HA-26 amplified quadrifilar antenna

[jonasolof]

Is presented at http://www.sanav.com/gps_antennas/ha-26.htm

It has 30 dB amplification, a SMA connector and consumes about 28 mA at 4.5-5.5 volts.

I ordered one from Sanav at CeBIt and will employ a modfied bias-tee from www.wi-sys.com to feed it 4.8 volts from an external battery pack for the iQue. It could prove to be an interesting antenna for hiking under canopy. It is often said that quadrifilar antennas function better under those conditions than patch antennas, although it could simply be that high end units such as the magellan sportrak and Meridians that use it, are also more sensitive. It should also be less sensitive to tilt than a patch antenna - and more susceptible to multipath, which may or may not be a disadvantage.

It is not a miniature quarifilar antenna with a ceramic dielectrum like the GeoHelix-H from www.sarantel.com but has about the size of the passive Quadrifilar antenna of the StreetPilot.

[wa4phy]

Jonas, that's a lot of current for an antenna. 28 ma will definately need some external source of power.. I think I measured the garmin antenna current draw at just under 5 ma. You are correct tho, it will definately be less prone to angular position.

Sam

[abid786]

Did you get your location, N 33 30.677 W 82 08.217, off your iQue? I've always wanted to do that, but I am iQue-less. lol:D

Abid

[jonasolof]

Originally posted by wa4phy
Jonas, that's a lot of current for an antenna. 28 ma will definately need some external source of power.. I think I measured the garmin antenna current draw at just under 5 ma. You are correct tho, it will definately be less prone to angular position.

Sam

In his ongoing tests on 16 (!) "low voltage " antennas, Sam Storm van Leuven found that the Garmin27C doesn't loose 3dB amplification under its optimal level until down to 1.4 volts. Consumption then is 4.5 mA. But absolute gain for this antenna is still much lower than for other antennas, which are mostly 2 stage. The Gilsson looses 3dB at 2.2 volts, and but won't get more than 2.0 volts from the iQue (drain 5.5 mA). The Gilsson still performs better than the Garmin27C.

This goes to show that NO antennas work within their optimal conditions when connected to a low voltage GPSR like the iQue (except for the Garmin 27C which drops out since its best isn't good enough).

Thus my interest for the HA-26, which might be a good antenna that one could let work under opttimal supply conditions. 28 mA is not much in comparison to what the iQue draws from an external power source.

There have been lots of discussions on sci.geo.satellite-nav on quadrfilar vs patch antenna performance, especially under canopy. The quadrifilar always tend to win in tests. Maybe because they are fitted to high end receivers, or should we say a good beginning to a high end. Since the enduser can't analyze antenna perfromance separated from receiver performance it is hard to know (well, with the latest units which have a quadrifilar antenna and an external antenna connector, one could test with the Gilsson, but it still wouldn't work under the right voltage supply conditions.)