UHF Amateur Satellite Antenna (QFH)
An independent review of this antenna was published in the November 2008 issue of QST Magazine [Ford, Steve, WB8IMY, "SHORT TAKES: Antennas.us 70-cm Satellite Antenna", QST Magazine, November 2008, pg 72].
The UC-4364-328 is a compact Quadrifilar Helix Antenna (8 cm/3" OD x 16 cm/6" H) designed to operate through Amateur Radio satellites, without requiring an antenna rotator. The original goal of this product was to offer Amateurs with severe space or community restrictions the ability to receive 70 cm HamSat signals, and communicate through orbiting repeaters (transponders). Our QFH Antennas within this Category are deliberately made to look inconspicuous to neighbors, to follow in the original objectives.
The UC-4364-328 antenna received an upgrade early this year (2020), to broaden its axial ratio performance over a wider range of frequencies. This upgrade made it rival the larger, next generation model UC-4364-531 in most respects, delaying its scheduled release.
Ham satellites normally operate cross-band, in other words, you transmit on one band, for example 2 meters (VHF), and receive on a different band, for example 70 cm (UHF). This is to simplify front end filtering requirements at the satellite. Thus, you will generally need a VHF uplink transmit antenna for 2-way communications (a common OSCAR Mode of operation). A companion VHF unit is available, model UC-1464-531. A Kit containing both discounted antennas is also available, Kit UC-AMSAT-KITP.
The above antenna is applicable to the SatNOGS project. We also offer a UHF LNA, Model LNAU-0436-648. See Low Noise Amplifiers Category.
Useful OSCAR relevant information
Useful web pages about Amateur Satellites and relevant information are below:
We came across the following webpage while navigating the internet, containing some recordings of satellite signals using the UC-4364-328R (RHCP/Right Hand Polarization version) about a foot (30 cm) above ground level. K6JEB website contains some real life Amateur Satellite signal recordings. The sound pitch drifts due to the Doppler shift of the rapidly moving satellite platform.
UC-4364-328 Technical Specifications 
- Frequency range: 435-438 MHz
- Coverage: Omni-directional, Hemispherical
- Polarization: Circular (AR 1 dB)
- Gain: +3 dBic
- Nominal Impedance: 50 ohm (RF)
- Input Power: Under 50 W CW
- VSWR: 2.0 VSWR Plot
- Connector: SMA Female, on the side of cylindrical housing, just above the flange base. Cable assembly may be purchased separately SMA Cables
- Dimensions:
- Housing 8 cm (3") OD x 16 cm (6") h
- Bottom flange 10 cm (4") OD x 10 mm (0.38") h
- Mounting: 4 screws, M4 (#10-32)
- Operating Temperatures: -40°C to +85°C
- Weight: 420 g / 0.9 lbs
- Shipping Weight: 750 g / 1.5 lbs
UC-4364-328 QFHA Drawing
NOTES:
- Does not require a ground plane
- Specifications and prices are subject to change without notice