Singularity 1280 V2

Owned by Daniel Puratich
Last updated: 2023-09-30
2 min read

Manufacturer Specs

This section contains the manufacturer specifications plus some commentary from yours truly to hopefully make it more sensical

  • Purchase Link: Singularity 1280 V2

  • Polarization: LHCP or RHCP

    • Option to be chosen at purchase time.

    • Intro do Antenna Polarization

      • Some nice visuals for circular vs linear

    • Antenna Theory Circular Polarization

      • “Circular polarization is a desirable characteristic for many antennas. Two antennas that are both circularly polarized do not suffer signal loss due to polarization mismatch. Another advantage of circular polarization is that a RHCP wave will reflect off a surface and be LHCP. This is advantageous because an antenna designed to receive RHCP waves will have some immunity to the signal-fading effects of reflected waves interfering with the desired wave. These are some of the reasons GPS signals from satellites are RHCP.”

  • Gain: 1.9dBic 0r 1.6 Bic

    • 1.9Bic is from TrueRC listing, 1.6 Bic is from GetFPV listing

    • ic = isotropic circular

    • Antenna Theory Radiation Pattern

      • “A pattern is "isotropic" if the radiation pattern is the same in all directions. Antennas with isotropic radiation patterns don't exist in practice, but are sometimes discussed as a means of comparison with real antennas.”

    • This low dBic value means this antenna is nearly omnidirectional.

  • Cross-Polar Rejection: -15 to -30dB, (2.2%)

  • Axial Ratio: 1.0

    • Antenna Theory Axial Ratio

      • “A circularly polarized field is made up of two orthogonal E-field components of equal amplitude (and 90 degrees out of phase). Because the components are equal magnitude, the axial ratio is 1 (or 0 dB).”

  • Bandwidth: 1250MHz-1290MHz

  • Radiation Efficiency: 99%

  • SWR: <=1.5:1

  • Weight: 15g

  • Dimensions(head): 40.5mm dia. X 22.5mm height.

  • Length: xxmm

  • Cable: RG402/RG316 coax.

  • Connector: True-SMA .

    • This is a normal SMA connector, they just want to be fancy

  • Patent: US. Pat. 10,804,618 ‘

Mounting Requirements:

  • Do not paint antenna

  • Do not mount close to conductors

  • Mount as far away from drone carbon as possible

  • Mount away from motors, escs, and other antennas

  • Feed line can mechanically be ignored (no electrical requirements for the feed line)

  • Try to maximize time the airside antenna has line of sight to the groundside antenna for common aircraft attitudes

    • This could be mathematically optimized for which side of the drone it should be on by looking at the CONOPs Map

  • SWR can be measured with a VNA after mounting

Project Pegasus Use

Project Pegasus uses this component as documented in for our 1.3 ghz video transmission system. This antenna will go on the airside connected to a transmitter either Foxeer 5 W VTX or Mateksys 800mW VTX . On the groundside this antenna could be connected to the RMRC VRX + Tuner as a part of the video tower system, however, in my engineering opinion the TrueRC X-AIR 1.3 is the preferable antenna here with the only drawback being size. The SWR of the TrueRC X-AIR 1.3 is not published however I [Daniel] measured it to be below 1.3:1 in the bandwidth of 1250MHz-1290MHz in our prototype tracking antenna setup with a NANOVNAH4 in Sept 2023.

Internal Testing

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External Resources:

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