[Elecraft] One-Way Propagation?

[Tom Althoff]

Consistantly over the past 40 years I reaffirm on a daily basis that, at 
least on 40M,  as the sun lowers in the west I can hear European stations 
about 45 minutes to an hour before they can hear me.

I have no explanation for it but suspect that the signal level is the same 
on both ends but the background noise from the daylight side masks the 
signal as it appears in Europe.

Tom K2TA

----- Original Message ----- 
From: "Kevin Rock" <kevinrock at earthlink.net>
To: <elecraft at mailman.qth.net>
Sent: Thursday, November 30, 2006 10:17 PM
Subject: Re: [Elecraft] One-Way Propagation?


> Howdy Jeff,
>    If you get on 20 meters in the morning, while you are in the early 
> morning hours and the operator with whom you are working is in an area 
> later in the day, you will find some odd occurrences.  Some days you hear 
> better than the other op and some days it is the reverse.  The ionosphere 
> is not a perfectly spherical reflector.  From empirical evidence I have 
> found it to be quite oddly shaped indeed.  Think of the layer you're 
> bouncing your signals off as a boiling layer where the surface changes 
> direction rapidly.  This describes rapid QSB.  Other times you'll hear 
> very slow, but deep, QSB.  At that point the reflecting layer is starting 
> to calm down a bit but there are still bumps in it.  Under perfect 
> conditions the received and transmitted signal meet a perfectly smooth 
> reflective sheet which allows the two of you to communicate quite equally.
>    As far as being truly one way?  Occasionally I hear ops extremely well 
> but they cannot hear me.  I hope it is not that they are ignoring me but 
> simply cannot hear me.  This is what I call one-way propagation.
>
> Please accept this as a non-scientific, entirely empirical experiment of 
> my own accord on propagation characteristics.
>    Kevin.  KD5ONS
>
>
>
> On Thu, 30 Nov 2006 17:05:12 -0800, Jeff <wb5gwb at optonline.net> wrote:
>
>> Kevin, KD5ONS, wrote:
>> "One way propagation is not unheard of..."
>>
>> Is there really such a thing as one-way ionospheric propagation?  My 
>> intuition says no, but I don't have the physics knowledge to back it  up. 
>> On the other hand, sometimes it sure seems that stations who ought  to be 
>> able to hear my QRP signal cannot.
>>
>> 73 & 72,
>> Jeff
>> WB5GWB
>> Long Island, NY
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