My experience, DXing from the New York metro area, is that in 1964 it was easy to hear Australia/New Zealand on the frequencies that were open then. The main criteria was to be DXing at 0430 local time, generally on Monday. Signals reached the east coast with some regularity and decent signals, when they did appear. The key was to have a clear frequency. A big drawback was the lack of any real-time reporting, and data correllation, the surviving records are either anecdotal, or just what was reported to Fred Van Voorhees in the NRC, by those who took the time to mail in their reports, and certainly reflect just a fraction of what was really heard then.
The typical AM station ran AN-6 and was silent Mondays, though it was even then fairly common for stations to have two xmtrs and be able to run AN-7. It was thought that Monday mornings had the fewest listeners. In 1964 I hrd/verified 2NA-1510, 1YC-880 and 1ZD-1000 and had audio from 1YZ (I think it was) Rotorua-800, hrd in northeast New Jersey. Many EC DXers were hearing these signals, Vinnie Cavaseno in Brooklyn is one name that comes to mind. Most of these DXers are no longer active, for whatever reason. Ben Dangerfield heard lots more DU than I did, and he is still active, he still lives in the Phila metro area. The typical receiving setup was basically a "short" "longwire" (typically 50 to 70 foot length) or more ideally a 3-foot or 4-foot air core tuned "tank circuit" loop, which is what I used. BOGs were unknown and Beverages were the domain of the New Zealanders who set them up at east-facing beaches. So, today's DXer has a tremendous antenna advantage that is still not good enough to offset the decreased propagation performance we now apparently have. In 1973 (the next solar minima) I heard 4QD-1550 at least a couple of times. That time I was in Nassau county LI NY. The biggest problem was the sign-on of WKFE Yauco PR which was just good enough to cover the 4QD details, that s/on happened about the time that 4QD would fade up to a usable level. Frequencies were still co-channel and there was by 1973-74 enough AN-7 operation that 1550 (thanks to CBC Windsor nightly s/off) was one of the few freqs that was still usably clear. If the frequency assignments had not changed, it would be easy to make the case that, during each solar minima, it became harder to hear DU only because of increased co-channel QRM. However since in 1978 the DU assignments moved off of the 10 KHz spcaing plan - and we STAYED ON IT - this created 90% virtual "clear channels" for the DU signals, which again was negatively impacted because of more NSP operation, higher noise from other sources, higher modulation levels generally, and now IBOC. I believe that if those other effects are discounted, and if the prop from DU to NA had stayed the same, then we should yet be having the type signals today (during solar minima) that we had in the previous minima, among which 1933 and 1954 are also historically remarkable. Those signals would be present, though impacted by the local interference effects. The fact that they are not present leads me to be in agreement with Patrick's remarks that "something" has indeed changed in long distance MW reception from DU and it is a change somewhat for the worse. I strongly believe this is the case. Some have tried to link this to air pollution, perhaps nitrous oxide, or hydrocarbons etc. I wouldn't discount it but I really don't know if that is a realistic possibility to explain what has apparently happened. It's not possible to compare with Tropical Band SW because the nature of the signals changed so much as transmitted. It's a shame the SDR radios have come along so late as this would have been possibly a good means to try to measure the level of the DU station RF carrier in the presence of QRM which would be harder to do in straight AM detection mode. The readout of an absolute RF signal level, with standard antennas, over a long time period, would help confirm or dispel whether true signal levels have dropped over time or not. - Bob PS - many today may not realize how close we came to having the entire western hemisphere also moved to a 9 kc spacing plan, which would have made "no" open frequency DXing of foreign signals possible. There was a lot of lobbying for it back then. >the comments from Patrick (and Nick) seem to indicate that in the "old" days, >the DUs were very >much stronger than they are now, and perhaps the Asians are >more numerous today. Something to >consider!.....Walt. > > Receiving the Aussies and Kiwis on > > medium wave seems much more > > challenging than receiving Japan or other TP's. _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
