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SWling Post contributor, Ron, recently noted that Jay Allen reviewed one of Paul’s inductively-coupled mediumwave magnetic loop antennas. Jay gave it good marks on performance as it compares favorably with the Grundig AN-200, Select-A-Tenna M, and Terk Advantage AM–even having a performance edge due to it’s larger loop diameter. (Note that Paul makes a number of loop sizes–click here to download PDF of catalog.)
In Canada last summer, I used the PK Loop on a number of field radio listening sessions.
But what really sets the PK Loop apart from its competitors is its durability. PK’s Loops are built to be incredibly rugged. I routinely throw my PK Loop antenna in bags/packs and–unlike most of my other radio components–never worry about how it’s padded or protected. There’s little to damage unless you’re intentionally abusive to this antenna. My Grundig AN-200 antenna, on the other extreme, has exposed coated wires around its loop that I’m constantly concerned about harming in transit.
Following up…
Ron’s message reminded me that I never followed up after posting a preliminary review of the PK Loop C-LOOP-HDSW6-18 in 2016.
Shortly after publishing the review, I had a fantastic opportunity to evaluate how well the PK Loop would perform in a typical hotel room. My buddies Eric (WD8RIF), Miles (KD8KNC) and I stayed overnight in a hotel on Wright-Patterson Air Force Base during our mini National Parks On The Air DXpedition.
My Elecraft KX2 connected to an external random wire antenna.
The hotel room was indeed dense with RFI.
We hooked my Electraft KX2 to both the PK Loop and to a simple random wire antenna.
Without a doubt, the PK Loop was much better at mitigating radio noise than the wire antenna we hung on the inside of the hotel window.
Unlike most modern hotels, however, this one actually had operable windows, so we tossed the random wire out the window and made another comparison. In this case, the external wire antenna consistently outperformed the PK Loop, no doubt because it had the advantage of being outside the radio noise cloud within the hotel’s walls. It goes to show that outdoor antennas–even if simply hanging from a room window–will almost always outperform comparable indoor antennas.
A late evening listening session on the condo balcony.
Last summer, I also spent two months in a condo near Québec City. The condo was dense with RFI–the PK Loop made the experience much more bearable. The loop couldn’t completely eliminate all of the persistent wideband noise, of course, but it did reduce noise to a level that I could enjoy some of my favorites like RRI, VOG, VOT, REE, WRMI, RNZI and even weaker stations in North America like the BBC and DW.
Even the shortwave version of the PK Loop can null out QRM to some degree by rotating the loop perpendicular to noise. I became quite adept at this by the end of our stay.
Summary
Since I purchased the PK Loop, it’s been a constant travel companion and I highly recommend it. I don’t believe you’ll find a more durable or effective portable mag loop antenna on the market.
PK Loops are built by Paul Karlstrand in Australia who has a stellar reputation with his customers. For those of us living outside Australia, there will be additional shipping costs, but they’re negligible and Paul has been exporting these loops for many, many years. I believe I received my loop within a couple of weeks of ordering it.
This year, I plan to purchase PK’s largest mediumwave loop, the model HDXLTAM that boasts a 20″ diameter. Please comment if you have experience with this loop or any of Paul’s loops!
Clearing the southern coastline of Maui en route to the Big Island. (Photo by Gary DeBock)
Many thanks to SWLing Post contributor and intrepid Ultralight DXer, Gary DeBock, who shares this DXpedition summary with recordings:
Kona, Hawaii DXpedition– Pacific Island Results
by Gary DeBock
From December 17-20 a Mini-DXpedition was conducted in Kona, Hawaii with a 5 inch (13cm) “Frequent Flyer” FSL antenna and a 7.5 inch (19cm) loopstick C.Crane Skywave Ultralight radio.
The FSL antenna was a new type designed to easily pass through TSA security checkpoints at airports, and provide inductive coupling gain roughly similar to that of a 4 foot air core box loop. South Pacific island reception was generally good from 0630-0800 UTC daily, but usually became problematic after that when powerful Asian stations tended to drown out the exotic Pacific island stations as sunset progressed over Japan, Korea and China. By 0900 daily only the most powerful Pacific island stations on 621, 846, 1098 and 1440 had much of a chance of surviving the Asian signal onslaught, and even some of those were drowned out. During a similar visit to Kona, Hawaii with identical gear in April (DXing at the same motel) the Pacific island stations were generally stronger, and had no co-channel competition from the Asians from 0800-1030 UTC. As such the South Pacific results during this trip were slightly down from April, although there were still plenty of strong signals to record.
The new 846-Kiribati on Christmas Island was a star performer as the strongest island DU station, with local-like signals shortly after the Hawaiian sunset each evening. Despite this it had an intermittent transmitter cutout issue, with the signal failing to transmit at odd intervals (including one stretch with six signal dropouts within one minute, as documented in an MP3 linked below). In addition 846-Christmas Island’s programming had a variable time delay with that of distant 1440-Kiribati in Tarawa, with both a 19-second and 35 second time delay noted. This may be related to the transmitter cutout issue, with the time delay changing after a major dropout. DXers looking for a parallel with 1440 should keep this programming quirk in mind. Although both 846 and 1440-Kiribati signed off at the usual 0936 UTC time on the first couple days of the trip, they had both switched to a 1009 UTC sign off on the last couple of days. Whether this is a permanent programming change is unknown, but the loud 1000 Hz audio tone is still being broadcast before power is cut, resulting in a very easy way to distinguish the stations at sign off time (even in heavy domestic QRM).
846 and 1440 weren’t the only exotic DU’s with transmitter issues. 621-Tuvalu came down with distorted audio on December 18th, a problem which got worse and worse on the remaining two days. By the last day it was sounding very garbled, making a bizarre combination with 621-Voice of Korea’s buzzing Japanese service transmitter. Whether 621-Tuvalu has repaired its garbled audio is also unknown.
540-2AP was somewhat weaker than it was in April, while 558-Radio Fiji One was MIA during the entire trip (probably because of Asian QRM). Efforts were made to track down 630-Cook Islands but only a weak UnID was recorded. 801-Guam was possibly received during a Pyongyang BS/ Jammer fade, but 990-Fiji Gold was given a golden knockout by 990-Honolulu. 1017-Tonga showed up for a couple of good recordings, but got slammed by Asian co-channels after 0830. Efforts to track down 1035-Solomons ran into heavy 1040-Honolulu splatter, while 1098-Marshalls became the only Pacific island station to have stronger signals than in April. Its overwhelming signals after 0700 daily were one of the bright spots in Pacific island reception. Finally the new 1611-DWNX in Mindanao, Philippines was received at a strong level at 0855 on December 19th, apparently with a major boost from sunset skip propagation.
540 2AP Apia, Samoa, 5 kW Christian worship music at a good level through the T-storms at 0751 on 12-17, but not nearly as strong as in April:
621 R. Tuvalu Funafuti, Tuvalu, 5 kW This station had very strong signals until around 0800 on most evenings, when it usually began to be pestered by Asian QRM (China, N. Korea and NHK1). It also came down with a garbled audio issue on December 18th, which continued to get progressively worse until I left Hawaii. Sign off time is still around 1006, but by that time it ran the gauntlet of powerful Asian co-channels during the December propagation.
Local employment offers read by the usual lady announcer at an S9 level at 0750 on 12-18. This was the last undistorted audio signal recorded from the station during this trip; after this the audio went “south”:
Full Radio Tuvalu sign off routine at 1003 on 12-18, but with China QRM initially. Tuvalu’s signal prevails during the national anthem, but the audio distortion is quite noticeable. The carrier apparently stays on for over a minute after the audio stops:
630 UnID While trying for the Cook islands (Rarotonga) I came across this weak Christmas music with English speech at 0742 on 12-17, although this could just as easily be a west coast domestic station playing the “exotic” to fool a hopeful DXer. Walt says this station is a notorious underperformer:
846 R. Kiribati Christmas Island, 10 kW This newly rejuvenated station had awesome signals, and was overall the strongest Pacific island station received. Of all the Pacific island DU’s it faded in at the earliest time after sunset, and maintained its strength even during strong Asian propagation — as long as it managed to transmit without its signal dropping out. Unfortunately this seemed to be a pretty common occurrence while I was in Kona. Island-type music at typical S9 strength at 0735 on 12-18:
After a prolonged 846 transmitter dropout it seemed like the programming time delay between the distant 1440-Kiribati on Tarawa Island and the new 846-Kiribati on Christmas Island would change. On December 17th I recorded two different time delays– 19 seconds, as in the following recording (the MP3 starts out on 846 at 0635, switches to 1440 at the 1:02 point, then switches back to 846 at the 1:34 point, with a 19-second time delay evident between the 1440 and 846 programming (846 lags behind):
Later on the same evening there was a 36 second time delay between 1440 and 846, with this MP3 starting off on 1440 at 0645, and switching to 846 at the 11 second point:
1098 R. Marshalls (V7AB) Majuro, Marshall Islands, 25 kW This station was very strong in Kona with its island music every night, and rarely had any Asian co-channels.
S9 Island music and native language speech (and possible ID) across the 0700 TOH on 12-17:
1440 R. Kiribati Bairiki, Tarawa, 10 KW Somewhat weaker than its rejuvenated 846-Christmas Island parallel (which has variable programming delay times, as explained above), this home transmitter could hold down the frequency until around 0800 every night, after which it was usually hammered by JOWF in Sapporo. Despite this it often put up a good fight until its new sign off time of 1009, and it continues to use the loud 1000 Hz tone right before the power is cut (an awesome aid for DXers hoping to ID the station through heavy QRM).
Typical island language speech and strength level at 0830 on 12-18, just as it is starting to get jumbled by JOWF (a Japanese female “Sapporo desu” ID is at 25 seconds):
Full sign off routine at 1005 on 12-19, including the National Anthem and the 1000 Hz tone before the power is cut. The tone gets through the JOWF QRM like a DXer’s dream:
1611 DWNX Naga City, Mindanao, Philippines, 10 kW (Thanks to Hiroyuki Okamura, Satoshi Miyauchi and Mauno Ritola for ID help) Received at 0855 on 12-19, this station was a mystery until the Japanese friends matched the advertising format with that of a new, unlisted station which just came on the air in the Philippines. The propagation apparently got a major boost during sunset at the transmitter:
73 and Good DX,
Gary DeBock (DXing at the Royal Kona Motel with a 7.5″ loopstick C.Crane Skywave Ultralight+
5 inch (127mm) “Frequent Flyer” FSL antenna.
Thank you for sharing your Hawaiian DXpedition with us, Gary! Your mediumwave DX catches with modest equipment reminds us all that when HF propagation is poor, there is still so much signal hunting below 2 MHz!
Many thanks to SWLing Post contributor, Rolf Snijder, who writes:
I have added an external antenna capability for mediumwave on the XHData D-808.
Simply add a 27 pF capacitor on the backside of the PCB on C10 to the the ferrite antenna.
The mod causes no loss on FM or shortwave!
I also replaced the Ferrite antenna with a bigger one so I now have more performance on MW!
Longwave is not good in my radio, even with an external antenna, it is not performing well.
Thanks once again, Rolf! I must assume that the Digitech AR-1780 could be modified in the same way as the radios appear to be near identical. Perhaps someone can verify this at some point!
I recently received a new XHDATA D-808 SSB portable receiver, after AliExpress had a $69 USD introductory sale. I’m intrigued by this new model, as it uses the SiLabs Si4735 DSP chip, the same “brains” that powers the Eton Satellit (and Executive version), and C. Crane Skywave SSB. I believe the same Si4735 is found in Tecsun’s PL-880 and the CountyComm GP-5/SSB. A key feature found in all of these radios is USB/LSB modes and 10-Hz tuning step in SSB.
It would be a mistake to assume that all portable DSP receivers with the same SiLabs chip will perform equally; quite the opposite! They all have reception differences that owners will notice. I certainly noticed differences in sensitivity, AGC action, audio quality, and (to some extent) variations in adjacent channel (splatter) rejection between receivers using the same bandwidth. I made these observations when I owned the PL-880 and GP-5/SSB radios. Differences in the circuitry surrounding the SiLabs chip, as well the sizes of MW ferrite loopstick antennas and SW/FM whip antennas contribute to each receiver’s personality.
Below are four videos showing the D-808’s reception of three weaker daytime medium wave stations from indoors at my suburban Seattle-Tacoma (WA) home, plus one video of a shortwave reception in the 41 meter band. The XHDATA D-808 is compared to C. Crane’s newest Skywave radio, the SSB model, and the Eton Executive Satellit. Although brief, these tests show how the new XHDATA portable is a welcome competitor to the field of modern, compact SSB-capable radios:
What about single sideband? These four videos show reception in AM mode only, but rest assured the D-808 is very capable on the SSB modes of LSB and USB! A separate fine tuning rotary wheel on the right side of the radio’s case offers adjustment in 10 Hertz increments. The effect feels very similar to tuning CountyComm’s GP-5/SSB “walkie-talkie” style receiver. The plus or minus (+/-) offset is displayed in multiples of 10 Hz steps as “-1”, “-2”, “-3”, and so on.
I hope to post some future videos showing SSB usage of the D-808.
Soft mute. The dreaded soft mute is present in AM and SSB mode to some degree, but I do not feel it is excessive. Like most radio hobbyists I’m not a fan of soft muting and prefer uninterrupted tuning with no sign of “chuffing” or lowering of noise or audio. The amount of soft mute on this radio seems the same as the Eton Executive Satellit in my opinion.
What else to like?My take–
Audio. I find the D-808’s audio quality to be slightly more mellow or warmer…I like that, especially on FM! Audio on the MW and SW bands still has a crispness that aids in DXing on those bands, however.
18650 Li-Ion battery. Not all may agree, but I like this style of battery. The D-808’s internal circuit shuts off when the battery is fully charged, or after 10 hours of charging. The radio comes with a 18650 battery and a USB cable; the owner supplies a common 5V USB charger.
RDS on FM. This is a feature lacking on the Skywave SSB, but it is present and performs as expected with the D-808. The XHDATA radio lacks the Skywave SSB’s NOAA weather presets, however.
AM filter bandwidths. Interestingly, this receiver supplies two additional narrow AM mode bandwidths lacking in the Executive Satellit: 1.8 kHz and 1.0 kHz. It’s good to have options, although such narrow filters in AM mode sound a little muffled (offset tuning helps). The Skywave SSB does offer 1.0 kHz in AM mode, but has a 2.0 bandwidth in place of 1.8 kHz.
Backlighting. If desired, the D-808’s easy-on-the-eyes white backlight for the display can remain illuminated continually. Bravo, XHDATA! Now, if we could persuade more manufacturers to add backlighting to the keys themselves (a la the Degen DE1103/Kaito KA1103/Eton E5), we’d have more choices use in low light conditions like camping or bedside use.
Handy size. Probably a third larger than the diminutive Skywave SSB, the D-808 is still a very handy size that will fit most coat pockets, and is a smaller receiver than the Eton Executive Satellit. As you can tell from my videos, reception doesn’t suffer due to the smaller size.
Design. OK, this one’s very personal! As a graphic designer I have a real soft spot for any receiver that looks as good as it sounds, no matter what the technology or vintage. The D-808’s look really appeals to me and adds to my enjoyment while operating it. There are no unnecessary protrusions, ridges, or visual do-dads on this XHDATA model. In fact, I seem some design clues from the stylish Tecsun PL-880 in the D-808. The radio also has a quality feel to the plastic case and buttons, giving it a more “upper class” impression during use.
Antenna jack. The D-808 has the standard 3.5mm antenna port on the left side of the receiver. This is an addition I appreciate, and wish that C. Crane had included one on their Skywave SSB model. I tried this external antenna jack with an amplified PK Loops’ shortwave antenna and the combination performs excellently.
Minor annoyances
So far, the list is short! As a sacrifice to style, the manufacturer has kept all front panel buttons almost flush with the case. The effect looks great, but they are almost too low and close to the front panel. Those with larger fingers may find operation awkward or frustrating. Also, entering a shortwave frequency with less than five digits (i.e., below 10,000 kHz) requires a trailing push of the Frequency (FREQ) button.
I encourage other new owners of XHDATA’s D-808 to leave their comments below. Where does this portable rate among other radios you may own?
Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.
In my recent post on the AirSpy HF+ vs Elad FDM-S2, I commented on medium wave reception only.
This past weekend I swapped out the Wellbrook ALA1530S+ for another Wellbrook loop, the ALA1530LN Pro. This LN Pro model is less likely to overload receivers at my suburban Tacoma, WA location. Both AirSpy and Elad radios performed admirably with the LN Pro and it was nearly impossible to find any reception differences on medium wave.
Before the antenna swap though I experimented with inline attenuation modules (“bullets”), typically used in cable TV installations. I used the same sample rates on the SDRs as described in the previous article. After some tests with different attenuation levels, I came to the following conclusions during daytime comparisons:
FDM-S2 with ALA1530S+ loop, medium wave: needs a minimum of 6 dB attenuation to avoid overloading. Anything less causes saturation of the spectrum & waterfall, “crunching” overload noises, and minimal or no received signal.
HF+ with ALA1530S+ loop, medium wave: I had to search diligently to find any signs of false signals or overloading, but finally noticed a weak image or spur of a S-9+60 dB (-13.5 dBm) local station on 1560 that was appearing very weakly on 1270 kHz, mixing with the station on that frequency. Sometimes it was there, other times the spur or image would drop down and disappear, leaving the 1270 signal alone. If I added just 3 dB of attenuation in the antenna’s feed line, the interference from the 1560 station was gone for good. The S-9+60 dB station is a very strong signal; it’s impressive that the AirSpy HF+ deals with this and similar powerhouse signals so well.
Long wave: Below are two screen captures from my local long wave reception in the evening, made moments apart with each receiver.
FDM-S2
HF+
As you can tell, there are a half dozen or so additional signals seen on the HF+ below 200 kHz that do not appear on the FDM-S2. These extra spikes are images or spurs from medium wave signals that were missing from the FDM-S2’s reception–bravo Elad! However, the remaining spikes on both radios below 200 kHz seemed to be noise or interference.
Each receiver had roughly equal performance in the bulk of the long wave spectrum, when I did A-B comparisons on the same beacon signals. I’m not a LW or NDB DXer however, so I can’t claim any expertise on these frequencies. In short, though, both radios seem neck-and-neck from about 200 to 500 kHz.
The DXer of LW frequencies may want to look elsewhere for a better performing radio than either the FDM-S2 or HF+. SWLing Post reader Tudor Vedeanu has commented that the SDRPlay RSP1A and the Eton E1 work very well at long wave.
Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.
Recently, I started posting Colin’s recordings on a schedule so that each recording is being published exactly 40 years from the original broadcast date. Check out the Shortwave Radio Audio Archive each day (or subscribe via iTunes) to listen to the recordings.
Below, I’ve embedded the recording from New Year’s Day 1978 where we learned that Yuri Romanenko and Georgi Grechko toasted the New Year with fruit juice (for obvious reasons, champagne was not allowed on the station!).
Many thanks to SWLing Post contributor, Eric McFadden (WD8RIF), who notes that the excellent website, Atlas Obscura, recently featured The Shipping Forecast:
Why a Maritime Forecast Is So Beloved in the United Kingdom
For the penultimate song on their 1994 album Parklife, Blur chose the swirling, meditative epic, “This Is a Low.” The song envisions a five-minute trip around the British Isles as an area of low pressure hits.
“Up the Tyne, Forth, and Cromarty,” sings the lead singer Damon Albarn, “there’s a low in the high Forties.” The song’s litany of playful-sounding place names, including the improbable “Biscay” and “Dogger,” may seem obscure to listeners abroad, but to a British audience, they resonate.
The song’s lyrics were inspired by the Shipping Forecast, a weather report that is broadcast on BBC Radio 4 on behalf of the Maritime and Coastguard Agency. Sailors working around the coasts of Britain and Ireland, recipients of the wrath of the North Atlantic and North Sea, are the ostensible beneficiaries of the forecast.
But, for listeners who tune in while tucked in bed rather than sailing the high seas, the reassuring sound—a simple, steady listing of conditions in the seas around the British Isles, broken down into 31 “sea areas,” most of which are named after nearby geographical features—is something more akin to the beating pulse of the United Kingdom, as familiar as the national anthem or the solemn chimes of Big Ben.[…]
When I lived in the UK, I would often fall asleep and/or wake up to the Shipping Forecast. Here in the States, I can listen to the forecast live via the U Twente WebSDR, but I rarely remember to do so.
And, of course, I can navigate to the Radio 4 website and stream current and past forecasts on demand, but I find the audio a little too clean and full fidelity. I prefer listening to my maritime poetry via Amplitude Modulation (AM)!
In 2016, I purchased portable shortwave magnetic loop antenna designed and built by Paul Karlstrand in Australia. I posted a “preliminary” review of this antenna in 2016 and since then have taken this loop on many travels.
