80 Metres

On the suggestion of John VK6FAAJ/VK6GJT (SK in 2023), a Group 80m net has started on the second Tuesday of each month – 1900 WA time on 3600kHz. All of a sudden, Amateur radio retailers and the supplier of the VK5TM X Phase kits reported an upsurge in sales of noise cancellers to WA.

The October 80m on-air night saw tough conditions – most people had technical dramas of one sort or another: Geoff VK6GHD had Urban QRN, Maurice VK6HLY had problems with an ATU, Terry VK6TTR had TX audio problems, and Mark VK6QI had problems with the computer operating the VK6XT remote HF station. We did have visitors though – VK6MIL, VK6AJP, VK5KVA, VK6MAD and one SWL Brett.

We had an interesting night on our November 80m net, with VK6FAAZ, VK6HLY, VK6GHD, VK6TTF, VK6FAAJ & pooch, VK6LJC and VK6MU on air, and VK6CX and VK6QI listening-in via the Australian Travellers Safety Net internet software defined receiver at Yarloop (thanks for the vector Maurice – a terrific resource). Everyone couldn’t hear someone, and there were a couple of technical problems that sprung up too. The biggest signal into Yarloop was David VK6FAAZ, closely followed by Terry the Noise-Canceller Destroyer VK6TTF.

Portable Ops
El Presidente Geoff VK6GHD operated QRP portable at Kalbarri in October, and continued his experiments on portable HF antenna configurations for 80m contacts back to Group members in Mandurah and Rockingham. Static crashes aside, the 80m half wave inverted Vee supported by a squid pole seemed to work the best over the 550km path, but conditions were marginal before dusk (ie before the Absorption Layer Frequency was below 80m). Tests were also conducted with Mark VK2KI operating QRP portable at Carcoar NSW (3400km) – some success with Peel home stations, but no luck portable to portable with 2 to 3 Watts at each end.

The tests continued a week later, with Geoff VK6GHD operating portable at Prevelly on the banks of the Margaret River using an IC-706 on low power (5 Watts PEP output) to an inverted Vee half wave dipole at squid-pole height. David VK6FAAZ did a great job as net controller but Tony VK6DQ was struggling with the noise – awaiting a 13 pin (!) DIN plug to hook up the PTT on his newly-returned MFJ-1026 noise canceller. Maurice VK6HLY had a big signal with 20 Watts from his home brew transceiver and 53 foot wire in the bushes, and John VK6FAAJ (10km North of Mandurah) was solid 59 at Broomehill, Q5 by David and Geoff, but not readable by Maurice (about 25km South of Mandurah) – sounded like ground-wave propagation only between them – either the E-layer wasn’t strong enough to reflect the high incidence signals, the absorption layer was still too strong at that time, or the antennas had too-low a takeoff angle – nice problem to have!

A morning sked on 80m was good fun – Geoff VK6GHD/p Prevelly Beach was 55 on the VK6XT remote HF station at Broomehill, and Maurice VK6HLY was 57 with 10 Watts from the mighty Wheatbix home-brew transceiver. There was a nice rolling swell (QSB) that morning and no surf (QRN) at Broomehill; Maurice had a bit of duelling electric fence interference but was copying Geoff well over the 140km path. Sounded like the television watchers in the caravan park were still in bed – so not too much noise at Geoff’s end on the half-wave inverted Vee dipole. John VK6FAAJ was listening in and had coms with Maurice on the PARG 2.4GHz mesh network.

Geoff tried swapping to the mobile whip mounted on the caravan draw-bar – the noise level jumped and the signals were pretty-much unreadable at his end; ditto for the listeners; we tried 40m – nothing heard by anyone. More success the following morning though – 5x8 into Broomehill.

The back to basics strategy has seen more members come out of the woodwork to enjoy the simple challenges of real amateur radio. All sorts of stealthy and not-so stealthy home antennas are being considered, and for those not able to get on just yet, the Australian Travellers’ Safety Net SDR has been well used.

Among the not-so-stealthy solutions, encouraged by Mrs Baz who wanted a better solution to the 80m dipole in the Hills Hoist, VK6MU twisted the arms of Tony VK6DQ, Terry VK6TTF and Paul VK6LL to put up a 30-foot lattice tower. Paul having a tower-like physique was just about able to walk the thing up as it turned out (don’t try this at home folks), with just a little assistance from a jib. We’re looking forward to hearing some big signals from Calista.

HF Noise Cancellers
2020 will go down as Noise Canceller year for PARG. So after Martin VK6EEE found the VK5TM X Phase noise canceller kit available at a very low price, Martin and Maurice VK6HLY bought and built a couple.

Maurice reported instant success, with the simple kit able to make a dent in what little locally generated QRN he experienced in the quiet zone of Bouvard. Terry VK6TTF also built a kit – after brushing off a spec of dirt, which he discovered was in fact one of the surface mount device Field Effect Transistors that he was supposed to be soldering to the board! 'My eyes are dim I cannot see, I have not brought my specs with me…’ could be heard echoing through the ether.

Anyway, like Maurice, Terry got his noise canceller going easily and they both brought them to show off at the October TechTalk/Workshop night. Of course it was then on for young and old, everyone wanted this neat solution to the QRN problem on 80m, and the supplier Terry VK5TM was wondering what was with the sudden interest from VK6.

When the Group was trying to hook up with VK6GHD portable at Kalbarri, we were all suffering from S9+ static crashes that just wouldn’t let up – it was almost as if every time Geoff’s FT-817 emitted a syllable, a lightning crash would occur.

Terry VK6TTF was heard to say: “it’s a pity that the noise cancellers can’t get rid of static crashes”…. and the discussion turned to what might happen if a sharp out-of-band antenna was used as the sense antenna, to pick up the static crashes but not pick up the 80m signals? The next day, Terry reported that he’d used a 20m mobile whip as the sense antenna, and it worked well on reducing the static crashes. Like the noise cancelling system for in-house QRN, we need a sense antenna that picks up the noise, but doesn’t pick up the desired signal.

Mobile whips generally have very sharp tuning – they’ll pick up signals on their resonant frequency, but because the close spaced windings just look like a choke to non-resonance frequencies, they’ll pick up very little else. So Terry had the perfect solution – a sense antenna that picked up the electromagnetic pulses from the lightning, but not the desired 80m signals.

TechTalk
Recovering from his Honeymoon, our Secretary David VK6FAAZ presented a TechTalk on Website Management to the Group in October. David then had so many volunteers to manage the Group’s web page that he was knocking them back with a stick (not really, but it’d be nice). The YouTube video of the presentation is available here: http://www.parg.org.au/workshop-technical - the video includes follow-on discussions on Morse keys by Tony VK6DQ, a superb example of a Crammond Commodore – 55A maritime transceiver by John VK6FAAJ, RF phasing HF noise cancellers by Maurice VK6HLY, PAKRAT configuration by Terry VK6TTF and a preview of a web-based magnetic loop antenna design solver by Miguel VK3CPU.

Not surprisingly, the November TechTalk and Workshop focused on HF noise cancellers – theory, demonstration and comparison of the MFJ-1026 and VK5TM X Phase units, as well as an experiment on reduction of both static crashes and in-building switch-mode power supply QRN. More about that in the next edition of AR.

Slow CW Contest
The Group has decided that the first of the February 80m slow CW contests would be held as an intra-club event, with a view to expanding to VK6 and maybe beyond down-stream. Timing of this article for AR Magazine won’t allow details to be advertised in time, but a note will be included in the WIA Broadcast closer to the event.

Materiel Supply
In conjunction with an increase in interest in building equipment, the Group will increase its stock of technical stores for sale. Paul VK6LL will source, list and price parts, such as LMR400, RG58, RG174, UHF/BNC connectors, and quality ladder line. There will be a small mark-up on bulk order prices to keep the cost to members competitive and support the club fund bucket.

Meetings
PARG meetings are now at 1900 WA time on:

· 1st Tuesday of the month – 2m net on VK6RMH

· 2nd Tuesday of the month – 80m net on 3600 kHz with 3595 as a backup

· 3rd Tuesday of the month – Technical Talk / Workshop meeting at the SES HQ in Greenfields and via Zoom Videoconference – links to YouTube videos of the TechTalks are available in the Workshop/Technical area on the Group’s website: www.parg.org.au

The Group is keen to encourage new members. People new to Amateur Radio who would like to find out more about the hobby, or perhaps get a helping hand toward getting an amateur license are most welcome – irrespective of where they live (we have several Eastern States members). More experienced amateurs will find that the Group is a terrific way to share both technical and social aspects of amateur radio. Contact the Secretary David VK6FAAZ parg.secretary@gmail.com or check the website www.parg.org.au for more information.


Cheers,

Mark Bosma

VK6QI / VK2KI