[amsat-bb] Re: HEO naivete

Edward Cole kl7uw at acsalaska.net
Fri Feb 6 23:29:03 PST 2009

At 04:28 PM 2/6/2009, Rocky Jones wrote:

>Bob...Your "rant" strikes me as pretty close to right on the 
>money.  I read the missive in the latest journal about 3.3 and 5.6 
>ghz links and thought "thats nice, It will never happen".
>A baseline requrement  for ANY Amateur satellites should be that 
>they work on frequencies and modulation methods which are consistent 
>with radios that are already commercially manufactured for the bands 
>in question...or can use some very easily (think the MDS converters) 
>commercial gear for other services.
>The instant the "bird" is designed with some type of radio in mind 
>that does not exist now and is limited to that bird...then the 
>entire adventure is nice but has little practical value.
>Why on earth is the AMSAT community wasting time on a design which 
>requires a ground station that is (by the latest Amsat Journal) 
>"beyond the scope of most hams".  Instead of spending time working 
>on  making an 'acp capable earth station within the reach of most 
>radio amateurs".
>Because if the equipment has little value beyond a satellite which 
>could do an Oscar 40 at any time how many are going to shell out the money?
>I dont have a clue why the AMSAT design folks seem to think that it 
>isnecessary to drive up into the microwave frequencies.  They never 
>seem to answer the question why a 2meter 70cm translator is not a 
>good solution...and the one that we really need.
>Meanwhile AO-7 flies on.
>Robert WB5MZO life member

Well, there are a few reasons:
1- 2m & 70cm antennas are large and it takes a large satellite to support them
2- Microwave antennas are physically smaller and yet will provide more gain
3- Microwave frequencies are quieter (low sky noise) so they work 
better with low noise receivers; some mw freqs. are less impacted by 
interference and/or pirate stations.

When such a mw satellite can be launched, many sources of equipment 
will surface.  Downeast Microwave and Kuhne Electronics will come out 
with equipment when there is a market for them.

73, Ed - KL7UW 

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