Sunday, November 29, 2009

Create 318Jr 10-15-20M Tri-bander

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.

Thursday, November 12, 2009

12M Three Element Yagi

Today I put up the home brew 24MHz three element yagi. The SWR is around 1.2 centre at 24.930 , now is waiting for some DX ...

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.