[Lowfer] Deviation?

[Ed Phillips]

John Davis wrote:
> 
> -----Original Message-----
> From: Ed Phillips
> 
> > Trying to figure what kind of a Hifer beacon I could
> > put up here, and what antenna arrangement I might
> > use.  Vertical quarter wave would be easiest, but is
> > something else worth the bother?
> 
> Not really.  The folks who use something else mainly do it because they
> already have another one available.  There's no point in putting up
> something special because the Part 15 limits at 13.56 MHz are based on field
> strength.
> 
> The rule of thumb is 1.8 mW into a quarter-wave vertical, but that's only a
> rule of thumb.  The actual objective is to produce a MAXIMUM of 10,000 uV/m
> at 30 meters from the antenna (the actual rule).  If you use a higher gain
> antenna, you'd need to reduce the transmitter power accordingly.  The field
> strength is the limit in any case, so there's no real point in going for
> higher gain.
> 
> 73,
> John

John:

	I wasn't thinking of higher directivity or gain, but of the effects of
different antenna configurations on polarization and both and horizontal
angles of radiation maximum.  At a particular azimuth the sloper could
sure have more directivity than a vertical and a different angle of
radiation, depending on the relative heights above effective ground
level.  By the way, don't recall anything which says whether the limit
on radiated field strength is in ANY direction, or in the direction of
maximum field strength.  The latter is perhaps implied, but don't think
it's in the reg's.  In any event, Dex is puting a great big signal out
this way and into England as well, so he must be doing something right
and I'd like to emulate it! 

Ed

Ed