Prominence definition help?


I’m wondering if there is a maximum limit to the area which is enclosed in the contour line which is 150m lower than and which encircles a summit?

For example the summit at:

45° 25’ 48" N 77° 18’ 18" W

is more than 520m ASL.

But the countour line at 370m which encloses this summit encompasses more than 100 square kilometers.

There is no higher summit within the area.

Does this summit qualify?

Is there a limit to the amount of area which the contour line which is 150m lower than the summit can enclose before the summit no longer qualifies?


In reply to VA3SIE:
Hi Martin. I’m happy to see you back in the game.
If a summit is the only 150m prominence in a large, relatively flat area, I know of nothing in the rules that would keep it from qualifying.
If the activation zone contains a nice hotel and restaurant, it may be a contender for the longest continuous activation.
Get back on the air soon! I need the chaser points!

In reply to VA3SIE:

You have to find the next highest peak and then work out how far you have to descend before climbing again. It’s a total pain working these out… as the col can be hundreds of miles away.
For example the col of Mount McKinley in Alaska is in Nicaragua !!

Here’s a good explanation…

In reply to VA3SIE:
As far as I know, there is no limit in the rules to the size of the activation zone or the size of the area around the summit, so as long as the peak qualifies even if it is a relatively flat peak with a wide flat area around it then it is good…but would love to get a confirmation on that from someone in the MT.



The “summit” described by VA3SIE would qualify under P150, therefore could be included as a summit in the association.


Also, remember to avoid confusion between the activation zone, and the area “dominated” by the summit. In the Canadian example quoted, the latter is the 100km2 area in which the 150m prominence is defined, but the activation zone will be much smaller. The activation zone is the area bound by the contour 25m below the summit - 495m ASL in this case.

AZs can still be large of course. Detling Hill G/SE-013’s AZ is pretty large here in G (several sq kms), while I understand that the new UT association includes a P150 summit with a vast AZ that covers a huge area.

The point about hotels makes me ponder the issue of operating indoors. Richard G3CWI has activated from inside a pill box on the Isle of Man, while Jimmy and I did a memorable activation from a turret on the Mourne Wall in Northern Ireland.

But there is a house on the summit of Detling Hill G/SE-013, a pub on Crowborough G/SE-007 and doubtless many other examples. Would operating indoors be acceptable providing that a portable power source was used?!?!? Discuss :wink:


In reply to M1EYP:

operating indoors be acceptable providing that a portable power source
was used?!?!? Discuss :wink:

If not, I will have to hand back my MG Trophy as my qualifying activation was done indoors.



In reply to M1EYP:
A pub on Crowborough and only 26 total activations? I can conclude that either the beer is very expensive or the service very rude.

In reply to KI6J:
Hi HI!!!

In reply to KI6J:

Hi Martin. I’m happy to see you back in the game.

Thanks, Stu.

I’ve been in Iran for a month and before that working hard and no time to play much.

But now I’m working with Bill VE3CLQ to launch a VE3 association.

Thanks everyone for their input.

  • Martin.

In reply to VA3SIE:
Woohoo! It won’t be long before all of North America is covered!


In reply to N2YTF:
"Woohoo! It won’t be long before all of North America is covered!"
With strangely outfitted men who attach themselves to wires and behave oddly. Yes indeed!

In reply to KI6J:

Gee! The next NA SOTA day will be fun as hell!

Martin, I am sending you a mail.


To resurrect this topic after 7 years!!!
Those of you with a real interest in prominence may like to read a recently published paper on the topic. If so be prepared for quite a detailed read and some interesting mathematics.

1 Like

Thank you for the link. Interesting paper!
This gives me an idea of what reasearch in the field of geography is like. The results are actually usefull.

Heinz, OE5EEP