[Moon-net] DL4MEA's first JA on 13cm (2424MHz)

[OK1DFC]

CONGRATS Gunter well done
Regards

Zdenek - OK1DFC
www.ok1dfc.com <http://www.ok1dfc.com>
QRV EME 144-432-1296MHz
WAC 432 - 1296 MHz
QRO 10m dish
ICQ-397994501


-----Original Message-----
From: moon-net-bounces at list-serv.davidv.net
[mailto:moon-net-bounces at list-serv.davidv.net]On Behalf Of Koellner, Guenter
(NSN - DE/Muenich)
Sent: Sunday, January 13, 2008 4:56 PM
To: moon-net at list-serv.davidv.net; moon at moonbounce.info
Subject: [Moon-net] DL4MEA's first JA on 13cm (2424MHz)


Hello,

happy to tell you that this weekend I managed to work JA4BLC on 13cm, my 1st
station in JA, my first QSO with 2320/2424MHz crossband. Signals were
439/539 on  both sides.

I am now QRV on 2320/2304MHz if somebody wants to try.

I had a little bit of troubles, because yesterday I blew the two LDMOS of my
feed-mounted PA. I then took the older outside equipment into the shack,
re-aligned it, and had to re-install in the morning. Just in time for the
sked I was ready on 2424MHz.

I am mixing 2424MHz down to 2324MHz using a cut out mixer from a GSM
exciter, probably used for the local RF loop. In front of it there is a
5pole finger filter. Sun noise on 2424MHz is ok. The mixer is inserted into
the RX using a transfer relay, so I am able to switch quite quickly.

Who knows clearly (no guesses necessary!) Each of the two blown MRF6S221140
LDMOS is showing a funny behaviour: While in original the gate is
high-impedance, and fed with bias using a high value resistor, the gate now
became low impedance. If I feed bias using a regulated power supply, the
gate draws about 1A at 3.5V, and the devices starts amplifying, I went up to
15A at 28V on the drain-source! Somehow like a bipolar NPN transistor.
Knowledge about the effect that might have happend would help me in order to
avoid it for a future try. I can supply some more facts if required.

73, Günter (dl4mea)
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