[Propagation] Critical vs. Maximum Usable Frequency map

["NW7US, Tomas" <nw7us@hfradio.org>]

On Sun, 26 Sep 2004 06:09:16 -0000, David Ackrill  
<dave.g0dja@tiscali.co.uk> wrote:

> If you want the local F2 Critical frequency (the one where signals go  
> almost straight up and down, try looking at this map.
> http://www.spacew.com/www/fof2.html

Excellent map for this.

Also of interest are the "live" (using real measurements) HAP maps from  
IPS:

North America HAP maps:
http://www.ips.gov.au/Main.php?CatID=6&SecID=4&SecName=North%20America&SubSecID=1&SubSecName=HAP%20Charts

North America Ionospheric map:
http://www.ips.gov.au/Main.php?CatID=6&SecID=4&SecName=North%20America&SubSecID=3&SubSecName=Ionospheric%20Map

The best jump off point for IPS HF-related data is:
http://www.ips.gov.au/Main.php?CatID=6

These HAP maps are "Hourly Area Predictions" of communication frequencies  
based on current observed conditions in the North America ionosphere.   
Because of the variability of the ionosphere this type of prediction can  
only be made for the current hour.

For paths that are more typical of "DX" (3000 km paths), there is also  
this map:

http://www.spacew.com/www/realtime.html

73 de Tomas, NW7US (AARØJA/AAAØWA)

: Propagation Editor for CQ, CQ VHF, and Popular Communications :
: Quarterly Propagation Columnist for Monitoring Times Magazine :
: Creator of live propagation center - http://prop.hfradio.org/ :
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: 122.93W 47.67N / Brinnon, Washington USA - CN87 - CW/SSB/DIGI :
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