BAL_UN
Hemos tratado de exponer información solvente; si se puede ,a dudas concretas es posible que si se pregunta , pueda
contestarse, ojo el número que va a salir en la loto ,no.
Conceptos, que no definiciones, obtenidos de diversas autoridades, y fabricantes
de reconocido prestigio.
Mi primo de Zumosol, recomienda no hacer extrapolaciones o traducciones.
En el lugar de ¿???? xx o XX, mi primo las ha sustituido, para que
el que lee, ponga lo que debe, no lo que quiera, con el fin de
adecuar.
BAL-UN (hay más conceptos, pero ya son bastantes)
.(La traslación podría equivocar)
Baluns will not improve SWR (the exception is where a balun used as part
of a matching network, i.e.x:1 baluns used in ????(cuando
es requerido)
They are not Lightning arresters. The winding inductance in most baluns
is far too low.
Also, built-in Spark gaps don't work. The radio equipment is destroyed long
before the 'gap' arcs over.
4. Baluns do not allow multiband operation of single band, coax fed, antennas
They do not make antennas more broadbanded.
These are all generalizations and, of course, there may be specific exceptions
to any of them.
A balun really has only two jobs(ésto es muy importante para decisiones)
Isolate transmission line
Provide balanced output current
PROPER DESING
A properly engineered balun will include these design points:
1.- High winding inductance (reactance)
2.-Low stray capacitance
3.-Very short internal transmission lines-
<< 1/4 wave, the shorter the better
4.- High power components- High voltage wire
& insulation to withstand high power or a mismatch.
5.Large wire gauge reduces I2R losses.
6.Large cores - prevents saturation and provide the necessary high inductive
reactance values on the low bands.
7.Mechanical considerations: Weather- proofing, rustproof hardware and a
strong case to withstand loads.
WHQ Baluns? (aquí el problema es saber lo que significa WHQ y puede
resolver la necesidad)
Most commercial baluns are ??????(algo)-types. As such, their performance
is poor unless they are operated under ideal conditions.
Even under the best of conditions, a perfect match, low power, etc. insufficient winding inductance and poorly designed transmission
lines sacrifice efficiency and reduce bandwidth.
The impedance of such a transmission line (two wires in parallel) is generally
between xx and xx ohms. This value is totally inappropriate.
It should be XX ohms if the balun is to be used with XX ohm coax. Otherwise, bandwidth will suffer and unwanted reactance can be
introduced into your antenna system. We use very carefully designed transmission lines. We use #xx wire and the spacing between the
wires determines the
line's impedance. This is carefully controlled to provide maximum bandwidth,
power handling, and minimum effect on antenna tuning.
Achieving this kind of result is difficult. It is difficult to produce the
necessary inductance reactance on the low bands without introdu-
cing unacceptable capacitive reactance and leakage on the upper bands. Broadband performance is possible only through the correct
application of both selected ferrites and properly designed transmission lines and x/x compensation networks. The mechanical construc-
tion of the balun also influences the final characteristics of any balun.
Wire Lead Length and Tuning Effects
The length of a balun's output lead can have an effect on the tuning of
your antenna. These leads are part of the antenna and in some ap-
plications, can make antenna resonance drop in frequency by a small amount. The effect is greatest on xx meters where the length of the
balun output leads are the longest in terms of antenna length. On x x
meters there should be no noticeable effect.
The Yagi Baluns have precisely measures leads. Occasionally you should take
the extra lead length into account. Most of the time, an
inch or two, will make little difference if Gamma or Beta matching schemes are used. The same can be said of most simple antennas.
(se ha dado soluciones)
Phase Delay(con esto también hay que contar)
All xxxx xxxxx line Isolatorstm have a specified delay time through Line
Isolators. This value is unimportant unless the Line Isolators are
used in matching sections, phasing line or similar applications.
If the length of the transmission line or matching stub is critical, use
the phase delay figure in the specifications to compensate for the ad-
dition of the Line IsolatorsTM to the system.
. To find the delay at a specific frequency, use the formula at right. Sometimes
the phase delay is important. Here is a simple example.
Suppose you are building a full-wave loop antenna for x.x mHZ. You plan
to use a xx ohm quarter- wave matching stub (commonly
known as a Q-section) to match the xxxx at xxx ohm impedance to xx ohms.
The formula for the matching stub is
A quarter-wave stub for x.x MHZ using a solid dielectric coax with a velocity
factor .xx is
Phase delay exists in all baluns and similar devices. We give you the numbers
to take advantage of it.
Power Rating (claro que ésto también)
Lo que quieras, después ténlo en cuenta
Saturation (Muy importante aunque no lo parezca)(por ésto ocurren
muchas cosas)
Pero………………………………..hay
que verlo.
When a ferrite core balun saturates, you will notice an upward drift in
SWR long before the balun fails. Core saturation can be caused
by too great a mismatch at the load (antenna) or by running two much power or a combination of both. If you see an upward movement
in SWR, locate the problem immediately. If you must stay on the air,
lower power until SWR drift ceases.
In new installations, tune the antenna system for minimum SWR. Apply a few
hundred watts of power on each band the system covers.
Monitor the SWR with power applied. Do not exceed the time limits of your amplifier. Increase power gradually until maximum power
output is achieved. Watch the SWR or reflected power meter closely. If the SWR drifts upward, locate the problem before continuing
operation.
Remote Balunstm( más)
Remote Baluns are a special case. They operate under the most difficult
conditions. The checkout procedure for the Remote Baluns TM
is the same as in the previous paragraph. If you notice the SWR drift on one or two bands, this usually means that the load impedance is
too high or too low for efficient balun operation. Changing the length of the balanced feeders (ladder line) by a few feet or ideally, 1/4 wa-
velength, will often remedy the situation and permit full power operation.
Installation(es un decir cojer lo que hay que cojer,todo lo que se dice
aquí vale)
While there are no special mounting requirements, I do suggest strain relief
for long unsupported transmission lines. Use standoffs for your
coaxial cable. This can improve the front-to back and front-to-side ratios of your beam antenna. It doesn't make sense to put up a good
beam and then let the feed line radiate (because of a poor balun). It also doesn't do your antenna system any good to couple your coaxial
cable to a large vertical antenna (like your tower). Taping your coaxial cable to a tower leg creates a large capacitor which effec tively cou-
ples your beam and vertical antenna (tower) together. Use stand-offs to hold the coaxial cable away from the tower leg. This procedure in
combination with a xxxxx xxxxxx balun can dramatically improve the front-to-side
ratio of some beams.
There are no special mounting requirements. The unit may be supported by
the eye-bolt or strapped to the antenna's boom and secured
with waterproof tape or quality hose-clamps.
Lightning Protection(no vale interpretar)
Some balun manufacturers will tell you that their baluns have built in lightning
protection. Those that do, use spark gaps which are absolu-
tely useless. The high winding inductance of our baluns offers some protection, but for proper protection, use devices intended specifically
for "surge" protection.
Weatherproofing
Más o menos es lo que hay que hacer cuando está hecho
All critical components must be completely protected even if water enters
the balun's case.
Moisture can enter the balun case only through the holes where the wires
emanate. You can completely seal your balun by putting a small
amount of CoaxSeal around wires leaving the case. Press the CoaxSeal firmly around the wire and against the case. Make sure the coax
seal 'wets' (or sticks) to both the wire and the case. This will insure
a weather tight seal. Always protect all coaxial connectors with CoaxSeal.
Seal all electrical components and coaxial connectors exposed to the weather.
Use CoaxSeal(r) to wrap any connector that is exposed to the weather. Generously
wrap each connector and mold the layers together with
your fingers to insure a solid, impenetrable seal.
El problema es hablar del balum magnético, sin conocer lo que es el Balum, algo puedo añadir sin meternos en profundidades, No hay que establecer diferencias, hay las que hay, y no es de dolor.
El UMB proporciona el aislamiento físico de la antena al feeder, transfiriendo solamente la señal. En la mayoria de las intalaciones de recepción el feeder está conectado al chasis del receptor.Esto puede ser la causa, el camino, la vía, por la que se produzca el ruido hacia el receptor porque uno de los conductores del feeder es el retonrno del path de la antena o simplemente por el ruido generado entre la antena y el feeder.Muchos otros tipo de Antenna Matching Baluns son simplemente transformadores wideband con el conductor de tierra de la antena conectado al screen del feeder. Esto es una limitacion seria de diseño que proporcionará ruídos y estallidos debido a los retornos del path de la antena que empiezan en el main earth feeder..El modo típico de instalar una antena long-wire con otros tipos de baluns es probablemente la peor forma de instalar un long-wire usando balun, porque la antena y el balun están inmersos en la zona de influencia del surround y los brickbrocs.Así mismo el feeder coge los ruidos que forman parte de la antena, porque no existe aislamiento adecuado entre la antena y el feeder. Grounding el feeder con tierra separada no es muy efectivo en medias y bajas frecuencias.
THE WRONG WAY TO INSTALL A LONGWIRE ANTENNA/BALUN:
THE CORRECT WAY TO INSTALL A LONGWIRE ANTENNA/BALUN:
Cuál es la forma correcta de efctuar la instalación de una
antena long-wire???????? (siempre es la misma, pero hay que atender a las
indicaciones de las autoridades en esta materia)
Hay que partir de las WH questions. El Isolator debería ser colocado
cerca del elemento a utilizar mediante conexion lo mas cortas posibles del
rod earth.que la antena esté situada lo más alejada de las
fuentes de ruído a un mínimo de X metros de las mismas.También
los ruidos absorbidos por el feeder es bajo si esta conectado cerca del
ground.
El retorno del path por tierra de la antena es un separado y no del ruído
del conductor tierra feeder como en casi todos los baluns.Esto puede reducir
el ruído casi en 20dB comparado con otros baluns.
El uso del Isolator proporciona asegurar que el ruido que accede lo frena
y acomoda el proporcionado por la antena igualmente así como el generado
en el feeder.El Isolator puede reducir el ruído en bajas frecuencias
por encima de los 40dB. Sin el Isolator el feeder está conectado
a la tirrra de la utilización que es una extensión de la tierra
del building alambrado lo más cerca de las fuentes de ruído.Conectando
la utilización directamente no baje el ruído porque es difícil
encontrar baja impedancia.
(si no entiendesa algo concretamente pregúntale a MI PRIMO)