[time-nuts] Testing a GPS mag mount antenna

[skipp isaham]

Hello to the Group,

I picked a box of used (removed from commercial radio APRS type service) 
mobile/vehicle GPS Antennas. They are mostly the classic square molded, 
black plastic magnetic mount type, about the size of a bar of soap when 
cut to square (2/3 the size of a large bar of soap). The coax length 
terminates to an SMA connector.

I'd like to use some of these unmarked (obviously also unbranded) 
antennas for a few projects. The initial goal is to first set up a 
system to test (good/bad) the antennas, then determine their operation 
voltage, I suspect them to be 3.x to 5.x Volts. They are probably not 
"new enough" to be the type to operate of 3 or 5 Volts DC.

For testing... I purchased a nice NOS Mini-Circuits bias-Tee.

The intent is to now operate the antenna through the bias-tee, in to an 
analyzer. I would initially start the bias supply off at 3 Vdc, while 
also monitoring current.  If I don't receive an adequate/valid GPS 
signal off air, I could increase the bias up to 5 Vdc (rinse/repeat).

Should I be able to "see something" on or around the GPS frequency other 
than what I suspect will be something visual looking like a noise/pulse 
source/signal?

I don't yet have a GPS receiver with a signal strength indicator, else I 
could probably not have to send this post.  But, I do have access to an 
analyzer, I bought the bias-tee (was reasonable in price) and I'd like 
to test these 30 antennas to see if they work and determine if 3.x volts 
is enough... or 5 volts is required.

Thank you in advance for any replies and comments.

cheers,

skipp

skipp025 at yahoo.com