5.8 antenna

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Fool question. What happen if i put a 5.8 antenna to solo controller that originally run 2.4? And whats the difference between 5.8 and 2.4 antenna?
 
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Fool question. What happen if i put a 5.8 antenna to solo controller that originally run 2.4?
You will have an impedance mismatch resulting in reflection of some of the power delivered to the antenna back to the transmitter rather than being delivered to the 'ether'. At the stock power levels the liklihood of damage is small but the power isn't headed towards the intended receiver so you will have less effective range.

And whats the difference between 5.8 and 2.4 antenna?
Size! A 5.8 GHz antenna is largely identical to a 2.4 GHz antenna except that each dimension of higher frequency antenna is 2.4/5.8ths of the corresponding dimension in the 2.4 GHz antenna.
 
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Changing the antenna does NOT change the operating frequency of the transmitter.

Sorry it doesn't work that way.
 
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You will have an impedance mismatch resulting in reflection of some of the power delivered to the antenna back to the transmitter rather than being delivered to the 'ether'. At the stock power levels the liklihood of damage is small but the power isn't headed towards the intended receiver so you will have less effective range.

Size! A 5.8 GHz antenna is largely identical to a 2.4 GHz antenna except that each dimension of higher frequency antenna is 2.4/5.8ths of the corresponding dimension in the 2.4 GHz antenna.
Is there any way to convert 5.8 antenna to 2.4?
 
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Positive.
Well we're glad of that. No. 5 was just so out of left field WRT anything that preceded it in this thread that I couldn't resist posting #6 but I hardly expected it to be taken seriously!

And then, of course, changing the antenna can change the frequency of a transmitter, if not by much, if the antenna is not thoroughy buffered from the oscillator. I don't think you will encounter that situation today but in the early days of radio it was an issue.
 
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Is there any way to convert 5.8 antenna to 2.4?
No, not practically. It is too small which means its input impedance will be pretty reactive at the same time the radiation resistance will be low. A 'top loading hat' on a monopole will take care of the reactance and it will be necessary to employ an impedance matching network to transform to the low radiation resistance but the problem with that, in addition to needing all the other stuff, is that the radiation resistance starts to become comparable to the ohmic resistance of the cables etc and efficiency goes way down. I've done it in a pinch (lowest frequency antenna I've got is for x MHz and they want me to transmit at x/4 MHz) but the losses are pretty big.

I assume you have inadvertently bought a 5.8 GHz antenna and are wondering what to do with it.
 
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Thank you guys for the answer. One more question. A little OOT. What if i use a splitter so solo remote can use 4 2.4ghz antenna. Will it possible? Will it be better than 2 antenna? Will the signal be stronger? For example. I put 2 alpha antena + 2 omni antena
 

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No, then you'd need extra amps too. Splitters lose some of the signal. So if you did that you would actually have LESS transmitting power than the stock 2 antennas unless they were amped.
 
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Thank you guys for the answer. One more question. A little OOT. What if i use a splitter so solo remote can use 4 2.4ghz antenna. Will it possible?
Yes, you absolutely can do that and in fact some antennas are sold based on this principle. But you must use a true splitter which is a device that divides the power equally between two output legs or combines the power from two input legs while maintaining an impedance match at all three ports. The device in the photo looks more like a 'tee' in which the center conductors of all three ports are simply connected together. This is not a splitter.

Will it be better than 2 antenna? Will the signal be stronger?
If you have two identical antennas and supply X dbm to one you will receive Y dbm at some distant point. If you reduce the power to the antenna by 3 dB (run the transmitter output through a splitter with one leg connected to the antenna and the other terminated0 you will receive Y -3 dbm at the distant point. If you remove the terminator and wire the other antenna to the freed terminal you will now receive two E fields, one from each antenna, and each carrying power Y - 3 dBm. But, if both are pointed directly at the receiving antenna and the cables at the transmitting end are perfectly matched, the two E fields will be exactly matched in phase and the comnined E field twice as strong as the Efield from each antenna considered separately. This results in 6 dB increase in signal level so by splitting and using two antennas you get Y - 3 + 6 = Y + 3 dbm and the array of two antennas has 3 dB more gain that either of the individual antennas IF there is no additional loss in the splitter and the extra cables 9and there always is. Thus each time you double the number of emitters you get a bit less than three dB increase in EIRP (effective isotropic radiated power). The increased EIRP is at the expense of narrower beamwidth.

For example. I put 2 alpha antena + 2 omni antena
Let's say the 'omni' antenna has 2 dBi gain and the Alpha 10. At some distance the E field from the Alpha antenna is 10^((10 - 2)/20) = 2.5 times stronger than the E field from the omni. The sum of the two is 1 + 1/2.5 times the strength of the E field from the Apha alone. 20*log(1 + 1/2.5) = 2.91 dB from which the 3 db (at least) from the splitter must be deducted leaving you with an actual loss from such an arrangement. The array gain is not enough to overcome the splitting loss. Two antennas must have gains within 7.69 dB of one another to give you any overall gain and the most you can get is 3 dB for each doubling. Thus one Alpha with one omni is not going to buy you anything over just the Alpha.
 
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Yes, you absolutely can do that and in fact some antennas are sold based on this principle. But you must use a true splitter which is a device that divides the power equally between two output legs or combines the power from two input legs while maintaining an impedance match at all three ports. The device in the photo looks more like a 'tee' in which the center conductors of all three ports are simply connected together. This is not a splitter.

If you have two identical antennas and supply X dbm to one you will receive Y dbm at some distant point. If you reduce the power to the antenna by 3 dB (run the transmitter output through a splitter with one leg connected to the antenna and the other terminated0 you will receive Y -3 dbm at the distant point. If you remove the terminator and wire the other antenna to the freed terminal you will now receive two E fields, one from each antenna, and each carrying power Y - 3 dBm. But, if both are pointed directly at the receiving antenna and the cables at the transmitting end are perfectly matched, the two E fields will be exactly matched in phase and the comnined E field twice as strong as the Efield from each antenna considered separately. This results in 6 dB increase in signal level so by splitting and using two antennas you get Y - 3 + 6 = Y + 3 dbm and the array of two antennas has 3 dB more gain that either of the individual antennas IF there is no additional loss in the splitter and the extra cables 9and there always is. Thus each time you double the number of emitters you get a bit less than three dB increase in EIRP (effective isotropic radiated power). The increased EIRP is at the expense of narrower beamwidth.


Let's say the 'omni' antenna has 2 dBi gain and the Alpha 10. At some distance the E field from the Alpha antenna is 10^((10 - 2)/20) = 2.5 times stronger than the E field from the omni. The sum of the two is 1 + 1/2.5 times the strength of the E field from the Apha alone. 20*log(1 + 1/2.5) = 2.91 dB from which the 3 db (at least) from the splitter must be deducted leaving you with an actual loss from such an arrangement. The array gain is not enough to overcome the splitting loss. Two antennas must have gains within 7.69 dB of one another to give you any overall gain and the most you can get is 3 dB for each doubling. Thus one Alpha with one omni is not going to buy you anything over just the Alpha.
Thankyou mate. Well explained. I think its best to stick with 2 antenna for now
 
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You wouldn't happen to have the Smith chart for that scan?
Wow smith chart? how old are you? lol I saw smith chart I think in Tech college and never saw it again! hahaha.... Answer is no I dont have a smith chart sorry bud!
 

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