Richard Clark wrote in
:

On Sat, 02 Jan 2010 13:21:03 -0600, Lostgallifreyan
wrote:

Well, my plan is to use a ground at the antenna end, right
underneath it.

This bodes ill if you do not tie that ground directly to the service
ground. Further, a "ground" as you describe it (incompletely) sounds
suspiciously like a ground rod. This is NOT the same thing as RF
ground - not even close unless you live within several meters of low
tide along a major ocean shore.

I'll get a
good 4' ground rod and rig up an 18' vertical whip as I learned of in
details I posted about earlier.

Suspicions confirmed....

I understand that good reception depends on a good
compromise between selectivity and sensitivity, and no doubt the antenna
'tuner' helps with that, though I'll mainly be concerned with good
ground and local common mode noise rejection.

This does not acknowledge the significance of INTERMOD problems.
Experience may have to teach that (when you make all these
improvements and have poor results for your effort).

My first attempt at the line between
antenna and receiver will be a balanced line with a toroid at each end
for current isolation

This is a very, very curious novelty. You do not describe a
"balanced" system with a ground rod and vertical, so any effort at
"balanced" lines is window dressing only. The reason for placing
"balanced" within quotes is due to the inordinate care and skill
required in obtaining a balanced design. It is more often achieved
with coax. Too often, "balanced line" is approached with the
mysticism of universal relief for whatever ails a listener.

and possibly the suggested Norton preamp on the receiver
input,

I must have missed that posting. Sounds like another elaboration.

but I'll try without it first as I suspect I'll get enough signal
strength to satisfy me for a while. If I have to use coax I will but
I'll try the easier options first. This basic plan does involve a 10:1
ratio in windings on the far end toroid which should help smooth out
peaks of resonance as described by John Doty and others as mentioned
before, and if nothing else, drives a stronger current in the balanced
line part of the system.

This is the doohickey I spoke of. It is basically the refuge
accessory of the lowfers where the span of frequencies is, maybe,
three to one and not like the ten to one of HF SWLing.

I'm no longer much concerned about matching impedances, but I will be
watching for results of changing antenna length if resonance seems to be
an issue.

This is at cross purposes. You don't have many realistic options of
changing antenna length (height) as you do with a simple tuner when it
comes to matching.

My interest in the 'doohickey' or any other widget was mainly in what
appeared to be a means of reducing the difference in signal strength
extremes due to resonance. I understand that if I subsequently have to
select the weaker of two close stations I'll either have to add some
'trap' for a specific offender, such as a trimmed lengh of unterminated
coax (though as far as I know, that trick is usually reserved for much
higher frequencies), or use a manually tuned system which I'll explore
if it becomes a dominant concern.

Traps don't work very well for adjacent AM/SSB stations, you need
cascade XTAL ladders to do that. Tuners, also, can only operate
within the combination of number of reactive elements and Q.

Please respond to your perception of the problem of INTERMOD as it is,
as I said, the silent killer of reception.

73's
Richard Clark, KB7QHC


I haven't a clue about intermod, yet. One thing at a time. Right now I see at
least three contradictions (re ground rods, transformers, and feedlines) with
advice from several people, one of which (the guy who wrote the description
of the antenna and balanced line I mentioned) is part of a group of hams who
is turned to for advice by the others. No guarantee of correctness, perhaps,
but if I keep on being told I'm wrong when my stuff is coming as directly as
I can get it from others with experience, then as far as I'm concerned I'll
do what I think best and get out of the crossfire. Specifically, many times
I've seen advice that service grounds are not adequate because of common mode
noise and local currents, hence the ground rod you vehemently negate. I can
ground to service ground at near end but if the receiver is on batteries, not
connected to anything except a transformer coupling RF from the antenna, then
the ground only needs to be at the antenna end, according to advice I've seen
in several places. Even if I do ground to a water pipe or other local ground,
all advice I see until now insists on having a ground rod as close to the
antenna as possible, no matter what else I do, yet now you urge against this.
I will stop asking for advice if all I see is vigorous contradiction between
people who claim knowledge I do not have. Diverting that disagreement to one
with me doesn't alter this, I did not originate the info behind the choices I
am considering. Even if all the various contributors come here and duke it
out between them it appears I'll be none the wiser.