DX Engineering 4-BTV - Tuning the 80 Meter Resonator Whip for the 5-BTV and 6-BTV

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Tuning the 80 Meter Resonator Whip for the 5-BTV and 6-BTV
An antenna analyzer is the best way to adjust the resonant frequency of an antenna. The RigExpert
line of antenna analyzers are ideal equipment for tuning a Hustler
®
BTV antennas.
Measurements should be made at the antenna using a short (5 or 6 ft.) piece of 50Ω coax between
the antenna and the analyzer. If you are too close to the antenna your presence can affect the tuning,
if you are too far, the coax length may act as a radial and resonate. Taking readings close to the
antenna also eliminates the possibility of a long or marginal feedline influencing the tuning or
causing erratic readings. You should tune the antenna for low SWR rather than resonance (X=0)
although they are often close or at the same point. Normally, the SWR goes down somewhat and the
bandwidth increases once the feedline is reconnected and you measure the SWR at the operating
position.
The whip must be trimmed for the frequency desired. The chart below shows good starting points.
Using the antenna analyzer will aid in getting the desired resonance. Make small adjustments to the
whip length and verify you are going in the proper direction. Use the old adage "Measure twice, cut
once".
If you desire to use two frequencies that are far apart (CW -vs- SSB), you may want to have two
whips. One whip cut for the lower frequency in the CW area of the band, and another whip cut for
the higher end in the SSB area of the band. (Part Number HSR-49-04-80S from DX Engineering)
Changing the whip is made easier when using the DX Engineering Tilt Base.
DIMENSIONS INDICATED ARE APPROXIMATE
FREQUENCY
(MHz)
Exposed Tip Rod
Length
Your Final
Length
4.000
18”
3.950
19-5/8”
3.900
21”
3.850
22-1/2”
3.800
24-1/8”
3.750
25-5/8”
3.725
26-1/2”
3.700
27-1/4”
3.650
29”
3.600
30-5/8”
3.550
33”
3.500
34-5/8
The above dimensions are the exposed tip rod
length. See illustration.
The DXE-VMN-1 Vertical Antenna Matching Network is designed for use on 160,
80 and 40 meter quarter-wave verticals and with the Hustler
®
5 and 6-BTV. In some
vertical antenna installations with excellent radial systems, achieving the best SWR
on the lower bands may be difficult without some means of adjusting the
impedance. The DXE-VMN-1 allows easy adjustment for lowest SWR. The DXE-
VMN-1 Vertical Antenna Matching Network will aid in tuning the customer selected
portion of the 80 meter band to the minimum SWR without affecting operation on the
other, higher frequency bands.