Monday, January 8, 2018

If You're Following My Antenna Project

This is for anyone following this project and wanting to duplicate it. 

I have an important update to Saturday's post.  I made a dumb mistake and connected the ground radial to the wrong place.  This picture explains:
Schematically, it looks like this:
That awkwardly shaped thing on the left is supposed to mimic the loop.  The ground goes electrically between the transformer secondary and the termination resistor.  In my implementation, that junction is about 2 feet long, which is electrically short enough to not matter.  I could have connected it just by moving the wire to the far side of the plexiglass strip on the left, but moved it to the one on the right. 

When I hooked up the loop yesterday, it didn't work. Receive signals were much weaker than signals from the vertical antenna I generally use.  While doing some troubleshooting, I noticed my mistake and fixed it this morning.  Using the vertical and antenna tuner, WWV at 10.000 MHz was moving between S5 and S9 (pretty crappy conditions); switching to the loop and engaging the radio's high gain preamp, it was the same, as accurately as I can tell.  With 25 dB swings like that, it sure isn't like using lab equipment and getting stable numbers.  I did a much briefer test on 40 m and the two antennas sound very close to each other in performance, if not the same.  

Now that I know it's working, it's time to try it out in use and see if I can find out if this whole project was worth the time, effort and cost (admittedly not much cost).


  1. Well at least your "Oops!" didn't cost "...billions of dollars,,,":

    1. That's a bad one. As usual with these black payloads, nobody can say anything officially so let the rumors fly. SpaceX says all their telemetry shows their hardware is fine, and Northrup isn't saying anything.

    2. What's special about this is that when the video cut out for the second stage, they claimed that was planned because the payload was classified. Now it's not so clear whether that was a planned drop out, or if they merely used that as an opportunity to cover up the real reason.

      Just as I wonder if their launch failure in 28 June, 2015 was really due to the cause they claimed, or if it instead was a result of the same problem that cost them their launch pad failure on 1 September 2016. It is worrisome if one cannot trust the "failure analysis" for a catastrophic event...

  2. The video always drops at that point with a classified payload onboard. It's probably in a dozen documents detailing it precisely....

    With the ground in the proper condition you now have link coupling, and much better signal transfer.