[TowerTalk] Low loop in a sloping configuration

[David Gilbert]

In general, there is nothing beneficial about simply having more wire as 
long as what you already have is electrically efficient. Yes, there are 
some configurations where "more wire" can help ... a loop high enough 
off the ground has a db or so gain over a dipole at the same average 
height, a curtain array has gain, a dipole extended in length with 
capacitance has a bit of gain, etc ... but in your case your additional 
wire simply moves more of the current distribution closer to ground, 
thereby raising your takeoff/receive angle.  It might be a bit quieter, 
but not necessarily in a good way ... in my opinion.

If you want to hear better toward Europe, maybe you could try running a 
rope westward off your tower to an anchor point as far from the tower as 
you can get it, and then hang a reflector wire off that rope about 100 
feet away from the tower.  The reflector would be pretty close to the 
ground, but might ... might ... offer some benefit.   Slight improvement 
in forward gain, modest improvement in rearward rejection, possibly 
decent sideward rejection, very slight lowering of takeoff angle.  If 
probably would alter your current tuning, but might be worth a try.

73,
Dave   AB7E



On 12/28/2014 7:35 AM, Rudy Bakalov wrote:
> I actually do have the exact same setup- an inv-V at roughly 90' with 
> both ends sloping a couple of hundred feet away from the tower. The 
> apex is more likely ~120 degrees than 90. It works really well 
> (skimmer data shows actual performance much better than theoretical), 
> but I was wondering if I can improve on it, particularly on receive 
> where I feel I don't hear well enough. I guess my question is "if a 
> piece of wire of certain length works really well, what happens if I 
> double the length of the wire".
>
> Rudy N2WQ
> ------------------------------------------------------------------------
>
> I'm curious what you desire to achieve from such an antenna.  It's not
> likely to be an improvement over what you already have.
>
> A few years ago, before I was able to put up my current tower and yagis,
> I suspended a 40m diamond-shaped loop from a 55 foot tall pole ...
> sloped toward Europe from here in Arizona and fed at the bottom apex.
> It worked OK, mostly because I live on a steep hillside facing Europe,
> but in my opinion it didn't offer anything special other than it was
> also possible to use it on other bands with a decent tuner.  Keep in
> mind that unless you feed it at one side for vertical polarization that
> half your current distribution is going to be pretty close to the ground.
>
> In my opinion, you'd be better off stringing an Inverted-V from the top
> of your tower if you want something horizontally polarized to complement
> your existing verticals.
>
> 73,
> Dave   AB7E