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Parallel DXpeditions Nick Hall‐Patch and Bill Whitacre NRC‐IRCA‐WTFDA Convention 2015
DXpeditions‐‐‐a history • DXpeditions have a long history • my first one was in Westport, WA over 25 years ago • Beverage antennas were favored in those days, and coastal locations if possible
DXpeditions‐‐‐a history . . . just a few of the sites I’ve DXed from over the years, but others have used many more
DXpeditions‐‐‐a history The “DX Radar” Grayland Motel. . . the go-to site for northwest DXers • Room for antennas • Tolerant hosts
Parallel DXpeditions – why? Sites other than Grayland have produced good DX • How do sites compare with each other? As DX conditions vary day by day, and even hour by hour, sites need to be compared at the same time and date. Particularly in the past, this has been difficult to do without serious preplanning
Parallel DXpeditions ‐‐ history Past parallel DXpeditions • October 1989: Ellensburg, WA and Pembina Forks, AB, both using Beverage antennas • Amateur radio link between the two sites • Northerly path Russians heard in Washington and not in Alberta • Reports to different editions of IRCA’s DX Monitor within the month • October 1995: Sombrio Beach, BC and Grayland, WA • No site to site communications • More Australians logged from Sombrio, but longer Beverage there • reported to same edition of DX Monitor • And other expeditions lost in the mists of time
Parallel DXpeditions ‐‐ the present • One reason to look for new sites is to cut down on travel time to old favorites • for me, Grayland is 10 hours away; coastal Tofino, BC is 5 hours away • could they be comparable DXing locations? • There was an opportunity to DX from there while Bill Whitacre was at Grayland
Parallel DXpeditions ‐‐ the present Equivalent? Not exactly. Grayland • Perseus receiver • DKAZ antenna 290° – FLG 100 amplifier – Placed close to beach – Out in the open Tofino • Net. SDR receiver • Flag antenna 270° – FLG 100 amplifier – Placed a few meters from the beach – Concealed in the trees, close to buildings
Parallel DXpeditions ‐‐ the present Japan 300° eastern Australia 243° New Zealand 223° Grayland Upside: 180 degrees western water path Downside: open country to big city transmitters
Parallel DXpeditions ‐‐ the present Japan 300° eastern Australia 242° New Zealand 222° Tofino Upside: hidden from major centers by mountains Downside: land path north of 290° Downside to this location: little room for larger antennas
Parallel DXpeditions ‐‐ the present So, there is a suspicion that Grayland might have the edge on Asians • even signal arrival from 300 degrees crosses nearby islands Japan
Parallel DXpeditions ‐‐ how to compare? Now we had two sets of SDR recordings. How to compare the two sites? • Absolute number of DX stations logged in a given time period? • Actual signal strengths of a number of target stations? • Visual representations of band conditions?
Parallel DXpeditions ‐‐ how to compare? • Absolute number of DX stations logged in a given time period? ØIn pre-SDR days, this number might depend on the DXer’s skill at each site ØWith SDR, this can be a useful measurement tool, comparing side by side recordings q. But we must compensate for different fading patterns at each site, so need to listen across a given time period, rather than just “on the hour” q. Do we ignore overall signal strength at each site over the period?
Parallel DXpeditions ‐‐ how to compare? • Actual signal strengths of a number of target stations? ØNot always easy, due to interference corrupting the desired signal ØAveraging a few strong signals over a specific period could give a good indication of the quality of each site ØProbably too challenging to address right now, though should be possible with SDRs
Parallel DXpeditions ‐‐ how to compare? • Visual representations of band conditions at each site? ØWe often comprehend visual indications much better than rows of numbers ØSDR waterfalls can give a good idea of potential DX signal quality. ØWith the same receivers and software at each site, visual site by site comparisons should be possible ØStay tuned for a description of just such a visual comparison from Bill Whitacre
Parallel DXpeditions ‐‐ the results Comparison of Asian DX from Grayland Tofino • With dissimilar radios and antennas, we simply looked at number of loggings at one time period, 1500 UT on 19 February 2015 • Grayland: 64 Asian stations • Tofino: 23 Asian stations • Compare levels at Tofino to Grayland for JOQR-1130 at Tofino JOQR-1130 at Grayland both at 1500 UTC 19 Feb
Parallel DXpeditions ‐‐ the results • Grayland generally suffered more domestic splatter, though local noise levels were better there • Even the post-sunrise Asians were better at Grayland: JOLF-1242 at Tofino JOLF-1242 at Grayland both at 1500 UTC 19 Feb
Parallel DXpeditions ‐‐ the results • We suspected that Asian reception might have been better from Grayland than from Tofino • But weren’t at least Down Under stations comparable? No, they weren’t. ØBill heard 12 New Zealanders at 0800 UT 18 February; I heard one. ØHawaii was heard better at Grayland; less QRM from California ØThe nearest to a comparable signal was 4 RN-792: 4 RN-792 at Tofino 4 RN-792 at Grayland both at 1200 UTC 18 Feb
Parallel DXpeditions ‐‐ the results Why were DXing results poorer from Tofino? • the idea that the Flag delivered a 6 d. B greater signal output than the DKAZ was mistaken • EZNEC suggests that the 160’ DKAZ will deliver a similar signal strength to that from the Flag, not less • Flag is near trees and buildings. A problem? • Paths from eastern Australia and from New Zealand touch nearby small islands.
Parallel DXpeditions ‐‐ more results Breaking news: Rockworks vs. Grayland’s corner fed antenna ---same as at Rockworks • Net SDR at Grayland; Perseus at Rockworks
Parallel DXpeditions ‐‐ more results Rockworks vs. Grayland • Rockworks is known for its excellent New Zealand reception • How does it compare to Grayland, about 80 miles north? We compared 3 minutes at 1225 UT , 27 June 2015. • At first hearing, Grayland took a back seat; ZB 1008 was stronger and more readable Rockworks ZB-1008 Grayland ZB-1008
Parallel DXpeditions ‐‐ more results Rockworks vs. Grayland • However, R. Sport on 1503 actually performed better at Grayland compared with Rockworks over the 3 minute period. Rockworks: Sport 1503 Grayland : Sport -1503 • And there were one or two others, like ZB-1278 and Tahiti on 738 • But this was only a 3 minute sample, and not entirely equivalent listening setups…. as always, more study is needed , it seems. We need to do better if we want to do serious propagation studies.
Parallel DXpeditions ‐‐ the results What would be the ideal parallel DXpedition? Hi, this is Mark, sneaking into Nick’s show, to tell you how much I admire the way he approaches his DX‐ing. I learn a lot from his sharing! Now back to our regularly-scheduled program
Parallel DXpeditions ‐‐ the results What would be the ideal parallel DXpedition? • Exactly the same antenna and receiver (preferably an SDR to allow recording the entire band) at each site. • Listening / recording at exactly the same times, preferably for long enough periods to negate the effects of fading • It turns out that Bill Whitacre has already done that. . .