Bird side antena.

[OnyFlyCookie]

Has anyone tried this mod? If so how should it be done... also is there any way to double the antenna to two of each so all 4 legs have a signal going out or coming in. What antenna shape, size, DB?. This is the bird not the controler I am talking about... I found a few pictures of what I meant

 

[just_bruce]

Theory says that for true diversity [which is what MIMO needs if I recall] wants the antennas further apart, not closer together. Hence the placement in opposing corner legs.

 

[OnyFlyCookie]

Theory says that for true diversity [which is what MIMO needs if I recall] wants the antennas further apart, not closer together. Hence the placement in opposing corner legs.

Makes sense. Any benifits to change to clover antenna from stock keeping original position?

 

[Michael Lione]

Seeing that's my photo (with ruler) I'll chime in. Sololink is based on N/MIMO diversity signal propagation. For best results diversity antenna spacing is one wavelength apart. 2.4GHz has a wavelength of 12.5cm or 4.92 inches. You can go up to 3 spaces (5, 10, 15 inches)

Not sure how this applies to what the Solo design provides. Controller spacing is 4" which is probably why they recommend you point the ducks down and spread them out 20°. The diagonal leg antennas are about 12" apart.

Bottom line, by proper spacing, the RF signal waves are not as likely to cancel themselves out. If you think of noise cancelling, it's accomplished by emitting a sound wave exactly one wavelength out of sync (opposite) to cancel out the offending sound.

My hearing aids are able to cancel out a loud background noise so I can hear what I need to without contention. Yes, I asked my audiologist several times if he can program them to cancel out the Pretty. No joy on that yet but technology is improving with each new generation so I haven't lost hope.

 

[just_bruce]

Couple things:

1. Wifi Center band wavelength is 12.24cm or 4.82 in. Not super germane but facts is facts.

2. You're assuming a simple spatial diversity arrangement of the antennas on Solo and the GCS, which I don't think is the case. It seems far more likely that there is some sectorization or [more likely since it is WiFi MIMO] adaptive/spatial beamforming or Spatial multiplexing.

In other words I don't believe that the antenna spacing at exact wavelength multipliers is going to affect performance in any significant way. But I am always a slave to actual data, so I'd be delighted to see test results to prove me wrong.

 

[Michael Lione]

Not smart enough to to argue your second point. I'm just parroting what I found in several blog posts.

As to the wavelength, 12.5cm shows up on countless sites as the length of a 2.4Ghz 802.11 (n in our case) wavelength. Not sure where you are coming up with 12.24cm.

 

[just_bruce]

Center frequency of the 2.4 Ghz band is 2.45 Ghz. That is where the 12.24cm comes from.


Almost no one is going to be at exactly 2.4GHz. For example, Channel 6 in the 2.4Ghz band [the one most likely to be used on the lower end of the spectrum in the US] has a center wavelength of 12.35cm. Channel 12 has a center wavelength of 12.15cm. It makes more sense to discuss center wavelengths since that is where the 'meat' of the transmission and reception is occurring.

Yes, technically speaking, the wavelength of 2.400GHz is 12.49cm. But that isn't really the truth of the wavelength propagating thru the air while the 2.4Ghz band is in use.

 

[Michael Lione]

Center frequency of the 2.4 Ghz band is 2.45 Ghz. That is where the 12.24cm comes from.


Almost no one is going to be at exactly 2.4GHz. For example, Channel 6 in the 2.4Ghz band [the one most likely to be used on the lower end of the spectrum in the US] has a center wavelength of 12.35cm. Channel 12 has a center wavelength of 12.15cm. It makes more sense to discuss center wavelengths since that is where the 'meat' of the transmission and reception is occurring.

Yes, technically speaking, the wavelength of 2.400GHz is 12.49cm. But that isn't really the truth of the wavelength propagating thru the air while the 2.4Ghz band is in use.

Got it and agreed.

We are talking antenna spacing. Conventional wisdom provides multiples of 5" up to three spaces. One and done. All the rest is interesting but only adds confusion.

Mounting the ducks the way I did is acceptable as it accomplishes the optimal spacing. Going diagonal (12") doesn't follow the perscribed spacing protocol but obviously produces an acceptable link. That implies that mounting the ducks in the removed leg positions should also work fine, perhaps better being front to back vs side by side.

Not sure if you caught my very unscientific antenna propagation study where I expiermented with several different antenna combos. One finding was there was very little difference between the leg antennas and the rubber ducks as I had them mounted. This was important to me as it patented that there would be no cost of signal quality when using retracts. Additionally if folks wanted to expierment with different antenna types they have the outboard sma connects to do so.