Butternut TBR-160X 160 Metre add on kit for Butternut verticals

Butternut 160 Meter Add-On Kit BUT-TBR-160X is designed specifically for the Butternut HF9V, HF6V and HF2V HF Vertical models. It is a parallel tuned circuit that consists of a coil and four high voltage RF capacitors with custom mounting plates, brackets and clamps.

This assembly is installed at the base of the BUTTERNUT® HF Vertical antennas to achieve operation on 160 meters.

These new capacitor plates act as heat sinks, to reduce frequency drift when the components heat up under RF power and environmental conditions. Recommended maximum 160M power is 1,000W PEP SSB, 500W CW, 150W Digital (FT8, FT4, RTTY, etc).

Your vertical antenna must be properly tuned on all bands Prior to adding this 160 meter kit. A very good radial system is a requirement for reasonable performance on all bands, but especially on the 160 meter band.

Due to the effect of the installed 160 meter kit, the other bands will need to be retuned and the original shunt coil will require significant adjustment.

SWR bandwidth on 160 meters is very narrow. When tuning the antenna with an analyzer connected to the antenna matching section coax, choose the EXACT frequency you desire. DO NOT use any antenna tuner to operate on an off-resonance frequency above 2:1 SWR.

Use of an antenna tuner is not possible because this is a very high-Q antenna inductor and capacitor combination that will not tolerate overheating. Prolonged tune-up at maximum power levels must be avoided. Exceeding these levels may cause damage to the antenna, amplifier or transceiver.

It functions as an inductive reactance in series with the antenna feedpoint, loading the antenna structure to resonate in the 160 meter band. On the higher bands the TBR-160X produces decreasing values of capacitive reactance, raising the resonant frequency (by 300-400 kHz) on 80 and 40 meters. Above 7 MHz this detuning is negligible and the antenna can be adjusted on all bands to compensate, as needed.

The only compromise that one must accept for the sake of 160 meter operation is reduced SWR bandwidth on 80 meters and to a lesser extent, on 40 meters with the HF2V/6V/9V. The TBR-160X SWR bandwidth of 2:1 or less on 160 meters will depend to a large extent on the efficiency of the ground system used with the antenna; 10 kHz is a typical figure with a fair-to-good ground system and a relatively short antenna such as the HF6V/9V. With the longer HF2V, especially if top loading "umbrella" wires are used, SWR bandwidths of 15 to 35 kHz between 2:1 points are possible.

Even if greater bandwidths are possible with poorer, higher loss ground systems, performance would suffer. The best possible ground systems should always be used with electrically short loaded antennas.

A critical component of this type of antenna system is a very good radial system; 30 to 60 or more radials of 45 to 65 feet each is a requirement. Even at best the bandwidth will be very narrow so when tuning for 160 meters, you will have to determine which frequency in the band you want to use.