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s-band antenna for LEO work and CAL130215



I'm making good progress on the CAL130215 modification. The crystal has been
installed, and although I don't have a bias tee set up, I can feed power in
using a f-connector pigtail and I'm getting a signal on the crystal freq.
Furthermore, with some loose capacitive coupling, I can hear a tone on 144 MHz
about where the 60th harmonic of my cheapo 40 Mhz oscillator should appear. The
tone disappears when the downconv. is turned off, and it changes frequency very
drastically if I blow on the oscillator, suggesting to me that I am indeed at a
harmonic, not observing some sort of mixing effect. Thanks to Woody et al. for
the hand up thus far.

Never having worked inside microwave equipment, I'm a bit mystified by the
combline filter. Both ends of the tines are supposed to be touching the case,
right? And the shorter screws will not touch the tines, but rather set up some
capacitance between the tine and the case/ground? Any good procedure for doing
this tuning? Should I just adjust each screw for peak signal in turn?

In order to build an antenna for this unit, I bought a panel plug, N-connector
male. It has a teflon post that protrudes about 1/2": this should count as part
of any antenna design, shouldn't it? Helix and patch antenna designs seem to
want the centre connector to be almost flush, so I assume that if I were to make
one of these, I'd need to cut down the post. Since I'm building this for SSETI,
AO-51 and other similar satellites, I thought I could instead build a
waveguide-in-a-tin-can antenna, subtracting the height of the post in order to
determine the proper height of the antenna element.

I bought the N-connector panel plug from Surplus Sales of Nebraska, having been
unable to find a similar device in Canada. Does anyone have a source for panel
plugs that fit flush so that I can work on a panel or helix antenna design?

Thanks again for all the fine discussion on this list. In my case, it has done a
wonderful job of providing me with an inexpensive introduction to a new band.

73, VE9QRP
  
Bruce
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