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First off, Merry Christmas!
Here is a classic novice (officially a technician who feels like a novice) story for your Christmas day.
I purchased my HB-1B and a 40/20m wire dipole antenna together a while back. At that time, I used an old, clunky antenna tuner (with sticky knobs that are very difficult to adjust) to test the transceiver/antenna combo. Since the SWR seemed to be within good parameters from the start, and because that tuner is such a pain to use (it will be trashed or sold for parts once I get my new smaller version in the mail), I put the tuner back on its shelf in the garage and have been assuming that the dipole was good to go. As it turns out, it might have been a really good idea to do some more research.
I am away from my normal QTH for the holiday, so I don't have access to that antenna tuner in the garage. I fired up the HB-1B at my sister-in-law's house in Golden, CO to see what kind of luck I'd have trying to make contacts from here. I noticed that the power output decreased over time, even though the input voltage remained unchanged. I charged the HB-1B's battery overnight to maximize the power input, and see how that affected things. This morning when I plugged it back in and started transmitting, the HB-1B's output was increased slightly over last night, but after sending out a few CQ's, the transmit power basically dropped to zero.
My hypothesis at this point is that maybe the RF energy is building up, and that I hadn't noticed it before because I was doing a lot more listening than sending. Now that I'm transmitting more, perhaps the reflected RF energy is building up and causing the transmit power to decrease. I could be wrong about all of this, but I'm going to have to investigate, as I don't want to damage the rig (if I haven't already) and I don't want to be faced with a sudden unannounced power out decrease when I'm out trying to make contacts.
I obviously need to learn more about how antennas work. I had been under the impression that if my dipole was cut to a certain band (in this case 40m) and seemed to be matched on one day, then I really didn't need to worry about using an antenna tuner at all. Perhaps that line of thought was flawed.
Anyway... I have a new MFJ-971 Manual Tuner ordered. It should arrive sometime before January 1st, 2016. I think I'll wait to try to send out more CW until it arrives just to make sure I'm not doing harm to my rig.
Any thoughts are appreciated. I'm learning slowly but surely. Hopefully I'll find that a good antenna tuner does the trick.
UPDATE:
So I think that I blew out the final amplifier. This is a real lesson. Despite the fact that the dipole was tuned, I think that the coax connection wasn't tight, therefore the transmitter was basically just transmitting into the coax with no antenna connected. Had I connected an antenna tuner, I probably would have noticed a high SWR right from the start. Teach me to be impatient and take short cuts. Tough lesson to learn. Luckily it seems that the part will probably be a relatively inexpensive fix.
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