[CQ-Contest] Is HF HF propagation reciprocal?

Tomas Hood (NW7US) nw7us at hfradio.org
Mon Jun 4 22:46:24 EDT 2007

Hello, fellow HF'er:

I'm letting this list know about some additions to my website (
http://hfradio.org/ ).  These new pages contain information that many
operators will find useful (based on the feedback I have gotten from
this material when the original was published in CQ Magazine and
Popular Communications Magazine).

One would think that ionospheric radio propagation would be
reciprocal. That is, the signal strength in one direction should be
the same as in the reverse, or reciprocal, direction. In HF ray-trace
theory, the distance is the same and the ionospheric control
points-the points where the wave is reflected (or more properly,
refracted) back to the ground-should be the same.  This is an
interesting topic for those competing to be heard at the far end.

I explored this (is HF propagation reciprocal?) in a recent CQ
Magazine "Propagation" column.  I've posted the meat of the text at:


I've also posted another recent CQ Magazine "Propagation" column,
where I explored basic HF propagation concepts (De-mystifying HF
signal propagation).  You can find it here:


I'm working on posting additional texts where I take various HF
propagation topics, and use modern software to model the concepts.  I
hope that this is helpful to those of you wishing to dig deeper into
the art of getting your signal from here to there...

73 es gud DX

Tomas Hood / NW7US / Heliophile

Check it out: http://nw7us.healthy-at-home.com/

: Propagation Editor for CQ, CQ VHF, Popular Communications :
: Associate Member of Propagation Studies Committee of RSGB :
: 122.93W 47.67N Brinnon, WA USA CN87 - QRP and CW/SSB/DIGI :
: 10x56526 : FISTS 7055, FISTS NW 57 : Lighthouse Scty #144 :
: NAm QRP CW Club 1774 : QRP Amateur Radio Club Int'l 12781 :
: Contributing editor on Wikipedia - Amateur Radio/Space WX :
: The journey of life http://ic-discipleship-ministries.org :

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