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Future Sats: L/U



Hi AMSATs,

Some comment from me about this message...

>I got into ham radio because as a kid I could "listen" to other hams on my 
>old SW radios. That got me hooked and many many years later I became a ham.

On SW radio you can hear many stations, but thats because you already 
recieve signals with a needle.

>The problem with AO-40 in my opinion is that I can not listen to it without 
>a lot of new gear. Although that was not too expensive the "idea" of S band 
>was the problem.

SW would not work very well with satellites, and the 2m and 70cm are already 
overloaded by many ham satellites. Other (higher) bands is one of the 
options...

>Most new highend base radios today are all mode. Most have the ability to 
>go upto L Band (1.2ghz) but not to S Band (2.4ghz). Maybe someday they will 
>but now they don't. Most of these rigs do NOT come with the L band module 
>installed because of price and limited use to a ham today.

An L-Band or higher frequency transciever is useless. It might only be 
usefull when you sit just 1m from the antenna feet point, but most amateurs 
need at least several meters coax cable from their shack to the antennas in 
the mast. This is exactly the problem on higher frequencies. The large cable 
lengths cause extreem losses, a lot more than on 70cm !!!
You can use mast pre-amps and mast PA, or very expensive low loss cables, 
but with only an L-band/S-Band transciever you can not work satellites...

A better solution is to use a converter from E.g 2m <--> S-Band. The 
converter must be placed in the mast, close to the antenna to avoid L-band 
losses. The 2m connection from the converter to your trax in the shack will 
be no problem. You can do it even with the RG58 HF coax :-)

SHF converters are widely available, and there are even many kits or 
descibtions of converter projects.
For example, look at:
http://www.db6nt.de/

Here you can find some S-Band downconverters. Put them in your antanna mast, 
just behind your S-band antenna, and you can start listening again to AO-40 
:-)

>But if there was a sat up there in space with a high orbit (easier to 
>track) that TRANSMITTED on U Band (70 cm) where all these rigs could 
>"LISTEN" to it ... hams could use their existing radio and antenna to 
>LISTEN to the new satellite. THEN if they got hooked and could see that 
>they could HEAR it, then they might opt to buy the L Band module so they 
>could TALK to it.

Thats why in the new P3e satellite a MODE-UV will be available for the 
new-commers .-)
Please don't forget that on AO40 there was also a 2m downlink in the 
beginning !!

>I will contribute to a new Amsat sat project BUT only to one that does the 
>above, as its primary mission capability. I believe it will be the best way 
>to get hams to join the SSB part of amateur satellites in the future... and 
>to join AMSAT. I contributed a good deal to AO-40.

>Could Project Eagle be reworked to do this?

>W4SCO
>Amsat Member

73 de PE1RAH, William Leijenaar
---

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