Above 2.5'ish I've only used it on the spectrum analyzer for stuff
like short range data transmission modules.

Below that, at 2.1-2.2 there are alot of deep space satellites
(it's a 'sport' trying to receive a carrier of far away signals).
ULNA Ultra Low Noise Amplifiers is required directly at the feed.
0.5dBF
Dish and feedhorn is the way to do this.

At 1.7GHz I've used it for reception of Meteosat pictures
(got some on my old site www.gravitywell.org , for instance
http://www.gravitywell.org/meteosat/...globe_vis2.jpg )
Wide FM, 30-40kHz bandwidth required.
Dish and feedhorn was the way for me... 180cm dish.
Picture at http://www.gravitywell.org/station/station.htm
Regular line-amplifiers for sat.tv worked so so but I'd
recommend an 1.0dBF LNA at least... )

At 1.5 there was Inmarsat telephone calls, where I also used a dish :-)
but here I used a broadband helical feed at the focalpoint as the
transmissions are over such a wide spectrum, dish was a 'small' 150cm
I do belive yagis are starting to get usuable around here...
Picture at http://www.gravitywell.org/station/station.htm

At 1.42 - where I use it today - I use an 0.2dBF ULNA on my
3 meter dish with dual probe feedhorn http://www.gravitywell.org/station/dish.jpg .
Officially I use it for hydrogen line amateur radio astronomy.
In-officially I use it for seti - people look at you so weird if you say this hihi :-)

Perhaps you'll find the block schematic setup interesting,
http://www.gravitywell.org/station/block.png

Every band use require a different feedhorn, not just the probe length
but also the tube length and diameter (usually)....
....there is no ultimate 1-3GHz broadband directional antenna.... sorry...


The main thing is if there was a broadband antenna for the frequency
of interest, the losses in the cable, even a few feet could kill a
signal above 1G .

but isn't that why we have active antennas? to overcome the losses?
also your comments contradict these antennas:
http://www.wimo.de/wifi-omnidirectio...ntennas_e.html
and they're supplied with cables that go up to 8 meters.


Sure, I use 30meter H-1000 cable at 1.4-2.8GHz, you just need adequate
amplification, most cable types have diagrams showing the attenuation
at certain test frequencies.
http://www.elfaelektronika.lt/cgi-bi...914-25&lng=eng
For instance.... there's more types of cable to compare with, but personally
I like the Belden H-1000, double-shielded with copper braid and foil,
all for a reasonable cost....
You simply just don't use 100m RG174 at GHz frequencies :-)

what type of antenna are you using for 2.8GHz?