Re: Transmit Output Power (CW) #v5
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Just a random thought ...do you have any way to check for harmonics/spurs at these settinjgs?
while tuning for "maximum smoke" is one way to do it, what you are measuring with the power meter is ..along with the fundamental frequency, ALL the spurs/harmonics/random trash being radiated...would be great to see some measurements of them before the modding as well as after
On Thursday, March 12, 2020, 2:13:41 AM UTC, Rob French (KC4UPR) <kc4upr@...> wrote:
I've collected all my parts to do Allison's transmit chain modifications (BFR106, 2N2222, 11 ohm resistors...). I'm ready to go... but I wanted to QC my output power first. Now, I have noticed on 40 meters (where I spend most of my time), that the output power is low, so now that I finally have a power meter, I went ahead and tuned RV1 while transmitting into a dummy load. I tuned RV1 to get 12W output on 3.500 MHz, and then checked the output power across the rest of the bands. This is what I got... is this representative of what other people have seen? I know I'd seen reports of crazy low output power (<1 W) on 10 meters, which I did NOT observe here, obviously. (Note, all of these were done with CW.)
Any thoughts? (a) Are these typical of what others have observed? (b) What can I expect from the transmit modifications, relative to this? Higher output on 30, 20, 17?
PS - Random aside. So I am using KD8CEC firmware version 1.2. I noticed something weird on 40 meters... If I tune to exactly 7.000.000 MHz, or lower, in the 40 meter band, I hear the T/R relay switch and the display indicates in CW transmit, but there's 0 W output power. But if I tune to 7.000.010 or higher, it's fine. It's kind of like it's enforcing transmit restrictions, except that the ONLY place that it seems to do this is on the bottom end of 40 meters! I've tried to trace code behavior for the band limiting, and could not identify anything that would make this happen. Has anyone else observed this???