WICEN Vic: WICEN HF Net 30/6/20

[Allen]

Hi All,

Just sat down to write up the night. Not a lot to add as yes extremely 
noise and poor contacts.

Thanks to VK3ZRX John and VK3YG for persisting. Both were in the noise 
but it was encouraging to get the contacts.

I did hear VK7AC however he failed to come back so left it at that.

Thanks for the charts John. I did go out and check the antenna was up 
this morning but the charts are clear.

next week 7th July is VK3JM Fred. Hoping for better conditions.

All good fun,73

Allen
VK3ARH
On 1/7/20 1:25 pm, Mark Hudson wrote:
>
> Thanks Allen and John.  I put out 3 calls last night and nothing 
> heard.  I could hear a very weak station in my S9 noise but could not 
> make them out.  Around 2040hrs I could hear VK3YG but well down.  No 
> other stations heard.
>
> *From: *wicenvic <wicenvic-bounces at vic.wicen.org.au> on behalf of John 
> & Bronwyn <jandbmorrissey at gmail.com>
> *Date: *Wednesday, 1 July 2020 at 11:21 am
> *To: *WICEN distn list <wicenvic at vic.wicen.org.au>
> *Subject: *WICEN Vic: HF Net 30/6/20 - propagation comments
>
> Hi everyone
>
> Thanks to Allen VK3ARH for a valiant effort to establish the WICEN net 
> in the face of very poor propagation last night.  I could only just 
> hear Allen (about Q2 to 3) and even Peter 3YG who normally has a 
> rock-crushing signal was close to the noise (which was about S3 here 
> last night).
>
> So what happened?   The charts below tell all!   (This chart, and many 
> like it for the EMCOM group, are publicly accessible at 
> http://www.sws.bom.gov.au/Products_and_Services/5/4 )
>
> These are Hourly Area Prediction or HAP charts.  What is a HAP chart?
>
> A HAP chart shows the approximate Maximum Usable Frequency (MUF) for a 
> given propagation path.  Below the MUF, the radio wave is reflected 
> back to earth (noting this depends on the angle of incidence to the 
> ionosphere), above the MUF the wave is lost to space.  The particular 
> charts above are centred on Melbourne but there are others.  They show 
> the MUF between Melbourne and some other point where you wish to set 
> up communication.  You select frequency based on the colour of where 
> you wish to communicate to (assuming you are in Melbourne).
>
> So on the charts above which cover the period either side of dusk, you 
> could have used 80m to communicate within Victoria at 1600 and 1700 
> hrs EAST (0600 and 0700 UTC) but from 1800 onwards 160m would be a 
> better choice.
>
> There are two sets of charts on the site - Hourly and Daily. The 
> Hourly charts are updated hourly from near-real-time radiosonde 
> information, so they are quite accurate. The Daily charts are updated 
> daily and are forecasts from solar flux and other information.  (Just 
> to confuse you the daily-update forecast charts are also called HAP 
> charts, because they are predictions for each hour of the day). The 
> charts above are the daily charts for this evening but last night 
> would have been much the same.
>
> Looking at the chart for 1000 and 1100 UTC (2000 and 2100 EAST)  it is 
> obvious why the sigs were so poor.   There would have been no NVIS 
> propagation on 80m  but 160m probably would have worked.  And it 
> explains why there were quite strong VK5's just up the band - they 
> were probably somewhere near the boundary between the red & yellow 
> zones (noting that yellow is 4 MHz MUF, so an MUF of 3.6 MHz would 
> have been a bit inside the yellow to red boundary).
>
> Hope this explains what happened - and that you can use the HAP charts 
> for propagation prediction in the future.
>
> Cheers,   John VK3ZRX
>
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