Is this scenario realistic?

[noether]

Hello,

I am reading a paper and the scenario is the next.

They have a small radio control plane with 6 antennas. The idea is to estimate the attitude angles and I do not know if their solution is realistic or not. Here are the relevant data:

- The frequency is 30MHz. A sinusoidal signal of amplitude 1. The main idea is to measure the phase delays among the different antennas.
- The transmitter is 1km far away from the plane (they are LOS).
- The signal must be about 0 or 10 dB SNR at the receiver (the antennas at the plane).

Assuming that the plane can not carry so much weight (and also there is not too space on board). Do you think it is possible to have this SNR at the receiver?

Thanks a lot in advance!

 

[Mityan]

The SNR will depend on transmitter power. What is '1'? And on antennas dimension. For 10 m wavelength they have to be rather big (lambda/4=2.5 m)
All the rest of the method is likely to be realistic.

 

[noether]

The SNR will depend on transmitter power. What is '1'? And on antennas dimension. For 10 m wavelength they have to be rather big (lambda/4=2.5 m)
All the rest of the method is likely to be realistic.

Thank you very much for your response. 1 I guess is Volts? (they do not specific units).

The dimension of the antenna is indeed too big. Do you know if it is possible to have a smaller antenna? The wingspan of the plane is 1.5m (0.75m for each wing), and there are 3 antennas per wing.

Also, the SNR depends on the transmitter of course, but the required power is still common? with common I mean according to the law for transmitters in the UE for instance.

EDIT
--------
I was looking up antennas, and I have found antennas of about 0.75 meters and the weight oscillates between 1.5Kg and 10Kg. Do you think is still possible to find them smaller and lighter?

 

[vfone]

While ago I was thinking to the same setup to measure the antenna pattern of an HF antenna. To use an HF receiver and a VHF transmitter (to send back the RSSI level information of the HF receiver), both mounted on a R/C airplane. Unfortunately I never put this in practice, but I think is suitable because the receive HF antenna mounted on the R/C airplane don't need to be large, when RSSI is related to the high level of transmitting power of the ground station.

 

[Mityan]

Try to google quarterwave antenna estimation. I've found that though the effectiveness of antenna significantly falls below lambda/4 length, they use shorter antennas together with lengthening inductance coils for criticalto dimensions design.
There is a formula for inductance:

where l is physical antenna length, r - antenna radius, F - frequency

- - - Updated - - -

Try to google quarterwave antenna estimation. I've found that though the effectiveness of antenna significantly falls below lambda/4 length, they use shorter antennas together with lengthening inductance coils for criticalto dimensions design.
There is a formula for inductance:

where l is physical antenna length, r - antenna radius, F - frequency

 

[BradtheRad]

The frequency is 30MHz.

72 MHz is the band presently allocated for R/C airplanes.

Lower frequencies have been used in the past. Some may not be legal for aircraft today. (Consult web link following.)

Link to Frequency Chart for Model Operation:



The FCC allocates 75 MHz for use by surface R/C models.

Do you know if it is possible to have a smaller antenna?

Notice that 72 MHz can use a shorter antenna due to the shorter wavelength.

 

[Alireza Nakhostin]

Hi
To reduce the size of the antenna can Use of fractal antenna..!