On Dec 23, 1:27*pm, Telamon
wrote:
In article ,





*David wrote:
Telamon wrote:
In article
,
*Telamon wrote:

In article ,
*David wrote:

RHF wrote:
The Verdict {One Man's Opinion} : Magnetic Longwire Balun Is Too
Expensive

http://www.hard-core-dx.com/nordicdx.../magbalun.html

-by- Alan Johnson

-source- Hard-Cord-DX website :http://www.hard-core-dx.com/
The Most Common Antenna Type
Randon Wire Antenna Problems
Enter the Balun
The Magnetic Longwire Balun (MLB)
In the Laboratory
After Four Rainy WeekEnds
I also did A-B Comparisons
* The Results
The "Resistance" Curve for the MLB
The N8KDV Transformer
A-B Testing was very Revealing.
* Recommenation
How Essential is a Perfect Match?
Based on Price and Performance
The MLB Definitely Wins

Originally Published in the NASWA Journal - July 1992
-by- Alan Johnson [N4LUS]

Magnetic Longwire Balun (MLB)
http://www.universal-radio.com/catalog/sw_ant/1484.html
http://www.dolstra.nl/Z&L-amateur/AN...tems/MLB_1.JPG
http://www.remeeus.eu/english/hamradio/mlb.htm
http://ham.srsab.se/graphics/antennas/mlbII.jpg
-by- RF Systems - MSRP Price ~ $60

Alternative "MLB" - MLB-1 Magnetic Longwire Balun
http://www.palomar-engineers.com/MLB-1/mlb-1.html
-by- Palomar Engineers - MSRP Price ~ $50

NOTE - While the 'N8KDV Transformer' is presently Not Available.
WinRadio does offer the LWA-0130 Long Wire Antenna Adapter
http://www.grove-ent.com/WR0130.html
http://www.winradio.com/home/lwa.htm
http://www.winradio.com/home/ax05e.htm
-by- WiNRADiO - *- MSRP Price ~ $40
READ - Good Deal on 9:1 Matching Transformer
http://groups.google.com/group/rec.r...e40978fdc32ac0
-by- William Fieldstone
More WinRadio LWA-0130 Long Wire Antenna Adapter Postings
http://groups.google.com/group/rec.r...7d380609eec592
http://groups.yahoo.com/group/Shortw...na/message/230

iane ~ RHF
*.

[D]iane,

The point is to keep the feedpoint Z below the transmission line Z.

What's the advantage of the feed-point Z being below the transmission
line Z?

OK I'll answer it. None.

Less pinching in the midriff...

There's a rule.

? OK here is the rule, when you have an impedance mismatch
? by some ratio it does not matter which system element is
? higher or lower so for example if the coax transmission
? line is 50 ohms and the antenna impedance is 25 or 75 ohms
? the result is the same amount of reflected power.
? 25 ohms and 75 ohms are equivalent in this regard.
? One is not a better situation than the other.

Telamon,

Wouldn't it be the Ratios :

25 Ù Antenna to 50 Ù Coax ~ 1 : 2

50 Ù Coax to 100 Ù Antenna ~ 1 : 2
-vice- 50 Ù Coax to 75 Ù Antenna ~ 2 : 3 (1 : 1.5)

~ RHF

- Take an extreme case of this where you have either a short
- or the coax is open with nothing connected on that end.
- In either case if you were to send RF power to the open
- or short end of the cable you would have 100% reflected
- power. The returned phase of the that power would be 90
- degrees different though.
-
- This is different situation then DC current where the open
- and short would have very different consequences.
-
- --
- Telamon
- Ventura, California