Hi John - thanks very much for your very useful comments!
I can agree with you about propagation at my latitudes. The band that seems to
provide the best propagation for me is 15 metres, using my DX Engineering 80/40
Thunderbolt vertical antenna, that is resonant on 7MHz (so I'm using it on its
3rd harmonic, with very low SWR). So even though I am not using an antenna
designed for 15 meters, I am getting good coverage.
I have tested my vertical antenna on 30 metres, but the take off angle is too
low ==> I'm heard on the other side of the world as a weak DX signal, but the
first skip zone is the area that I really want to cover, ie the Indian Ocean
etc.
I am waiting on a 30mb collinear wire antenna to arrive, which I'll test at a
lowish height to see if it will perform as a NVIS antenna, (but 10MHz is a bit
high for NVIS).
I have to say that I've been monitoring 10.148MHz for days, but receive no
PSKMail server beacon signals whatsoever :(
I will dedicate a server and Yaesu FT857 rig to this service. So I want to
ensure that my expense on these items is not 'wasted' because no-one can use my
server. If it can provide good coverage west over the Indian Ocean for
mariners, and over south-east Asia for landbased/emcomm/NGO etc etc, then that
will meet my aims.
I think the best that I can do is to set up server and rig, and then do some
tests on different bands at different times. Maybe I operate on 15mb during
the day and possibly on 40mb at night.
I will check out the propagation links you provided to help me in my decisions.
Simon
PS - How 'popular' is your server? How many emails/connections do you
typically have per day/week??
--------------------------------------------
On Thu, 28/5/15, John Douyere <vk2eta@xxxxxxxxx> wrote:
Subject: [pskmail] Re: Server in Asia - 30mb antenna question
To: "Unname" <pskmail@xxxxxxxxxxxxx>
Received: Thursday, 28 May, 2015, 9:56 PM
Hello
Simon,
That's a great
idea, and totally feasible in my opinion.
Some feedback based on my tests here
in Sydney that may be useful for your
installation.
I found
that 30M in the lower latitudes has a limited reach during
most of the time. I got reliable links back to my server on
30M up to about 1500KM.
I tested my server all the way to
the tip of Cape York in north east Australia which is
located at -12 degrees latitude (similar to Phuket at +9
degrees) and I could get back to my server in Sydney (approx
2500KM strait line) reliably only on 15M and sometimes on
20M.
So based on your
objectives I would advise to consider scanning a few
frequencies rather than just 30M. I would propose scanning
30M, 20M, 17M and 15M. Maybe with two consecutive minutes on
30M to make up the 5 minutes scanning cycle.
Now my base antenna may be a
contributor to the limited reach of the 30M band as it is an
inverted V at 12M above ground level with an autotuner. But
I suspect it is not the main factor as it seems that in
Europe they get reliable 30M links up to that distance even
with vertical antennas. And they are at a much higher
latitude where lower frequencies work a longer distances in
average.
If you look at the example below of
the prediction chart for 11:30AM local time in Phuket (the
chart is centered on Brunei but the latitude is similar at
about 4 degrees North) you will see that to get a good
coverage of the indian ocean you need to go up to 24Mhz, but
my guess is that even if you stop at 21Mhz you will get
decent DX capability.
If you want to run propagation
simulations, the Australian IPS services provide some
interesting tools (see http://www.ips.gov.au/HF_Systems/6/6/2
and select Brunei Bay Radio for example).
Hope this helps,
73, John
On Thu, May 28, 2015 at
6:24 PM, Simon Luttrell <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
Since
there seem to be no PSKMail servers in Asia, I am thinking
of setting up a server from my QTH on the island of Phuket,
south Thailand. This should provide coverage over the
Indian Ocean and southeast Asia land masses.
I have a first question. For the PSKMail servers that
already operate on 30mb, what antennas are you guys
using?
I'm sure that I will have more questions, but this is an
important one to see if my idea is feasible.
Simon
