fspl = 36.6 + 20 log D + 20 log F where D is miles and F is MHz.
D = 22400
F = 5800
36.6 + 87 +75 = 198 dB. Yep.
Screwed up somewhere.
From: Mathew Howard
Sent: Tuesday, February 23, 2016 4:23 PM
To: af
Subject: Re: [AFMUG] Fw: Force 200 Ptp distance
Something still isn't working out for me... I'm coming up with just under 200db
of free space loss for geosynchronous orbit... 30dBm txpower + 25dBi antenna +
25dBi antenna - 200db free space loss, gets me a signal of -120, that just
isn't going to work!
On Tue, Feb 23, 2016 at 5:11 PM, Chuck McCown <ch...@wbmfg.com> wrote:
Yep, the sheet I was looking at didn’t say that. So yes.
So feel free to use it out to 77,625 miles.
You can use it for geosynchronous orbit with some fade margin!
From: Mathew Howard
Sent: Tuesday, February 23, 2016 4:09 PM
To: af
Subject: Re: [AFMUG] Fw: Force 200 Ptp distance
I see now, I was confused where the 158 was coming from... but the Force 200
spec sheet says the antenna is 25dBi and trasmit power is up to 30dBm... so,
shouldn't that get us 173?
On Tue, Feb 23, 2016 at 5:04 PM, Chuck McCown <ch...@wbmfg.com> wrote:
22 dBm transmit power with a 23 dBi integrated antenna == 45 dBm EIRP
RX sensitivity, adaptive = –93 dBm.
To me that would be a system gain of only 138 dB.
Oh, but you have to add the RX antenna, so another 23 dBi and you get 158
dB.
There ya have it.
From: Chuck McCown
Sent: Tuesday, February 23, 2016 4:01 PM
To: af@afmug.com
Subject: Re: [AFMUG] Force 200 Ptp distance
If you max out the EIRP and go for minimum usable RX signal level, Cambium
says that difference is 158 dB.
(system gain)
The rest is a free space path loss formula run backwards.
From: Craig House
Sent: Tuesday, February 23, 2016 3:58 PM
To: af@afmug.com
Subject: Re: [AFMUG] Force 200 Ptp distance
I understood it perfectly. Up to the period after sheet . It got a bit
fuzzy after that.
Craig
----------------------------------------------------------------------------
From: "Mathew Howard" <mhoward...@gmail.com>
To: "af" <af@afmug.com>
Sent: Tuesday, February 23, 2016 4:57:33 PM
Subject: Re: [AFMUG] Force 200 Ptp distance
Your math confuses me...
On Tue, Feb 23, 2016 at 4:52 PM, Chuck McCown <ch...@wbmfg.com> wrote:
158 dB using 23 dBi integrated antenna according to the spec sheet.
158=20 log D + 20 log 5800
7.9=log D +3.76
4.14=log D
10 to the 4.14 power = 13,804 miles
From: Joseph Marsh
Sent: Tuesday, February 23, 2016 3:45 PM
To: af@afmug.com
Subject: [AFMUG] Force 200 Ptp distance
What is the max distance for a force 200 Ptp link?
