Singularity 1280 V2

Owned by Daniel Puratich
Last updated: 2023-09-30
3 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 2024 System Architecture 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

<TODO>

External Resources:

<TODO>