50 MHz The Magic Band defies previously accepted propagation theories

Today, 24th July 2018 at solar cycle 24 minimum the 50 MHz band defied long established propagation theories and observations when the station of Gary Ashdown VK8AW near Darwin, Northern Australia in locator square PH57 worked several stations in Europe and was heard by many more between 0700-0800 UTC. The furthest station received being G3TXF in England, locator square IO71VE at a distance of 14,118 km and -09dB signal strength!

The weak signal FT8 data mode was being used.

This is absolutely remarkable as in all previously published theory and observations 50 MHz Sporadic-E signals usually never exceed 7,000 km by multi hop, and there should be no F2 or TEP propagation, unless at solar cycle maximum, which we most definitely are not.

Therefore it is probable that these remarkable distances were likely achieved by a combination of TEP and Sporadic-E.

It seems the very weak signal mode FT8 is now allowing us to transmit and receive signals and achieve distances that only solar cycle maximum previously supported and we were able to detect. The FT8 use of standadised frequencies and automatic decode with internet reporting is greatly assisting detection. This is extremely exciting for pushing the VHF boundaries of this radio hobby and our understanding of propagation.

 

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2018 Sporadic-E season and FT8 data mode

This has been an excellent year for Sporadic-E in 2018, much better than for some time. Openings started here in IO84 square in May on the 50 MHz band (50.313 FT8) and have also been on 70 MHz (70.154 FT8) too.

The new FT8 data mode used with WSJT-X software and JT-AlertX and DXKeeper logging has been fantastic for VHF DX chasing. Very easy and quick to automatically be alerted in the shack, house or garden to needed stations whilst ignoring anything else. Weak signals from single or double hop Sporadic-E are easy to work and my humble antennas of a loop for 50 MHz and a Colinear for 70 MHz, both only 2m AGL hidden in garden bushes due to a no visible antennas restriction have allowed me to work many new DXCC Countries and squares on both bands.

Single, Double-hop and even Triple-hop Sporadic-E to South America have been observed in the past 24 hours.

On the subject of DXKeeper logging it syncs perfectly with the other software mentioned above to automatically upload contacts to both E-QSL and LoTW, a really nice way to do everything without time consuming manual input.

Meteor Scatter (MS) thriving

I have just returned to my favourite Amateur Radio propagation mode of Meteor Scatter (MS) and found that the 50 MHz (6m) band is absolutely full of activity and thriving more than ever with operators.

The new MS mode on the scene in 2017 is MSK144 mode with 15s intervals and appears to have completely taken over from the previous commonly used mode of JT6M, which was very prevalent as recently as 2015/16.

Most activity on MSK144 mode occurs around 50.280 MHz and the software in use appears to be either the long running and well known WSJT or the newer MSHV by LZ2HV.

Other frequencies seen are 70.280 MHz again with MSK144

This mode would also appear to be very suitable for Aircraft Scatter (AS) propagation and will be interesting to see how it performs there.

73 de Philip G0ISW

Where have all the Amateur Radio technical conversations gone?

I became a SWL in 1983 and a Radio Amateur in 1985, back in those halcyon days we were not permitted to talk at all about Politics or Religion in case it caused offence and the vast majority of conversations to be heard were usually technically related to antennas, radios, propagation etc.

How things have changed now………..I have just been listening to 3.6-3.8 MHz LSB this morning using my Wellbrook ALA1530+ (modified to 100MHz) Active Loop Antenna and the range of non-technical conversations included:

Toe nail clipping, motorcycles & stolen cars!

On the positive side there were a few technical conversations overheard about:

IP cameras, OFCOM & RF breakthrough 

Not technical, but interesting was:

Stoats and wild rabbits & flooding

 

HF/VHF Mobile Operation

Well it seems that the VHF/UHF repeaters I have been complaining about having a lack of activity may actually have been more active than I had thought! Turns out my old Yaesu FT-857D radio had developed a fault with 2 out of 3 of its ceramic filters rendering my receiver virtually deaf except to very strong local signals. This is apparently a very common hardware design failure for this model of radio that has since been rectified with newer ones sold having different filters not subject to this problem.

Had my FT-857D repaired very quickly and cost effectively by the staff of Martin Lynch & Sons and it is like having a new radio in my vehicle once again, I also took the opportunity to have the radio modified to transmit on 5 MHz for portable operation too (mobile 5 MHz operation not being permitted here in the UK).

This has enthused me to be more active when mobile (or Portable) and using either a dedicated 144/432 MHz colinear or a Yaesu ATAS-120A for the 7-50 MHz bands or a dedicated single band 5 MHz aerial left me with the question did I have anything to use on the 3.5 MHz band?

A quick search in the garage resulted in me dusting off my old 0.9m long Australian Terlin Outbacker Stealth Plus antenna to see if it would tune around 3.760 MHz without an ATU so that I could potentially participate on the Worked All Britain (WAB) net. Many years ago before 1998 I used to be very active on the WAB net from my car on 14 MHz and drive all over remote mountain areas to activate the grid squares for WAB awards collectors.

Initially the SWR was found to be far too high and seemed high even at its lowest frequency around 3.5 MHz  I had added a 3/8″ to PL259 adaptor to the antenna which was part of my problem, the other was I had lost the original 36″ wander lead and had only a slightly longer lead available to me for shorting out the coils for the bands I want to operate on. Basically the aerial was electrically too long to resonate in the part of the band I needed.

I looked again at the Outbacker Stealth Plus and wondered if instead of using the 80M socket would the SWR be any better using the 75M socket nearer to 4 MHz? As luck would have it this worked with the tuning stub lowered to minimum and 1:1 SWR without an ATU seems to be around 3.740 MHz and still low enough at my desired 3.760 MHz.

Now I know people will say how can a 90 cm long antenna be efficient on 3.760 MHz? Well it can’t, however when I used this antenna before from home as a base antenna I had fantastic results with it, so I’m going to give it a go on the vehicle and see what happens!