[sarex] Re: further late reply regarding ISS simplex

McGrane tmcgrane at suffolk.lib.ny.us
Fri Aug 11 16:25:24 PDT 2006

hello kenneth- the point I was making is that the ISS should be operating
simplex. pat

On Fri, 11 Aug 2006, Ransom, Kenneth G. (JSC-OC)[BAR] wrote:

> It sounds like your issue is not that split frequencies are bad but that
> multiple uplinks makes it difficult for the crew to listen to one
> uplink. ITU region regulations for ground station operations are the
> culprit. Space has no borders but Earth does so have of the problem is
> getting everyone to agree on a single uplink. Not everyone in the world
> has the same frequency allocations nor do they use the available
> spectrum in their region the same way.
> The issue is not the 20-30 miles but the number of callers in the 2000
> km wide footprint. The station has to listen to all of them. Since you
> can't hear all of them, it becomes difficult to know when someone is
> talking or not without guidance from the station operator.
> In the MIR days, the crew did not have the luxury of near full time
> satellite communication that provides voice, email communication and an
> IP phone that lets them make phone calls. If the MIR crew wanted to talk
> to someone, they needed to use the ham radio or the Russian VHF space to
> ground system. The ISS crew has plenty of options to choose from when
> they want to communicate and it depends on the personality of the crew
> as to which ones get utilized.
> Kenneth - N5VHO
> -----Original Message-----
> From: sarex-bounces at AMSAT.Org [mailto:sarex-bounces at AMSAT.Org] On Behalf
> Of McGrane
> Sent: Thursday, August 10, 2006 6:43 PM
> To: Manned space BBS
> Subject: [sarex] further late reply regarding ISS simplex
> Greetings from patrick N2OEQ
> Despite support of the present frequency scheme for the ISS I still wish
> to disagree with the policy of split operation with different phone
> uplinks.
> Back when the MIR was up, the russians operated simplex and left the
> radio on to listen for callers.
> On several occasions, I called the MIR according to my tracking program
> and was rewarded several times with a response.
> With two different uplink frequencies, the astronauts are less inclined
> to leave the radio on to listen for callers. 
> When there were several callers here on simplex responding to a CQ call
> from the MIR, we acted civilized and took turns and everyone made
> contacts so I dont buy the absolute need for split operation.
> Besides, how many callers could there be within 20 or 30 miles up to the
> horizon.
> We've had years of robot like amateur radio on the ISS. How about
> loosening the ties!
> Thanks for the soapbox..... pat
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