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RE: being heard over LEILA siren



Agreed ;-)

I believe this discussion should be one of how your signal level compares
to the beacon.  The official recommendation has always been to keep your
uplink so that your signal level is -10 dB from the beacon's level.  I have
never heard it differ in regard to which uplink band (U or L).  Obviously,
the agc's function differently and LEILA only notches the U uplink.

I suppose if you can determine the the siren level is related to the beacon
level (same, lower, higher....how much?) then you can make statements to
compare uplink levels to the siren.
====================================

Here is the gain of various diameter* dishes (assuming 55% effciency) at
1269 MHz:

4-foot (1.2m)   G=22.6 dBi	G=184
5-foot	(1.5m)	G=24.6 dBi	G=287
6-foot (1.8m) 	G=26.2 dBi	G=413
7.5-ft  (2.3m) 	G=28.1 dBi	G=646
8-foot (2.4m)	G=28.7 dBi	G=735
10-foot(3.0m)	G=30.6 dBi	G=1148
12-foot(3.7m)	G=32.2	dBi      	G=1653

*Note I do not give gain below 4-foot diameter as a dish is not useful at
1269 below that size.

So using 1w on mode-L your EIRP will equal the last column in watts.  To
get other EIRP multiply your power level times the gain ratio.

For comparison a rather standard (if such exists) mode-L antenna is the 45
loop-yagi (G=20 dBi, G=100).  I found that 10w into that antenna supplied a
signal 2 s-units below the beacon and barely legible on ssb.  That was an
EIRP = 1000w.  Of course that suffers linear to circular polarization loss
of 3 dB, so maybe my effective EIRPc = 500w?

The example given of 5w using a 1.8m dish would result in EIRP = 5 (413) =
2065w.

I'm not going to suggest any particular EIRP for mode-L as it has been over
a year since I tried it.  I am not sure any EIRP has been established as
"standard" for mode-L?

73, Ed - AL7EB

At 01:22 PM 8/22/2003 -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
>
>
>
>
>At 02:49 PM 8/22/2003 -0500, you wrote:
>>Do we really have to have a repeat of this war?
>>
>>73 de N8AU, Jim in Raymore, MO
>>
>>
>>-----Original Message-----
>>From: Wayne Estes W9AE [mailto:w9ae@earthlink.net]
>>Sent: Friday, August 22, 2003 11:08 AM
>>To: amsat-bb@AMSAT.Org
>>Subject: [amsat-bb] being heard over LEILA siren
>>
>>
>>I wrote:
>>
>>I would argue that you are running TOO MUCH UPLINK POWER if your voice is Q5
>>copy on top of the LEILA siren.
>>
>>Jim KL7QR wrote:
>>
>>In my case I use just 5 watts on L mode with a 1.8 meter dish and I can be
>>heard through LIELA. I have had several situations on the air where I was Q5
>>through LIELA even though I am a QRP station.
>>
>>My conclusion is that L mode works better.  You can often times outperform U
>>band uplinks with just a fraction of the power.
>>
>>Wayne replies:
>>
>>You are NOT QRP if your voice is Q5 on top of the LEILA siren.  To be Q5 on
>>top of the LEILA siren, your signal must be stronger than the recommended
>>downlink signal (beacon-10dB).  5W is QRO with enough antenna gain.
>>
>>Yes, L-band stations can get far stronger downlinks before they start
>>degrading things for everybody else.  The L-band and U-band AGC
>>characteristics are so extremely different that one of them surely is
>>"broken" from a practical point of view.  I don't know which it is.  L-band
>>AGC lets people get away with running far too much power?  U-band AGC
>>reduces gain prematurely?  A little of both?
>>
>>Wayne Estes W9AE
>>Mundelein, IL, USA
>>----
>>Sent via amsat-bb@amsat.org. Opinions expressed are those of the author. Not
>>an AMSAT member? Join now to support the amateur satellite program! To
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>>----
>>Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
>>Not an AMSAT member? Join now to support the amateur satellite program!
>>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
>
>W0EEC - CM87tm
>ARRL - AMSAT - MSARC - ARCA - Project OSCAR
>http://www.emilyshouse.com/W0EEC
>http://www.experthams.net/ao7
>http://www.projectoscar.net
>
>
>----
>Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
>Not an AMSAT member? Join now to support the amateur satellite program!
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> 


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