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The 2015/2016 official SOTA Challenge


#62

That was measured with over 12m of RG58, I don’t think I could worsen the Q on 10m with such a simple wire antenna. I have the same broad match with the 15m 1/4 wave vertical essentially flat 1:1 across. After trying it on a fair few hills it doesn’t seem to be as fussy as some others have reported with varying ground conditions either. It seems to work well though.

Maybe its worth loading the 1/4 wave with a loading coil on higher frequencies to improve the Q ?


#63

MMANA’s view of a 1/4GP with sloping radials.

I’d expect a 15m/10m to have a similar profile.


#64

Yes my 20 meter version is pretty close to that in reality. However the 3:1 bandwidth is slightly wider on 15m and up for the same construction. I need to play with some software I think.

I suppose the question is if the wider 3:1 really makes that much difference to radiation resistance on the higher bands.

A small wide diameter coil might just provide enough loading to increase the Q. I guess that is why you see mono band wips with loading sometimes even with small antennas.


#65

Jonathan,

I don’t understand why you would aspire to increase the antenna Q? Q strikes me as a not so interesting ratio for antennas - at least not something you’d set out to maximize. The ratio of loss through radiation to loss through “lossy” losses is more pertinent I would have thought. Aiming for high Q could result in unnecessarily narrow bandwidth.

I suspect that when people load antennas with reactive elements they are mostly doing this to bring the antenna to a state of resonance / match to the feed with whatever current distribution (and phase) they’re after (e.g. to achieve a desired radiation distribution). Sure that will affect the internal energy, and consequently the Q, but likely as not also non-radiative losses too. So I don’t think you’d do it for the sole reason of increasing Q as such. More of a consequence you might have to live with! But certainly a very low Q might well indicate some horrible losses.

Building something that’s say lambda/2 or thereabouts tall at 6m to go on a decent fishing pole does seem a bit of a waste of the available height. More so even on your big 10m pole. So loaded 5/8 or co-linears look interesting for their lower radiation angles.

Still not tried my 6-m Slim JIM, and not going to get up a hill for a couple of weeks yet :grimacing:

Simon


#66

Yes that is the reason for loading, I say by increasing Q as more of a indication of improved narrower bandwidth efficiency and a better radiation pattern possibly as a result ?

But getting from the power bandwidth relationship to radiation efficiency for a particular antenna is not so easy mathematically without modeling and with all the other variables associated with it.

When I built my Cobwebb I noticed that it was very sharp, I agree its not desirable. But it may as Andy originally suggested a wide BW is likely to produce poor efficiency. A good match never can give a true indication to good radiation efficiency. To me its a mere indication that the energy isn’t coming back down the feed system.

If my BW is getting higher on higher frequencies It would suggest that my Q is worsening and my antenna is suffering from a lack of capacitance assuming a relatively fixed R and thus needs the loading OR lengthening, the latter being preferred because it improves radiation eff \ angle and I get a match on 5/8L

A 5/8L on 15m and up would be the best solution I think your right Simon, After the 20m band and with a 10m pole it doesn’t seem logical to stick to 1/4L, its either that or mess around with loading or cap hats. My original motive was to lift the plain off the ground and increase efficiency that way, but in reality I think the bigger dimensions win over having the CP closer to the ground.

Anyway that is all the rubbish going around in my head, I guess that is why they call it “amateur radio”

I too won’t be going out that much on the hills, improving kit writing some software for STAR and various other tasks has put me into hermit mode for the next month. Although the new challenge should make things interesting.

Jonathan.


#67

As a simple electrical engineer I could follow that description. However, other analysis of the 5/8th wave vertical suggest that it it is, for a variety of reasons, not the best radiator system for VHF or UHF vertically polarized FM signals.


#68

Andy,

This may have already been addressed and is buried in this reflector, so sorry if that is the case…

Will there be “6M only” winners/scoring in the challenge? There is a 10 meter only button on the results page, but not one for 6M only.

Will there be awards for 6m only, 10m only, and then one for both?

It seems to me that if we don’t have both bands scored as an “only” that everyone might just stay on 10 meters and neglect Six…people will go where the action is, which translates into 10 meters most of the time. I can see myself on a summit working quite a few stations on 10M and virtually nothing on Six Meters as it is not open. Even with ES skip 10 is open a lot more, and better, than 6M will be in the summer.

Any thoughts on this?

thanks

Pete
WA7JTM


#69

The advantage of getting onto both bands will be that you will work a greater variety of people. There will be amateurs on 10m but not 6m and vice versa. Remember that in this challenge it is the number of unique callsigns worked, not the total number of QSOs. You’ll find more different people if you can find openings on both bands.


#70

Agreed…but it just seems to me that everyone will migrate to 10 meters if 6 meters is dead, which it will be most of the time by the way. Once everyone works all of the 6m local stations during the first few weeks I can see this turning into a 10 meter challenge only, which is OK, but Six Meters may be left behind. We will have failed in our efforts to stimulate 6M activity.

Since we have a Ten Meter only class, I just thought it would be nice to have a Six Meter only class as well.

I believe a 6M class will encourage people to stay on Six longer, and not go to ten Meters after making just one six meter QSO to get the multiplier. People serious about scoring points in a 6/10 meter class will go where the action is, and than means 10 meters if there is no stand alone 6M class. face it, 6M can’t compete with 10M when it comes to activity levels, even in June.

At least that is my theory from the view point of a six Meter addict who will be on 6 for this event as much as I can.

tnx

Pete
WA7JTM


#71

There isn’t a multiplier for each of 10 and 6 per unique summit. Just one, once a contact is made or 10 OR 6 from a particular summit.

The idea of the 10m only class is to cater for those places where 6m is not available for /P. My prediction is that the leading stations in this challenge will be regularly active on both bands, but time will tell.


#72

OK. I did not realize that. This changes my plans completely.

Thanks for the clarification.

Pete
WA7JTM


#73

A few more questions before I throw in the towel on the 10 meter challenge. Can you explain to me what this line in the 10 meter challenge rules means?

“For every unique summit you chase on 10m OR 6m you get a multiplier.”

Does this mean that during the 10 meter challenge if I chase the same summit on two different days one month apart I get only one multiplier? That is, I only get multipliers for unique summits as repeat summits worked, even if they are a different band and station, produce no new multipliers?

So when I work the summit on 10 and then 6 meters I get just one multiplier?

What are your thought on the following scenario:

I activate a particular summit, and work all 20 of the active six meter stations in Phoenix. Everyone would have that summit it their log. One of those 20 active stations activates the same summit a month later. No one would need to work him for a multiplier, as they already have that multiplier in their log because they have worked me???

thanks for the clarification

Pete
WA7JTM


#74

So when I work the summit on 10 and then 6 meters I get just one multiplier?

Yes, that’s right.

What are your thought on the following scenario:

I activate a particular summit, and work all 20 of the active six meter stations in Phoenix. Everyone would have that summit it their log. One of those 20 active stations activates the same summit a month later. No one would need to work him for a multiplier, as they already have that multiplier in their log because they have worked me???

No, but they would need to work him to get another unique callsign point. Plus the chaser points for the summit. Plus the SOTA Complete for anyone that had already activated it (or had plans to do so).

Plenty of carrot there!


#75

Still confused…so a chaser can work the same summit on two different days and get two multipliers?


#76

For the Challenge, out of all your 6m and 10m SOTA chasing contacts:
Each unique summit is one multiplier.
Each unique callsign is one point.
Total Challenge score is points times multipliers.

A SOTA contact on 6m or 10m may score you nothing for the Challenge but give the person at the other end something for the Challenge (and vice versa).

However, a contact can count both for the Challenge (if it’s on 6m or 10m) and (independently, by the usual rules) for normal SOTA scoring.


#77

OK. Thanks

Pete
WA7JTM


#78

I did my opening SOTA activation for the 2015/16 Challenge on Saturday 16th May 2015. Before reporting on that, I’ll briefly record some details of other SOTA activations since returning from EA8:

Tuesday 14th April 2015 - The Cloud G/SP-015

432MHz contest night. 51 contacts - 50 SSB + one CW, all on 70cm. Not a great night on The Cloud. 11 (22) mults - 72, 74, 81, 82, 83, 84, 91, 92, 93, 94, 02.

More mults heard but not worked - 86, 90, 00 plus IN99. Known to be about but not heard - 01, 03. Usual squares not heard of at all - 64, 75, 80, 85.

Wishing I’d gone up to Merryton Low now with Nick (M1DDD) being out of action and Erik (G8XVJ) staying at home.

Wednesday 15th April 2015 - The Cloud G/SP-015

This was a trial activation ahead of the 6/10m Challenge, to see if I could use my end-fed plus tuner to operate on the target bands. Well I could, although I only achieved one CW contact on 6m and none at all on 10m! A couple were then added on 20m CW and 13 on 40m CW, including two S2S.

Tuesday 28th April 2015 - The Cloud G/SP-015

Uninspiring contest for me. Just 60 QSOs, and a dismal 9 multipliers: 64, 82, 83, 90, 91, 92, 93, 02, 03.

I heard, but didn’t work: 65, 73, 74, 81, 00, 01.

I really think that M7 has spoiled the UKACs. Activity seems much harder to come by, and half the stations are just beaming to the continent like the bad old days. I haven’t checked the data, but my instinct is that participation is falling too, after year-on-year rises for a number of years under M5.

I’m also rather unimpressed with just how blinking cold it was. 3 degrees C, and we were within a week of May Day!

Fellow Tall Trees Contest Group members worked: M1DDD, M0HGY, G8WUY, G3RKF, G3KAF, G3TDH, M0VAA, G3UJE, GW4ZAR.

Monday 4th May 2015 - The Cloud G/SP-015

A friend’s QTH was not available as an option last night, as he was out for a Bank Holiday meal. So no 10 watts, no 80m doublet and no warmth and comfort!

Instead, it was back to the old routine of participating SOTA style from Cloud summit. 52 was probably the best I have done in that circumstance. I do need to at least try to run for some small block of time near the end, but I’m not sure the receive or filtering on the 817 is ever going to be up to it. At least the 52 is in the QRP section.

Tuesday 5th May 2015 - The Cloud G/SP-015

84 QSOs into 29 (14 + 1) for me. Not bad QSOs but mults let me down. Only the one from 75 from GM. Never heard 94, 80, 90 or 00 that I would have wanted.

Much easier on the rx without Erik XVJ on Merryton Low, or Jake from Crewe on Mow Cop!

Tuesday 12th May 2015 - The Cloud G/SP-015

Back round to 70cm contest night, but still we did not appear to be clear of winter. It was cold and windy, even if the longer daylight was welcome.

Anyway, I was still finding the UKAC hard work. Conditions were evidently bobbins, but the south and eastern participants beaming at the continent for the first two hours, and the continuing boycott by the Scottish stations made for another rubbish night. M7 rule - progress? I think not.

Just 50 QSOs, 49 on 70cm SSB and one on 70cm CW.

Wednesday 13th May 2015 - The Cloud G/SP-015

It was back to this slightly familar summit once again, this time for the RSGB Club Contest 80m Data session. Unfortunately, I couldn’t get my new HTC One phone to receive signals through the cable into the phone’s headphone jack. Fortunately, I had taken my old Galaxy S3 phone up as back-up just in case.

Fifteen QSOs were made on 80m PSK63 in the contest, followed by six on 80m SSB afterwards.

I am at a bit of a loss to understand why the new phone isn’t working. DroidPSK springs to life when I disconnect the cable, with the audio from the FT-817’s speaker being heard via the phone’s microphone. Triggering TX from the phone works OK, just not RX. The supplied earbuds / mike with the phone all seem to work OK, so I can’t work this out!


#79

Saturday 16th May 2015 - Gun G/SP-013 - SOTA 10m/6m Challenge

So I thought I’d have a bit of a change and went up to Gun! The notoriously waterlogged path was bone dry, so it was OK to stay in trainers for the short walk.

I set up the SOTAbeams SB6 antenna for 6m, and heard Italian and Spanish stations on the band. On CW, I worked a couple, followed by a couple more on SSB. I did’t have any more luck than that though on the alleged “Magic Band”.

I swapped over to the 10m groundplane antenna, and heard lots of activity on the band. I didn’t have much joy in getting back to most of the CQ callers though! One I did get, who was working by numbers and operating split, was T77C, San Marino. Another station of interest was AO150T - one of a number of stations celebrating the 150th anniversary of the ITU. I also heard another Spanish ‘150’ station - and a Uruguayan ‘150’ station - but didn’t get in the log of either. Argentina (LU) was heard calling, but I was similarly unsuccessful.

At noon, I decided to bring a long and slow activation to a halt, with just 15 QSOs in the log:

6m CW: 2
6m SSB: 2
10m SSB: 7
10m CW: 4


#80

2015-05-16 6m from Moel Ysgyfargod
A break in my just-repaired linked dipole spoilt my plans for GW/NW-038 so I put up my 6-m Slim JIM. It takes the whole 8-m pole. I heard Tom on Gun, but very very weak. First 6-m QSO was actually on the VX-7’s rubber duck - Jonathan GW2HFR on Mynydd Mawr. After a bit of jiggling about of the antenna system signals started coming in on the Slim JIM. I added a few UK stations to the log. Some very strong continental stations were coming through, but I couldn’t make myself heard.

On taking down the Slim JIM I found a little whisker of braid was shorting to the coax’ centre at the feed!

2015-05-16 10m on Manod Mawr
This time I set up my 10-m GP. Calling was fruitless. RBN wasn’t hearing me on CW. The big problem was a lack of power due to a break at a Powerpole. When a hiker appeared at the summit and attracted my attention to the direction of my antenna I saw why it wasn’t working - it was lying on the ground! lifted back up it worked much better, and several 10-m QSOs were logged, including one of the 150 IARU stations.

With a pair of summit multipliers I was amazed to find myself topping the G challenege (activator) table. Of course it won’t last!

Today the 10-m GP will be tried out on my 4-m Clansman mast, prior to trying to beat Tom on 2m!

Blog entry with pictures later…

Simon


#81

Well I’m sure you will have beaten me Simon. I quit in despair after less than an hour of the Backpackers’ Contest, suffering very high SWR and completely unable to solve the problem. I managed just ten 2m SSB contacts and one 2m CW QSO in the contest, chancing it with the high SWR with relatively local stations.

Earlier, I had arrived on Shining Tor summit around 8am local on Sunday 17th May 2015, and got cracking on 10m. It was unreasonably cold for the second half of May, and I sheltered from the harsh wind by squeezing into the small gap between the wall corner and the wooden bench - “Michael’s Seat”.

The going was very slow again on 28MHz. I tried S+P and running on both CW and SSB, limping to 25 and 7 QSOs respectively. Was there any redeeming feature of the activation at all? Well I worked Azerbaijan, Kazakhstan and Israel amongst others, and the broccoli and stilton soup was nice.