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L-Band Sanity - was "being heard over LEILA siren"



Dear Friends,

As suggested by Emily, let's look at some numbers:


1. A 1.8m (6') dish has around 27 dB gain at 1269MHz

2. Let's assume around 2 dB for the cable loss
    (i.e. 70' of LMR-600 has about 2.1 dB loss)

3. A 5 watt transmitter into this antenna system
    puts out a little over 1.5 kilowatts EIRP.

This might sound like a lot but...

*** the path loss at 1269 is 10dB greater than at 435 MHz ***

So this is like running 150 watts EIRP on U-band which is
in the right ballpark and is more than 10 dB below the beacon
at 60,000 Km.

The exact levels will depend upon a number of factors such
as the actual cable loss, the dish efficiency, the distance
and squint from AO-40 etc.

Ok, now an opinion; I think you could easily hear this station
over the LEILA siren since there is no notch. You can often hear
U-band stations over LEILA as well even with the notch.

Comments are welcome!

73,

Tony AA2TX

---


At 01:22 PM 8/22/03 -0700, Emily Clarke wrote:


>Oh please yes!  :-)
>
>Seriously I wouldn't want to have a war break out but a good discussion 
>would be nice.  I just started working on AO-40 and hearing some good pros 
>and cons would be helpful.
>
>73
>
>Emily

----
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