On 10/03/2005 1:04 PM, Cecil Moore wrote:
clvrmnky wrote:

The lack of good RF ground is going to be a challenge, and may
preclude any of this.


If you use a balanced antenna system, you don't need
an RF ground for the receive function.

Hmmm. I can probably make a decent-sized folded dipole out on the
patio. It will have to turn a corner, but I can probably get a
fair-sized loop out there.

On 10/03/2005 4:15 PM, clvrmnky wrote:
On 10/03/2005 1:04 PM, Cecil Moore wrote:

clvrmnky wrote:

The lack of good RF ground is going to be a challenge, and may
preclude any of this.



If you use a balanced antenna system, you don't need
an RF ground for the receive function.


Hmmm. I can probably make a decent-sized folded dipole out on the
patio. It will have to turn a corner, but I can probably get a
fair-sized loop out there.

Ok, further to this. Even if I'm not to care about impedance matching
or choking, my receiver has an unbalanced antenna input. One side of
the antenna connection simply goes to "chassis" ground.

This implies that I should use a traditional BalUn to make the balance
connection work for me. Otherwise, one side of a dipole or looped
longwire is just going to go straight to ground (such as it is.)

I built myself a reasonably stealthy random-wire running along the top
of my wooden balcony railing (which turns a 90-deg corner around the
building) for a total length of around 25-30 ft. I was considering
simply looping the wire to make a bent, untuned, "folded dipole" (the
wires would be 5-6 inches apart) just to get more wire into the wind.

To realize this, I am supposing I'll have to use a true BalUn to get the
signal into my unbalanced front-end somehow. Since most designs for a
true BalUn assumes I have a decent ground, I'm a bit stumped by your
comment. Perhaps the ground of the BalUn can just go to the coax sleeve?

Thanks for all your suggestions.

On Mon, 14 Mar 2005 13:02:20 -0500, clvrmnky
wrote:
This implies that I should use a traditional BalUn to make the balance
connection work for me. Otherwise, one side of a dipole or looped
longwire is just going to go straight to ground (such as it is.)

Hi OM,

You reject the BalUn (matching/choking) to only presume the
implication (one wire goes to ground) forces you to use it for another
reason?

Wrong implication, even if the solution works. The one side of any
dipole/loop antenna design going "straight to ground" (ground a
euphemism for Hell?) is not a loss in any sense of the design. The
receiver is sharing the same path - unless it is strictly battery
operated without a charger connection.

Your radio wants to see a signal potential applied across its input
and chassis (as you put it, which is suitable enough). With a
monopole the input is satisfied, but you need either a ground or
counterpoise connected to the chassis. With a dipole or loop, the two
returning wires meet the radio's needs at the input/chassis
connection. A ground connection or counterpoise for the dipole/loop
would be benign in the practical sense. You won't need it (unless you
have lightning phobias); and with the common specie of radio you will
have it, somewhere, anyway (it will then simply be uncontrolled and
variable).

Perhaps the ground of the BalUn can just go to the coax sleeve?

That will work fine.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote

A ground connection or counterpoise for the dipole/loop
would be benign in the practical sense. You won't need it (unless you
have lightning phobias);

Well said. And most of us who get anywhere near as much rain as Richard
does (in WA) unfortunately have a LOT more lightning to deal with in the
summer. In that case, shield-grounding the coax of a dipole should happen as
soon as the feedline is down at ground-level, and again at the station
entrance/single point ground, where it should connect to a coax
surge/lightning arrestor.

Perhaps the ground of the BalUn can just go to the coax sleeve?

That will work fine.

73's
Richard Clark, KB7QHC

Indeed, matching transformers such as Industrial Communications Engineers
make, insist the metal xfmr case be grounded for safe and proper operation.
I ground long wires on both an I.C.E. xfmr and a current-type Balun,
directly to ground rods that the equipment is mounted on. This is also the
connection point for ground radials for the long wire, if used.

Best regards,

Jack Painter
Virginia Beach, Virginia

On Mon, 14 Mar 2005 16:53:57 -0500, "Jack Painter"
wrote:
And most of us who get anywhere near as much rain as Richard
does (in WA) unfortunately have a LOT more lightning to deal with in the
summer.

Hi Jack,

In all actuality, Seattle sees the least lightning nationwide. If
you drew a line from Seattle to Miami, you would find that the
incidence of lightning grows roughly ten-fold as you progressed along
that line.

73's
Richard Clark, KB7QHC

On Mon, 14 Mar 2005 16:07:50 -0500, clvrmnky
wrote:
Right now I'm running battery only because I have perfectly useful
rechargeables. Anyway, it is giving me a chance to see if the PS adds
any noise. It doesn't appear to.

Hi OM,

That is fortunate. Try not to introduce any grounds such as you
discuss below.

It would seem this is another place where various holy wars have waged
over the years. My survey of the literature indicates that a great many
people don't even consider a dipole of any stripe fed to an unbalance
RX/TX as a "dipole."

Dipole has only one meaning of value: Two Poles. Each pole acts as
the electromotive opposite of the other. Without opposites, no
current flows (and in a sense, a monopole finds its dipolar opposite
in ground).

Isn't this the notion of many of those cheapo plastic baluns one gets to
feed coax to an older TV which would have accepted parallel line?
Well, I suppose these are ostensibly to match impedance, but they are
described as converting balanced to unbalanced connections.

BalUns are so simple that the cheap ones work quite well.

I understand that ground (as a notion) is not an absolute. I have what
I have. I *may* be able to convince my landlord to let me trail a wire
off the balcony to the ground. We'll see.

Don't go there. Introduction of alternate grounds, especially if they
do not conform to code bring the almost certainty of ground loops.
You don't even want to consider the insurance risk. There is probably
no reception advantage over the already available service ground found
at the wall socket. (I am perhaps mistakenly presuming this was for a
receiver only.)

According to what you suggested so far, both sides of my loop can go
directly to my antenna input.

The input and chassis, per accepted terms for both.

Ok, can do. I'll give it a try and see
if things work measurably better.

You may find you are already at the knee of the curve of diminishing
returns. What will pay off is

1. making the antenna connection as remote as possible;
2. using coax;
3. choking that connection;
4. providing for antenna tuning at the radio.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote
"Jack Painter"
wrote:
And most of us who get anywhere near as much rain as Richard
does (in WA) unfortunately have a LOT more lightning to deal with in the
summer.

Hi Jack,

In all actuality, Seattle sees the least lightning nationwide. If
you drew a line from Seattle to Miami, you would find that the
incidence of lightning grows roughly ten-fold as you progressed along
that line.

73's
Richard Clark, KB7QHC

Hi Richard, I knew that, and meant by inference that it was admirable for
someone (you) with so little lightning, to realize it is not a minor-thing
for others.

I might act like my station is bulletproof (because I spent the time and
money to try to make it so), but when you watch that line of a storm
approaching, and lightning is striking every few seconds on a path you can
see coming straight for you, the realization that one is likely to land on
top of you is real, not a phobia, lol. All too often, it does strike one of
the tall pines in my yard, sometimes jumping to non-conductive things like
wooden fences, which it splits on its way to ground.

In Virginia Beach, we get more than half the lightning Miami gets, but
slightly less than half what the 100+ area of West-Central Florida does. It
serves to make summer a lot less fun for those with masts, wires and towers
up in the air!

Best regards,

Jack

On 14/03/2005 5:51 PM, Richard Clark wrote:
On Mon, 14 Mar 2005 16:07:50 -0500, clvrmnky
wrote:

Right now I'm running battery only because I have perfectly useful
rechargeables. Anyway, it is giving me a chance to see if the PS adds
any noise. It doesn't appear to.


Hi OM,

That is fortunate. Try not to introduce any grounds such as you
discuss below.


It would seem this is another place where various holy wars have waged
over the years. My survey of the literature indicates that a great many
people don't even consider a dipole of any stripe fed to an unbalance
RX/TX as a "dipole."


Dipole has only one meaning of value: Two Poles. Each pole acts as
the electromotive opposite of the other. Without opposites, no
current flows (and in a sense, a monopole finds its dipolar opposite
in ground).

I've had an epiphany of sorts, and I think you may be partially to
blame! Well, that and "Basic Electronics" published by the US Navy.

The reason I'm so doggedly trying to get all this is that I'm also
working on getting my amateur radio license. One problem with this is
that I may be conflating "best practises" I'm reading about for TX with
RX purposes. This is the danger of just enough knowledge. I'm
determined to learn how these devices work, and how to best use them.

However, last night I realized that I can think about a RX antenna as an
HF AC current /generator/ running with a small voltage potential (i.e.,
~1 uV), and that my receiver completes this AC circuit.

Then it follows that a longwire needs an RF ground (of some nature) to
"complete" the circuit. Hence, the use of a counterpoise in some
situations. My receiver is one part of an AC circuit that wants some
kind of RF ground to see the voltage potential being generated by the
antenna. Crystal radio sets seem less like magic now.

Of course, grounds for lightning, static or noise attenuation is
related, but not specifically part of the antenna as an AC generator.

So, my "folded dipole" (or, likewise, any doublet) does not rely on
ground to complete this AC circuit, and works relatively well as an AC
generator with a small voltage potential it presents at the receiver
front-end. It follows that all the ground I should need (for good
operation) is a good chassis ground, even if that is only the neutral
side of the wall-wart (is that where it is?). Other issues like ground
loops, reduction of common-mode noise &etc. is a separate issue; these
can *sometimes* be solved by different devices on the antenna system,
but I see now how they could also add problems.

So, when people complain about balance/unbalanced situations, they often
talk about the radiation lobes of a TX antenna being uneven in some
manner they would like to minimize. Perhaps there are gain issues, as
well. I have no idea how my analogy works in this regard with RX
antennas (perhaps my dipole will be slightly "deaf" on a particular axis
if I do not balance/tune it before plugging it into my receiver), but I
can take a baby step and suggest that the various things we can put
between the antenna and the receiver are often RLC circuits meant to
lengthen or shorten the electrical length of the wire. The main intent
is to manipulate the resonance of the antenna for whatever purpose.

I know my explanation has a certain amount of hand-waving and holes, but
it is really helping me understand how the antenna fits into the
receiver as a total system.

The rest of your comments make a lot more sense to me when I think of
things in this manner.

Thanks to everyone in this thread for coaching me in what I hope is the
right direction.

-- cm

On Tue, 15 Mar 2005 12:53:33 -0500, clvrmnky
wrote:
I've had an epiphany of sorts, and I think you may be partially to
blame! Well, that and "Basic Electronics" published by the US Navy.

Hi OM,

I was an Instructor at the Navy's Electronic Technician School at
Treasure Island. Get yourself a copy of Terman's "Electronic and
Radio Engineering" (the 1955 version) to find the level of coursework
that was offered at this school. It is very accessible reading and
noteworthy for being comprehensive without being a sleeping pill.

However, last night I realized that I can think about a RX antenna as an
HF AC current /generator/ running with a small voltage potential (i.e.,
~1 uV), and that my receiver completes this AC circuit.

Good that you picked this up yourself. It is a useful metaphor.

Then it follows that a longwire needs an RF ground (of some nature) to
"complete" the circuit. Hence, the use of a counterpoise in some
situations. My receiver is one part of an AC circuit that wants some
kind of RF ground to see the voltage potential being generated by the
antenna. Crystal radio sets seem less like magic now.

Quite so.

It follows that all the ground I should need (for good
operation) is a good chassis ground, even if that is only the neutral
side of the wall-wart (is that where it is?).

Well, this is getting close to the mystery of your understanding. As
simple as ground is, it is so often taken for granted that many don't
really understand it at all.

As for the Neutral connection of the mains NO THAT IS NOT GROUND!

DO NOT PROCEED FURTHER with any wire work at that service until you
research this completely.

However, as a point of intuition, ground is so tightly coupled to this
wire (at RF) so as to be the missing half of the longwire system.
This is why I commented on the distinction of being completely battery
operated (hence no ground coupling).

Other issues like ground
loops, reduction of common-mode noise &etc. is a separate issue; these
can *sometimes* be solved by different devices on the antenna system,
but I see now how they could also add problems.

This goes again to the common misunderstanding. You won't suffer a
ground loop until it occurs. Solving it will be one of life's
greatest struggles, and the solution, if stumbled upon, will appear to
be one of life's greatest mysteries. Again, battery operation creates
its own bubble of isolation from these issues - however, adding a
charger brings the prospects back into the equation.

So, when people complain about balance/unbalanced situations, ...

Here you get into uncharted waters. Spend some more time here before
you solo again.

73's
Richard Clark, KB7QHC

On 15/03/2005 8:33 PM, Richard Clark wrote:
On Tue, 15 Mar 2005 12:53:33 -0500, clvrmnky
wrote:

[...]

I was an Instructor at the Navy's Electronic Technician School at
Treasure Island. Get yourself a copy of Terman's "Electronic and
Radio Engineering" (the 1955 version) to find the level of coursework
that was offered at this school. It is very accessible reading and
noteworthy for being comprehensive without being a sleeping pill.

I'll look for that title. I'm finding some of the older technical
instruction books very useful.

[...]

It follows that all the ground I should need (for good
operation) is a good chassis ground, even if that is only the neutral
side of the wall-wart (is that where it is?).

Well, this is getting close to the mystery of your understanding. As
simple as ground is, it is so often taken for granted that many don't
really understand it at all.

As for the Neutral connection of the mains NO THAT IS NOT GROUND!

DO NOT PROCEED FURTHER with any wire work at that service until you
research this completely.

Absolutely. I actually have home wiring experience (I don't have my
electrician's ticket, but I could wire my own home, and it would pass
inspection.) I'm surmising that the ground my receiver is seeing (at
least the DC components within it) is the neutral wire. My comment was
more of a rhetorical comment, not a threat to use the white wire on my
AC outlet as ground!

However, as a point of intuition, ground is so tightly coupled to this
wire (at RF) so as to be the missing half of the longwire system.
This is why I commented on the distinction of being completely battery
operated (hence no ground coupling).

Other issues like ground
loops, reduction of common-mode noise &etc. is a separate issue; these
can *sometimes* be solved by different devices on the antenna system,
but I see now how they could also add problems.

This goes again to the common misunderstanding. You won't suffer a
ground loop until it occurs. Solving it will be one of life's
greatest struggles, and the solution, if stumbled upon, will appear to
be one of life's greatest mysteries. Again, battery operation creates
its own bubble of isolation from these issues - however, adding a
charger brings the prospects back into the equation.

Fair enough.

I get a bit of a boost in signal running off the wall-wart, but it is
actually more convenient for me to run off batteries. I end up moving
the receiver around quite a bit. I can pick the big blowtorches and the
relays from Sackville quite nicely off the whip, so I often listen to
them in the kitchen or when doing chores around the house. For "DXing"
I settle in near the door where I've got my antenna experiments going.

This month I'm going to rig up that big loop and see how things change
from the random wire.