[sarex] Re: further late reply regarding ISS simplex

Stan Vandiver w4sv at arrl.net
Fri Aug 11 18:32:35 PDT 2006


The "transmit-at-will" method of split-frequency operation is also 
inconsiderate, since no attempt at all is made to take turns (with 
those near you) in a gentlemanly manner.  For that we are "rewarded" 
with a clear downlink... most of the time.  I still find 
unknowledgable people transmitting on the downlink from time to time, 
and I try to educate them to proper splits and operation so they can 
make a QSO too.

If you have 10 callers in the Chicago-land area, courteously taking 
turns calling the ISS on simplex... that may be as much as a 90% 
reduction in the QRM (only 1 out of 10 calling at a time) from this 
area.... but probably a little less due to the randomness of calling 
patterns.  I realize the ISS footprint is much larger, and you can't 
take turns with the whole country... but if every urban area were to 
operate similarly, there would indeed be at least some reduction in 
QRM for the crew.

Inconsiderate people on simplex too?  Sure, sometimes.  But the key 
is to educate people to proper operation, whether simplex or split.  
And on simplex, you can IDENTIFY who is inconsiderate of others.

Best regards,
Stan/W4SV


On 11 Aug 2006 at 20:17, Robert Bruninga wrote:

> > Hello again- the astronauts will hear everyone calling 
> > whether its split or simplex operation so why not make it
> simplex!
> 
> Because many of us live near inconsiderate operators that step
> all
> Over the downlink by transmitting on the uplink.  Simplex is
> just not a good idea.
> The downlink should be separate from the uplink so that everyone
> can hear the downlink without interfererence from uplink
> stations.
> 
> Bob 
> 
> > -----Original Message-----
> > From: sarex-bounces at AMSAT.Org 
> > [mailto:sarex-bounces at AMSAT.Org] On Behalf Of McGrane
> > Sent: Friday, August 11, 2006 7:43 PM
> > To: Kenneth G. (JSC-OC)[BAR] Ransom; bruninga at usna.edu
> > Cc: Manned space BBS
> > Subject: [sarex] Re: further late reply regarding ISS simplex
> > 
> > 
> > Hello again- the astronauts will hear everyone calling 
> > whether its split or simplex operation so why not make it
> 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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> AMSAT-NA.
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> > > 
> > 
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