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RE: Mode B vs. Mode S






>From: Estes Wayne-W10191 <W10191@motorola.com>
>To: "Frederick M. Spinner" <fspinner@hotmail.com>, amsat-bb@AMSAT.Org
>Subject: RE: [amsat-bb] Mode B vs. Mode S
>Date: Wed, 1 May 2002 17:56:06 -0500
>
>I haven't heard of anybody LATELY who thinks AO40 is dead.  After >all, 
>there was a QST article a few months ago about successful AO40 >transponder 
>operation.  But the QST article still doesn't motivate >the average ham to 
>invest in equipment that can only be used to hear >ONE satellite that has a 
>history of problems.

$50 for a Transystems is pocket change compared with most ham radio 
equipment and projects. Primestar dishes go for free-$40 on ebay.  And my 
previous comments about AO-40 being "dead" was from only less than a year 
ago.  I think you'll find a lot of hams out there who think AO-40 is dead or 
crippled enough not to use.

>The original P3D plan didn't include 2m until a lot of people said >they 
>refuse to contribute money unless it has a 2m transmitter.  >That's not 
>politics.  It's a natural evolution from a theoretical >design to actual 
>development of a customer-driven (and >customer-funded) product.

If threats aren't a form of politics, what is?  I do believe that
these kind of threats force a "design-by-commitee" type of operation, which, 
of course, by definition is quite political.  Is that necessarily bad 
though?  No.

>
>2m and 13cm downlinks are so different that they are VERY >complementary.  
>For any given problem one is "strong" while the other >is "weak".

I agree.  But, I personally think the net sum of all of the tradeoffs is 
that 1269 MHz is a good choice for an uplink (it would have been super for a 
downlink, but we can't do that), and 70cm is a good choice for a downlink.  
When the sat is at apogee and squint is ok, then microwaves are the best 
choice.  2m is okay, but we are bandwidth limited, and the ambient (QRN) 
noise is high.  I am actually a bit more saddened by the loss of the 70cm TX 
than the 2m TX.


>I've already contributed generously to Project Eagle.  If the project >plan 
>includes a "definite" 2m downlink I would be motivated to >contribute even 
>more.

I wish I could afford to.  I'm unfortunately not in the position to 
contribute much monitarily at this point in my life.  But I'd like to help 
technically, even with the limited time I have available.

Fred W0FMS


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