Do we have dates on when the optional telemetrys will be available (speed, temp, voltage)??

I would think you would have no problems with that, your receiver pack should be able to deliver all the amperage you need. The capacitor fix is for speed controls that can't deliver enough amperage for the newer servos.

The length of an antenna at 2.4ghz is very important, however, if the antenna is very poorly matched to the frequency, it can still function ok, it will just have a reduced range. Coiling up the antenna can radically change it's resonant frequency, coils in fact are used for RF tuning to adjust resonance, but again, it can work no problem coiled up, it just might get glitches from cell phones or pagers if it happens to tune to their frequencies. Bends in the antenna can have some effect but not as much. Note also that the RX property of an antenna is identical to its TX property.

Technically, it is a FCC violation to modify the antenna, funny how they say you can do it in their manual.
But note it is also illegal to change crystals for FM systems. I like how my M8 manual says it is violation of federal law to change them, and then tells you how to change them. :)

Just a little FYI, hope it helps.
Note our DART system has a tiny 2.5 inch antenna.

Actually, I'm quite interested in the requirement for a large Capacitor with the Spektrum. If you've had to install a cap to get it to work properly, please send me email to website at nimblemotorsports dot com, I'd like you to test our system to see if it has the same problem or not. I have yet to see this problem in our testing.

thanks!

you don't have to consider bends in an antenna. if it crosses itself, that reduces the effective length, but if it coils, it will still resonate in sympathy with the signal - the length is still the same.

I wrap mine around my roll-over and put a plastic body-washer on top so that it stays under the body.

If you've ever seen a 1/12th body cut the antenna that's wrapped around the roll-over. . . well, glitch glitch glitch! :D

It doesn't take a big cap, a small one works just fine. All it does, essentially, is to smooth out the downward voltage spike when we stab the throttle or the like. This drop in voltage causes the receiver to go into failsafe mode (looks like a reset) for a few seconds.

Some ESC's don't do it - they give more voltage through the BEC circuit.

Using a receiver pack should also solve it - it eliminates the ESC from the BEC circuit.

Is that the antenna wire wrapped around the base of the antenna? :confused:

Yep - he has his antenna wire wrapped around a shortened tube. Very convenient! :D

Hi, i am having difficulty finding the email address on your site. Please could you PM me with the correct address.

Look at this 5dBi Gain antenna.

You'll notice the coiling of the wire at a precise location which has the effect of actually creating two antennas in phase, which increases the gain. If the coils are not done right, the antenna is not in tune for a specific frequency. You might take this information as an opportunity to put in coils in just the right place and increase the range of your Spektrum... :)

so where on the spektrum antenna will we need to put the coils and how many?

:)

Guys - just cut the wire to 3.6" and be done with it.

This is a topic that has been discussed on the ARL boards for forever. ARL, for those who don't know, is the amateur radio body. If anyone around here would know more than they about practical usage of radio, antenna, etc. I'd like to know who it is.

The crimps, the coils, etc. are there to reduce the physical length of the actuall antenna assembly, not the length of the antenna WIRE.

Let's look at another from hyperlinktech, shall we?

http://www.hyperlinktech.com/web/cop.../re05u_350.jpg

From this, you'd think that the little coil in there is to increase signal strength, etc.

Until you look at the physical size of the antenna. This is a 6" antenna as compared to 10" for the one with the dual crimps. Basically, there is about 4" of antenna that is coiled up to shrink it's length from around 10-11" down to 6".

A longer antenna (lower harmonic) for this is going to be 21" (used for higher gain antenna or marine or places where length doesn't matter so much) - and you can see THOSE there too.

{{sigh}}

This is basic EMF theory. The length of the antenna wire must coincide with a harmonic of the wavelength of the signal in order to get optimal reception. It's as simple as that.

for a 2.4GHz frequency, the wavelength is just over 4" (thus the length of the antenna being 8" is 2x the wavelength which is normal). You could likely use 4.whatever (full wave) and would work great. However, why do that when you can use the 3.6" and be just as good.

the 3.6" antenna length is the 3/4 wave harmonic and is one of the ideal lengths.

Please note - I used a straight 2.4GHz for calculations - I did not get the exact frequencies within that range so numbers are somewhat approximate.

btw - your 2.5" antenna for the Nimble system would be right at the 1/2 wavelength. I'm not sure if the Spek system would be happy with that length, but theoretically it should be possible.

Boomer, it is ARRL, American Radio Relay League.
Although I did have a previous business manufacturing and selling 2.4Ghz antennas, I will not argue further.

boomer,

I understand the harmonics and such, but I beg to differ. The coils in the antenna does reduce the effective length of the antenna, but if you were to straighten that coiled antenna out, it would not be the legth of any of the harmonics for what that antenna is tuned to. My point is that the coils and bends do change the attenuation of the wire(antenna) and therefore changes the effective length of the antenna. so the question is to get optimum range would we increase or decrease the length of the spektrum antenna, if we were to coil the antenna as in howard's pic.

and a matter of symantecs, but the antenna accebly for our case is the length of wire, because the actually antenna for the specktrum transciever is the wire and therefor we are talking the same thing. The length of the wire is the length of the antenna assembly itself.

Will Spektrum work with KO Propo Mars R?