Lindy is up in the Air!

Well,

Remember the antenna I was describing back here:

http://g0mgx.blogspot.co.uk/2013/12/whos-lindenblad-i-wonder.html

I've finished it and stuck it up in the air:

The antenna analyser thingamabob suggests that the actual resonant point of the antenna is about 149MHz, but the SWR at 145.9 MHz is still only 1.4:1.

If I stick the antenna on the RLB I started to make here:

http://g0mgx.blogspot.co.uk/2013/09/return-loss-bridge-where-does-it-lead.html

Then this is what we see:

I explained the trace we see above using the Return Loss Bridge with the Spectrum Analyser back here:

http://g0mgx.blogspot.co.uk/2013/10/so-lets-get-bit-smarter.html

So there is a definite resonate point at 150.7Mhz, but there is also a very good match at 144.5MHz, at my target frequency of 145.9 the SWR is 1.38:1 which is perfectly acceptable.

Whilst I have been up and down ladders today, the cat has been completely useless as per normal:

Fun, egh?

Who's Lindenblad I wonder?

Well,

Since the launch of the new cubesat Funcube-1:

http://funcube.org.uk/

I've been watching the path of the satellite while I've been in the shack (tracking it with logger32) and downloaded telemetry data on a number of the birds passes using the funcube dashboard (available on the link above).

I've only been using a vertical "white stick" that I have on the side of the house, and the antenna is far from optimum for listening to Low Earth Orbiting Satellites (LEOs).

So, I did some research and found this:

http://n3ujj.com/manuals/Lindenblad-2meters.pdf

This is an easy to construct Lindenblad antenna - designed specifically for LEOs reception. Now, "easy to construct" for me was not so easy. Anyhow, I ordered the metal I needed and some other bits and bobs and today I have been to see my friend Paul who has a metal workshop. He has helped me cut, bodge, bend, hit and rivet stuff. I've brought all the bits home and assembled something that looks like this:

So what we basically have is four dipoles all slightly non-resonant such that they present a 200 ohm impedance so when they are connected together we end up with a 50 ohm antenna.

The feeder arrangement is rather odd; the pdf linked above suggests soldering the four cables into the N-Type socket but that looked as near to impossible as makes no odds so me - I'm trying this bodged arrangement first!

I'm just off to get the "corporate" antenna analyser that covers 144MHz - then we will see if I have created an antenna or a clothes line of some sort.

Cat's been no use whatsoever today:

Interesting, egh?