Re: [time-nuts] Procom GPS4 quadrifilar antenna...
Time-nutters--
The Procom website lists the noise-figure of their quadrifilar
LNA as:
GAIN > 30 dB
NOISE FIGURE < 3 dB (incl. input filter).
Typ. approx. 3 dB
I am a little surprised at this relatively high NF for a
product in this price category. Even most low-end
mass-produced consumer grade GPS antennas are
spec'd at 1.5 to 2.0 dB NF.
Mike Baker
On 6/8/12 5:20 AM, Michael Baker wrote:
Time-nutters--
The Procom website lists the noise-figure of their quadrifilar
LNA as:
GAIN > 30 dB
NOISE FIGURE < 3 dB (incl. input filter).
Typ. approx. 3 dB
I am a little surprised at this relatively high NF for a
product in this price category. Even most low-end
mass-produced consumer grade GPS antennas are
spec'd at 1.5 to 2.0 dB NF.
One thing to check on NF specs is the temperature range over which they
are valid. A "consumer" spec might be "at room temperature only", a
more rigorous spec might be "at -20 to +50C".
Is it worth driving from Thousand Oaks to Altadena for Snowcones (qty 5) tomorrow ?
--- On Fri, 6/8/12, Jim Lux jimlux@earthlink.net wrote:
From: Jim Lux jimlux@earthlink.net
Subject: Re: [time-nuts] Procom GPS4 quadrifilar antenna...
To: time-nuts@febo.com
Date: Friday, June 8, 2012, 6:23 AM
On 6/8/12 5:20 AM, Michael Baker wrote:
Time-nutters--
The Procom website lists the noise-figure of their quadrifilar
LNA as:
GAIN > 30 dB
NOISE FIGURE < 3 dB (incl. input filter).
Typ. approx. 3 dB
I am a little surprised at this relatively high NF for a
product in this price category. Even most low-end
mass-produced consumer grade GPS antennas are
spec'd at 1.5 to 2.0 dB NF.
One thing to check on NF specs is the temperature range over which they
are valid. A "consumer" spec might be "at room temperature only", a
more rigorous spec might be "at -20 to +50C".
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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On 6/8/12 9:21 AM, steve heidmann wrote:
Is it worth driving from Thousand Oaks to Altadena for Snowcones (qty 5) tomorrow ?
--- On Fri, 6/8/12, Jim Luxjimlux@earthlink.net wrote:
http://www.jpl.nasa.gov/events/open-house.cfm
Well.. they've got all the stuff setup for JPL open house.. Is it worth
an hour's drive?
The weather is nice. There's lots of MSL related stuff out. If you have
little kids, there's the usual "drive a rover over a row of children"
thing.
I don't know if the totally cool Athlete rovers will be out. Hopefully
yes. The Mars Yard is always fun, and they'll have something out
crawling around.
http://www.jpl.nasa.gov/video/index.cfm?id=922
Will there be tours of the frequency and timing lab? (which would be of
particular interest to time-nuts).. nope.. But, if you're in the area
some other time, send me a note, and I'll see what I can do. Down in my
lab, we don't have anything nearly as good as what they've got up there.
(but they send me their maser derived reference on a fiber optic pipe...)
That would be great. Softball tournament on Saturday in Newbury Park , JPL openhouse Sunday.
--- On Fri, 6/8/12, Jim Lux jimlux@earthlink.net wrote:
From: Jim Lux jimlux@earthlink.net
Subject: Re: [time-nuts] Procom GPS4 quadrifilar antenna...
To: time-nuts@febo.com
Date: Friday, June 8, 2012, 1:26 PM
On 6/8/12 9:21 AM, steve heidmann wrote:
Is it worth driving from Thousand Oaks to Altadena for Snowcones (qty 5) tomorrow ?
--- On Fri, 6/8/12, Jim Luxjimlux@earthlink.net wrote:
http://www.jpl.nasa.gov/events/open-house.cfm
Well.. they've got all the stuff setup for JPL open house.. Is it worth an hour's drive?
The weather is nice. There's lots of MSL related stuff out. If you have little kids, there's the usual "drive a rover over a row of children" thing.
I don't know if the totally cool Athlete rovers will be out. Hopefully yes. The Mars Yard is always fun, and they'll have something out crawling around.
http://www.jpl.nasa.gov/video/index.cfm?id=922
Will there be tours of the frequency and timing lab? (which would be of particular interest to time-nuts).. nope.. But, if you're in the area some other time, send me a note, and I'll see what I can do. Down in my lab, we don't have anything nearly as good as what they've got up there. (but they send me their maser derived reference on a fiber optic pipe...)
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
On 8 June 2012 13:20, Michael Baker mpb45@clanbaker.org wrote:
Time-nutters--
The Procom website lists the noise-figure of their quadrifilar
LNA as:
GAIN > 30 dB
NOISE FIGURE < 3 dB (incl. input filter).
Typ. approx. 3 dB
I am a little surprised at this relatively high NF for a
product in this price category. Even most low-end
mass-produced consumer grade GPS antennas are
spec'd at 1.5 to 2.0 dB NF.
Mike Baker
I know at least in antennas, consumer and at low/mid end professional
products rarely meet their specs.Even SWR, which is fairly easy to
measure is often not met on antnenas. Gain is never measured - the
figures are just made up. It seems everyone lies, and needs to lie to
remain in business. Just look on eBay and see some of the redicusly
high gains for some antennas, where the sellers has a feedback of
10000 and 99.9% positive. Of course, for radio hams, dramatic lies
about the SWR would be detected, but gain figures are unlikely to be
challenged.
That said, I don't undeerstand how something can have a spec of < 3dB
NF, then have a typical noise figure of approximately 3 dB. But I bet
a lot of manufactures of GPS antennas have the NF of their device
being that of the amplifier chip they use, and all losses, like those
of filtering, are ignored.
Dave