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End-Fedz FAQ
- Can the EndFedz be used on bands other than the design band?
- In general, no. These antennas are monoband. Using them
with a tuner for other bands wil guarantee that the coaxial
shield will become part of the radiating structure and may
harm the matchbox.
- What is the radiation pattern of the EndFedz?
- Characteristics are identical to a center fed dipole.
- How can I extend the bandwidth of the EF-10/20/40 on 40M?
- In designing the EF 10/20/40 we intended to make
an antenna that would be portable and easily deployable. As
a result, we use a choke to isolate the first 33' from the
remainder of the antenna. The choke, then, acts like an
inductor shortening the 40M half wave from 66' to 40'. If
space permits, a 66' wire may be attached to the matchbox;
yielding wider 40M BW, and slightly more 40M gain. On 20M
the antenna will appear as a full wavelength. A 1 wavelength
antenna has a null at the horizon, and thus may not be
suitable for DX work if the antenna is deployed as a
vertical. Deployment as a sloper or horizontal overcomes
this problem.
- What limits the power on the EF-10/20/40?
- The matchbox.
- Can I use the EF-10/20/40 matchbox on other bands?
- Yes, remove the factory supplied radiator and
substitute a radiator whose length is 1/2 wavelength long on
the desired band - from 60M up to 10M.
- Can I use my monoband EndFedz matchbox on a different band by replacing the wire?
- No. Each matchbox (with the exception of the EF-10/20/40) is different and band specific.
- Do the EndFedz require a ground?
- The simple answer is no. With over 4,000 antennas in the field,
we know of one instance where RF was "in the shack."
This occurred with the antenna directly over the operating position.
Moving the antenna solved the problem. If you do ground the antenna
at the matchbox, you will likely see no change in VSWR or resonant
frequency. The only conditions where we were able to measure significant
RF on the outer coaxial shield occurred when:
- The coaxial length was an odd multiple of va wavelength AND
- The rig was grounded.
In this instance we measured current -7dB down
from the peak antenna current. Changing the coaxial feedline
length OR removing the ground significantly reduced the
currents.
- Do EndFedz require a tuner?
- No tuner is required, nor should one be used. Take the short time
required to tune the antenna.
- Can I add additional 1/2 wave wires to the EF-10/20/40 matchbox
and work multibands?
- No. Unlike a center (current) fed dipole in which a fan
arrangement of wires allows for multiband operation, the
wires on an endfed (voltage) must appear in series- either
through a trap/choke arrangement or harmonically related
frequencies (eg. 7/14/21/28 MHz).
- Can I combine coaxial cables from different EndFedz for a single downlead?
- No. You will need a remote switchbox or separate feedlines.
- What is the best grounding arrangement for the EF-SWL?
- Unfortunately, there is no one answer. That is why we have
provided separate grounds on the matchbox. Lug 2 is the
ground end of the antenna side of the transformer while #1
is ground for the coaxial shield. Depending on the source of
noise, it may be advantageous to: 1. Leave the factory
shorting strap in place and attach either lug to a suitable
RF ground at the antenna. 2. Remove the strap and ground
only lug 1 at the antenna site. Then, the receiver may be
grounded or left ungrounded- whichever results in lower
noise.
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