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[time-freq] Efratom GPS Antenna

2005 at bobby.net 2005 at bobby.net
Mon Jul 5 14:59:09 UTC 2010

First, I don't know anything about this antenna. 

If you can't find docs or data anywhere...
Assuming (which might be a mistake) it is an active antenna, and that DC is
fed up the coax, here are some ideas you can try. 

First using a multimeter check for an open, diode junction, or perhaps a DC
short on the coax.

If it looks like an active antenna, try applying 3V to it via your receiver.
Look at the signal quality indicators, you might only have signal strength
for the individual SVs being tracked, or worse only the number of SVs being
tracked. You can (and probably should) also monitor the antenna current
supply for rapid ramping.

Slowly increase the voltage to 3.3v and see if the numbers get better or
It is unlikely this antenna requires any more than 5V, so I would not go
higher than without some other information indicating a higher voltage was

Good luck.

73, Bobby k4bga

Original Message:
From: Eric Lemmon wb6fly at verizon.net
Date: Sun, 04 Jul 2010 20:47:45 -0700
To: rmeiring at iinet.net.au, time-freq at tapr.org
Subject: Re: [time-freq] Efratom GPS Antenna

No, but what does it have to do with the voltage required by an Efratom GPS
antenna?  Nice project, though...

73, Eric Lemmon WB6FLY

-----Original Message-----
From: time-freq-bounces at tapr.org [mailto:time-freq-bounces at tapr.org] On
Behalf Of rmeiring at iinet.net.au
Sent: Sunday, July 04, 2010 6:55 PM
To: TAPR time and frequency projects; John Koster
Subject: Re: [time-freq] Efratom GPS Antenna

Have you seen this little project for the GPS?



On Sun Jul 4 17:17 , John Koster sent:

	Eric, if you don't get an answer here, there are a couple of other
	you might try:
	On Sun, 4 Jul 2010, Eric Lemmon wrote:
	> I have a new Efratom GPS timing antenna that I hope to use for a
	> GPS-disciplined frequency standard. The antenna itself is a black
	> about the same shape and size as a disposable 10 ounce foam coffee
cup. The
	> base of the antenna has a sticker that reads: EFRATOM PN
012003-004 GPS
	> ANTENNA. The electrical connection is through a female TNC jack.
	> antenna is mounted with four screws to the top of an aluminum
fixture that
	> has a female N connector on its bottom end. The antenna and
fixture, along
	> with an Andrew cold-shrink kit and some hardware, are packaged in
a foam
	> tray that has the part number 104545-001.
	> In order to use this antenna without either damaging it or
operating it
	> inefficiently, I need to know what voltage it is designed to
accept. My
	> searches on the Internet have been fruitless. Can anyone on this
list share
	> some details about its specs?
	> 73, Eric Lemmon WB6FLY
	> _______________________________________________
	> time-freq mailing list
	> time-freq at tapr.org
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	John, W9DDD
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