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Showing posts from February 2, 2019

144 200W PA WSPR report

Below is the MRF186 VHF 100W PA eBay  2 x parallel coupled
excellent quality kit
High quality well designed PCB
Remarkable it covers 3 VHF bands 6m 4m  and 2m   100W
The PCB includes a 3 stage LPF and SWR bridge.
This is how all PCB designs for VHF / UHF should be!
Lot of tropo DX  at 144.174  last year with just 10 or 8W in FT8
13 dB more ERP  will let me reach the weaker DX running more then QRP..


see building report Jon Joyce GM4JTJ
The SWR bridge forward level is about 4V at 100W 144MHz .
Measured at board 26.5V 6.5A delivers about 100W  drive 3W 50MHz  1W drive  50W
with 28V easy 100W my power supply 27.2V dropped over wiring to 26.5V
2 boards parallel deliver 200W / 26V 12A  at 144MHz   about 4W drive
The used balun type  50 to 2 x 50OHm  couplers do not work at 50MHz
It is a ferite binoculair core  with a single loop teflon 50Ohm thin coax (1 turn # 3uH )
It must be possible to modify this balun to work for 6 4 and 2 m using 2 turns f.i.
Possible I test that but my goal was a …