2
TESTING AND ADJUSTMENT
braid of the coaxial cable should remain attached to the mounting post. The top of the small impedance
matching/grounding coil ("Q") should be disconnected from the base of the antenna, but the lower end should
remain connected to the mounting post for possible use later.
2. Loosen the wing nut on the lower coil clamp and stretch the coil by sliding the clamp down tube C until the lower
edge of the clamp is approximately 4-3/4" (12 cm.) from the lower edge of clamp D. This setting should produce
lowest SWR between 1800 and 1900 kHz. Tuning is very sharp so SWR checks at intervals of 5 kHz may be
necessary to determine the resonant frequency with the initial setting. If no frequency can be found where the
SWR drops to a minimum value, simply stretch the coil out an inch or less, and begin another series of SWR
checks. Once the low SWR point has been found, it is a simple matter to make adjustments for any frequency
between 1800 and 2000 kHz. To raise the frequency of lowest SWR, stretch the coil a slight amount. To lower
the frequency, compress the coil. Final adjustments should be made with changes of 1/2" or less. For operation
above 1900 kHz it may be necessary to short out or remove several turns of the coil if it cannot be stretched
sufficiently.
3. After the TBR-160-S has been adjusted for 160 meter operation it will be necessary to readjust the 80 and 40
meter resonator circuits for greater inductance . Do this by compressing the coils for those bands. The circuits
for the higher-frequency bands should not require adjustment. In some installations, however, it may be found
that the previous 10 meter resonance moves to a lower center frequency and shows narrower bandwidth, while a
second unwanted resonance occurs in the 27 Mhz range. If the lower resonance cannot be moved above 28 Mhz
by shortening the upper section of the antenna (Model HF6V-X/HF9V-X), it may be necessary to neutralize the
27 Mhz resonance by shunting the capacitor across the lower few turns of the TRS-160-S coil. Should this
measure become necessary for proper 10 meter tuning, please contact our customer service department for
detailed instructions and appropriate materials. In the case of the HF2V, which is not designed for operation
above 10 MHz, this problem will not arise.
MATCHING CONSIDERATIONS
It is totally unrealistic to expect a perfect match to 50 ohm cable over the 1.8 to 28
Mhz range with a single antenna, because earth losses, antenna radiation resistance,
and conductor losses, all of which determine the feedpoint impedance of the antenna,
can vary greatly over the HF spectrum. With poor-to-fair ground systems SWR
resonance on 160 meters should be less than 2:1. With better ground systems, SWR
may exceed 2:1, although the antenna will perform more efficiently. In such a case, it
may be desirable to reconnect the free end of the impedance matching/grounding coil
to the feedpoint of the TBR-160-S and adjust for lower SWR. In general, however,
the reactance of this coil is not sufficient to keep 160 meter energy from passing
through it to the ground, even with the coil fully compressed, at settings that provide
the best match on 80 meters unless the feedpoint impedance is much less than 50
ohms, as would be the case with a good ground system. If necessary, additional
inductance may be placed between the base matching/grounding coil and the 160
meter feedpoint for the sake of a better match on that band. Unfortunately, the
amount of inductance that provides the best match on 160 meters will probably not
provide the best match on 80 meters, in which case it may be necessary to settle for a
compromise adjustment for both 160 and 80 meters.
HARDWARE PACKAGE
PARTS LIST
3 V00153 #10 X 1 1/4" Screw A V00339 Coil Assembly 160 Meter
1 V00131 #10 X 1" Screw
B V00267 Coil Clamp 160 Meter
1 V00226 #10 X 3/4" Screw
C V00196 Coil Support Tube
6 V00132 #10 Flat Washer
D V00266 Capacitor Assembly 160
6 V00133 #10 Lock Washer
Meter
5 V00134 #10 Hex Nut
1 V00135 #10 Wing Nut
