Early this year, I replaced the driven element trap coils (10/15M)of the Create 318jr tri-bander becasue of high SWR. Today I have the same problem again, so I start to check what happen inside and root out problem sources.
The 10M trap looks fine:
However, the 15M trap coil spacing is not in equal spacing, so I removed the winding and found the coil form was melted.
I need to find suitable time and method to fix it. For the time being, running QRP with the Fritzel vertical.
Sunday, November 29, 2009
Thursday, November 12, 2009
12M Three Element Yagi
Sunday, November 8, 2009
Six Meter with SB-200
Recently I performed several enhancement work to the SB-200 which converted to Six Meter many years ago, including:
1) change the ventilation fan to box fan, it gave out more air flow towards the 572B
2) change the plate choke, Teflon rod with 0.6mm wire , 60 turns.
3) improve input circuit to achieve as low as 1.1 . It worked very fine and power output significant improving, with 65W in , power output reached 600W.. acceptable result.
1) change the ventilation fan to box fan, it gave out more air flow towards the 572B
2) change the plate choke, Teflon rod with 0.6mm wire , 60 turns.
3) improve input circuit to achieve as low as 1.1 . It worked very fine and power output significant improving, with 65W in , power output reached 600W.. acceptable result.
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