Thanks Steve,
I'll have to look at that article again.
Thanks also for your reporting of your personal experience corroborating
this. Confirms my belief that raising the antenna by 10 ft can make a
noticeable difference to a little pistol on a city lot by improving its
low angle performance by a couple of dB.
73, Jim VE7FO
Steve London wrote:
> The original source for the "2 dB improvement" quote probably comes from
> QST, September 1966, "Station Design for DX" by W3AFM:
>
> "Incidentally, in progressive antenna changes at W3AFM, increments of
> only 2 dB in antenna gain have opened up, in each case, a new layer of
> workable central-Asian DX."
>
> 73,
> Steve, N2IC
>
> Jim Smith wrote:
>> Hi Jose,
>>
>> What an interesting analysis. Thanks for doing this Jose.
>>
>> I was particularly intrigued by your statement that a 2 db improvement
>> in signal strength will provide access to another level of stations. A
>> little further on you state that an additional 2 dB will open an
>> additional level of stations.
>>
>> Where do these these figures come from?
>> Generally accepted by the contesting community?
>> Statistical analysis performed by someone?
>> Your personal experience?
>>
>> Seems to me that this info would be very useful when making station
>> design decisions.
>>
>> 73, Jim Smith VE7FO
>>
>> José Nunes CT1BOH wrote:
>>
>>> Why did the Canadians (PT5M) beat the Americans (PW5C) in WRTC 2006?
>>>
>>>
>>>
>>>
>>>
>>> The answer to this question is actually quite simple: Not enough Americans
>>> worked PW5C on 40 meters. No, it was not a national boycott to the American
>>> team by their fellow compatriots as you will see below…
>>>
>>>
>>>
>>> After reading the answer to the first question I will just ask one more
>>> question:
>>>
>>> Do we need a handicap system for WRTC's?
>>>
>>>
>>>
>>> The 2006 WRTC is over and done, and to start with I think it is not enough
>>> to say the PY's did a FANTASTIC job. I repeat a FANTASTIC job. Although I
>>> was not able to attend, because of my first child birth, everyone who was
>>> there and I talked to had nothing but praise words to the incredible effort
>>> put up to make WRTC 2006 the best WRTC so far.
>>>
>>>
>>>
>>> I worked the event from home and followed with particular interest the hour
>>> by hour live scoreboard and the battle between the first two teams PT5M
>>> (VE3EJ + VE7ZO) and PW5C (N6MJ and N2NL) with PW5C leading the first hours
>>> and then a turn around with PT5M claiming victory.
>>>
>>>
>>>
>>> With all the logs available on WRTC official web site I retrieve these two
>>> and begun analyzing them to try to explain why such a turn around in the
>>> last hours of the event.
>>>
>>>
>>>
>>> Just looking at raw QSO data, plotting the difference of QSO's between PW5C
>>> and PT5M, it is interesting to note that the difference in QSO's between the
>>> two was always up and down between 0 and around 50 QSO's from the start of
>>> the contest at 12:00z the first day until 03:00z the second day (note: the
>>> Americans were leading in score because they had a better multiplier total).
>>> At 03:00z the difference between the two teams was just two (2) QSOs. After
>>> 03:00z until 10:00z the Canadians gained about 215 QSOs. After 10:00z and
>>> until the end of the contest at 11:59 again there was not much difference in
>>> the effort of the two teams to work QSO's. The edge the Canadians gained in
>>> QSO's during 7 hours of the contest (03:00-09:59z) eventually was enough to
>>> overcome their multiplier disadvantage and win the event.
>>>
>>>
>>>
>>> The astute readers will realize one very important fact to explain why the
>>> answer to the first question is so simple: propagation on 40 dies between
>>> PY5 and Europe around 03:00Z as all the logs demonstrate it. 20 meters was
>>> dead and 80 was not productive. All there was to work was USA and the
>>> American continent, as the rest of the world QSOs was negligible. Repeat
>>> there was no Europe to work as all the logs show it. It is also important to
>>> note that after 10Z with sunrise approaching contesters tend to move to the
>>> high bands.
>>>
>>>
>>>
>>> Click the link below to see the graph (at 13:24 for instance a value of -43
>>> means PW5C is 43 QSO's behind PT5M)
>>>
>>>
>>>
>>> http://ct1boh.planetaclix.pt/wrtc/pt5mvspw5c.JPG
>>>
>>>
>>>
>>> Wow! What happened in those 7 hours between 03:00z and 09:59 that dictated
>>> the final outcome of the WRTC 2006 winner?
>>>
>>>
>>>
>>> During those 7 hours both stations were on the low bands (mainly 40 and
>>> occasionally on 80), but their efforts netted very different results, and
>>> the key element is the fact that because of propagation characteristics in
>>> Brazil and the low part of the sunspot cyle, the contest during those 7
>>> hours turned basically into a 40 meter/USA only event.
>>>
>>>
>>>
>>> Let's check PT5M QSO's 03:00 – 09:59z
>>>
>>>
>>>
>>> 20 meters: 2 QSO's
>>>
>>> 40 meters: 477 QSO's
>>>
>>> 80 meters: 56 QSO's
>>>
>>>
>>>
>>> Looking for 40 meters the continent distribution was:
>>>
>>>
>>>
>>> Europe 8 QSO's
>>>
>>> Japan 20 QSO's
>>>
>>> Other 97 (basically North and South America) QSO's
>>>
>>> USA 352
>>>
>>>
>>>
>>> Let's now check PW5C QSO's 03:00 – 09:59z
>>>
>>>
>>>
>>> 20 meters: 0 QSO's
>>>
>>> 40 meters: 272 QSO's
>>>
>>> 80 meters: 50 QSO's
>>>
>>>
>>>
>>> Looking for 40 meters the continent distribution was:
>>>
>>>
>>>
>>> Europe 3 QSO's
>>>
>>> Japan 5 QSO's
>>>
>>> Other 62 (basically North and South America) QSO's
>>>
>>> USA 202 QSO's
>>>
>>>
>>>
>>> During these 7 hours, while on 40, the Canadians ended up working a lot more
>>> QSO's and those QSO's were the difference to their victory against the
>>> Americans.
>>>
>>>
>>>
>>> And what were the state side boys doing these hours? Well they couldn't do
>>> much, they were crying like babies but mom and daddy did not come to feed
>>> them…They were calling CQ, CQ, CQ, CQ,CQ and getting not many answers.
>>>
>>>
>>>
>>> Let's check for every one of these 7 hours, how many minutes each team had
>>> with 0 (zero) QSOs:
>>>
>>>
>>>
>>> Hour PT5M PW5C
>>>
>>> 3z 10 21
>>>
>>> 4z 11 32
>>>
>>> 5z 17 22
>>>
>>> 6z 12 15
>>>
>>> 7z 22 37
>>>
>>> 8z 30 42
>>>
>>> 9z 24 41
>>>
>>>
>>>
>>> Total 126 210
>>>
>>>
>>>
>>> In these 7 hours the state side boy's team had 210 minutes with zero QSOs,
>>> and I bet they were not sleeping or taking a time way to pee….
>>>
>>>
>>>
>>> If we now look to the minutes with QSOs we can check that the Canadians had
>>> 294 minutes with QSOs – 535 QSOs at a rate of 1,82 QSOs per minute and the
>>> Americans had 210 minutes with QSOs – 322 QSOs at a rate of 1.53 QSOs per
>>> minute, i.e. the Canadians were working stations faster and at least two
>>> levels of stations PW5C could not work or copy as we will see why ahead in
>>> the text below.
>>>
>>>
>>>
>>> Now if you remember, in the first 15 hours of the contest both teams worked
>>> almost exactly the same number of QSOs:
>>>
>>> PW5C 1757 QSOs and PT5M 1759 QSOs
>>>
>>>
>>>
>>> So if these two teams had such similar performances why such a difference
>>> now on 40?
>>>
>>>
>>>
>>> The answer is LOCATION/TERRAIN and LOW ANGLES…
>>>
>>>
>>>
>>> With latitude and longitude coordinates of both locations PW5C 27 44 20S, 48
>>> 30 41W, PT5M 26 08 52 S, 49 10 47 W) and Google Earth it is possible to
>>> check the PY5 – USA path from the two sites, and use the terrain data to
>>> analyze the take off angles of the signals using HFTA (N6BV great
>>> program).. For this analysis I used the PY1 to US data available in the ARRL
>>> Antenna Book CD.
>>>
>>>
>>>
>>> Click below to see the terrain characteristics of both teams toward USA and
>>> the figure of merit of the two antennas on 40 taking into account the
>>> terrain and the angle information of the signals between PY5 and the whole
>>> of USA.
>>>
>>>
>>>
>>> Terrain graphs:
>>>
>>> http://ct1boh.planetaclix.pt/wrtc/pt5m_pw5c_terrain.JPG
>>>
>>>
>>>
>>> Image of view of PT5M towards USA:
>>>
>>> http://ct1boh.planetaclix.pt/wrtc/pt5m_usa.jpg
>>>
>>>
>>>
>>> Image of view of PW5C towards USA:
>>>
>>> http://ct1boh.planetaclix.pt/wrtc/pw5c_usa.jpg
>>>
>>>
>>>
>>> Figure of merit of antennas taking into account terrain:
>>>
>>> http://ct1boh.planetaclix.pt/wrtc/pt5mvspw5c_fom.JPG
>>>
>>>
>>>
>>>
>>>
>>> What's so interesting about these graphs?
>>>
>>>
>>>
>>> To start PT5M had a geographical location advantage towards USA over PW5C.
>>>
>>> Now let's check the low angles and the antenna performance (Dbi) according
>>> to the terrain data:
>>>
>>>
>>>
>>> First, PT5M 40 meter antenna/terrain has a FOM (figure of merit) of 6.9 DBi
>>> compared to 4.7 DBi of PW5C. Those 2.2 DBis open a level of stations.
>>>
>>> Second looking at the very low angles, surely used by signals for this part
>>> of the cycle we have:
>>>
>>>
>>>
>>> Angle PT5M PW5C
>>>
>>>
>>>
>>> 1 -3.7 -7.0
>>>
>>> 2 1.2 -2.0
>>>
>>> 3 3.4 -0.6
>>>
>>> 4 4.4 -0.9
>>>
>>> 5 5.4 -1.6
>>>
>>> 6 5.5 3.4
>>>
>>> 7 3.8 3.9
>>>
>>> 8 4.9 4.3
>>>
>>>
>>>
>>> >From 1 to 6 degrees on average PT5M is 4.15 DBi better than PW5C. It's two
>>> levels of stations.
>>>
>>>
>>>
>>> PT5M beats PW5C all the time in the low angles, and these zero to eight
>>> degree angles represent statistically 34% of the incoming signals.
>>>
>>>
>>>
>>> No wonder PW5C is about 40% down on QSO's on those 7 hours against PT5M.
>>>
>>>
>>>
>>> It is clear to me Location/Terrain was the factor for N6MJ/N2NL loosing all
>>> those QSO's during those 7 hours on 40/80 between 03:00 and 09:59z.
>>>
>>>
>>>
>>> Note I'm not saying N6MJ/N2NL should have been the winners, although I have
>>> my own thoughts. We do not know what their performance would be at the
>>> command of PT5M on those 7 hours. Nor we know what VE3EJ/VE7ZO would do at
>>> the command of PW5C from 12:00 to 03:00z and then from 10:00 to 11:59z. But
>>> the fact remains that PW5C lost ground and eventually the contest because of
>>> what happened from 03:00 to 09:59z on 40 meters.
>>>
>>>
>>>
>>> Anyway, what is all this about?
>>>
>>>
>>>
>>> Well it is clear that WRTC is not a plain level field event!
>>>
>>>
>>>
>>> I just looked into two stations but I'm sure a lot more differences exist,
>>> and unless everyone goes to the flatlands of Russia , or to BS7H rocks with
>>> verticals probably no WRTC will be even, unless a handicap system is
>>> developed. We have the technology to adjust each location to it's true radio
>>> potential, using programs like HFTA. Perhaps then, with a handicap system,
>>> WRTC will truly measure team operator performance.
>>>
>>>
>>>
>>> 73
>>>
>>> José Nunes
>>>
>>> Contest CT1BOH - www.qsl.net/ct1boh
>>> _______________________________________________
>>> CQ-Contest mailing list
>>> CQ-Contest@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/cq-contest
>>>
>>>
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