Tag Archives: Jerome van der Linden

Beating the Quarantine Blues: Readers build homebrew NCPL antennas

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My homebrew version of the NCPL antenna.

Recently, I published a step-by-step guide on building a Noise-Cancelling Passive Loop (NCPL) antenna. Evidently, this antenna project really resonated with readers! [See what I did there? If so, my apologies!]

I think this passive loop antenna project has been so appealing because (1.) most of us around the world are sheltering at home due to the Covid-19 pandemic and (2.) this project is simple and you likely have all of the components in your tool shed or junk box at this very moment.

A number you have written to tell me about your antenna builds and some of you have agreed to allow me to share your projects with the SWLing Post community.

Below, you’ll find three fine homebrew examples of the NCPL antenna–all of which were made with what these fine radio enthusiasts had on-hand:

Jerome van der Linden

Jerome’s NCPL antenna

Jerome writes:

Hello Thomas,

Well, I took up the challenge and built a NCPL antenna pretty close to your instructions.

Unfortunately, the coax I had available used (had aluminium shielding, and too late into the project I discovered solder would not take to it. My solution was to cannibalize a coax cable joiner (see photos attached), where – normally – the centre conductors are joined / held by a plastic centre piece and screw fittings.

The braid / shield for the two bits of coax is clamped / squeezed by an outer metal piece. My cannibalising effort involved removing the plastic centre bit which joins the two centre cores, and keeping just the outer metal component which I used (after completely cutting through the coax) to clamp the two metal braid sections, while the two centre copper bits were far enough apart for me to solder the leads for the ferrite balun.

Of course, I could not do the same at the top of the loop where the internal and external conductors need to swap over. I soldered some quite thick copper wire (perhaps 2mm in diameter) to each center core, pushed the center core into the opposing coax and coiled the 2mm thick copper tightly around each end of the coax.

Once it was all taped up it looks no worse than yours, and it does indeed WORK! [see photo above]

Here in Oz, I could not source the identical ferrite, but I think it’s pretty close. Best performance for me is on 11MHz, where the Radio New Zealand signal on 11725 is markedly better using the loop than the internal whip on my Tecsun PL-880. Other bands not quite so significant, but the Noise level is definitely lower.

As you say, Jerome, once all packaged up, it looks great! Sure, the mixture of materials you had on hand wasn’t ideal (aluminium shielding, etc.) but you found a way to make it work from the resources you had in your home. And I love the fact it’s lowed your RFI level!  Thanks for sharing!

Giuseppe Morlè (IZ0GZW)

Dear Thomas,

I’m Giuseppe Morlè (IZ0GZW), from Formia, central Italy, on the Tyrrhenian Sea.

I wanted to build your noise canceling loop seen on SWLing Post …
seems to work well especially from 40 meters. upward…
the diameter is 50 cm.
I will do other tests soon.
You can see the initial test on my YouTube channel via this link:

Thanks for the nice idea and a greetings from Italy.
73. Giuseppe IZ0GZW

Thank you, Giuseppe! What an amazing view you have there from your balcony! I’m quite impressed your PL-660 can take advantage of this design so well. We look forward to your other tests! Grazie mille!

John Mills

Hi Thomas,

My idea was to use a fitness hoop 75cm diameter bought off eBay. I removed the flashy striping to reveal a plastic like hoop that was joined in one spot with a plastic insert.

I have wrapped the whole hoop in tin-clad copper foil tape that has a conductive adhesive backing, but to be sure I have soldered all the overlapping seams. I drilled two holes opposite each other for the upper foil connections and the lower exit to the Balun.

Hopefully the three pictures will be helpful, I did the 4 turn design on Airspys website and it works really well connected to my RSPdx.

73

John

Thank you, John. What a fantastic way to build the NCPL antenna without using a coax for the loop. Indeed, since your plastic hoop has a small insert in the middle, you’ve an ideal spot to make the shield to center conductor cross-over.  Very clever! I also like how you mounted the 1:1 Balun (or Unun) on a small board. Thanks for sharing this.

Got Loops?

Post readers: If you have your own unique NCPL antenna design, please consider sharing it with us! Contact me with details and photos. I’ll plan to publish at least one more post with examples here in the near future.

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VKS-737 Australian HF Communications services for travellers

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Many thanks to SWLing Post contributor, Jerome van der Linden, who writes:

At the Adelaide Caravan & Camping Show this last weekend, I picked up a brochure outlining the services of the VKS-737 HF Radio Network operated by a Public Benevolent Institution Established in 1993.

Its mission statement is to provide emergency and general radio communications assistance services to travellers in rural and remote areas of Australia using Base stations located in Adelaide, Alice Springs, Cairns, Carnarvon, Charleville, Charters Towers, Darwin, Derby, Meekatharra, Mount Isa, Newcastle, Perth, Port Hedland, St Marys, and Swan Hill. Some of these stations are Royal Flying Doctor base stations.

The brochure details the Channels / Frequencies used as follows: 1: 5,455kHz; 2: 8,022; 3:11,612; 4: 14,977; 5: 3,995; 6: 6,796, and 7: 10,180kHz

The VKS-737 web site also has an interesting and at times humorous example of a couple of videos showing travellers making use of the system.
https://vks737.radio/how-good-is-hf-radio/

Apparently, apart from licensing requirements, the equipment required is not cheap, being in the order of AU$3,800 to $4,300. I think the equipment is made by Codan. The brochure also makes the point that HF radio can be used for entertainment such as to receive BBC World Service and Radio New Zealand. Clearly, the group is up to date in being aware that Australia’s own short wave broadcasting services are now – regrettably – a non event.

Thank you for sharing this, Jerome! I’ve heard of the VKS-737 service, but did not realize their network was so robust and that it piggybacks on a portion of the Royal Flying Doctor network.

Post readers: Anyone here familiar with the VKS-737 network?  Have you ever used the system  Please comment!

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Sydney Hobart Yacht Race Frequencies

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Many thanks to SWLing Post contributor, Jerome van der Linden, who writes:

I just found after reviewing a 16 page PDF of regulations etc from the Cruising Yacht Club of Australia, some relevant information for listeners who may want to try to hear the boat to shore communications of yachts participating in this annual yacht race, which is quite famous in this part of the world.

This race will commence at 1300 Sydney time 26th December, which is 0200 UTC, by my reckoning (today, down here). The race normally runs for about 3 or 4 days depending on conditions. It’s not clear to me just when the boats are expected to report their positions, other than that shown below for Green Cape, which is in southern News South Wales. Perhaps someone else can add the time schedule if they know it.

“Boats shall be capable of transmitting/receiving, as a minimum, on the following frequencies:

– VHF – International Channels 16, 72, 73, 80 and 81
– HF/SSB – 4483kHz and 6516kHz and such other frequencies as the Organising Authority may determine”

“Boats shall maintain a 24 hour listening watch for the duration of their race on VHF Channel 16.

For radio communications, a boat’s name may be limited to not more than two words. The Race Committee may alter names where appropriate. The Sailing Instructions will require that boats report by radio when they are in the vicinity of Green Cape and make a declaration confirming their time of passing as well as the following:

  • The HF radio is fully operational
  • Liferaft(s) are on board
  • Engine and batteries are operational
  • Boat and crew are in a satisfactory condition to continue
  • The skipper has comprehensively considered the most current weather forecast and the boat and crew are fully prepared for the conditions forecast.”

[Note that] I just found, from a post a couple years ago, that the time for reporting may be 0735 and 1905 Australian eastern time, which would mean 2035 and  0805 UTC while the race is in progress. It also suggests the 6516kHz frequency is the main one, with 4483 being the backup.

Brilliant, Jerome! Thank you for sharing these frequencies—how I would love to listen to some of the craft report in on HF. I think I’ll be spending some time down under on the KiwiSDR network the next few days!

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4KZ update: Transmitting low power for now

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The 4KZ transmitter is located in Innisfail, Australia

Many thanks to SWLing Post contributor, Jerome van der Linden, who writes:

Have been communicating with Al Kirton (4KZ, Innisfail, Queensland Manager), and by virtue of my membership of a couple of Facebook groups for caravan (trailer to you) owners in Australia, have publicized the fact that Al is keen for reception reports from people in the target area.

Al also advised that they’re not even on 500 watts at the moment:

“We are only on 300 watts due to the fact that we only have one of the two 600 watt RF modules working.(Half of the 600 watts in the good module is lost into the combiner). It should be much better on ~ 1 Kw when the part arrives from the USA and the module is repaired.”

Thank you for the update, Jerome!

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4KZ Update: broadcasts will commence after transmitter repairs

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Many thanks to SWLing Post contributor, Jerome van der Linden, who shares an update from 4KZ Station Manager, Al Kirton:

Hi Jerome

5055 is not on the air yet.

The transmitter failed and requires some inexpensive parts which are not available in Australia. They should be here any day from the US.

We hope to be able to commence in the near future.[…]

Best wishes

Al Kirton
Radio 4KZ

Thanks for sharing this update, Jerome. For more information about 4KZ, check out this previous post.

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