V of Vcc not 14.? ?THe true power gain turns out to be about six times or 7.8 dBp but that's as it is for the MRF 186 plus they generally use a pretty crappy OPT using? split cores in? type 43 material.? As in? RF clamp suppression cores.
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one problem he found was that withe some? Tcvrs the tcvr PTT would not pull down hard enough to? enable the amp. He? put in a darlington transistor on the amp trigger and it all went swimingly.? These amps are designed for PTT use and not CW use.? Note that some earlier Qmxs were set up for 5V assert = transmit and these will need to have a Bs 170 or othe small signal N channel mos? in between them and the? MxP-50M to work . More modern? Qmx s give you options on amp triggering.?
The pluses or one is? are they seem to be near indestructible if you get a good build.? Some have been run open circuit? for over a minute and not blown.?
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If you are operating portable you will need to have some method of kicking your voltage up to? 18V or operate with 14 +6 V and have a connector system that guarantees that? you can't put the 20 V into the Qmx.? (comment applies to Mx-P50M.
The? ?Hamradioshop on? ?Ali express sells that 50M amp and many others with dubious claims. Get that vendor to send you a Paypal quite and pay through Paypal if you want to deal with him.? (Ali Express is the work? of the devil and you might get your CCard stripped out? if you use it )? ?He also sells stripped out chassis for that design with no LPF.? There are some tappings on the side where you can add coax going off? to your LPF .? ?It's up to you to arrange cabinetry and? the LPF arrangement if you go for the Pallet amp option.
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For an extremely high quality multiband? LINEAR? amp that? will give? 50 W from? 8mW of signal,? have a look at the? offerings from? 60dbm.com (Ukrainian outfit) . However you pay for what you get as in $160 or so for the basic board . They have other offerings? but this? is the one most likely to suit you.? This amp uses the Mitsubishi RD16HH mosfet in an two plus two arrangement with another RF mosfet as a driver.? These people also sell fully built up Linear RF? amps.
Timothy Fidler