[Lowfer] 472-479 kHz

[Douglas D. Williams]

Craig,

I do not necessarily disagree.

You make some very valid points, IMO.

Thank you!

-Doug KB4OER



On Tue, Sep 25, 2012 at 6:04 PM, craig wasson <craig at wasson.com> wrote:

> Well - we can agree to disagree then.   My point is there may be some
> advantage to intentionally using a less efficient antenna if it gives
> you lower losses beyond the antenna.  It's just something I don't
> think people ever look at except for receiving - where losses don't
> matter much anway.  Given the reversability of paths - maybe what
> makes a good RX antenna would make a good TX antenna if the efficiency
> was not a big factor.   Obviously within reason.
>
> Energy that is measured for ERP would exclude that which went into
> heating the antenna, loading coil, etc.  Maybe even local ground
> losses depending on how far away you measure ERP.  Once those photons
> fly off the antenna then they will land somewhere.  So my point is
> those losses don't matter if the goal is to net out at some fixed ERP
> (photons per second) limit.
>
> For a 1 megawatt commercial/military station a 3db increase in antenna
> efficiency might be cheaper than another megawatt.  But for us - going
> from 10w to 100w to compensate for 10db in antenna losses is not such
> a big deal.
>
> I've been experimenting with "small" (like in 50') loops on 1750M.  My
> problem is the wire in the loops is too small so I burn up way too
> much energy in the resistance of the loop.  Going to multiple loops or
> zigzags like some cellular loop antennas use did not help because the
> resistance of the longer wire cancels out the efficiency gains.
>
> My QTH is in a forest and vertical antennas couple too much energy to
> the trees, so I have not given up on the tx loop idea.
>
> Craig - N6IO