Specifications

73
Vertical Feedline
Current Choke
When quarter-wave antennas are constructed over
a good radial system, they have a feedpoint
impedance of about 36 Ω and currents are
equal between the vertical section and the
radial system. If the radial system is less than
ideal—due to short radials, too-few radials or
poor soil conductivity—the antenna system
will try to use the feedline shield as part of
the radial system. This leads to a loss in the
e iciency and a higher take-o angle. O en the
current introduced on the shield of the feedline
causes RFI at the operator position.
Placing a vertical feedline current choke (VFCC) at the
base of the quarter-wave antenna forces the currents to
equalize between the vertical section and the radial system,
even if the radial system is less than ideal. The balanced terminals of the VFCC should be
connected directly to the base of the antenna and radial plate with appropriate lengths
of low-inductance tinned copper braid.
The DX Engineering VFCC is supplied with an insulated mounting shelf to isolate the
feedline shield from ground. Purchase the optional V-Saddle Clamp for mounting the
VFCC to pipe up to 2 inches O.D.
• Equalizes vertical and ground currents
• Improves signal e iciency
• Lowers radiation angle
DXE-VFCC-H05-A Vertical Feedline Current Choke Kit, 2/5 kW, HF ................ $134.95
DXE-VFCC-H10-A Vertical Feedline Current Choke Kit, 5/10 kW, HF .............. $189.95
DXE-SSVC-2P V-Saddle Clamp, for 1" to 2" O.D. Pipe ..................................$11.95
RBA Series Baluns
LDG Electronics designed these baluns to let you easily connect
ladder line and long wire antennas to LDG’s automatic antenna
tuners. For more versatility, these baluns can operate without
an LDG tuner and may be used with any of your long random or
ladder line antenna projects.
LDG-RBA-4-1 4:1 Voltage Balun ....................................................................$27.95
LDG-RBA-1-1 1:1 Current Balun....................................................................$28.95
Accessories
LDG-ALK-2 Audio/Linear/Key 2-Port Switch ............................................$49.95
Visit DXEngineering.com to learn more about LDG baluns and accessories!
LDG-RBA-4-1
LDG-RBA-1-1
Permatex® Neutral Cure RTV Sealant
Have you ever sealed a piece of electronic gear with ordinary RTV
sealant, only to open it later to find that the component had become
corroded? It wasn’t moisture that caused the corrosion—it was the
RTV. Ordinary RTV gives o acetic acid when it cures (that’s the vinegar
smell); it’s the acid that causes the corrosion. DX Engineering has
located a Neutral Cure RTV that is non-corrosive and safe for sealing
baluns and other electronic gear that will be out in the weather. Applies
just like “normal” RTV, dries in one hour and cures in 24 hours at 70 degrees F.
UMI-82180 Permatex Neutral Cure RTV, 3.35 oz. Tube, Black......$5.99
Hazardous, limited to domestic UPS Ground shipping only.
Broadband Ferrite Balun
This balun matches your 50 Ω direct coax-fed,
hairpin/beta matched or trap tri-band Yagi
antenna. It can couple into any 50 Ω balanced system,
like dipoles, multiband doublets and beam antennas. The
BN-86 Balun handles 800 watts SSB and 1,500 watts CW, while
covering the 80 to 10 meter bands. Using stainless steel hardware, this
sturdy boom-mounted balun will give you years of reliable service.
HGN-BN-86 Broadband Ferrite Balun ...................................................... $79.95
B4KC Current Baluns
Palstar B4KC Current Baluns are
available in both 1:1 and 4:1 ratios.
They’re intended for indoor use on
Lo-Z antenna applications for center-fed wire antennas with open wire
and twin lead transmission lines. B4KC Baluns feature steatite insulators
and a large 3.25" ferrite core with Teflon® 12-gauge wire. Rated up to
4,000 watts, these are useful additions to your antenna.
PAS-B4KC-4-1 4:1 Current Balun.....................................................................$89.95
PAS-B4KC-1-1 1:1 Current Balun.....................................................................$89.95
BN-4000B Broadband Beam Current Balun
This 1:1 balun provides the proper current path
between unbalanced coax and your balanced antenna
feedpoint. It’s compatible with 50 Ω direct coax-fed,
hairpin/beta matched and trap tri-band Yagi antennas.
Using ferrite beads over a short length of coax, the BN-4000B
e ectively chokes the flow of RF on the outside of your coax
shield. You can use this balun from 160 meters all the way to
6 meters. It handles 2,000 watts of continuous duty.
HGN-BN-4000B Broadband Beam Current Balun .............. $109.95
LDG-ALK-2
50 and 75 Ω Choke Baluns
Choke baluns ensure that RF does not
flow on the outside shield of feedlines,
phasing lines, etc. COMTEK SYSTEMS’
baluns feature 100 Amidon beads on a
length of RG-400 PTFE double-shielded
silver coax terminated with Silver PTFE
PL-259 UHF connectors. Assembled
baluns are covered with 3M heat shrink
tubing. RF bead kits are available if you
wish to assemble your own chokes.
COM-CFC-50 50 Ω Balun, Assembled ................................ $93.95
COM-CFC-50K 50 Ω Balun, Kit .............................................. $69.95
COM-CFC-75 75 Ω Balun, Assembled ................................ $94.95
COM-RFB-160 RF Choke Bead Kit, 160M ............................. $89.95
COM-RFB-80 RF Choke Bead Kit, 80M ............................... $84.95
COM-RFB-40 RF Choke Bead Kit, 30 and 40M .................. $67.95
COM-RFB-20 RF Choke Bead Kit, 10, 15 and 20M............. $38.95
Accessories
DXE-RADP-3 Stainless Steel Radial Plate with 20 Bolt Sets ..................... $54.50
DXE-SSVC-2P V-Saddle Clamp, Fits 1" to 2" Tube ...................................... $11.95
CQ Magazine Publications
W2FMI Understanding Baluns and Ununs
W2FMI Jerry Sevick’s compilation of balun performance and
design criteria. It o ers clear explanations to prompt further
discussion of theory and applications.
CQM-SEVICKBALUNS W2FMI Understanding
Baluns and Ununs ........................$19.95
RU Series 4:1 UNUN
If you’re using 50 Ω coax to feed your 43 foot vertical antenna,
then this UNUN is essential to create a perfect match. Rated
at 200 watts, it will easily tame your resonant verticals and
will come in handy whenever you need a 4:1 match for an
antenna project.
LDG-RU-4-1 RU-4:1 UNUN ....................................$27.95
Baluns, UNUNs & Chokes
FREE Standard SHIPPING for Orders Over $99, See Page 58 for Details