Hi all... I briefly checked some LW reception around sunrise this morning using my Tecsun PL-606 resting on a barbed-wire fence across the street from my house. I came across an interesting signal on 302 kHz. On the fence, which is oriented north/south, it was reading approximately 17/24. Apparently the fence was oriented to partially null the signal, as when I took the radio off the fence and faced mostly east (slightly angled to the north) to peak the signal, I was getting a 15/22 reading, sometimes briefly showing 15/23 and I thought I saw 15/24 once. (Please excuse the grainy photo - I shot it without flash at ISO 1600 with my Canon SX10, as the flash was making it look like it was nighttime and it was still too dark to handhold with one hand using a lower ISO.) Then, I decided that since it was a strong signal, I would check it while inductively coupled to a utility ground wire on a telephone pole. (Normally it severely desenses/blocks reception of longwave signals, often giving me 49/00 or 50/00 readings IIRC, especially toward the upper end of the LW band.) There, I got a reading of 37/25, and also briefly saw 38/25 a couple times. The desense did rear its ugly head, though, manifesting itself as a noticeable increase in the background noise level. I also went outside to check using a long chainlink fence, and saw it reading 40/25 (although I have no photo as I didn't take the camera out there). I also got interesting readings when I set the radio on top of my upright (1950s Baldwin Hamilton) piano. I also placed the PL-380 there for comparison & curiosity, and both radios seemed to be indicating comparable signal strengths. I saw each one hit 15/25 several times, sometimes while the other was indicating 15/24, and they sometimes traded places on the readings, but as patient as I was waiting with the camera, I never saw them both simultaneously indicate 15/25 (although I really wanted a photo). Unfortunately there was absolutely no modulation that I could detect on the signal - it was just an open unmodulated carrier. Is there anything on 302 kHz that's east (slightly north) or west (slightly south) of 32°45'40"N 116°56'40"W that could be a potential target? I just checked a few minutes ago, and was getting a 15/07 reading on the PL-606 in the house, and about 17/10 or so with the radio sitting on top of the piano. (Interestingly, the PL-380 was still showing about 15/24 sitting on the piano.) Other than that, there wasn't much. The only signal I actually could confirm was a NDB on 400 kHz from Ensenada, BCN, which I've heard before. Most of the time it didn't even lift the S/N reading above "00". Also on 279 kHz I thought I could just barely detect a slight trace of audio modulation, but it was too weak even to discern whether it was speech (female? based on the pitch) or music. (The noise did have the unstable sound like there was a trace of a signal there, not the steady sound I normally expect when no signal is detectable.) There were also numerous other frequencies that had a similar sound like there was a hint of audio, but most of them were "off-channel", so I'm wondering if it could have been the beginnings of mediumwave locals threatening to exceed the capacity of my radio to block intermodulation distortion. I also briefly checked 279 kHz using utility ground and the chainlink fence to boost the signal. Unfortunately with the fence and util ground being untuned, the local mediumwave stations desensed the radio quite severely, giving me a dBµ reading in the mid 30s and completely blocking any possible trace of a signal. A $150 FSL is way out of reach for me and I need the FM/SW jack to continue to function for that reception due to a fragile whip antenna. Is there another way I could make something with which I could inductively "tune" the fence or utility ground, thereby peaking the desired signal while pushing the undesired local mediumwave stations into the mud? I sometimes use a Select-A-Tenna for tuning mediumwave with the fence and utility ground, but it still doesn't tune quite sharp enough, and won't work for longwave. The combination does have a lot of gain, though, boosting (with utility ground - the wire running down a telephone pole) a couple 50kW stations 7 and 9 miles from me to a level that I had to be within 10 feet of a 2.5 kW station's tower to receive it that strong using only the built-in ferrite. (I estimate the two 50kW stations to be about 125 mV/m or 102 dBµV/m here based on the M3 map and groundwave curves, while the 2.5 kW could be 330 V/m or 170 dBµV/m based on inverse distance RMS field, resulting in an estimated gain of about 68 dB.) I would like to be able to harness that gain for longwave reception if at all possible, as well as tuning sharper on mediumwave so I can DX between my blowtorch locals. :) 73 and good DX, Stephen _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca
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