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RE: Re: Thoughts on future "FM birds" (was: proposal f or maximizing fm le o contacts)



>On Fri, 18 Aug 2000, Tony Langdon wrote:
>
>> But is SSB the be all to end all? ...
>> Surely there are other modes that can be tried...
>
>Yes, Actually, we began our search for a new "easy-sat" by looking for
>a way to do 10 channels of FM ...  So we looked hard at how to do FM
>right... and just could not come up with anything viable...
>
>1) 2m is out, due to not enough bandwidth
>2) 70cm has the bandwidth
>3) But then you need 1.2 or 2.4 GHz as the other band.  ANd we can only
>   use 1.2 Ghz for transmit uplink
>
>Now then you get all kinds of baggage encumbering an "easy" solution:
>
>  = 70cm downlink of 10 FM channels to OMNI receivers requires at 
>    least 40 Watts of continuous transmit power.  This needs a BIG
>    satellite, at least 1 meter square
>
>  = Fortunately we are beginning to see some 1.2 GHz FM HT's, but they
>    would need handheld dishes or long yagis to get into the bird.
>    Sort of what we do with the Arrows now.
>
>  = No easy off the shelf 2.4 GHz transmit capability ...
>
>  = etc...
>
>
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>
Bob et al, actually not only are there 23 cm handhelds but the 16 element 
yagi's can be
easily handheld as well as I know from terrestial experience. Whether or 
not such a low gain device will work remains to be demonstrated in 
practice or calculated by the path loss method. Actually the 23 cm 
combination is as easily handled as the Arrow is on 70 cm - 2M. 
Unfortunately the 23 cm HTs that I am familiar with are FM transmit only. 
My old Kenwood 790 has SSB capability but unfortunately that is not 
easily transportable and I plan to utilize its precious 10 w. for P3D 
assuming that it is enough coupled with the 16 ele. yagi.

In a similar vein, I am currently unaware of FM birds operating on 23 cm. 
I know that P3D is designed for 23 cm but that is SSB (fortunately) and 
uplink only.

As far as 2.4 GHZ, there are readily portable yagis available but no HTs. 
A need for the future?

Ideas and comments?

Regards,


Pete de WK9K

ARS WK9K
605 Maiden Street
Mineral Point, WI 53565

e-mail: WK9K@arrl.net
fax: 503-210-6618

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