AXE1 40 Meter Extender
The AXE1 extender allows any Elecraft AX-line whip (or the KH1 transceiver's whip) to be used on 40 meters. It adds 6 inches (15 cm) of length to the whip. The whip can be attached directly to a hand-held transceiver, or supported by an AXB1 bipod for table-top use (KHRA1 for the KH1).
AN ANTENNA TUNER IS REQUIRED BECAUSE THE WHIP + AXE1 EXTENDER IS VERY NARROW BANDED. See setup and matching instructions below.
CAUTION: MAX TRANSMIT POWER IS 30 W. REDUCE POWER TO 15 W MAX FOR SAFE HAND-HELD RADIO OPERATION.
To set up the AXE1:
An illustration shows the AXE1 extender, a cylindrical metal component with threaded ends, and a coiled radial wire.
- Attach the supplied 33 ft (10 m) radial wire to the transceiver at a point near the antenna jack. The KH1, KX2, and KX3 provide thumb screws for this purpose. The whip's supplied 20 m radial and the AXE1 radial may both be connected to the rig at the same time.
- If you do not use the radial, your transmit signal will be 20 to 30 dB weaker, and you may experience RFI problems.
- Elevate the AXE1's radial a few feet if possible by stringing it across foliage, rocks, picnic tables, etc. This will improve your transmit signal.
- Thread the AXE1 extender onto the AX1/2/3 or KH1 in place of the whip (AX1 shown at left). Then thread the whip onto the extender. Do not overtighten; this may make disassembly more difficult.
- Use the whip's 20 m setting for 40 m. Use the 17 m setting, if applicable, for 30 m (to reduce the ATU reactance needed).
- All short whips are very narrow banded. Their resonant frequency is affected by terrain, antenna height, and orientation, and body capacitance. An antenna tuner will nearly always be needed to obtain a low-SWR match (3:1 or lower recommended). If you're using the ATU in a KX2 or KX3, note that tapping ATU TUNE a second time within 5 seconds may find a better match.
- For receive-only use, antenna matching is optional, though it may improve receive sensitivity, especially on the lower bands.
Tips
- Tip #1: For transport, wind the radial wire in a figure-8 pattern (on your fingers) to eliminate kinks and allow the radial to be deployed quickly.
- Tip #2: Operation with a short antenna can be challenging. Start by calling strong stations (S7+ CW, S9+ SSB). In poor conditions, consider using the AXE1's radial wire itself as the antenna, using a tree or other support. Use a second wire as a counterpoise. Attach these wires to the transceiver using a binding post adapter (e.g., Elecraft #BNC-BP).
