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RE: AO-40 status report by DJ4ZC




All,

Well, I made a conscious decision when re-establishing my P3 station to
only include the microwave bands.

Even though I live in the middle of nowhere I still do not escape the noise
levels on 2m - so as the saying goes , the only way is up.

I have been involved in microwaves for many years now and I can honestly
say I would be quite right in saying that a microwave station for
p3d can now be built without any specialised microwave knowlegde and from
completely commercial amateur sources.

The performance that a microwave station should be able to offer over and
above any V/U mode should be quite astounding on AO-40.

For anyone interested I had an article in the October issue of 73 Magazine
on how and what is required to establish a P3D uWave station.
Take a read - in it I predicted that Mode B/J would die as we progressed
and that microwave modes will be become the norm in the future. My decision
to NOT build V/U links into my station is an attempt to show how easy it
can be. This WILL happen as we get forced off 2m/70cm due to QRM/QRN

Read the James Miller article on P3D microwave links and then tell me how
any reasoning technical person can tell me why we should be using V/U bands
for up/down links. Yeh sure I am now going to get flooded by email saying
how wrong I am - well the figures and evidence speak louder than words I am
afraid and its purely microphobia that stops the sane thinking process
(thats a fear of microwave equipment BTW!).

A few years ago James also wrote an article on the trials and tribulations
of commanding a P3 satellite. His comments about  how difficult the
commanding was using 70cm uplinks (due to radar interference) was enough to
put any person off for life!

Sorry but we need to head upwards and onwards technically and a move higher
in freq is neccesary! Do you still find commercial sats using VHF/UHF for
commanding??? I doubt it.

Don't be microphobic! Its not rocket science - honest! (pun intended!)

Simon GM4PLM
Editor European Microwave News/ Dubus Microwave Europe Column/Radio
Communication Microwave Column









"Edward R. Cole" <al7eb@ptialaska.net>@AMSAT.Org on 22/11/2000 10:16:58

Sent by:  owner-AMSAT-BB@AMSAT.Org


To:   amsat-bb@AMSAT.Org
cc:

Subject:  RE: [amsat-bb] AO-40 status report by DJ4ZC


>From: Tony Langdon <tlangdon@atctraining.com.au>
>Excellent to see the status report, at least we now know what the score
is.
>Hope something can be done with the 70cm Tx, and that there's no other
>problems with the bird.

I'm sure you are not alone in this wish.

{Note:  I wrote this reply before reading all the subsequent replies, so
sorry for being repetitive!  Hope you still find my comments interesting}

Noting the discussion about QRM from AO-10 and RS-13 [especially mode
KT...the 15m uplink] and, in general, the growing noise floor problem on 2m
from computers birdies, TV's, and out-of-band Intermod, I believe mode UV
may soon become unusable.

For instance, I recently heard a prediction that moonbounce may become
unusable on 2m in a couple years due to noise & interference.  Already many
moonbouncers have abandoned 2m for the microwave bands!  So mode VU may
become quite important as the primary AO-40 mode.  Thus we need that 70cm
Tx.

Of course, I hope that the microwave mode transponders also work and that
modes US and LS become popular.  But being realistic, probably the main
activity will still be on VHF & UHF.

I do wonder about the wisdom of running RS-13 in mode KT during the sunspot
cycle peak.  I know, some folks only have an HF rig and a 2m handie, but
when weekend 15m contests wipe out other satellite use, perhaps the utility
of mode KT is diminished!

When AO-40 is commissioned, I wonder if this may become more than just a
nuisance?  Food for thought!

Anyone for mode LX? ;-)  Laura?  Phil?

Ed
50-144-432-1296-2400-10368...& maybe 24 GHz

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