Given the biblical weather we had here yesterday in the Lake District - heavy rain and flooding - the last thing on my mind was the possibility of a SOTA activation. However, having had a lazy start to Sunday I checked the weather report and was surprised of the modified prediction of light winds and no rain. Sunshine even later! So I hurriedly topped up a LiFePo4 battery and threw my usual SOTA kit into a rucksack. Arriving possibly quite unusually by motorbike at the Kirkstone Inn car park I took the 45 minute stone staircase to the summit. I was expecting it to be wet under foot but most of the stone was dry and easy.
I setup at the tarn near the trig and got going quickly on 40m having found that I still have issues with the 80m section of my linked dipole. Cracking run of 20 chasers on 40m mostly in Europe but some UK stations. Two S2S’s initially with OE5REO/P on OE/OO-345 and HB9CRY/P on HB/LU-010.
Moving to 20m band conditions were still good even though there was a Scandinavian competition on. Moving to 2m brought in some local chasers and two contacts on C4FM. Back to 20m another two S2S were completed with OE9HRV/P on OE/VB-465 and HB9DIZ/P on HB/LU-025.
It was time to brave a CW contact - I’m still very much a noob - in then end I thought I would be able to copy DL0FUL/P - a club callsign - on 40m. It was going well until the MCHF rig totally hung and required a reboot which lost the frequency, but at least this was after callsigns and signal reports were exchanged. Not brave or competent enough yet to try a CW activation. I chased one SOTA activator last week - but at least chasing you get a chance to copy the activators callsign a few times to ensure correct.
I then noticed the spot by Herbert @OE9HRV on O/VB-465 saying ‘state side is open’ (what a great thing to put in a spot Herbert!) so I moved back to 20m for another run including Phillip @VE1WT which was great!
With the SOTABeam 10m compact mast strong enough to support both the HF antenna and the Slim-G 2m/70cm antenna I was fortunate enough to catch Viki @M6BWA calling CQ on 2m from G/SB-007. Earlier I had noticed her alert and used the Solwise Wireless Elevation Tool to find that it was pretty much line-of-sight from Red Screes (skirting over the top of a North Pennine summit). So we managed both a 2m and 70cm QSO without any difficulty.
I then talked to a couple of others calling CQ on 2m including MM6JIG in Wigtown, Scotland, for whom I was his first contact ever as an M6!
To top all this the sun came out and I happily donned my sunglasses and took the opportunity to take some great photos. Roll on the winter bonus!
Hi Mark,
Lovely photos. Good WX and good use of the available band conditions. It’s about time 7 MHz did some work. You bit the bullet and did CW too.
Thanks for Solwise. Never heard of it until now but what a gift! I have been looking for a replacement for the site we all used years ago for that purpose.
73, John
Having heard from the Microwavers just a couple of days ago that interest in such elevation tools was minimal at best, I was tempted to delete the new elevation profile tool (still in development) in the new, not-yet published, SMP as a waste of my time. And now I read here that such tools are actually being used.
So, I fired up the tool and made an elevation profile between G/LD-017 and G/SB-007 to see how that would look in comparison to the one from Solwise. Here’s how it looked:
And here’s the same profile, but now adding in the earth’s curvature between the two summits (remember the earth gets in the way somewhat over distance ):
Now, I’ll be the first to admit that I don’t know anything worth knowing about propagation in the VHF++ bands, so I’ll leave interpretation of these charts to others better qualified. But you may agree with me that the results are intriguing.
Hi Rob. Well I can confirm that I use elevation tools all the time
Even more interesting is the final image with Earth curvature taken into account! Clearly there is a huge difference between the ‘flat Earth’ model and an accurate one. As soon as I saw the image taking into account Earth curvature I immediately question any of the elevation profiles I have previously created!
Looks like a great tool to me.
Regards, Mark. M0NOM
I also “discovered” the mapping feature to show all peaks within a donut that seemed useful for pursuing uWave awards in being able to set the interior of a donut to say 50km on a known chaser.
According to the Solwise tool this is line of sight but I’ve never been able to chase someone on Snowdon on 2m from that location (it is 5 mins from my QTH and the highest spot I can get to quickly). I suspect your tool will show something very different.
The first zone must be kept largely free from obstructions to avoid interfering with the radio reception. However, some obstruction of the Fresnel zones can often be tolerated. As a rule of thumb, the maximum obstruction allowable is 40%, but the recommended obstruction is 20% or less. (Wikipedia)
So, you’re in for a bit of a struggle there… EDIT - BUT, see below…
That path should be fairly easy to work via normal troposcatter on 2m SSB with smallish Yagis at both ends. But simple verticals and FM may make it really difficult. You would need to get the antennas clear of the ground, say 3-4m. Positioning the Snowdown end on the edge of any sharp drops would help. Mark’s QTH looks rubbish with lots of vegetation and no obvious ground gain to be had. Getting the antenna well clear should produce a big improvement.
Should be (for various definitions of should be) possible with a bit of antenna choice and planning. Very dodgy for someone running up to the local high spot with a handy though.
(Hopefully not teaching you to suck eggs here Rob)
Troposcatter is available nearly all the time at VHF and is the normally mode used for paths beyond LOS. Typically there will be a volume of troposphere a few km above ground that both stations can see and dirt/moisture/stuff in that volume of atmosphere will scatter some RF. You need a directional antenna, some watts and a decent sensitivity which can discount FM and rubber ducks in many cases and makes SSB a better choice.
Tropoducting is when you get layers of air at a different temperature trapped between other layers. This is when you get significant long range propagation at VHF and up. Typically as a result of prolonged periods of high pressure starting to decline. To benefit, antennas needs to see the duct opening at both ends and can result in 1000’s of km of propagation. Moving height only a small amount or position a few kms can result in the duct not being visible. ISTR reading the duct depth needs to be 10-20 wavelengths high to work. So quite deep for 2m and that requires more extreme conditions that for higher bands where small ducts form more easily and ducting on 6m is much less common. Ducts form all the time over long water paths and cause havoc to commercial links, they normally need to have multiple antennas and different heights (maybe one antenna 50m higher than the other) and use automatic antenna diversity to maintain comms as the ducts form and break up.
Well, your image is amazing Rob and quite succinctly explains why I never had a hope of getting a contact! So now we have hills at both ends and a bit of ocean to get through. I do have a delta quad antenna that works well which does a good job of sucking a signal in but I’m guessing that the average activator of Snowdon is going to be either on a handheld of a vertical roll-up of some description.
I’m quite staggered that the curvature is that much mind. Well, I’m really looking forward to the tool being available, it’ll be great to have a play and work away from my QTH to find somewhere suitable.
Well, let’s not forget that the vertical scale on those diagrams is much exaggerated. The actuall bulge/curvature is just under 530 meters over the distance of 160-odd kilometers. Here’s another view of that:
So, you’re going to have to factor in this tropo stuff as Andy suggests, and with a couple of decent antennas at both ends, and a bit of extra height (try some Gary Glitter platforms - I’m sure Tom @M1EYP could loan you a pair), you should manage the link OK.
Oh I love the baiting there As it happens, to go full circle, I heard Tom when coming down from Red Screes - a small world eh? He even returned my callsign, but was mobile on the M6/M55 and couldn’t hear me again.
Your images remind me of the Father Ted Cow sketch… where I am doing a great Dougal impression!
I think the solution is obvious - pick one big hill round here and get a S2S instead. I’ll bet there are no issues once I’m up Coniston Old Man. Maybe I can borrow his shoes as well…