Flex-5000 on the 630m band

[ke9ns]

I found out the reason why the Flex-5000 will not output below the 160m band.

The original schematic (HTRX board) for the 5000 claims a LPF for 160m in the Transmit section of the circuit (Between K16-K17).
This is the LPF's before the PA Drivers.

When I opened up my 5000 I found that Flexradio had modified the 5000 by removing the original 160m LPF parts from the HTRX board, and replaced it with a Daughter board (PC-0054 Rev A) between the K16-K17 points.

This very small PC-0054 RevA board is a "Passive 4 pole LC Notch Filter" Using my NanoVNA, it is a Notch that allows transmit from 1.4mhz to 2.4mhz

I un-soldered the 3 connect points on the daughter board. I then replaced the original Inductor 3.9uH, and 3 caps (1800pf,1800pf, and 180pf) to put it back to the original LPF

Now the PA of the 5000 differs from the 3000 slightly. The 3000 has a slightly different 13.8v feedback transformer design, but I dont think that will effect 630m operation

Darrin