Posts

The Xiegu G90 Junkbox Manpack

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Executive Summary  Yep, still doing these summaries- your time is important, and you may decide to cut and run :) 1) The G90 needed an easy grab and go way to carry a battery, mount an antenna and operate easily in the field. 2) The G90 also needed a bit of protection from field abuse; so 3) A manpack configuration was designed that:      a) uses two vented clamshell case halves and four clamps to secure the radio between eight Sorbothane shock absorbing pads;      b) has a tray with hook and loop straps for securing a battery; and     c)  provides an antenna mount for a whip antenna. Disclaimer : Calling this a "manpack" is a bit of a euphemism. I'll be the first to admit that a true manpack is portable, has rechargeable batteries, is relatively impervious to dust and water, and rugged enough to take a licking and keep on ticking. This ain't that. It does provide some protection and impact resistance without compromising cooling as a sealed enclosure might, and handl

Whip Me Longer - A Few Thoughts on KX2 Handheld Antennas

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Executive Summary You can use a relatively long 6 to 8 foot non-resonant handheld whip with the KX2 bracket and KX2 tuner.  It might outperform a 4 foot whip by 5 dB or so. Experiments showed that: 1) The KX2 tuner will tune a 7 foot whip to an SWR near 1:1 on 10 through 20 meters. 2) Adding a small Buddipole coil as a series inductor (about 6.4 uH) to the base of the 7 foot whip, the whip can be tuned to 1.3:1 on 30 meters; 3)  Adding a large Buddipole coil as a series inductor (about 18.2 uH) to the base of the same  whip, the whip can be tuned to 1.6:1 on 40 meters; and 4) 60 meters was a bridge too far with the large coil and a 7 foot whip; and 5) Substituting a 6 foot whip for the 7 foot whip gave similar but marginally poorer results; and 6) These results aren't limited to whips tuned by a KX2.  Resonant operation of antennas like an MFJ-1898 slider coil antenna, or a Buddistick, benefits similarly from being almost double the length of a 4 foot whip. What are we trying to d

A Funky Little Antenna Bracket for the IC-705

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In the unlikely event you've read the last two blog entries you'll know that I'm preoccupied with brackets this month. Because the KX2 and FT-817 handheld 3/8-24 stud mounting brackets in those entries worked better than I hoped, I had to try to do something similar for the IC-705. But not even KA9P is crazy enough to try the IC-705 as a handheld.  Sure, you could make the bracket and use it for a bit, but the radio is heavy, and sideways. So it wouldn't get used much. I decided the next best thing would be a bracket that let me set the IC-705 down on a flat surface, screw in an antenna, and operate.   My hope was that the weight of the radio would counterbalance a halfway decent vertical antenna that did not require a tuner.  I rate this bracket a qualified success with the MFJ-1898 slider coil vertical, and better than that with the lightweight Buddistick shown below that uses a Featherweight whip and the small 10 - 20 meter coil. Front and side views of the finished

A Nearly Universal Whip Adapter for the KX2

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This is a pic of my most recent KX2 whip mounting bracket.  I revised this bracket a bit to make it easy to build and use with antennas like the MFJ-1898. Why bother?   Well, blame Elecraft.   Wayne often mentions the joy of using the KX2 handheld with an AX1 or AX2 antenna.  This is a pretty sweet set-up if being able to put everything in your pocket is your most important operating criteria. But I'm fond of at least four more criteria.   PRICE - You might already have another antenna available, and not want to spend close to a hundred bucks for a 4-foot whip. MOUNTING FLEXIBILITY - I already have other short antennas I'd like to use with the KX-2, for example, the old BNC mount all-band ATX (see also MFJ-1899 clone) and an Outbacker Joey, fitted with PL-259 hardware.  These are all heavier than an AX antenna and could not be used without a better mount than the chassis mount BNC connector on the KX2. BAND FLEXIBILITY - The ATX and Joey have taps for many more bands than the A