My tower / dipole plans

[w1vtp]

Here are my plans for my dipole.  The ends will be approximately 35' off the ground so it will be a form of inverted vee.

I'm torn between (at first) trying a Cobra Ultralite Senior  ant which will, of  course, require some sort of open line feeder system.  I admit that I have a lot of trepidation of using that approach.  Yes, there are literally hundreds of posts on AMFone regarding open feeders / link coupled tunas etc  etc but I'm still wrestling with that approach.  As an aside, anyone had any experience with the Palstar BT1500a balanced tuner?   My first reaction to it is that they spec the power rating so close to 1500 watts PEP.

The other approach would be a trap 160 / 75 meter trap which will allow me to do a coax run into my shack.


Bottom line: the center of the dipole will be raised to double height and ~ 1/4 wavelength at 75 meters.  I have the order into Matt KC1XX.  It's just a matter scheduling and this @#$% winter.  After the mast is installed (.22" walled 2", 22' long) I'll have to adjust the south leg of the ant to accommodate the new dimensions.


Al

[K5UJ]

Hi Al, plans look good.   I don't think you mentioned the high bands so I'm gg to focus on the low bands.   On 160 I'd go with a base fed vertical (inverted L if necessary) driven against ground.  Lots of radials.  Feed it with coax since it is unbalanced.  Tune in the shack or at feedpoint with a L network tuner.   For 80 and 40 I'd go with the center fed dipole like you plan.   A dipole on 160 will be too low unless you can get it at least 100 feet high (which is like 50 feet on 80 m.).   At the risk of offending some, the guys here who are hard to copy on 160 are the ones with dipoles under 100 feet (unless they are close by).   The guys who have big signals are always the ones with some kind of vertical working against ground and lots of radials.   It changes on 80 where a dipole can really play at 70 feet or higher.   If you can get the f/p up 70 feet like I think  you plan, and  the ends up to 50 feet that would be pretty good.   That would be 60 feet average.   Just make the dipole with some dacron rope, dog bone insulators and no. 12 copper stranded housewire.   Feed it with balanced feed made with the same wire or get that W7FG stuff.  For what that palstar tuner costs you could buy 3 or 4 KW matchboxes, and they would be more efficient, easier to use and handle more power.   Or build a link coupled tuner.   Some guys like those parallel roller inductor balanced tuners and they may have more impedance range but the one I had here did not work out as well for me as the Matchbox. 

I have a hard time with antennas, more so as I get older, so my antennas as modest as they are, were hard for me to put up and I had to get help.   But the results were pretty rewarding, so I wish you luck and say when it's all over you'll be glad due to the performance.

73

Rob

[Steve - K4HX]

Rob makes a good point. Using the L for 160 meters means you can make the dipole shorter. This means the ends will be higher making the average height greater. You could make the dipole an 80/40 fan type, feed it with coax and avoid using a tuner completely.

Or just put up a fan dipole for 160/80/40.

[KF1Z]

If you have to use a tuner anyway.... why bother with a "Cobra"?
Why not just a regular doublet?
Just curious...


I'm sorry, but I have a hard time with the theory behind the Snake antenna since I saw it in an old handbook ( 1952? ).

Or as Steve says, maybe the Fan dipole approach...?