Amateur Radio Station

435 MHZ Helical Antenna

With trying to work the  AO-51 Satellite I am curretly putting together a set of antennas for 2m/70cm.  I decided to go with a 435 mhz helical antenna, and I had a handheld 3 element beam here that I am going to tune up for the cause..   

I dont have the copper helical trimmed to length or fastened to the boom section yet in this picture.. Been looking for a package of plastic clips that I had here in the house, now that I need them, they are among the missing... (of course)

 More detail at the feedpoint, after  I get the copper in place I will need to tune. This is done with the first half wind of copper, being spaced from the alumium just right to give proper swr and impedence.  Dont ask what the other hole is or in the alumium, I don't know what I was smoking when I drilled that one....


So I pretty much finished up the hardware work today, got the clips on the tubing and cut to length.










  The all important spacing between the first half wrap of coil and the alumium plate. It wasnt too bad, within a few minutes I had it down to 1.7 SWR. 

 Still need to secure this spacing so it dont get out of tune.








Decided to wrap a peice of 1/8 tubing around the outside of the mesh as it was quite sharp.  Try splitting 10' of tubing with a razorblade...  that took a while.










This little beauty is nice to have around ....  Thanks to VE9HC, Hugh, for lending this to me. Certainly makes life easier.....










3-25-08  So this evening I took the antenna out and tested on receive only as the AO-51 Satellite made it's pass. GREAT results!  I had reception for the total pass, only as it was coming up over and back down the horizon did the signal become distored a little, but this could have been due to doppler effect as well. Not sure if doppler effects receive signal? I think it does.  

Anyways, quite happy with it... was getting nearly full scale rx at a few points.  Certainly worth the effort. Now to get my 3 element yagi for 2 meters tuned up!


 So I have been working on getting a mast built for the antennas...  Also I ordered a Duplexer and I have it here now. Need to make up some cables to connect antennas to duplexer.

It's plenty ruggid, all 3/16" plate bent and fabricated into shape.  no fear of it blowing away! Also have feet to mount on bottom of the legs. Wanted to make the setup reasonably portable so I can set up at the school sometime maybe and possibly other events for display. Hope to have some more done before the weekend.... 

June 21, 2008

This past week I managed to find some time to work on the sat antennas...  I mounted a  8 element beam on the boom mast along with the helical.  It's a bit overkill but its what I have on hand...hihi

 I got the mast painted today and hope to be able to set it up tomorrow night and try working some satellites.  More pictures to come ASAP...

June 22,2008

Well today I got to get it all put together........

The 2 meter is a bit big but it's what I have on hand at the moment..hihi   But it will work well, also can use low power, so I may use my handheld to xmit on VHF and receive on the dual bander on UHF...   This will let me check my signal as well, see if I am even hitting the bird!

Hopefully get to try this out this evening, as long as the rain holds off.  If all goes well I will video a pass and post it here via youtube.


More to come as the satellite project continues. ....