KL7UW
Lindenblad Satellite Antennas
Introduction
The Lindenblad antenna is originally a design for aircraft tower communication but has characteristics
that are very good for satellite operations. The antennas were described in articles by Anthony
Monteiro, AA2TX: "An EZ-Lindenblad Antenna for 2 Meters" and "A Parasitic Lindenblad Antenna for 70cm".
In these papers Tony gives a very good review of the Lindenblad design.
In brief the Lindenblad antenna produces an omni-directional circular polarized radiation pattern
which is perfect for optimum reception of earth orbiting satellites. Below I show my version of Tony's
Lindenblad design.
Where I differed on design is the use of 1-inch sched-40 pvc pipe. I found it nested perfectly with aluminum
sched-40 pipe, easing assembly. I ran the four foot RG-58 coax inside the UHF driven dipole by drilling a
small hole for the shield and insulated center conductor to pass thru the 4-way pvc hub (photo-1). The PVC
fit to the aluminum well without need for pvc cement.
Antennas were tuned with a MFJ-269B analyzer. The VHF Lindenblad was a shade low in frequency so a 8 pF
silver-mica capacitor was used to shunt the coax connector bringing the frequency up.
The UHF antenna is fitted with a mgf-1302 preamp so is only usable for receive (mode-VU). Mode-UV or VU
are possible by use of the satellite antennas on tower-3.
Construction Details
- Photo-1,2: Shows the white pvc four-way nipple dilled to accept the vertical dipole with coax run inside
- Photo-3: Shows the two ferrite-beads at the lower end of the vertical dipole
- Phtot-4,5: Shows the completed UHF "Parasitic" LIndenblad
- Photo-6: Shows both VHF and UHF Lindenblad antennas on tower bracket
Installation on Tower-2
- Lindenblad antennas mounted at 30-feet on Tower-2; HF, dual-6m, 70cm and dual 222-yagis above.
- The small plastic box houses a coax relay and 432 GasFet preamp that is shared between satellite and
the 432 yagi used for terrestrial contacts
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Installation on Tower-2
