[Amps] Amplifier for 630 meter band

[Larry]

On 11-Nov-17 9:33 AM, Jim Thomson wrote:

> ##  My array solutions Powermaster  20 kw coupler works from 500 khz to 30  mhz.  Apparently  it works quite well for
> AM broadcast purposes.   The AS  10 kw coupler works from  1.8 to 60 mhz... and ditto with the AS 3 kw coupler, same deal,
> 1.8 to 60 mhz.

My PowerMaster 3 KW coupler let out all the magic smoke after a couple 
minutes of 400W on 475 kHz. I didn't bother to try the 10 kW coupler. 
Before the smoke appeared, it was reading the correct power and SWR.

Forensic analysis proved that the "voltage" sense torroid had too little 
inductance to work at that low frequency. In fact I am amazed it doesn't 
burn up on 160 m!

I reverse engineered the coupler and built a new one with different core 
material and now it work great on both 475 and 137.

73, Larry - W7IUV / WH2XGP