[amsat-bb] RF power required for linear satellites?

[Stephen E. Belter]

Ken,

I agree with Bryan, for 364 of the days of the year.  5 watts is usually fine and sometimes too much for the linear satellites.

This is really a function of how busy the satellite is, and how much power the other operators are using.  On a quiet pass, some operators report success with only 50 milliwatts.

The one day of the year that you may have trouble with is Field Day, with lots of traffic, and a few QRO stations.

I'm not encouraging you to use more power, as that can cause real problems on AO-7 (usually causing it to crash or reset to Mode A) or FO-29 (usually causing severe FM'ing of the entire passband).  But be aware that your experience on Field Day may be different than the rest of the year.  

I do encourage you to use a good antenna (e.g., Arrow or Elk), a relatively short length of quality coax (6-10 feet of LMR-240 Ultraflex, not RG-8), and no connector adapters.

73, Steve N9IP
--
Steve Belter, seb at wintek.com



On 6/20/18, 5:57 PM, "AMSAT-BB on behalf of Bryan KL7CN" <amsat-bb-bounces at amsat.org on behalf of bryan at kl7cn.net> wrote:

    Five watts is definitely sufficient for the common linear satellites.
    
    There are circumstances when it is nice to have a little more -- maybe 10 watts -- such as on a very low pass from a high location.
    
    But, there are so many who use the 5-watt FT-817ND that you will soon hear a chorus. :)
    
    -- bag
    
    Bryan KL7CN/W6
    Location: CM98, usually
    E-Mail: bryan at KL7CN.net
    Telephone/SMS: 408-836-7279
    
    > On Jun 20, 2018, at 00:18, Ken M <va7kbm at outlook.com> wrote:
    >
    > Hello AMSATers,
    >
    > I’m wondering if 5 watts is generally sufficient RF output to work the common linear satellites using a handheld satellite antenna (Arrow or Elk)?
    >
    > For example, would an FT-817ND (or the new FT-818) suffice for the uplink radio, or would you need an amplifier with those 5 (6) watt radios, or just a more powerful radio such as the FT-857D?
    >
    > Thanks & 73,
    > Ken  VA7KBM
    
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