Author Topic: Amplified GPS Antenna  (Read 787 times)

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Offline Siskiyou

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Amplified GPS Antenna
« on: January 01, 2006, 02:06:43 PM »
I have been testing a Gilsson Techonlogies amplified antenna with a 90 degree MCX connector with my Garmin Mapping 76C gps.  The same antenna will work with many other gps units.  They claim it is the same as the Garmin GA-27 low profile automotive antenna.  Garmin's price is around $99.00.

I chose to get mine with a nine foot cord.  Different cord lengths can be ordered.  I order mine with the windsheild suction cup mount.  

The amplified antenna is powered by the gps unit through the same cable as it received the signel.  While I plan on using the antenna from a vehicle I also wanted to see what impact it has on battery life.  I charged up a set of 2500 mAh Energizer batteries for the test.  The batteries lasted 19.5 hours.  

I started out the test by plugging the antenna into the gps unit and placing it on our dinning room table.  Normally I recieved four satellites at this location, and five on and off.  During the same period I had a Garmin Legend w/o an external antenna operating.  The Legend was recieving four satellites most of the time, but would drop down to three on and off.

When I powered-up the 76C with antenna it quickley brought up nine Satellites.  During the testing period it consistantly showed eight and nine satellites.  Not bad under a roof and large oaks outside the windows.  

My next test results came as a surprise.  I went for a hike with the antenna attached, and placed in a vest pocket.  Reception was very poor.  I was down to 2 satellites.  I disconnected the antenna, and with the gps out of my pocket it was recieving four satellites.  Normally this is not a great location and four satellites with the 76C and the Garmin Legend is normal.

I have read articles where some people have sewed a pocket in a cap to hold the antenna.  I will not try that, I do not believe that is good for the old brain bucket.  I could put a L shape mount on the frame for my Alice pack and try that. But I do not normally use a packframe except to carry gear or meat.  The power cable is light and easly coils so that is not a problem.

I then tried the antenna on the suction mount in my vehicle.  I stayed in a stationary position with the sky on blocked by a large oak and a few other trees.  A poor location but the Satellites page showed four stronge bars and a couple of bars in the middle of the grid.

I need to test it on the road hooked with the gps unit powered off the vehicle.

Current testing shows a fifty to seventy percent improvement in reception, except when carried in a vest pocket.  

Price:  $28.76 along with the windsheild mount, tax and shipping.
There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.

Offline victorcharlie

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Amplified GPS Antenna
« Reply #1 on: January 02, 2006, 03:44:22 AM »
Good info........As I sit here at the computer, my legend has 6 sats, and the accuracy is 13 feet.  If I move over next to the fridge, it'll go searching for sat's............

The legend won't take an external antenna, but I like the idea!  Not sure I'd want the extra weight and the annoyace of all the wires and stuff while trying to slip through the brush, and I may have an exceptional receiver, but during the winter hunting season I seldom loose signal or go less than 4 sats.  

Man, you pegged the rechargables.....best thing I've bought in awhile.
"Extremism in the defense of liberty is no vice. Tolerance in the face of tyranny is no virtue."
Barry Goldwater

Offline Siskiyou

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Amplified GPS Antenna
« Reply #2 on: January 02, 2006, 07:38:53 AM »
The antenna is lighter then half a peanut butter sandwich.  I have the 9ft lead in a three inch coil.  I have the coil tied with wire ties in two locations and the wire is not much of a problem.  But the short tail to the gps could be a hangup crawling under brush or in low limbs.  

 I agree and for most of my hunting the antenna will stay in the rig.  I might give it a try while geocaching.  Which reminds me, one of my caches maybe under water now.  I'll have to go look for it in a few weeks if the weather settles down. :roll:
There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.

Offline victorcharlie

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« Reply #3 on: January 02, 2006, 08:24:33 AM »
Little bit of rain out your way?
"Extremism in the defense of liberty is no vice. Tolerance in the face of tyranny is no virtue."
Barry Goldwater

Offline Siskiyou

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Amplified GPS Antenna
« Reply #4 on: January 02, 2006, 03:32:29 PM »
Lots of rain all the way to the top of the mountains last week.  The rain wiped the snow off the Serria's.  It is raining again but the good news is that the snow level is dropping down to about 4000 foot elevation.  That will slow the rush of water off the mountains.  But local flooding will still be an issue the next few days.  It has slowed down.  This latest storm was lighter then expected and I only measure around 2.5 inchs of rain in the last 24 hours.


The fishing in the Sacramento River Delta will be wiped out for a month or so because of the high flows.  Lots of debra which will make it dangerous for boaters.  Rivers like the Klamath and Eel also took a beating but should be fishable in the late spring.  I suspect some Steelhead found their way up into the upper drainages this year.  

The good news for guys like me that fish man-made lakes is that the rivers are bringing in a lot of debra.  That should slow the water skiers down later in the spring.  A large stump or log floating just below the surface is hard on the body.

I made sure all the batteries for my portable radio's are charged up.  We have a good supply of bottle water, and chow.

We were having dry weather before the big storms and I was gearing up to go fishing.  I think I will put that off for a few weeks.

Mud slides will be a big issue the next few months.  Every time it rains the hillside will start moving.
There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.

Offline victorcharlie

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« Reply #5 on: January 02, 2006, 04:01:21 PM »
I've been following this on the news......seems Texas and Ok could use some of the rain your getting.

Weather man says your going to dry out some this week as the jet stream returns to a more northerly flow.......

Sounds like a real mess out there.......
"Extremism in the defense of liberty is no vice. Tolerance in the face of tyranny is no virtue."
Barry Goldwater

Offline Siskiyou

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Amplified GPS Antenna
« Reply #6 on: January 02, 2006, 07:38:48 PM »
We are lucky here.  The weather keeps breaking when it starts looking bad.  If the heavy rain kept up it would have been nasty.  But the folks downhill are getting wet.  It is 2222 hrs. here.  I just went out and looked to the West.  Clouds are lifting and it looks like it is clearing.  But this is not the old days.  I just checked the NOAA site and it looks like it is clearing up all the way to the Pacific.

I just talked to a brother who is down stream a long ways.  His job site is shut down for a few days because of run off and high tides.  But the bottomline is that my family has been lucky and has not suffered any real damage.  We are concerned about those who have suffered damage.

I would like to send a few inchs of rain to those folks who are dealing with the fires.
There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.