Telstar 1 carried a single transponder with 6390MHz uplink and 4170MHz downlink. All the 72 ports in the small-aperture ring were ganged together to make a single receive antenna with a toroidal pattern that extended 30 degrees above/below the equator of the satellite, but had even gain as the satellite spun. The 48 ports in the larger-aperture ring worked the same way for transmit. The overall energy budget was amazingly marginal. The solar cells only provided 14W, feeding a 3W TWT. There was no power (and probably no weight budget) to do anything other than to make the antennas from passively combined ports in a time before high-frequency semiconductors. The satellite had to be spin stabilized (with a passive coning damper), and there was no way to aim a higher gain antenna. [![enter image description here][1]][1] Source: "[A General Description of the Telstar Spacecraft][2]", R.H. Shennum and P.T. Haury, 1963, published in NASA SP-32 p.801. See particularly Figure 4 on page 806 which shows the single transponder circuit, and section VII (pp 812-816) on antennas, which includes as Figure 6 the top image in the question and the pattern described above as Figure 7 and 8. [![enter image description here][3]][3] For more technical detail, please see "[The Spacecraft Antennas][4]", J.T. Bangert, R.S. Engelbrecht, E.T. Harkless (yes, that Harkless), R.V. Sperry and E.J. Walsh, 1963, published in NASA SP-32 p.869. [1]: https://i.sstatic.net/nf56I.png [2]: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1963NASSP..32..801S&defaultprint=YES&filetype=.pdf [3]: https://i.sstatic.net/qxfQc.png [4]: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1963NASSP..32..869B&defaultprint=YES&filetype=.pdf