[600MRG] DX-60 on 166 kHz

[Paul Signorelli]

Here are some more DX-60 details:

I am using  2 - T200-3 Amidon powered iron cores taped together for the final tank circuit.

Wound with 68  turns of #16 wire for primary and 13 turns of #10 wire for secondary.

If you use fewer turns for the secondary you will be under coupled, if you use more turns you can over couple and kill the output.

0.003MF for tuning cap at 166 kHz off the plates of the 2 - 6146's in my DX-60.

No core heating.

Of course I have a big 5 pole Butterworth external filter in the output.

It uses 3 - T-225-2 Amidon powered iron cores for 166 kHz, Cut off at 233 kHz.

L1 & L3 are 52T of #14 solid wire.

L2 is the middle coil, 73T of #14 wire.

C1 & C2 are .023 MF.

I have a fan on the finals and another one on the power transformer.

Putting out 80W into 50 ohm load.


There is an article on fixing up the DX-60 in QRP Quarterly, April 2017, p.22.
 You start with a good DX-60.
 Mine has 2 - 6146's.
 You build an oscillator for 475 kHz or find a crystal.

Remove all the RFC's and replace them with big coils resonate at your operating frequency.
 You don't need  RFC's, you just need resonant coils.
 I use old fan motor coils and remove wire until they are close to freq.

 All bypass caps need to be bigger, 0.005 to 0.1 MFD. You don't need to remove the old ones,
just parallel a 0.1 MF, One will do in the final RF section.
 Increase all coupling caps also.

Replace the tank with a Ferrite or Powered  Iron core.
 If you are going for 475 kHz you can wind an air coil.
 I used 2 Amidon T-220-3's for my 166 kHz transmitter.

All you get is a Class C transmitter, not a linear.

Paul   wa2xrm