On Jun 26, 1:16*am, m II wrote:
- Anyone have a way of measuring the varying
- efficiencies of the following?
- Let's say 5 to 20 MHz frequency range.
-
- This would be the base number for comparison, assign it a one:
-
- a: Straight connection of a random long wire antenna


OK so this is your starting point "Basic Standard"
with an assigned Unit Value of One [1]

Therefore this is not about 'efficiency' but Relative Merit.

- The others...
-
- b: The same long wire connected through
- a television (75/300 ohm variety)

Depends on the relative quality a design of the
TV Matching Transformer. Plus the quality of
the Coax Cable and a good earthen Ground.

1 - A 'good-one' will reduce some of the apparent
noise coming from the basic long wire antenna :
So that is a +One-Half [+1/2]

2 - A 'good-one' will reduce some of the AM/MW
Band Signals coming from the basic long wire
antenna : So that is a +One-Half [+1/2]

Relative Merit Unit Value of One + One-Half + One-Half
for a Total of Two [2] --- to One

- c: Same antenna with a 9:1 ratio transformer

First most of the very broadband 9:1 Matching
Transformers that are shown for Shortwave Radio
Listening (SWL) are also designed to cover the
AM/MW/BCB down to 500 kHz and SW Bands
up to 30 MHz. These usually recommend about
a 10-Turn Primary for the Feed-Line to the Radio
and about a 30-Turn Secondary for the Antenna
side.

Note - That you set a 5 MHz lower 'limit' so you
might want to cut the number of turns in half and
have a 5 -Turn Primary with a 15 Turn Secondary.

A good 9:1 Matching Transformer :

1 Will reduce much of the apparent noise coming
from the basic long wire antenna : So that is a
+One [+1]

2 - Will reduce much of the AM/MW Band Signals
coming from the basic long wire antenna : So that
is a +One [+1]

Relative Merit Unit Value of One + One + One
for a Total of Three [3] --- to One

- I'm assuming everything else remaining the same.

As am I : Same Long Wire Antenna +plus+

* Same good earthen Ground#
# Note - Many SWL'ers only use an in the house
Water Pipe Ground with their Long Wire Antenna
-so- Going from an in the house Water Pipe Ground
to a good outside 8-Ft earthen Ground Rod may be
another +One [+1] all by itself for those who make
the switch to an outside 8-Ft earthen Ground Rod.

* Same Coax Cable#
# Note - Many SWL'ers only use an Insulated Wire
for their Feed-in-Line from their Long Wire Antenna
-so- Going from an Insulated Wire to a Coax Cable
may be another +One [+1] all by itself for those who
make the switch in the Feed-in-Line.

- I'm interested in the variation, shown ratio wise,
- between the above. Are there any handy
- online calculators for this?

Online Calculators will give you Generated Numbers
for a given set of parameters; and not Relative Ratios
{side-by-side comparisons -aka- Relative Merit} .
-
- mike

iane ~ RHF