Re: MOSFET PA RF Choke?
Leland L. Bahr
Yes, I agree with everything you said. I also don't understand
how 25 ohms could choke out RF from feeding back into the power
On 4/21/2019 5:20 PM, Curt via Groups.Io wrote:
Studying a 5 watt 40M Transmitter that uses an IRF510 for PA, what is puzzling is the RF choke is specified as a T68-2 with 10 turns. By my calculations this presents an impedance at 7 MHz of about 20 ohms, which seems way less than the 30 times output impedance rule. Am familiar with 10 turns on an FT37-43 which presents an impedance of about 1500 ohms, have encountered other IRF510 PAs that used that type choke. How can the low impedance choke keep RF from leaking out of the output circuit to the power supply?