I've been running my ATS-909X portable on AC lately, since I have no need to take it elsewhere, especially during the winter. Besides, the adapter supplies 9 VAC, not the conventional DC, because the conversion to DC is done inside the radio itself, so the adapter doesn't produce any RFI. As an experiment, I unplugged the 23-ft. reel antenna and extended the whip vertically to its full length. Surprisingly, there was no drop in signal strengths on HF, but a rather dramatic decrease in the noise level. As soon as I plugged the external antenna back in, the noise level increased without strengthening the signals, so that some of them became unreadable.
On the other hand, using just the whip and running the radio on fresh alkaline batteries results in a big drop in both the signals and the noise level. Am I right to suspect from this that the cord from the AC adapter to the radio is acting as an antenna, or maybe as a counterpoise to the whip?
The external antenna runs horizontally along an outside wall close to the ceiling on the top floor of a wood framed building. Unfortunately, that makes it parallel to the power lines outside. They are lower than the building's roof, so they're at eye level when I'm standing up. I'm in a corner suite, so I'm surrounded by power lines at the front of the building and others at right angles to them at the side of the building. Slung below them are lines from the local cable TV company. The lines are major ones supplying homes and businesses here and on adjacent streets. Since the whip is vertical, is that making it less susceptible to power line noise?
On the other hand, using just the whip and running the radio on fresh alkaline batteries results in a big drop in both the signals and the noise level. Am I right to suspect from this that the cord from the AC adapter to the radio is acting as an antenna, or maybe as a counterpoise to the whip?
The external antenna runs horizontally along an outside wall close to the ceiling on the top floor of a wood framed building. Unfortunately, that makes it parallel to the power lines outside. They are lower than the building's roof, so they're at eye level when I'm standing up. I'm in a corner suite, so I'm surrounded by power lines at the front of the building and others at right angles to them at the side of the building. Slung below them are lines from the local cable TV company. The lines are major ones supplying homes and businesses here and on adjacent streets. Since the whip is vertical, is that making it less susceptible to power line noise?