2021-08-22, 07:46:40
I've read lots of criticism of the EICO 753 on account of the drifting, never used one. It had two 6DQ6s in the PA, same tube as used in my 723. TV sweep tubes, an inexpensive way to get RF power, used by many ham manufacturers (e.g. Swan, Drake).
At the UNB club where I learned ham radio we obviously knew what SWR was, but we never gave it much thought. We had a triband yagi & an 80m inverted V on the roof of our building, & as long as the TX would load into the antenna it would work. Of course all the tube rigs had a built-in "manual antenna tuner" (called the pi-network plate circuit), and the tubes could tolerate a certain amount of reflected power. It was only when solid state rigs with fragile PA transistors & fixed broadband output circuits came along that constantly worrying about SWR became part of routine ops. Nowadays we take the need for low SWR for granted and have moved on to stamping out other evils like common mode current :-)
73
Dave, VE3WI
At the UNB club where I learned ham radio we obviously knew what SWR was, but we never gave it much thought. We had a triband yagi & an 80m inverted V on the roof of our building, & as long as the TX would load into the antenna it would work. Of course all the tube rigs had a built-in "manual antenna tuner" (called the pi-network plate circuit), and the tubes could tolerate a certain amount of reflected power. It was only when solid state rigs with fragile PA transistors & fixed broadband output circuits came along that constantly worrying about SWR became part of routine ops. Nowadays we take the need for low SWR for granted and have moved on to stamping out other evils like common mode current :-)
73
Dave, VE3WI