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Object PHG settings
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Randy Allen
I'm setting up objects for a couple of local Winlink nodes.
Winlink inputs them to the IS stream, but I wanted them to be available locally on RF. Transmitting objects is simpler than attempting to set up APRS transmitters at each location. The objects are W6CDR-10 (Winlink RMS), W6CDR-4 (Digipeater, same radio and antenna) and W8GCA-10. I offset the position of W6CDR-4 digi a bit to show as a separate station at my usual zoom (12.4 mi which shows my whole county and parts of the surrounding counties.) When I tried to set up the PHG for the objects, I am unable to get them to save the settings I input (50W 330FT for CDR, 50W, 250Ft for GCA). The only values I can get to save are the ones in the drop down boxes of the PHG configuration screen. So they are now set at 49W at 320FT for CDR and 49W at 160Ft for GCA. The block to enter the actual PHG value is greyed out. So I can't enter PHG7500/ for CDR or PHG7400/ for GCA. (as calculated at http://digined.pe1mew.nl/tools/phgcalculator.htm) In this case the differences are insignificant for operations. I'm just interested if I'm missing something. 73 Randy KA0AZS -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
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Fred Hillhouse
Hi Randy,
toggle quoted messageShow quoted text
Read this: http://www.aprs.org/aprsdos-pix/phg.txt I think you will find that your absolute heights, power, etc., may not be in the spec. You need to pick the closest. Fred N7FMH
-----Original Message-----
From: APRSISCE@groups.io [mailto:APRSISCE@groups.io] On Behalf Of Randy Allen Sent: Tuesday, November 03, 2020 12:19 PM To: APRSISCE@groups.io Subject: [APRSISCE] Object PHG settings I'm setting up objects for a couple of local Winlink nodes. Winlink inputs them to the IS stream, but I wanted them to be available locally on RF. Transmitting objects is simpler than attempting to set up APRS transmitters at each location. The objects are W6CDR-10 (Winlink RMS), W6CDR-4 (Digipeater, same radio and antenna) and W8GCA-10. I offset the position of W6CDR-4 digi a bit to show as a separate station at my usual zoom (12.4 mi which shows my whole county and parts of the surrounding counties.) When I tried to set up the PHG for the objects, I am unable to get them to save the settings I input (50W 330FT for CDR, 50W, 250Ft for GCA). The only values I can get to save are the ones in the drop down boxes of the PHG configuration screen. So they are now set at 49W at 320FT for CDR and 49W at 160Ft for GCA. The block to enter the actual PHG value is greyed out. So I can't enter PHG7500/ for CDR or PHG7400/ for GCA. (as calculated at http://digined.pe1mew.nl/tools/phgcalculator.htm) In this case the differences are insignificant for operations. I'm just interested if I'm missing something. 73 Randy KA0AZS -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
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Robert Bruninga
There is only 1 digit for height. So it uses powers of two.. Just pick the closest one. Bob, WB4APR
On Tue, Nov 3, 2020 at 12:36 PM Fred Hillhouse <fmhillhouse@...> wrote: Hi Randy,
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James Ewen
Also this height is not altitude above sea level. It should match your height above average terrain (HAAT). Also if your coverage is offset somewhat by local terrain, you might want to report a directional pattern even if your antenna pattern is omni. The PHG pattern drawn on the map should try to approximate the actual coverage area of your station even if the numbers don’t reflect the numerical values in your station. The intent is to provide those observing the output with an idea of the coverage to expect, not to brag about the exact specifications of the equipment in use. If your APRS client is drawing a PHG plot on the map, and you are within that area, you should be able to use the asset being described. Putting a huge circle on the map just because it looks more impressive doesn’t do anything to assist those who are wanting to make use of these equipment that the exaggerated circle describes. Fudge the numbers to make the information put in front of others as useful as possible. Those just seeing the raw numbers aren’t going to bother with trying to plot the coverage out in their heads. They will try it and see if it is reachable or not. James VE6SRV
On Tue, Nov 3, 2020 at 2:59 PM Robert Bruninga <bruninga@...> wrote:
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James VE6SRV
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Randy Allen
Fred,
Thanks! That explains it all perfectly. I think I knew that at one time but have not set up a PHG in so long I had forgotten it. 73 Randy KA0AZS
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Randy Allen
Bob,
RR. The link that Fred posted (to a page I think you wrote) refreshed my memory and explained it perfectly. 73 Randy KA0AZS
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Randy Allen
James,
Roger that. I am aware of the differences between AGL, MSL and HAAT. The heights were given to me by the Trustee. Since one of the numbers does not match where I know the antenna is AGL, I'm assuming he took that into consideration. I'll discuss it with him next time we talk. This is my first approximation. Right now I think the transmitted PHG circle is actually smaller than the actual coverage. We don't have a lot of data yet as the sites have only been really advertised recently as we have been gearing up for the Red Cross Winlink drill this month. (I'm less than 5 miles from the site and am literally line of sight to tower when I step outside of my house) As we get in actual user reports I'll look into adjusting numbers to match actual coverage as close as possible. And by actual user I mean a user on the ground. I know the Digi can reach another Winlink RMS 30 miles south of here, but since both are on high towers, I'm not figuring that into our coverage area. Hopefully the Red Cross drill will give us some additional data on the actual coverage. Thanks 73 Randy KA0AZS
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Robert Bruninga
The PHG circles are drawn at HALF the calculated range to account for about 6 dB of mobile loss due to flutter, etc. Most programs also allow you to draw then full size which might work for some fixed stations, but not fo r mobiles so are very misleading bob
On Wed, Nov 4, 2020 at 11:56 AM Randy Allen <ka0azs@...> wrote: James,
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Randy Allen
Bob,
Understood. 73 Randy KA0AZS
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