Posts by DB8TF
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Here you see how i mounted the helical.
The right angle was adjusted after this picture was taken.
Here is a link to a Wimo dish feed and this one is mounted like a standard LNB.
http://www.dd1us.de/Downloads/…er%202400%20MHz%201v1.pdf
Vy73
DB8TF
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i mounted the reflector of the helix on the usual plastic lnb holder on the outer side of the holder facing away from the dish.
But those 10mm shouldn't really make a big difference in gain.
VY73
DB8TF
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My Setup is one 90cm dish with 4 turn LHCP helical feed for TX Uplink and
a 130cm dish with octagon PLL LNB for vertical linear RX.
At first i thought the Wlan grid antenna should also work satisfying as Uplink
antenna but after i read About the Problem with the linear polarization i build the dish with the helical feed.
So i will compare the Wlan grid dish with the helical feed dish as soon as we can use the satellite.
vy73
DB8Tf
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thanks for the good explanation.
i will compare my andrew t2400 linear polarized Wlan grid 24db antenna to a 90cm dish with lhcp 4 turn helical when the sat is released for ham use.
73 de db8tf
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i read somewhere that linear polarization could cause fading of the signal when it passes through the atmoshere, i don't know if thats true...
vy 73
DB8TF
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Is there some kind of live Webcast from the launch available on the net?
VY DB8TF
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Hier ein Bild wie das auf dem Masterrechner der sich auf die Beacon/Telemetriefrequenz eingelockt hat aussieht.
Der Empfangsfrequenzverlauf innerhalb einer Stunde ist oben mit etwa 6kHz Drift zu sehen und unten rechts die stabilisierte Demodulation mit vielleicht noch 10Hz Drift.
Gruß
DB8TF
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Zum Thema Eliminierung des Frequenzdrift bei RX habe ich seit Monaten schon eine kostengünstige Lösung:
http://www.floroy.de/db8tf/hail2.htm
Keinerlei LNB Modifikation, GPSDO oder Dergleichen nötig.
Schöne Grüße,
DB8TF