[TowerTalk] Takeoff angle
rxdesign at ssvecnet.com
Sun Jul 23 19:33:09 EDT 2017
If you are using the HFTA from the ARRL AB then you have all that info there
already! It’s the Elevation File. They have one for every state for EU, AFR,
AS etc etc ...
for the most part the lower the better... there are times, rare, when higher
is actually better. For example I can select top/bottom/BIP/BOP with 2
stacked 20 meter yagis using a RemoteQTH match ... the TOP is never the best
(for all practical purposes) so the choices are BIP, BOT, BOP in that order
... and indeed there are times, like in the afternoon going from here to
Africa where the BOP position can be as much as 10 db stronger than the BIP.
The differences are 8° and 19° for my terrain and location.
Be sure to put YOUR local terrain profile in. Either manually (not as bad as
some make it out to be) or using Stu, K6TU's site... unless its flat there
might well be some differences ... I literally used HFTA as one of the top
criteria (for me it was THE top) in selecting where we moved to when moving
back to SC! On some paths there can be 10's of db enhancement (or
From: Dave Clemons
Sent: Sunday, July 23, 2017 2:35 PM
To: 'Jeff Draughn'
Cc: towertalk at contesting.com ; Dave at egh.com
Subject: Re: [TowerTalk] Takeoff angle
A number of years ago Dean Straw gave some presentations on takeoff angles.
His presentation included a big binder of information (I think called "All
the Right Angles"). I don't remember who published it, perhaps K8CC or
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Jeff
Sent: Sunday, July 23, 2017 12:39 PM
To: towertalk at contesting.com
Subject: [TowerTalk] Takeoff angle
I've been playing around with HFTA trying to figure out the best height/
configuration for my antennas and it dawned on me I wasn't sure what the
best take off angles are. I know low is better than high for DX, I'm
assuming it's a range that I'm looking for.
When looking at the plots what would be considered good take off angles for
DX contests from the midwest.
What is considered too high of an angle for DX?
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