HyperAmp 900, by HyperLink Technologies
One of the most significant factors affecting the operating range of 900 MHz SS
installations is antenna feed cable attenuation.
In practical applications, where cable lengths of 30, 50 or over 100 feet are common,
cable attenuation is significant. Even the best low-loss cable, like Belden 9913 is
lossy at 900 MHz. Unfortunately, it is seldom
practical to mount a SS transceiver right next to its antenna.
The HyperLink Technologies HyperAmp 900 is a clever SS communications accessory
which places both an RF drive switched power amplifier and a low noise receive
amplifier only inches from the antenna. The amplifier measured switching from
receive to transmit in under 2 microseconds. Its operation is independent of the
modulation techniques used, so it should work with just about any 900 MHz Part 15 transceiver.
The concept sounded great, so we decided to evaluate HyperAmp for ourselves
in our lab. The HyperAmp is both well designed and a solid performer. It also
is rugged and should be highly reliable.
The amplifier is actually three components: (1) a switching power supply;
(2) a coaxial bias-T and (3) the amplifier unit itself. The amplifier unit is housed
in a small cast aluminum enclosure measuring about 4" x 5" X 1.5." It weighs about a
pound. Two flanges provide mast mounting capability using the included U-bolts. An "N-type"
connector at the top of the unit connects to the antenna feedpoint via a short adapter cable,
while a female "F-type" connector at the bottom attaches to the antenna feed from the SS radio.
HyperAmp's heavy-duty switching power supply is conservatively rated at 15
VDC @ 3.7 Amps. It carries UL, CSA, and TUV markings and is over-voltage and over-current
protected. Its wide range of input voltages (85-245 VAC) and standard IEC320 input connector
make it suitable for international use.
The evaluation unit tested was rated at 1.0. -2.4 W output and a receive gain of 23 dB.
HyperLink Technologies has introduced several lower and higher power models as well, but
they were unavailable at the time of this review.
According to the manufacturer's specifications, the HyperAmp 900 can operate reliably
with anywhere from 1 to 10 mW transmit power at its input. In the case of a 250 mW Wavelan /
AirLan card that represents anywhere from 14 to 24 dB cable attenuation between the transceiver
and the amplifier unit.
The unit delivered more than 1 watt output with 16 dB cable attenuation inserted
between the Wavelan card and the HyperAmp unit. That represents over 300 feet of Belden 9913!
In the next test we used a GRE GINA 5000 SS transceiver at 0.96 Watt output with 23.3
dB cable loss, producing about 2.5 Watts output from the HyperAmp unit. HyperAmp's
linearity looks very good (two-tone IM3,< -33 dB), even at 2.5 Watts PEP out.
On the receive end HyperAmp was no slouch -- noise figure tested at 6 dB and gain was 23.5 dB.
HyperAmp may very well be the ultimate addition to Wavelan / AirLan installations,
finally giving them the "muscle" they deserve. It is also a solid solution
to long antenna feeds for just about any SS transceiver. The high power HyperAmp units
could offer significant advantages for export applications where the 4 Watt EIRP
limitation does not apply.
HyperLink Technologies is marketing this amplifier for export sales and to manufacturers
of SS equipment who would package the unit with their products for FCC type acceptance under
part 15 Rules.
Shown below is a typical pulsed DS-SS output spectrum plot from the HyperAmp 900,
when driven by a 0.25 Watt AirLan board, through 175 feet of RG-59 cable. For more
details on the HyperAmp 900 or HyperLink Technologies call (516-822-1127).
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