Deluxe Tenna Dipper

Hendricks QRP Kits
Affordable QRP kits at exceptional value

Hendricks Deluxe Tenna Dipper Kit

Designed by Steve Weber, KD1JV

The Deluxe Tenna Dipper provides a simple means of determining the 50 ohm resonant frequency of an HF antenna or ATU (Antenna Tuning Unit). The small size and battery operation makes the unit ideal for use in the field. It's perfect for antenna experimenters that don't want to tie a bunch of money up in the higher priced analyzers. It's even priced lower than most swr bridges, and this tells you "where" you are resonant, not just that it's matched, or not matched, like a simple swr bridge.

Features:

Wide tuning range: ~3 MHz to ~30 MHz in two ranges
Four digit digital display with display shift down to 100Hz
Eliminates the need for a transmitter and SWR bridge when:
Trimming length of resonate dipole, and portable vertical antennas
QRM free adjusting of antenna tuners and antennas
Quickly adjust short, portable vertical antennas, eg. PAC-12 & Screwdriver antennas, etc.
Current draw is approximately 50mA
Weight w/batteries: .66 lbs./10.6 oz./ 300g

How it Works:

A voltage controlled R/C oscillator generates a 5 volt square wave signal. This signal drives a resistive Wheatstone bridge. One leg of the bridge is the "unknown" resistance, the antenna. A wide band step up transformer is connected across the bridge to detect the signal produced when the bridge is unbalanced. This signal is farther amplified by a Darlington pair transistor amplifier. A high brightness LED is used to visually indicate the current in the collector of the amplifier. When the antenna impedance at the unknown leg of the bridge is equal to 50 ohms, the bridge is in balance and the LED will go out. Hence the name for this device, the Tenna Dipper, as we dip the brightness of the LED to find the 50 ohm match.

Supporting Files and Documents

Deluxe Tenna Dipper Assembly Manual (4/24 update)

Deluxe Tenna Dipper Decal Install)