2403 MHz Microwave Equipment of
VK3BJM.
Here is a little look at the gear I’ve played around
with for the 13cm Band (2.4-2.45 GHz).
In 2000, I built a 2.4 GHz transverter – a kit from
Charles Suckling, G3WDG. Designed for
use with a 147 MHz I.F. rig, bare-foot it produced 1 milliwatt. This was feed into a G3WDG 30 dB Power Amp,
to give me 1 watt. I’ve certainly made
contacts with it; but 1 watt, even into a 900 mm dish (for about 24 dBi of
gain), was a little underpowered.
Recently, SSPAs of several sizes have become available via eBay, and
thanks to one of these I now have 25 watts available when operating in the
field.
Inside the transverter case…
On the left is a photo of my 2.4 GHz gear set up at Cahill’s Lookout, near Katoomba, in the Blue Mountains, NSW, in March 2001. I was attempting to work Peter Freeman, VK3KAI, who was operating from a spot in the ACT. Sadly the attempt was not successful – probably due to the weather – lots of cloud in the path, and water is no friend of 2.4 GHz signals! At the time I was only capable of transmitting one watt. On the right is another view looking across the Megalong Valley.
In anticipation of trying
out AEP on 2.4 GHz from some remote location, a 1200 mm (4 foot) dish is being
prepared.
Which means the 900 mm grid-pack dish can be retired
to home-duties… The picture above shows
the 2.4 GHz transverter sitting in the rack, with the “Spectrian” 200-watt
Power Amplifier sitting underneath.
The grid-pack will be mounted in the middle of my
tower’s H-frame, at about 11 metres above the ground. Fed with 20 metres of LDF5-50, I should see about 150 watts at
the feed-point. There will also be a
VK5EME mast-head preamplifier immediately behind the dish.
Both the home station grid-pack and the 1200 mm dish
will be fed using Andy Sayer’s cavity feed design, as described in the
GippsTech 2008 proceedings.
To be continued…
Last update: 25/5/2011
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