Hi David,

No, no ground plane. Don’t really have a lot of room for that in the window. Out of curiosity, how large of an impact have you found with a ground plane?

Btw, I love the pan!

Denny

Hi

You very much do not want to put a ground plane on one of the modern survey
antennas.(Chinese or US or Canadian or …)  The better ones are very explicit
about this. They are optimized to sit on a pole in free air. Anything else and the
pattern is degraded. ( = multipath gets worse)

Bob

I can see that on survey situation but will it affect timing installations?
Will you give me an idea how far those bullet type antenna needs to be?  My antenna sits on a very short pole (2 feet?) and its base is mounted to frame of my screened in porch.  Roof and structure is aluminum, which is very much like ground plane and reflective.

(Mr.) Taka Kamiya
I'm stuck in a wormhole....  Hello, worms!

On Tuesday, April 30, 2019, 5:01:05 PM EDT, Bob kb8tq <kb8tq@n1k.org> wrote:  

Hi

You very much do not want to put a ground plane on one of the modern survey
antennas.(Chinese or US or Canadian or …)  The better ones are very explicit
about this. They are optimized to sit on a pole in free air. Anything else and the
pattern is degraded. ( = multipath gets worse)

Bob

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and follow the instructions there.

Hi

The pictures shown earlier are of a “survey antenna”. In the post I was careful to refer to a “survey antenna”
as the point of the post. Ideally you want to be meters away from any metal.

Bob

Yes, I saw your particular mention of survey antennas.  My concern was that multi-path will affect any setup. 

I've seen pros and cons of placing a cookie sheets and pizza pans under antennas to enhance "efficiency".  I'm not exactly buying into this idea but I thought your discussions were similar.
I have two identical antennas and one is already installed in a manner I described.  I suppose I could purchase a pole and mount it all by itself in middle of my yard.  Comparison will be very interesting.
Thanks for your reply.

(Mr.) Taka Kamiya
I'm stuck in a wormhole....  Hello, worms!

On Tuesday, April 30, 2019, 6:28:11 PM EDT, Bob kb8tq <kb8tq@n1k.org> wrote:  

Hi

The pictures shown earlier are of a “survey antenna”. In the post I was careful to refer to a “survey antenna”
as the point of the post. Ideally you want to be meters away from any metal.

Bob

Yo All!

On Tue, 30 Apr 2019 22:52:26 +0000 (UTC)
Taka Kamiya via time-nuts time-nuts@lists.febo.com wrote:

The best explanation I have seen is here, with lots of pretty graphs:

https://www.u-blox.com/sites/default/files/products/documents/GPS-Antenna_AppNote_%28GPS-X-08014%29.pdf

The %28 is a "(' and the %29 is a ')'

See section 5.  Especially this: "A good allowance for ground plane size
is typically in the area of 50 to 70 mm2."

RGDS
GARY

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
gem@rellim.com  Tel:+1 541 382 8588

    Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin

Hi

For a variety of reasons, a puck antenna is a bad choice for a lab timing receiver.
Because the ground plane (and other issues like feed line) are a variable, getting a
good pattern is a matter of luck. Multipath ( = low angle) rejection is rarely going to
work well with them. They also are not really good at standing up to years and years
of exposure outdoors.

Since “real” antennas are a sub $20 sort of thing at L1 and sub $70 at L1/L2 … why
bother with the minor leagues? Get something that does the job properly and use
that.

No matter what you do, (survey or timing) multipath is what gets you. Rejecting it
is what you design the antenna for. Stuff that is properly polarized, you keep. Stuff
that is not properly polarized you strongly reject. Very low angle stuff (especially below
zero degrees) you strongly reject. Your typical ground plane acts as a knife edge at low
angles to “help” below zero degree stuff …. not good.

Indeed some light weight antennas take off into spurious oscillation land under this or
that condition. When they do nothing works well. The answer there is to get another
antenna. We’re talking the price of a case of beer ….

Bob

Denny Page via time-nuts writes:

As long as we're talking ceramic patch (puck) antennas, I've seen around
15dB improvement repeatedly (as reported by the receiver statistics)
with otherwise non-optimal placement of the antenna (indoors, viewing
the sky through a wooden roof covered with rolled roofing).

As mentioned elsewhere in the thread, the better antennas come with
their own (optimized) ground plane if they need one.  Good luck finding
data sheets for the puck antennas, but if you do get hold of one,
sometimes they do show how the directivity changes with different sized
ground planes.  If you have a magnetic puck you best use a magnetic
steel surface, the cap of a large diameter can works quite well also.
Otherwise aluminum foil is just as effective and easily cut or folded
away if you want to try to exclude reflections.

With multiple active patch antennas going to different receivers, I've
found that at least the antennas I have do not like to be placed very
close to each other.  Spacing them at least half a wavelength from each
other seems to take care of that.  If the backside shield of the active
patch antenna is connected to ground, then the ground plane must be
isolated from all (but possibly one) antenna; otherwise the resulting
ground loop will degrade reception.

Regards,
Achim.

+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Samples for the Waldorf Blofeld:
http://Synth.Stromeko.net/Downloads.html#BlofeldSamplesExtra