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Contacts by Distance

This graph plots the number of contacts/100km bin. All bands peak at 500-800km with another peak for the preferred mode on each of 50 (PH) and 144 (CW) at 1500-1800km. (As will be shown, the extra peak on 6m is from PH Es contacts with N1JEZ. The extra contacts on 2m are all E-W paths. It is not clear why this group of 2m contacts forms an extra bump, rather than a smooth shoulder.) The shapes of the curves are similar for all bands, indicating possibly that the difficulty with AU propagation at the higher frequencies is not one of distance.


Does the distance for contacts change with time? There's only enough data to analyse the AU opening on 50MHz and 144MHz. The most noticable time-distance effect was seen on 50/PH and 144/CW (these being the mode used for most contacts on these two bands).

Time-Distance 50MHz/PH, 452 contacts


Contacts for 50MHz/Ph fall into 2 groups

Here is an animated map of the 6m PH contacts colored by QSO path length (all lines are great circles, which look straight at this scale). Path length is indicated by color.

click on map for linked animation (3,795,379 bytes) or download compressed 50MHz PH time-distance animation (2,679,437 bytes). qso.50.PH.time-distance.200007.anim.gif

The long distance contacts (green, 100-2175km and blue, >2175km) in the 2nd opening are all from N1JEZ who said in his logs that all his contacts were Es (non-aurora). Although it is possible that other non-aurora (Es) contacts are in the logs, eleminating N1JEZ's contacts (all known to be Es) from the 6m PH logs should give a better picture of the AU opening. Here's the time-distance map without the contacts of N1JEZ.


There is now very few long contacts on 6m phone, but the opening at 2800-3000 (i.e.0400-0600 16 Jul) is clearer.

Here's the animated map for 6m (all modes), without the Es contacts from N1JEZ.

click on map for linked animation ([an error occurred while processing this directive] bytes) or download compressed 50MHz PH (no Es) animation (1,994,553 bytes). qso.noN1JEZ.50.200007.anim.gif

Time-Distance 144MHz/CW, 1663 contacts


Contacts for 144MHz/PH fall into 3 groups

It is possible that the island of long distance contacts is an artifact of the non-verifiable gridlocators of 28% of the operators. To test this, here is the data again using only QSO's with verifiable gridlocators.


The second island of contacts in the distance range 1100-2175km persists, indicating that it isn't an artifact caused by including QSOs with unverifyable (and possibly incorrect) gridlocators.

Why are there 2 groups of contacts (and why only on CW)? Here's the animated map for these contacts. See if you can see any difference between the shorter red (0-500km)/yellow(500-110km) contacts on one hand and the longer green(100-2175km)/blue(>2175km) contacts on the other.

click on map for linked animation (4,200,467 bytes) or download compressed 144MHz CW time-distance animation (3,024,344 bytes). qso.144.CW.time-distance.200007.anim.gif

Although it wasn't obvious to me, many of the audience at the NEWS talk shouted out that the longer contacts were east-west (E-W) rather than north-south (N-S).

Here is the bearing-distance data is for 144MHZ, both modes (1739 contacts). This was plotted from the bearing and distance at both ends of the QSO, calculated for the great circle path (since we don't have the headings at each end). Each QSO is represented twice, one for each end of the QSO. The height on the Z axis is halved to compensate.


Contacts are either on a N-S line for short distances, or to the N.E. or S.W. (following the population distribution on the east coast of USA) for longer distances. The E-W tendency is the classic pattern for AU, but the NE-SW population distribution on the east coast appears to dominate. The E-W effect can be seen in the 50 and 222MHz data but is not as pronounced.

Here's the animation for 2m (all modes) for the short (<1100km) contacts with contacts marked by direction; N-S and E-W. This data shows that short contacts have no directional preferance.

click on map for linked animation (4,021,156 bytes) or download compressed 144MHz CW time-distance animation (2,859,643 bytes). qso.144.lt1100.png

Here's the animated data for the long (>= 1100km) 2m contacts It's clear that the long contacts are (nearly) all E-W. This data can't tell whether the E-W effect is due to the E-W distribution of population, or due to better propagation by the aurora in the E-W direction.

click on map for linked animation (3,733,914 bytes) or download compressed 144MHz CW time-distance animation (2,637,132 bytes). qso.144.ge1100.png

Time-Distance 222MHz, all modes, 117 contacts

There's not a lot of contacts on 222MHz. However the data appears to be one group, unlike the data with 50 and 144Mhz.


Here's the location of hams at the other end of the QSO relative to you for 222MHz.


There is a slight E-W effect on 222MHz.

(C) Joseph Mack 2000-2002, Joe NA3T, jmack (at) wm7d (dot) net,

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