RunRyder - looking inside a stock antenna

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Aerial Photography and Video > looking inside a stock antenna

ELOSSAM
Veteran
Location: Es

If someone has interest to know what´s inside the stock wireless system antennas this is one of them.Seems to be a simple dipole.

On the other side here´s a 5db one quite different builded. Cant say nothing about it,the type of antenna it´s or the best use we can expect from it: receiving, transmitting,along its axis, perpendicular, directional or not... May be someone wants to explain me/us about it.

Elossam

11-30-2003 Over year old.

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MPA
Elite Veteran
Location: Australia

E

Top one is a 1/4 wave dipole

Bottom one looks like 5/8 wave so requires a base loading.
Could wrong on that its a bit long for 5/8 2.4gig

5/8 wave is ok but you need power because of its loading so generally one of those screwed on a low power AV unit will not be as good as the shorter 1/4 wave dipole

Ive done it and the 5/8 wave was crap on low power and still have the 1/4 wave.

Rgds

11-30-2003 Over year old.

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ELOSSAM
Veteran
Location: Es

Thanks Dave. Do you know how abouth how these antennas radiate/receive better?
Elosam

11-30-2003 Over year old.

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ELOSSAM
Veteran
Location: Es

Tks John. Have not noticed any improvement between both of them and have currently changed to a "Pal-rotor" antenna with circular polarized combo that works great together but as I´ve two stock and a 5db unused ones I can play with them without risk

http://runryder.com/helicopter/t49030p3
+
http://www.blackwidowav.com/patchantenna1.html#

Elossam

12-01-2003 Over year old.

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MPA
Elite Veteran
Location: Australia

not sure on that E

I use the same 1/4 wave dipole is Julian (bill "y2b" antenna), Julians is much better build, its very important to have precision in 2.4ghz range so its not just for good looks his will work better no doubt.

Any base loading on a Tx antenna will have to have some power used up to drive the loading so I think the low power units dont have enough, in simplistic terms.

On the patch antenna, I was told by someone who doesnt post here that flyboys antenna was a 5db or 8db patch, I spoke to Julian about this some time ago and intended to get one myself as flyboy seemed to be getting good results from it, the source that informed me claimed they where good to go for the job.
Glad to see they work well.

Fact is I dont use a downlink anymore on the heli as Im doing it solo and not getting paid for it I dont have to fuss too much on the pics, I might setup some POV flight like you guys do when I can afford some headset glasses.
I will be using the downlink and pan tilt soon on another platform (still in construction) I can get paid for operating. (not a flying one)

Rgds

12-01-2003 Over year old.

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FlightPower
Veteran
Location: Herts UK

E,

With the stock antenna like you show, I've accidentally got great success by having the TX dipole stick out horizontal instead of vertical.

(I knocked it and it worked so well I never put it straight).

I'm sure I'm losing more than 50% straight up in the sky but the "dead-spot" straight out of the end of the antenna is no longer pointed at the RX. I'm also using Bill's patch antenna on the RX, works great...

I imagine the Julian-built / Yb2normal design 1/4 wave groundplane antenna will have more suitable radiation pattern for our use and better overall gain than a horizontal-mounted stock dipole but you can probably fly out of sight with either depending on your eyesight and how crazy you feel that day.

Julian.

12-01-2003 Over year old.

MPA
Elite Veteran
Location: Australia

Im using the dual quad, works OK but if Im gunna try the fly by glasses deal Ill fkn ****e mself if I loose contact.
Might try Bills patch antenna too, probably better than the dual quad..

12-01-2003 Over year old.

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ELOSSAM
Veteran
Location: Es

Julian.
With the stock antenas I´ve tested all possible combinations, both stock; stock+5dg receiver; 5db tx + stock receiver and all possible angle:180º; 45º and 90º. The best of all was the 5db tx full extended horizontal to groung and same with the receiver stock one but far away from the ground plane + circ.polarized combo . This combination gives me some glitches when hovering (may be it´s too much directional) but as soon the helis has more tha 5 mts high the image is terrible estable and have noticed only a single 1 sec. glitch after 1 hour flying and due to it this is the one that gives me the needed confiance to do some out of sight excursions

Have not tested your option: stock + Bill patch. May be the day yours one breaks I´wiil give it a chance.

Dave the tx has 500 mW output (cant say if real but thats what the box said)

Elossam

12-01-2003 Over year old.

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GauchoVolador
Senior Heliman
Location: Buenos Aires, Argentina

900mhz tx/rx

Guys

I've just bought a 900Mhz system.

Couldnt try it on flight yet but made a couple of tests on the ground with the standard stock whip antenna in both sides.
The maximun line-of-sight range i've achieved was about 130mts (about 450feet).

Have anyone of you experienced with colinears omnis on the rx?
Any thoughts to improve 900mhz system?

Thank you responses!

12-02-2003 Over year old.

yb2normal
Senior Heliman
Location: Broomfield, CO

MPA,

Generally speaking, higher gain antennas achieve their gain at the expense of a 'tighter' radiation pattern. Your poor results with the 5dbi antenna might be attributed to that, since that antenna will have more null spots than the smaller, lower gain antenna.

Gaucho, I know of some guys in Floriday who used a 15dbi collinear antenna and one of my 1 watt 2.4ghz transmitter to fly over 5 miles away. Keep in mind however that this gain comes at a price as I mention above... They were flying fairly low during this test. The higher the gain of your collinear antenna, the more squashed the signal coverage pattern will be (a donut around the antenna). This is not a problem for point to point communications on the ground, since the antennas are sitting firmly in the coverage area of each other, but could cause problems in aerial applications where you find yourself flying high over yourself versus ranging far out in the horizontal.

Regards,
Bill

12-02-2003 Over year old.

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ELOSSAM
Veteran
Location: Es

Gaucho
Desconozco el tema de 900 mhz pero seguro que aqui encuentras quien te ayude
http://www.rc-cam.com/forum/index.php?showforum=2

12-02-2003 Over year old.

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GauchoVolador
Senior Heliman
Location: Buenos Aires, Argentina

yb2normal

Thank you for your comments about collinears, I've also been peeking on your site and I found some SUPER-INTERESTING projects, some of them solving many of my concerns. Congratulations!! and thnks

ELOSSAM

Muchas gracias por el link, justamente navegandolo termine llegando a la pagina de yb2normal y de ahi saque varios proyectos. Si bien hace tiempo que vuelo helis, recien ahora me estoy metiendo en el tema de usarlo como plataforma de produccion de video. Asique encontre muchas cosas interesantes. Un abrazo grande y seguimos en contacto. Saludos!!!

Saludos a todos!

12-03-2003 Over year old.

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