[pskmail] Re: Server in Asia - 30mb antenna question

  • From: John Douyere <vk2eta@xxxxxxxxx>
  • To: Unname <pskmail@xxxxxxxxxxxxx>
  • Date: Fri, 29 May 2015 14:56:51 +1000

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

[image: Inline image 1]


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


PNG image

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