baerster

Hello,

I bought a DSMX 2.4 ghz receiver that has a short, insulated wire as an antenna. I have questions about how those antennas work:
1. If carbon fiber in the fuselage of the plane and the metal servo rods might interfere with the signal, does it do any good to have part of the antenna wire stick out of the fuselage into open air?
2. Is that length of the antenna wire critical? For instance, could making it longer actually make reception worse?
3. Is it important for the antenna wire to be straight, such that if it's bent it could make reception worse?
4. Does that little antenna have just one conductor, or is it like a loop, or something else?
5. Is it critical for the antenna to be coated with insulation?

Thanks for any answers to these or related questions you may have,

-Tom

Joseph Frost

You must not alter the short RX antenna, try to keep it as far away as practical from motor, ESC, Batteries, Servos etc. Keep it as strait as possible, sticking it out of fuse can only improve reception and insulation covering wouldn't make any difference. Just a tip, fit a short piece of heat shrink as it exits the casing to prevent breakage! As an example, I just got small 6ch. RX for micro models, the short antenna doesn't have any insulation on it to minimize the weight, for extreme light models. It might have some clear spray coating to stop oxidation, perhaps.

speedracerntrixie

My Feedback: (29)

Beg to differ on the external increasing range. Unless the model is 80% or higher CF in its construction.

Joseph Frost

There's a difference between an "improvement of reception" and increase of range, so I also differ, LOL.

speedracerntrixie

My Feedback: (29)

My Supra pro sailplane has a fair amount of CF, I fly Jeti radio systems that has telemetry for signal strength and it has never shown less then 100% for both antennas.

The OP is looking for validation that a couple CF rods in his model is what causing his issues rather than his off brand RX or his ESC.

Hydro Junkie

Don't know if that's true or not but that's why I haven't posted in this thread. I'm going to change that to answer a few questions
The length of the EXPOSED antenna probably isn't critical but could be, and probably is, very important for proper reception. I've had no issues with my Futaba R304SB receivers and they all have 1.1" of exposed wire from the factory
The antenna wire doesn't have to be straight but it can't be kinked, looped, wrapped around anything or sharply bent
ALL receiver antennas are a single wire, They don't loop or anything else. In fact, the signal from the transmitter creates a signal inside the receiver wire that the receiver circuitry uses to control the aircraft, car or boat's servos and, ultimately, the model. Therefore, if the antenna or circuitry is not performing properly, you can expect you plane to consistently crash. That said, as we've discussed in the other thread, your antenna would have to be pretty much enclosed in CF to have that be an issue.

Just got to thinking, did you ever tell us what brand and model receiver and servos or ESC you're using?

Joseph Frost

Carbon Fiber never worried me in any of my models, I use huge amount of it in every foamy model to keep it riggid! 6+ meters in my lightest model at 144grams, not to mention huge amount sandwidged inside Depron sheets with these Delta GIANTS. No issue with reception.

6+ meters in this one.

Huge amount of CF in these 10Kwatt Depron GIANTS.

mkjohnston

My Feedback: (2)

Hi ,2.4 Ghz RF Technology is short wave length tech. With 72mhz tech the wave length was much longer and you had a long antennae that your routed outside you airplane for best reception When you look at your antennae do you one or two antennae? at the very end of the antennae there is a section that should be in clear insulation and the wire should be visable and is stranded wire. This is you actual antennae the the wire connecting it to your receiver is the conductor. Do not cut this wire of as it will kill your reception. The carbon fiber parts should not cause any problems as long as you don't let your antennae come in contact with them. if you have a good system there should be ample filtering that keeps reception good.
I hope that helps
Michael Johnston

Joseph Frost

Few cat whiskers sticking out of the noses to help reception with these little toy gliders converted to EDF powered jets. To safely fit them in, throught the fuse I had to cut out slots in the foam first, after, filled up and glued, to avoid sharp bending/breaking of delicate antennas in very restricted place.
Over the years I also bought number of receivers S/H on RC/Traders, a bad mistake! Most of them had the tiny antennas partially broken at casings exits. In few cases I have managed successfuly to replace them, but nowdays I always ask for a close up pics before I buy.

Micro soldering to replace broken antennas on mini RX I bought S/H.

After replacement of damaged antennas, all good.

Safest positon of mini antennas sticking out of the nose.

Another alternative to keep the areal outside of the model through the yellow plastic tube.