Moss Trooper Posted July 26, 2002 Share Posted July 26, 2002 Hi folks I have just taken delivery of a Re-Radiating antenna.. and on first use.. Recievin antenna outside (not at the best angle, it should be horizontal)and the Transmmiting antenna on my desk things are looking good. Just to give you some idea, here are a couple of piccies. Ant off http://www.staff.ncl.ac.uk/ian.paterson/ante%20off Ant on http://www.staff.ncl.ac.uk/ian.paterson/ante%20on.jpg I'm working on a set up I can use in car and field.. Should be interesting Moss de Boss... Sorta Quote Link to comment
+jeremyp Posted July 26, 2002 Share Posted July 26, 2002 Could you post a piccy of the antenna? I'd like to see how big it is. Also, does the GPSr show the position of the antenna or the GPSr? If it's the antenna, it'd be good for in cars and houses but not so good for locating caches in trees unless it's a) better at picking up the signal than the poxy Vista patch antenna and portable enough to carry around. If it shows the antenna position just think of the applications. You could place a few near your caches and have hours of fun while geocachers get confused about where they are. ------- jeremyp The second ten million caches were the worst too. http://www.jeremyp.net/geocaching Quote Link to comment
+Slytherin Posted July 26, 2002 Share Posted July 26, 2002 quote:Originally posted by jeremyp:If it shows the antenna position just think of the applications. You could place a few near your caches and have hours of fun while geocachers get confused about where they are. Or stand 35ft away and see how long it takes before The Hornet turns up. Alex. Quote Link to comment
Moss Trooper Posted July 26, 2002 Author Share Posted July 26, 2002 Sorry bout the quality but me batteries are low in my digi cam an flash didn't go off. Antenna pic http://www.staff.ncl.ac.uk/ian.paterson/antenna.jpg The Tx Antenna is about 60mm high.. Does it show it's own location or that of the GPS.. I dunno as yet.. will do a little experiment later and find out. The system amplifies the RX signal by about 35db I belive.. and this Tx antenna has a range of 2-3 meters. The Patch antenna has a magnet in the base.. ideal for sticking on the care roof and the Tx antenna has a couple of suckers for mounting inside the car or where ever. Leads are about 5 mtrs long. Moss de Boss... Sorta Quote Link to comment
Ben Pid Posted July 26, 2002 Share Posted July 26, 2002 Hi Moss this Anntenna looks really great...Im sure it is aswell. Sorry to plead ignorant all the time with GPS technology Im not exactly a whizz....but what does it do? Watch out its a Golfcourse... (Team Dan and Pid) Quote Link to comment
Ben Pid Posted July 26, 2002 Share Posted July 26, 2002 As in literally...Like the simple meaning of what it does...what it acheives...your post above I cant make head nor tail of. Pid Watch out its a Golfcourse... (Team Dan and Pid) Quote Link to comment
Moss Trooper Posted July 26, 2002 Author Share Posted July 26, 2002 The signal from the Satalites is very weak.. hence when your gps picks them up they are effected by buildings, TREES (everyones favourite) etc. Therefore when you look at the bars on the satalites page they indicate the strength of the recieved signal from the sats. The lower the bar the weaker the signal. On the Re-radiating antenna there arw two aerials, one recives the signal (Rx) and one Re-transmits the signal (Tx) The signals from the sats are picked up by the Rx aerial (antenna) and fed via the cable to a small amplifier in the base of the Tx aerial. The amplifier boosts the weak signal into a stronger one and then sends to a small transmitter which sends it to the TX aerial and so to the outside world. The GPS picks up this much enhanced signal. The advantage is that in trees or cities you get a signal which the GPS can work on. It won't improve things in dence woodland, but if you have a location of say 70-80 ft error in a wood, with this you should get back to your 20 odd ft mark.. It won't better that as the algorithums in the GPS software have theire limitations also.. Moss de Boss... Sorta Quote Link to comment
+Lassitude Posted July 26, 2002 Share Posted July 26, 2002 I guess this is to get round 'GPS proof' Car Windscreens. My eMap works fine in the car. I would buy anything that would help me find Caches under trees but I don't fancy lugging a car battery about and/or wiring myself up so I look like a Borg. Cheers Chris LASSITUDE- (noun) Tiredness and apathy: a state of weariness accompanied by listlessness or apathy[15th century. Via French from Latin lassitudo , from lassus 'weary'.] Quote Link to comment
Morseman Posted July 27, 2002 Share Posted July 27, 2002 quote:Originally posted by Lassitude:I guess this is to get round 'GPS proof' Car Windscreens. Wouldn't one of the small, flat, antennas that have a magnetic 'foot' be less expensive? I have one which I adapted from a GPS PCB that I bought some time ago. I took the plug which came with the antenna off, and soldered a BNC socket (which is what my GPSIII+, and some other units use) on instead. Signals are much improved using this antenna on the roof of the car. I suppose people who use units with no facility for attaching an antenna connected with a length of cable have to use the re-transmitting system though. I have thought about mounting a small metal plate on a pole, and taking this with me to mount the external antena on when walking. A bit awkward, but might make a bit of a difference when under the trees. I think I've seen pictures of people with antennas on poles, in the USA, as well. Anyone know where these come from? --... ...-- Morseman Quote Link to comment
+Lost in Space Posted July 27, 2002 Share Posted July 27, 2002 quote:Originally posted by Slytherin: Or stand 35ft away and see how long it takes before The Hornet turns up. Another believer!! Quote Link to comment
+The Hornet Posted July 28, 2002 Share Posted July 28, 2002 So all I need to do is get a 35' long pole and I'll know where I am Quote Link to comment
Ben Pid Posted July 28, 2002 Share Posted July 28, 2002 Almost Peter...... LoL. Watch out its a Golfcourse... (Team Dan and Pid) Quote Link to comment
+Subarite Posted July 28, 2002 Share Posted July 28, 2002 Re-radiating antennas only work when you are very close to the Tx (transmitting) antenna due to the huge path loss from it, which will overwhelm the gain from the Rx (receiving) antenna/amplifier gives. It will probably be OK for use in a car but Hornet has absolutely no chance of it being any use at all!! Andy. Quote Link to comment
+The Hornet Posted July 28, 2002 Share Posted July 28, 2002 So it seems I'm fated to spend my life never knowing where I am. A bit like the ancient mariner perhaps. And I thought this thing round my neck was a very large dead budgie Quote Link to comment
Moss Trooper Posted July 29, 2002 Author Share Posted July 29, 2002 I hope to get the other version of this type of antenna and rig it to my day pack. The Tx range is only 0.45cm as against 2-3 meters so should be no problem with Tx swamping Rx. As they draw only about 30mA a seald 12v 1.3Ahr lead acid battery should keep it powerd for a good days caching at an all up wight of 0.6 kilos. By my reconing this is no worse than running round with yer GPS in one hand and your PDA in the other and 0.6k is nowt to the weight of junk I carry when I'm out an about Moss de Boss... Sorta Quote Link to comment
Team Tate Posted July 31, 2002 Share Posted July 31, 2002 I saw a Magellan re-rad antenna for about £70 in Maplin about a year ago. I thought this was a bit steep so I set about building my own. Luckily enough, I had a spare Motorola active antenna which was the basis of the project. Using some other spares and about 20p's worth of extra material, I built the antenna and it has performed well to this day. Total cost - 20p! OK, the antenna would have set me back about thirty quid, but £30.20 is still better than £70! Team Tate Remember - if it's moving, it's not dead... Quote Link to comment
+paul.blitz Posted August 1, 2002 Share Posted August 1, 2002 My boss has one very similar on his car, and he found that the rx antenna was a mag mount, so just "places" on the car... He says it works very well Team Blitz Ok, we've found it, now where did we put the car? Quote Link to comment
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.