Many thanks to SWLing Post contributor and Ultralight DX enthusiast, Gary DeBock, for sharing the following guest post:
Nulling a local pest with dual FSL Loops
by Gary DeBock
After many dual FSL antenna experiments I’ve finally determined how to effectively cancel out QRM from a local pest that is off to the side (ideally 90 degrees different, but practical from 50 degrees to 90 degrees different) from a weak DX station, although I’m not quite sure of the theory behind this discovery.
This experiment was an attempt to cancel out QRM from a local pest, 950-KJR in Seattle, WA (35 miles/ 56 km to the north) and chase 950-KKSE in Parker, CO (1005 miles/ 1617 km to the southeast) during the early morning hours. The receiver was a basic (non-SSB) C.Crane Skywave, and two identical 5 inch ferrite rod FSL antennas were used. Please refer to the photo (above) to follow this description.
Step 1) Null out the pest station with the portable radio’s loopstick (away from the FSL antennas). Set the radio down in this nulled position, so that the pest station is as weak as possible, while ensuring that there is space to set up the FSL antennas to the back and side (see photo).
Step 2) Take the “Reception FSL” and use it to peak the pest station’s frequency, setting it up parallel to the portable radio as shown, at the position providing the maximum inductive coupling gain. This will temporarily boost up the pest station, which previously was nulled.
Step 3) Take the “Nulling FSL” and pretune the frequency to that of the pest station. You can do this either by adjusting the variable cap plates to match those of the “Reception FSL,” or by temporarily peaking the pest station’s signal in a position in front of the portable radio. After setting this frequency, set the “Nulling FSL” off to the side of the portable radio as shown, with the spacing identical to the spacing between the radio and the “Reception FSL.”
Step 4) Slowly and carefully tune the “Nulling FSL” until you hear the pest station’s signal take a sharp drop. This setting will be very sharp, but once you find this position you will have nulled out the pest very effectively, and if another station is on the frequency, it may suddenly become dominant, even if it is far away (like 950-KKSE in Denver).
Some MP3’s from this morning’s experiments:
950-KJR in nulled position with the portable only
950-KKSE generally dominant over the local pest KJR when the “Nulling FSL” is peaked
Fascinating, Gary! I don’t understand the dynamics of why this works, but it’s amazing that it does so effectively. I can think of two MW frequencies in particular where I could put a system like this to the test.
Many thanks to SWLing Post contributor, Gary Debock, who shares a short report he originally posted on Facebook from the Rockwork 2020 Ultralight DXpedition:
Rockwork 2020 started off with a monster session, with S9 signals from the likes of 320-AI (Aitutaki, Cook Islands), 352-RG (Rarotonga, Cook Islands), 558-Radio Fiji One, 603-Radio Waatea, 1017-Tonga, 1107-Magic Talk and the new 1503-Gold.
The session was kind of wild, with three different sets of visitors asking about my gear setup at Rockwork 4 (typically during critical moments of live DXing, of course :-). Despite this both Longwave and Medium Wave featured great propagation to New Zealand, with the long range beacon 238-KT (Kaitaia) opening up the fun around 1225. Switching back and forth between Longwave and MW in a live DXing format wasn’t exactly ideal, and no doubt my long time DXpedition partner Tom R. could have really cleaned up on the South Pacific beacons this morning with his SDR and broadband loop setup. As it was I came away with 238-KT, 320-AI (a monster signal), 352-RG and 366-PNI from across the equator, with 558-Radio Fiji One probably having its best session ever at the awesome ocean side cliff (extended S9+ periods between 1300-1330).
I promised long term “Cliffhanger DX” partner Craig Barnes that I would go all-out to receive some exotic DX in his honor, and the Cliff more than cooperated.
The Longwave and Medium Wave DX this morning [Auguest 5, 2020] was phenomenal, and there are still two more days before Tom gets here. Hopefully these conditions will stick around!
320 AI Aitutaki, Cook Islands Great signal but shaky sounding CW tone at 1239– best signal ever at the Cliff:
352 RG Rarotonga, Cook Islands In an S9 snarl with 353-LLD (Hawaiian mega-beacon) at 1256:
558 Radio Fiji One Suva, Fiji Overwhelming S9 signal and ID’s both before and after an island music song at 1312:
1017 A3Z Nuku’alofa, Tonga Female Tongan in an S9 snarl with DU sports co-channel (2KY?) at 1253:
More New Zealand monster signals from yesterday morning, courtesy of the “Kiwi Cliff.” This place’s preference for New Zealand signals is wacky to the extreme!
603 Radio Waatea Auckland, NZ 5 kW S9 Maori island music // 765 followed by a female Maori chant at 1309:
1107 Magic Talk Tauranga, NZ 10 kW Meltdown level Kiwi conversation between host and lady caller at 1255:
1503 Gold Wellington/ Christchurch, NZ 5/ 2.5 kW The old Radio Sports’ Yankee-accented English (from Fox Sports Network) has now been replaced by rocking oldies, such as Phil Collins with powerful strength at 1307:
73 and Good DX,
Gary DeBock (DXing at the Rockwork Ocean Cliff near Manzanita, OR, USA)
7.5″ loopstick CC Skywaves, PL-380 & XHDATA D-808
12″ Longwave FSL + three new 8″ Medium Wave FSL’s
Thank you so much, Gary, for allowing me to share your reports on the SWLing Post. Many of us would love to experience mediumwave DXing from your Rockwood perch, but we’ll have to live it vicariously through your excellent reports! We wish you excellent DX!
Many thanks to SWLing Post contributor, Gary DeBock, who shares the following guest post and update from the August 2019 Rockwork DXpedition:
Gary DeBock DXing with Craig Barnes at the Rockwork 4 ocean cliff near Manzanita, Oregon, USA
Once again the largest FSL antenna collection on the planet made its way across the Columbia River bridge during an overnight trip to NW Oregon, finally being deployed at the original Highway 101 plunging cliff turnoff– Rockwork 4. There has been a drastic decrease in the squatter population, so that Craig Barnes and I were able to easily set up all four PVC bases for all-out DU-DXing at the dream site this morning (see photo). Unfortunately Chris Black came down with a health issue at the last minute, and needed to cancel out.
Craig and I had some excellent signals from the regulars (including 531-More FM, 558-Fiji and 1017-Tonga), although it wasn’t quite a stellar morning for rare DX. We were kind of spoiled last year with 1017-Tonga staying a S9 practically throughout the session, but this morning it was “only” at S9 for a few minutes at a time. This meant that as soon as I notified Craig of 1017’s potent status, the signal tended to nosedive. Maybe the cumulative effects of humidity and salt water exposure are beginning to take their toll on the Tongan big gun? 558-Fiji showed up with decent signals for a couple minutes at a time, which meant that Craig got the short end of the stick after I notified him of the potent signal. 531-More FM hit an awesome S9 peak around 1312 (including the usual split-second female ID), making it once again seem totally bizarre that no trace of the 2 kW modern rock station has ever been received at Grayland for the duration. The Rockwork Cliff is typically focused in like a laser on New Zealand, and this was a typical morning!
531 More FM Alexandra, NZ 2 kW Potent S9 modern rock signal from this Rockwork regular, with female “More FM” ID at 19 seconds:
Many thanks to SWLing Post contributor, Gary DeBock, who shares the following notes and recordings from the latest Rockwork DXpedition.
Top Ten DU signals from the August 2018 Rockwork DXpedition
– Gary DeBock
Life is good– breathtaking ocean scenery, an innovative compact antenna, thunderous DU signals and even a partner (Craig Barnes) to share in the bounty. Who could ask for more?
Listed below are the Top Ten DU signals recorded during the recent Rockwork ocean cliff trip (near Manzanita, Oregon) from August 1-9, including several low-powered Kiwi stations which acted like “big guns” pretty much throughout the DXpedition. All of these were recorded with 7.5″ loopstick portables (CC Skywave SSB and XHDATA D-808) and “Airport Unfriendly” 15″ and 17″ FSL antennas (guaranteed to send TSA agents into a security alert).
531 More FM Alexandra, New Zealand, 2 kW The obscure modern rock station usually managed at least one S9 peak each morning, and was fully competitive with Kiwi co-channel PI for the first time. This TOH recording at 1300 on 8-8 demonstrates its potent capability at the cliff
531 PI Auckland, New Zealand, 5 kW Pacific island music at a huge level at 1248 on 8-7 was typical from this low band powerhouse, which was frequently in an all-Kiwi snarl with its overachieving co-channel More FM
558 Radio Fiji One Suva, Fiji, 10 kW The donated Japanese transmitter still puts out awesome signals for this native-language powerhouse, including this island music with a Song Medley ID (“Radio Fiji One, na domoiviti”) at 1:38 into this recording at 1252 on 8-1
567 RNZ National Wellington, New Zealand, 50 kW After demolition of its old tower the RNZ big gun has sometimes sounded anemic on the west coast, but certainly not at 1320 on 8-3 with Indian-accented English
594 Star Timaru/ Wanganui, New Zealand 5 kW/ 2 kW Another Kiwi overachiever, this low powered network was socking it to the Oz big gun 3WV all week, including with this powerful Christian music // 657 at 1326 on 8-3
657 Star Wellington, Tauranga, New Zealand 50 kW/ 10 kW The flagship Star station sure was playing the part with Christian music at an overwhelming level at 1238 on 8-6, including an ID at the end of the recording
765 Radio Kahungunu Napier-Hastings, New Zealand 2.5 kW The overachieving Maori station was its usual potent self with island music and Maori chants at 1218 on 8-1; it was usually slightly stronger than its 603 parallel (Waatea)
936 Chinese Voice Auckland, New Zealand 1 kW One of the most incredible signals of the entire DXpedition– the 1 kW ethnic station pounds into the cliff at an S9 level at 1309 on 8-2– ocean cliff propagation at its finest!
1017 A3Z Nuku’alofa, Tonga 10 kW Yikes! The rejuvenated Pacific island big gun thunders into the cliff with the strongest signal I’ve ever heard recorded in North America, featuring island music at 1314 on 8-1… almost loud enough to wake up the sleeping squatters
Many thanks to SWLing Post contributor, Gary DeBock, who shares the following notes and recordings from an Ultralight DXpedition in Kona, Hawaii:
April 2017 Kona, Hawaii Ultralight DXpedition
The first long-range test of a “Frequent Flyer” FSL Antenna
By Gary DeBock, Puyallup, WA, USA April 2017
Ever since the U.K.’s Graham Maynard published his innovative article about the “Ferrite Sleeve” antenna in early 2011 an enthusiastic group of DXers and tinkerers has continually refined and upgraded the design, with most of them going in the pursuit of maximum possible gain. Monster FSL models were designed with weights of up to 38 pounds (17 kg), and considering the size, weight and subversive appearance of the typical model, the general assumption was that this new type of antenna was highly unsuitable for air travel, since it would send airport security personnel into a serious panic.
This situation continued for a full 6 years, during which the FSL antenna became a star performer in the related new niche of ocean cliff transoceanic DXing. But was there another possible application for the antenna’s compact performance advantage? What if a very lightweight, high-performing model could be designed which would not only provide a huge boost in DXing gain, but fit inside a hand-carry suitcase, and routinely pass airport security screening inspections around the world? This was a tough design challenge, but well worth the effort if successful!
Since the new antenna would need the maximum possible performance for its small, lightweight size, the use of the Russian surplus 100mm x 20mm x 3mm ferrite bars was mandatory. Every possible effort would be used to make the antenna as compact and lightweight as possible, although the choice of the highest-sensitivity 1162/46 Litz wire was critical for best performance. The PVC frame would be shrunk down to the smallest practical size. Finally, in a major experimental effort here over the winter season, the first of the new 5 inch (127mm) “Frequent Flyer” FSL’s became a reality. The finished antenna had a very non-subversive appearance, and could fit inside a custom-sized plastic tote within a hand-carry suitcase. Most importantly, it could still deliver a serious amount of inductive coupling gain– roughly similar to that provided by a 4 foot (1.22m) air core box loop, but with the advantage of somewhat lower noise reception.
Because the Russian surplus 100mm x 20mm x 3mm ferrite bars are extremely scarce (without any current supply source) only five of these original “Frequent Flyer” models would be made, although alternative models using the commonly available 140mm x 8mm ferrite rods were also designed. These antennas would be somewhat heavier and larger, but these “Baby FSL” ferrite rod models could be easily assembled from parts available on eBay, fit inside the hand-carry suitcases, and still deliver a lot of DXing performance (while routinely passing airport security screening). Finally, an economic model using the commonly available 62mm x 12mm x 4mm Russian surplus ferrite bars was also designed. This lightweight FSL can be constructed for around $65 US, and can still provide a serious DXing gain boost to a stock Ultralight radio. For want of better terms, these three classes of “Frequent Flyer” FSL antennas are called the “first class,” the “business class” and “coach class” models, with FSL sensitivity scores (ferrite length x coil diameter) of 585, 490 and 300 respectively.
From April 9-12 a Mini-DXpedition was conducted on a 6th floor oceanfront room at the Royal Kona Resort Motel in Kona, Hawaii. This was the first of many long-range DXing trips based upon the performance boost provided by the compact new antenna– which was specifically designed to easily pass through airport TSA security checkpoints. A 5 inch (127mm) “Frequent Flyer” FSL antenna was packed inside a matched-size plastic tote within a hand-carry suitcase, and breezed through TSA security screening in both the Seattle and Kona airports (without even a single question ever being asked). This was one of the “first class” Frequent Flyer models described previously, and was used to boost DX station gain on a 7.5″ loopstick C.Crane “Skywave” Ultralight radio. This combination was effective enough to track down many exotic Pacific Island stations (540, 621, 1440, etc.) at S9 levels during transmitter-site sunset skip propagation into Kona, as well as Asian TP-DX of varying strength around local sunrise.
This Kona trip was primarily designed as an anniversary celebration with my wife, so before we took off I had (somewhat reluctantly) agreed that DXing would have a secondary priority to sightseeing over the four days. Because of this there were many frequencies that could not be investigated in Kona, but I knew very well which Pacific island stations were tough challenges in both North America and Japan, and I was determined to go after them with a vengeance. 540, 621 and 1440 would all receive serious attention in Kona– not because they were great challenges in Hawaii, but because most DXers in both North America and Japan needed all possible information about them if they were to have any chance of reception at all. Besides this I was eager to try my long-range luck chasing exotic Asians around local sunrise with the innovative FSL antenna, but I knew that east-west propagation was almost totally dependent upon solar activity– and as it turned out both the A and K indexes shot up after our arrival.
Overall the Kona MW propagation to the Pacific islands was exceptional around local midnight (as expected), but the sunrise propagation was somewhat challenging for long range Asians. Perhaps the biggest success of this entire trip was the interest and excitement that the “Frequent Flyer” FSL antenna series (the major experimental project here this past winter) has inspired among DXers who routinely travel to foreign countries and other faraway venues. As I write this Craig Barnes of Wheat Ridge, Colorado is conducting his own 5 inch “Frequent Flyer” FSL- based DXpedition to Hawaii. Good luck, Craig!
[Note: a selection of audio files have been embedded in the post below, but all audio is available to download and stream via the links provided.]
531 6DL? Dalwallinu, Australia Presumably the one with the same-sounding announcer and program as the one on 630-4QN at the time (at 1547 on 4-9; see MP3 for 630-4QN), but it didn’t seem to be exactly parallel (maybe a time zone delay?)
540 2AP Apia, Western Samoa This station features a lot of Samoan music (with both male and female announcers), and dominates the frequency in Kona at night as long as it transmits. Unfortunately it doesn’t follow the listed PAL sign off time of 1000, but runs past this time routinely, which made it tough to track down an exact sign off time during my limited sessions. My guess is that it signs off sometime between 1030 and 1100. The following MP3 is of S9+ level Samoan Christian worship music at 0931 on 4-9. This overwhelming signal was one of the most awesome recorded during the entire DXpedition:
558 Radio Fiji One Suva, Fiji Somewhat of an underperformer considering its South Pacific location and (nominal) 10 kW power level. My guess is that the station has some transmitter and/ or antenna issues. Here is some fair level male speech with island music at 1001 on 4-9, which was the strongest signal it managed during the entire trip
621 3RN Melbourne, Australia This LR network station would start to fade in just when Radio Tuvalu was about to sign off (around 1000), although it never provided any serious competition for the exotic station. This MP3 was made just after Tuvalu’s sign off at 1006 on 4-9
621 Radio Tuvalu Funafuti, Tuvalu A very tough station to track down on the mainland, but certainly a “piece of cake” in Kona. Routinely has sign off at 1003 UTC, preceded by island choral music and the national anthem (sung by the same choral group). Around 0950 a female announcer begins the routine by giving a monolog news broadcast about 5 minutes long, typically followed by an island music song right before the fixed 5-minute sign off routine. The latter two features are included in the following 8 minute recording (at near S9 strength) made at 0955 on April 10
The usual female announcer with her 5 minute news broadcast at near S9 strength at 0955 prior to the sign off routine on April 11. The lady giving the correct pronunciation for “Tuvalu” is at the 11 second point
630 4QN Townsville, Australia This 50 kW station was far and away the strongest Australian signal heard throughout the trip. Unfortunately it wasn’t in the same time zone as fellow LR network stations on 531 and 558 in Western Australia, making parallel checks seem dubious. Here is a typical signal at 1543 on 4-9
657 Pyongyang BS Pyongyang, N. Korea This bizarre station was far and away the strongest Asian heard during the trip– almost like it was a South Pacific semi-local. When solar activity cooled off it could blast in with serious power, such as at 1555 on 4-9
693 UnID-TP This mystery signal showed up at 1604 on 4-9, after NHK2 (JOAB) sign off. Obviously there is male speech and some kind of backup music at various times, but I’m totally unfamiliar with stations on this frequency (except for JOAB). Any hints or suggestions? This station only showed up on 4-9; rising solar activity brought in only 690-Honolulu splatter on the other three days
1035 Newstalk ZB Wellington, NZ Received late in sunrise enhancement at 1611 on 4-12, this was a rather modest signal from the Kiwi big gun, which never seemed to get anywhere close to its Oregon cliff strength during the entire trip
1098 V7AB Radio Marshalls Majuro, Marshall Islands One of the regular Pacific island stations received in Kona, and one of the best bets for Mainland reception. The frequency has very little QRM, although Newstalk ZB could be weakly received in between the island music songs after around 0900.
Strong island music at 0955 on 4-9 (its best performance during the trip)
1440 Radio Kiribati Bairiki, Kiribati Because of its domestic frequency this obscure station is another of the toughest Pacific island stations (and countries) to receive on the Mainland, but some very helpful identity clues were discovered in Kona (where the station is a breeze to hear). The station routinely signs off at 0936 UTC each evening, with a very loud 1000 Hz audio tone right before it cuts power. The sign off routine includes station ID’s in both the local language and English around 0932 prior to the choral music national anthem, although because of her heavy accent the fact that the female announcer is talking in English might well go unnoticed. The full sign off routine is included in the following MP3, preceded by an Island music number (during which a 1440 Spanish pest attempts a run on the frequency, only to be immediately drowned out)
The American country music format can be heard prior to the 4-bong time signal.
Prior to the sign off routine this station also uses its female announcer to give a final news update (like 621-Tuvalu). This recording is of such a news update at 0925 on 4-11, with several mentions made of the American president
1566 HLAZ Jeju, S. Korea Fairly regular with its Chinese Christian service around 1530 each morning in Kona, but never at very great strength (possibly due to unfavorable solar activity). Here at 1609 on 4-9 it is the music station playing the Chinese version of “I Would Rather Have Jesus,” in a mix with the (presumed) Mainland Chinese Yanbian Jammer
1566 Yanbian, China (Presumed location, Jammer) Because of Chinese inflection this is the apparent co-channel of HLAZ in the same recording at 1609 on 4-9; it was also received at 1600 on 4-10 with Chinese 5+1 time pips (thanks to Chris Kadlec for his assessment)
Many thanks to SWling Post contributor, Gary DeBock, who shares the following note about his latest FSL antenna experiment:
Medium wave DX FSL antenna phasing experiment– 1593-CNR1 (Changzhou, China, in Mandarin) boosted up to strong (S9) peaks by two 5 inch “Frequent Flyer” FSL’s at 1435 UTC on February 25th in my frozen back yard in Puyallup.
Unlike other high gain MW antennas, the FSL’s can provide cumulative gain at very close inductive coupling ranges.