[amsat-bb] Tuning M2 LEO pack antennas
Carl A Estey
carl at esteys.net
Mon Apr 20 17:19:03 UTC 2020
Recently I bought through AMSAT the LEO pack and assembled and installed it this weekend. The SWR on the 2-meter antenna is 1.4:1 from 144.1 to 146.1 with resistance of 58 ohms and 2.5:1 at 148 MHz. The 70-cm antenna has the best SWR (3.0:1 and resistance of 25 ohms) at 442.6 MHZ. Obviously neither is great.
How should I tune the antennas? It appears that the only tuning possible is to adjust the shorting straps for distance from the inside edge of the shorting bar to there boom. ShouldI I be able to achieve 1.1:1 on both antennas? How should the coax be routed from the junction block? I have the LMR-400 feedline zip tied along the boom to the cross bar and then around the rotors.
What suggestions do you have?
The instructions particularly concerning the location of the 1/4-wave phasing line and the 1/2 wave balun were not very clear. Does anyone have any pictures or illustrations that show placement of the tasing line and balun?
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