YouTube video about the
(former) K7RJ 10 GHz microwave beacon in grid DN31it
in remote northwestern Utah. This beacon, which had been operating on
10368.250 MHz, was regularly heard in the Salt Lake
area (approx. 100 miles, 160 km distant) via
reflection from mountains and is weak enough to be a
good test of one's receive system. A shorter version of this video may be seen
here.
A 10 GHz power
amplifier using a VSAT power module - This
page describes the extrication and testing of the RF power
amplifier portion of a low-power satellite uplink
module. These systems - intended for home and business
use - occasionally show up on the surplus market. The K7RJ Beacon (see the link
to the video to the left) uses one of these power
amplifiers!
A
temperature-compensating Gunn controller - One
of the common ways to keep a Gunn oscillator on frequency is
to control its temperature, but what if you were to monitor
the Gunn's precise temperature and use that to keep
it on frequency instead? I decided to try out this
idea and ended up with this!
The K7RJ 10 GHz Microwave Beacon, 10368.250 MHz
- Formerly operating from
remote north-western Utah, this beacon operated on a "key
down" frequency of 10368.250 MHz using FSCW
(Frequency-Shifted CW) with the "key-up" frequency being
lower by 1.5-2 kHz or so. This beacon sent a 30 second
"key down" signal followed by an ID with the grid square and
also telemetry indicating the temperature indoors, outdoors,
and also within the outdoor beacon enclosure. The
transmit frequency of this beacon was been very stable and
the "key down" frequency was always within 1 kHz of nominal
under varying operating conditions - For a "tour" of this beacon, see the video to
the right!
Ron, K7RJ, has moved from Utah and this beacon is not
currently on the air.
The WA7GIE 10 GHz Microwave Beacon, 10368.200 MHz
- This beacon operates from the Oquirrh (pronounced
"Oh-kerr") mountains west of Salt Lake City and provides a
strong, local test signal around the Wasatch Front and it
can be heard throughout northern Utah. This beacon
operates on a nominal frequency of 10368.200 MHz but has
been recently found at approximately 10368.188 MHz - about
12 kHz low. This beacon has been operating since 2004
and it was rebuilt in mid 2011. At this time a new
crystal was installed in an oven-controlled oscillator and
set for the new frequency, but being a "green" crystal it
quickly drifted down several kHz after installation, but its
drift has slowed over time and is occasionally reset to the
nominal 10368.200 MHz. The beacon's message cycle
consists of an ID along with its grid square and the
beacon's internal temperature.
10 MHz Crystal-based
frequency reference - This is a frequency
reference that is used to keep microwave transverters within
"shouting distance" of the intended frequency. Based on
an Isotemp "ovenized" crystal oscillator, it will keep a 24
GHz transverter within 500 Hz of the intended frequency over a
fairly wide temperature range.
10 MHz
rubidium frequency reference using the Efratom LPRO-101
- This rubidium frequency reference provides extremely high
frequency accuracy in a portable package. As it turns
out, the LPRO-101 is one of the better inexpensive rubidium
units when it comes to providing a 10 MHz reference for
microwave transverters!
Avantek
3cm
preamplifier details - A few details
concerning the use of a surplus 3cm GaAsFET preamplifer that
appeared on the surplus market in the mid 90's and can
occasionally still be found.
