[NLRS] [Mw] Fwd: [Moon-net] EME Path-Link Analysis for Owen Valley 40m Dish (fwd)

[Barry VE4MA]

Practically speaking for a 3 ft dish it WILL take at least 100 W of tx power 
to work the big dish. They should be easy to hear with a 3 ft but you have 
to keep the  ERP going to them high in order to overcome the moon noise that 
they hear. There is also a decoupling factor since they only hear signal 
from part of the moons surface. For a 10 ft dish which is the norm to work 
others with a 10 ft dish, the usual TX power is 15 to 20 W, so if you drop 
10dB of antenna gain by going to a 3 ft dish it is going to take 10 dB more 
TX.  There is a good article by DJ7FJ on the PA0EHG web page for those that 
are interested  see http://home.planet.nl/~alphe078/whatis.htm.

Barry VE4MA

----- Original Message ----- 
From: "Chris Cox, N0UK" <chrisc at chris.org>
To: "NLRS" <NLRS at mailman.qth.net>
Sent: Thursday, February 24, 2005 6:24 AM
Subject: [NLRS] [Mw] Fwd: [Moon-net] EME Path-Link Analysis for Owen Valley 
40m Dish (fwd)


>
>
> FYI
>
> ---------- Forwarded message ----------
> Date: Thu, 24 Feb 2005 02:16:29 -0900
> From: Edward R. Cole <al7eb at acsalaska.net>
> To: microwave at lists.valinet.com
> Subject: [Mw] Fwd: [Moon-net] EME Path-Link Analysis for Owen Valley 40m
>    Dish
>
> I am posting this here on the mw list, since there may be many who have
> non-eme mw stations that will be capable of working the 40m dish at OVRO
> this coming fall.  ARRL MW-EME weekend has not been published, yet.
>
> 73's Ed
>
>>I have analyzed the EME path-link for working the Owen's Valley Radio Obs.
>>40m Dish and placed it on my website.
>>
>>I ran path analysis for:
>>1) my 8-foot dish/50w and the 130-foot dish/10w
>>2) a 3-foot dish/10w and the 130-foot dish/10w
>>
>>It appears that even small dish users will see a chance working the big
>>dish but not with much margin over noise.
>>
>>Anyone with an 8-foot or larger dish will enjoy "large signals"!
>>
>>For Moon noise, I made the assumption that cold-sky was 5K, then 
>>integrated
>>the apparent disc of the moon (190K) as percentage of main beam area.  I
>>hope that is a good approximation.  I did discover that the OVRO dish
>>efficiency = 42% vs. the 50% assumption.  This will lower their gain
>>calculation by 0.8-dB.
>>
>>There is a link to my EME Path-Link spreadsheet which you are welcome to
>>download.  Here is the webpage for the analysis:
>>http://www.qsl.net/al7eb/emeOVROcalc.htm
>>or go to:  http://www.qsl.net/al7eb
>>
>>Please tell me what you think...especially any corrections needed!
>>
>>73's Ed - AL7EB
>>
>>
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