Joe,
For over a year now, we have successfully been running a 2m net here in South
Carolina on 144.257 + 1000 Hz tone frequency, using PSK63.
No repeaters are used.
Typical range is over 100 miles between 10 dBi beams at 30 feet and 25 watts.
We have one regular checkin from 200 miles distant running 25 watts to a 5
wavelengths beam and can work him with only one watt to 13 elements in my
attic, as well as on my wide-beamwidth 7 dBi antenna that I use for the net,
but he is on a 200 foot high hill with a clear shot in my direction.
Copy is usually 100%, except when a strong multipath reflection crosses the
main signal, and then copy goes to zero for a short time, no matter how strong
the main signal is. However, when fairly weak reflections are seen on the
waterfall, copy is not disturbed.
We run the net a little differently from a typical VHF net. All stations beam
in the direction of Net Control, which is usually myself, and I use an
skeleton-slot bi-directional antenna with about a 160 degree beamwidth and 7
dBi of gain. This means that anyone who can copy Net Control can be copied by
Net Control, but not necessarily by some stations too far away or off the beam
path of that station. So, I cut and paste all incoming text and retransmit it
for everyone else to copy. This means some stations get the copy twice, but at
least everyone gets it at least once, so nobody gets left out. This is an
informal ragchew net, BTW.
Because we are using PSK63 at 100 wpm, and people typically type at around 20
wpm, the retransmission of the text takes little additional time, since the
average incoming transmission is around 2 minutes or less, and takes less than
30 seconds to retransmit.
We also tried DominoEX 16 instead of PSK63 in hopes of negating the multipath
reflection problem, but it did turned out to be only a little better in that
regard, so we stick with PSK63 which works well enough for a ragchew net.
I am told that my QST construction article on the antenna I use for Net Control
will be appearing sometime within the next few months.
If you try this approach with a net, I'd appreciate an email letting me know
your experience to [EMAIL PROTECTED], or just posting it on the reflector here.
73, Skip
KH6TY
7. Ideas for VHF/UHF digital net?
Posted by: "Joe Veldhuis" [EMAIL PROTECTED] electrode_kd8atu
Date: Wed May 2, 2007 6:01 am ((PDT))
Well, the spring/summer propagation is back in force, at least here, so as I
said in my previous post, we should restart the net.
So, I want to know 2 things:
1. What sort of modes should we use, and should we try using some bands
besides 2 meters?
2. As I asked before, is there anyone in the upper midwest/Great Lakes region
with a good VHF/UHF station that would want to be the net control station? I've
only got a single 13 element beam at 30 feet for 2m and a single 25 element
beam at 35 feet for 432 MHz, both going into a barefoot Yaesu 857, so my
effective range is quite limited.
Opinions?
-Joe, N8FQ
