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Hi John,

You said your station latitude is 42.24° N.

In the Antenna Manual v2.1:



Fig 1.2 shows how Jupiter's declination changes throughout time. I see the confusion with the explanatory text in the paragraph following that figure. I'll re-word that for clarity in the next manual revision.

What was meant: Jupiter can be observed from almost* any terrestrial location by steering the beam of the antenna by using the appropriate element height and delay cable length.

*Almost because if one's latitude is larger than ±70°, there will be times when Jupiter's transit elevation is below one's horizon. For example, in 2025, Jupiter will never rise above the horizon for the people at McMurdo Station. Similarly, in 2031, the people at Prudhoe Bay will never see Jupiter rise above their horizon.

Fig 1.3 shows Jupiter's transit elevation for 40°N during 2025 averages about 72.5° for 2025. But you're 2+° further north, so the transit elevation for you for 2025 is right at 70°.

Fig 3.11, middle plot, shows the elevation pattern for a 10' antenna height with a 90° phasing cable on the southern dipole placing the beam at 60° elevation. This is the closest configuration for your situation and will work very well.

An important factor is beam width. The 3 dB beam width, or half-power beam width, or HPBW, of that elevation pattern is roughly 60° in the north-south direction. With the emission source (Jupiter) at 70°, the plot shows it'll be about a half a dB down from peak. In real world HF band radio astronomy terms, 0.5 dB down is just as good as 0 dB down (emission source right on the beam centerline).

One could always model the dual dipole array in EZNEC and fiddle with the parameters for element height and delay line length to put the beam right on 70° elevation. It's a fun exercise and one sure learns a lot about antenna modeling in so doing. You can obtain EZNEC for free now, here:



Hope that helps, John!
--
Dave