HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 21, 2011, 03:21 AM
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Australia, QLD, Regents Park
Joined Mar 2007
3,605 Posts
Discussion
AMOS Antenna for Boating

While I am waiting for the rest of my bits and pieces for my FPV boat, I built the antenna recommended to me by Alex (IBCrazy).

I've only managed to trial it in the backyard at about 15 metres, but it does work at that range

Its designed for very narrow vertical beam-width and about 120 deg horizontal and a gain of 11.5-12.5 dbi. Whether mine works properly???


Nick
nick_75au is offline Find More Posts by nick_75au
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 21, 2011, 05:40 AM
FPV addict
Giske, Norway
Joined Aug 2009
521 Posts
Is it needed to ziptie those cables in picture 3?
And I think the bend of the cable is too much, it will affect the signal curve inside the cable.
I work with RF and a general rule of thumb is not to bent the cable so that it gets stretch marks in the inside of the bend.
This will cause the curve of the signal to be degraded.

Kristian
KristianS is offline Find More Posts by KristianS
Reply With Quote
Old Jun 21, 2011, 11:57 PM
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Australia, QLD, Regents Park
Joined Mar 2007
3,605 Posts
Hi Kristian,

I'm not sure, I followed someone else's work and built it the same way, I only re-measured for 1280 MHz. I had to deviate with the size of the wire as well, up-scaled antenna wanted 4 mm wire, mine is about 1.5 mm, Maybe a wrong assumption but the original antenna was radiating as well as receiving, this is receive only so I hope I haven't screwed it up by reducing the wire size.

Cheers
Nick
nick_75au is offline Find More Posts by nick_75au
Reply With Quote
Old Jun 22, 2011, 04:32 AM
FPV addict
Giske, Norway
Joined Aug 2009
521 Posts
Hi Nick,
Could be that the bend is ok though.
Difficult to see from the picture.
If you run your finger on the inside of the bend, and the surface of the cable is smooth, then it's ok
If you feel that the cable has wrinkels and it looks "damaged", then I would have swapped the cable.

But, try it, my guess is that it will work as it is
And post the video of the boat trip!

Cheers
KristianS is offline Find More Posts by KristianS
Reply With Quote
Old Jun 22, 2011, 06:34 AM
Gamble with Gravity
Gamblerman's Avatar
Joined Jun 2011
65 Posts
Did you scale your 4:1 balun to 1280MHz as well?

I made one of these antennas for a WiFi connection a while ago and it worked really well. This might be the antenna to use for land FPV vehicles.

-Alex
Gamblerman is offline Find More Posts by Gamblerman
Reply With Quote
Old Jun 22, 2011, 04:03 PM
Registered User
SW England
Joined Aug 2009
799 Posts
Why not use Circularly Polarised antennas on a boat?

CP will give you much less multipathing as opposed to linear (especially over water).

Nigel.
Devonboy is offline Find More Posts by Devonboy
Reply With Quote
Old Jun 22, 2011, 09:09 PM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
10,299 Posts
Nigel, I recommended he use the AMOS as multipathing off the water has such a shallow angle it will likely show up as little more than a color distortion. besides, the AMOS has a beam of 120 degrees and a gain of 11dbi! Perfect for boating

-Alex
IBCrazy is offline Find More Posts by IBCrazy
RCG Plus Member
Old Jun 23, 2011, 12:10 AM
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Australia, QLD, Regents Park
Joined Mar 2007
3,605 Posts
Hi,

I scaled the Balun as well, it ends up at 77 mm.

I just received the Easy Cap so I might be able to get a video this weekend, I discovered one of the 12 AH Gels in the boat had collapsed yesterday maybe just run on 12 v

Again thanks Alex for your time.

Nick
nick_75au is offline Find More Posts by nick_75au
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion For some in these parts the boating season has started. Prins Willem Dock Talk 9 Mar 25, 2011 04:24 PM
Gallery Sick rapids surfing!! Jet boating 4mods Racing Boats - Electric 9 Mar 21, 2011 01:56 PM
Sold Scratch Built Amos Moses, Cheap, Central TX, LPU only. tryharder Aircraft - Electric - Airplanes (FS/W) 0 Mar 11, 2011 02:52 PM
Video Going for a swim and fighting a tree with an Amos 3D foamy cleatis Electric Plane Talk 3 Jul 02, 2008 04:26 PM
Video Amos...Called it Amos Moses!~ fr0g_D Electric Plane Talk 3 Jan 07, 2008 10:26 PM