On 11/28/2017 3:31 PM, Mike Ricketts wrote:
2. I've also seen a configuration where the coax shield was then connected
to a radial field (I do not have one available), so this is not the likely
scenarion.
End fed antennas generally need some form of counterpoise to transmit
well. If you don't give them one, they'll use whatever they see, like
the shield of the coax and whatever it's connected to.
Both of these configurations have been done connected to the end of a
downspout, so the antenna is basically end fed.
I have 2 downspouts that come down together, but then go different
directions, providing me with an extra 50' or so of gutter.
3. Would it be better to connect the coax shield to the other downspout and
try to go with an OCF type of situation, since one gutter side has about
50% more length to it?
Probably not -- what you would end up with is a low dipole, which also
would not radiate very well.
I have a friend near Chicago who has loaded the HVAC ducts in his wood
frame house on 160M. I've worked him from my QTH near San Francisco. Not
very different from what you're thinking about. Don't know what he uses
as a counterpoise.
Some important concerns with either of these improvised antennas: 1)
lots of RF close to the shack and to electronics in the home to cause
RFI; 2) if you use it on receive, you'll hear lots of RFI from noise
sources in your home (and probably from your neighbors as well; 3)
there's a good chance that poor connections within the downspout will
rectify both your signal and received signals, creating intermod
interference. On receive, #3 would typically show up in the form of
interference from AM broadcast stations.
73, Jim K9YC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|