[NLRS] Question on Arecibo dish

[Barry VE4MA]

I have had email troubles so missed this discussion....the 300ft dish is in 
WVA.    As Eddie says Arecibo is 100ft but not sure what the efficiency is 
like. The surface is certainly not very good at 10 G......think its 
derated...if perfect it would be about 88 dB on 10 G

Barry
----- Original Message ----- 
From: <tosca005 at umn.edu>
To: "Barry VE4MA" <ve4ma at shaw.ca>
Cc: <w0zq at aol.com>; <nlrs at mailman.qth.net>
Sent: Monday, May 10, 2010 9:11 AM
Subject: Re: [NLRS] Question on Arecibo dish


> Hmm... Jon sez 305 meters, Barry sez 300 feet. It is 305 Meters, from what 
> I see on the Internet.
>
> I seem to recall that on the AMSAT reflector, they were saying that the 
> gain on 432 MHz was about 80 dB.
>
> Would it be 24x as much on 1296 MHz (24 x 432 = 10368)? That's about 14 dB 
> more added onto 80 dB = 94 dB. Seems a bit high to me.
>
> These articles...
>  http://www.naic.edu/~astro/aotms/performance/AO_perf_oct02.shtml
>  http://adsabs.harvard.edu/full/1996ASPC..106..389V
>
> ...talk about the performance of the Arecebo dish on various frequencies,
> but I could not find a simple dB gain figure in there...
>
> On May 8 2010, Barry VE4MA wrote:
>
>> I am not sure how much to derate it because it is a spherical dish
>> ...but it would be about 83 dB if the surface accuracy and mesh was
>> good.....the 300 ft dish is  W VA should be about 79 dB and it is
>> more than accurate enough.
>>
>> Beamwidths way less than 0.1 degree
>> 73
>> Barry VE4MA
>>
>>-----Original Message-----
>>From: nlrs-bounces at mailman.qth.net [mailto:nlrs-bounces at mailman.qth.net] 
>>On
>>Behalf Of w0zq at aol.com
>>Sent: May 8, 2010 11:57 AM
>>To: nlrs at mailman.qth.net
>>Subject: [NLRS] Question on Arecibo dish
>>
>>Can someone tell me what the gain is for the 305m Arecibo dish on X band ?
>>Approximate number is good enough.
>>
>>73, Jon
>>W0ZQ
>