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Re: Ao40 was stronger now!

William PE1RAH wrote:

Today I could hear the Ao40 downlink some more better. Signals were still like Ao10 signals. I did emediatly tested my inflatable foil dish and it worked great. Signal levels were equal to its solid dish sister.  Now there is no more doubt if this material can be used hehe.
After these tests I was able to make my first three contacts via Ao40.  What suprises me is that uplink signals have to be strong, 50...100W into my 32 el. X-yagi RHCP.

Wayne replies:

If your uplink antenna and feedline are working correctly, 50-100W to a 32 el. RHCP X-yagi will attract the attention of LEILA almost constantly.  If you are NOT hearing the LEILA siren, then something is probably wrong with your feedline or your antenna.

If you activate the LEILA siren to hear your downlink, then you need to improve your receiving equipment.  More antenna gain, better feed, or lower noise figure.  Another possibility is that squint was too high for good AO40 reception, but I presume that you were operating when the squint was less than 20 degrees.

With your inflatable dish or your solid dish, how many S-units is the beacon above your noise level?  In my opinion you need to hear the beacon at least 4 S-units above the noise level in order to make SSB contacts.  Then most SSB signals will be 2 S-units above your noise level.  A few stations use high power on the L-uplink to achieve downlink signals nearly as strong as the beacon (there is no LEILA on the L-uplink).  Your receiving system is not good enough if you can only hear the stations that are using high-power L-band uplinks.  You need to hear the other 90% of the stations, including yourself.

I am interested in portable AO40 receiving antennas.  I would very much like to know how well your inflatable dish hears the AO40 beacon (how many S-units above the noise level).

A final comment.  Last Saturday I heard you calling CQ on AO40.  Two stations answered your CQ, but you didn't hear us.

Wayne Estes W9AE
Mundelein, IL, USA

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