[time-nuts] GPS antenna voltage/current -- some tests

[John Ackermann N8UR]

While working on a current limiter circuit for a GPS bias tee, I decided 
to measure some antennas I had laying around to see what voltage they 
wanted and at what current.  I thought others might be interested in the 
results.

I used a network analyzer to sweep 1 - 2 GHz with a little stub antenna, 
and set the antenna next to that.  The resulting signal level at the 
peak frequencies seemed reasonable.  For each antenna, I started at 0V 
and increased until the amplitude of the filter peak stopped getting 
bigger, and recorded that voltage and frequency.  Other than voltage and 
current, everything was very uncalibrated and random.

Results below, in no particular order

John

++++

Motorola ANT1A07975 mag mount hockey puck:
	Full gain: 4.7V @ 19mA

Generic hockey puck of unknown age (but old):
	Full gain: 6.5V @ 23mA.  At 5V, down about 3dB
	and current 17mA.

Generic bullet timing antenna:
	Full gain: 4.2V @32mA; 37mA @5V
	-- fairly sharp filter peak

Symmetricom 53532A L1 Reference Antenna (bullet):
	Full gain: 3.8V @ 18mA
	-- *very* sharp filter peak

u-blox ANN-MB-00-00 mag mount dual-frequency hockey puck:
	Full gain: 1.9V; 17mA @ 3.3V

Ashtech ASH11661 dual-freq survey antenna (pretty modern):
	Full gain: 2.6V @ 54 mA

AeroAntenna AT2775-42NTW-TNCF-000-RG-26-NM
dual band survey antenna:
	Full gain 5.8V @ 44mA

Trimble Zephyr Geodetic:
	Full gain: 4.33V @ 96mA (!)
	-- at least 10 dB more gain than any other