[TowerTalk] Liberal Arts Question on Dipole Antennas
k0wa at swbell.net
Thu Jun 1 10:26:07 EDT 2006
Ladies and Gents....
Recently, I had to replace my 40 meter dipole (more of an Inverted-Vee) antenna because the coax center lead had broken off the. The dipole worked OK, but I was never really sure that I liked it. What is there not to like about a dipole antenna? (I sure I get some wise cracks here). The dipole did not seem to have a resonate point. It was below 1.8:1 on CW and was about 3:1 on SSB. So, the antenna was long.
The new antenna, using a Budwig connector this time, shows the same characteristics. I cut the the antenna at 66 feet and I made sure that both sides of the antenna were the same length....33 feet. The antenna is mounted at 45 feet using a bracked that runs through the tower. The antenna in question is on the east side of the tower while an 80 meter antenna is on the west sime of the tower mounted on the same bracket. The feed points are about three feet apart....on seperate coax feeds.
The end of the Inverted-Vee on 40 comes down to about 20 feet off the ground...while the 80 meter antenna ends about about 12 feet off the ground. The 80 meter antenna is in a straight line, while the 40 meter antenna has a slight VEE to to the tie points. So it has VEE to the the east....and a Vee down. This is hard to explain in words. I hope you experts get this.
The new antenna was failry good on SSB but not great ... about 1.8. I attached two test leads to each end and the antenna show that it was at 1.8 on CW...around 7.025. It seems that the test leeds were too long and now it is resonate below 7.0.
But, there seems to be a crazy problem that I cannot get the anntenna any lower than 1.8 to one....thinking that there should be a length in there that should be "perfect." I cannot find the "perfect point" which I would like to have around 7050.
Reading the Antenna Handbook...this antenna is working as stated although I did not anticpate the length of an inverted Vee to go longer. I've read the articles, but it seems there is something wrong with the antenna.
Is there an interaction between the tower...the 80 meter antenna...the Vee to the east?
Is the coax bad? IT has been up there for quite some time and it was used at another location before I put it up here.
Comments, flames, postulations, editorials, and pontifications are all welcome. They might show on my web pate later on....so...you have been warned.
Thanks for the discourse on a simple dipole
Lee Buller - K0WA
In our day and age it seems that Common Sense is in short supply. If you don't have any Common Sense - get some and use it. If you can't find any common sense, ask for help from somebody who has some common sense.
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