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 AX series of antennas or (obviously) the 4 foot monobanders like the ones from MFJ. And there are slider antennas like the MFJ-1898 that are general coverage antennas over a large part of the HF spectrum.
EFFICIENCY - Don't want to turn this into a math discussion, but it's fair to note that short vertical radiation resistance increases about with the square of the length, all other things being equal.
At a very rough cut, it's likely that an 8-foot 20 meter antenna will be 6 dB down from a 16 foot, full size 20 meter vertical. But the 8-foot antenna will be about 6dB better than a 4 foot vertical. For me, I'll haul around an antenna with foot-long parts all day if it buys me 6 additional dB, or any large fraction of that.
For those reasons I built Rev. 0 of my KX2 mounting bracket, shown below. This was bashed out with some scrap aluminum (and scrap screws - more on that later) before a trip to Guernsey in 2019. I used this bracket extensively until this year, when I simplified the build.
That fairly heavy-duty bracket did a great job of holding up my Buddistick hardware.
In the picture below you can see I used a standard Buddistick 12-inch base whip section, a standard coil, and a standard whip. This yields a total antenna length of about 7 feet.
You can see below the first version of the bracket and whip in action overlooking St. Peterport on Guernsey, GU/KA9P. It was fairly easy to make CW QSOs on 17 thru 30 meters - the only open bands available in my operating slots.
As an aside I should point out that I'm operating from an overlook on the hotel balcony. I used a resonant radial draped over the balcony railing, a trick I learned from Bud, W3FF, when operating with him on St. Lucia. To this day I carry drag wire resonant on 20, with knots to adjust it to resonant lengths on other bands anytime I can dangle the wire freely from above. I'm sure this outperforms the normal 13 foot drag wire, though I've made no effort to quantify the difference.
But you don't need palm trees to have fun with this set up. Snow works too.
The shot below is from Winter Field Day 2020, where I made several 20 meter KX2 SSB contacts using the Buddistick while walking Bailey, the bordador.
The GU/KA9P operation reminded me of something I failed to consider when building out the antenna, and the WFD operation reinforced the point. Many locations, especially on water, have high winds.
On Guernsey I often experienced wind gusts in excess of 30 MPH. The Buddistick has enough surface area that when holding the radio in one hand, the wind and antenna really want to push the KX2 downwind.
I looked for a way to minimize the wind resistance, and decided to use the small Buddipole coil - less than half the size and still works 10-20 meters - and the Buddistick featherweight whip. This made a noticeable reduction in wind resistance.
In the pics below you can see I also added the LY2H coil slider in an effort to make coil adjustment easier. Linus' idea is clever, but under windy and rainy and salt spray conditions, I had infrequent issues with reliable coil contact, so continued to look for an improvement in antenna adjustability.
Then last month I noticed the MFJ-1898. This antenna is a slider-style base-loaded whip, with an overall length of between 8 and 9 feet. More significantly for me, the antenna uses a 3/8-24 stud mount, and would thread right on to my existing bracket.
After agonizing for about a week at the thought of paying $150 for another short base-loaded vertical, I "pried the wallet off my butt" and waited.
In the meantime, it seemed like the bracket could be improved to make it easier for others to copy.
The improvements included:
1) Using easier to work, thinner aluminum - 0.06 inch thick aluminum instead of the 1/8 inch thick scrap aluminum used in the original bracket.
2) Using easy to find hardware store aluminum bar stock. By switching to standard 1-inch-wide aluminum, rather than making the bracket as wide as the side of the KX2, you simplify the metal working (see below).
3) Use of thinner stock allows the reuse of the cabinet screws, rather than looking for longer ones as required by the 1/8 thick original plate. You may be tempted to use longer screws given the potential force on the bracket, but I've found it unnecessary.
If you decide to use longer screws, make absolutely sure THAT THE NEW SCREWS DON'T TOUCH ANY CIRCUIT BOARDS OR COMPONENTS INSIDE THE RADIO!
4) I added a blue bullet connector to the jumper cable - this makes it easy to add a bullet connector-equipped radial or drag wire. On the old bracket, I had used a screw to hold the drag wire/radial to the bracket, and it liked to come loose. The bullet connector is a much better arrangement, won't vibrate loose and will detach if tangled.
The aluminum stock I used to make the new bracket is Hillman flat aluminum 1/16 inch by 1 inch #6237, though there's nothing magic about it.
If you look at the picture below comparing the old bracket and new bracket, you can see that the narrower width eliminates the need for the BNC hole, instead only requiring a small notch to clear the connector. This material choice also eliminates the need for a substantial notch to clear the cabinet thumbscrew.
So the new bracket only requires cutting the bar stock to length, drilling three cabinet screw holes for the three cabinet screws, drilling the 1/2 inch hole for the stud, and filing a bit of clearance for the BNC connector. About an hour's work, at most.
The new bracket was finished before the antenna arrived. When the antenna finally arrived, I threaded it on to the bracket, added a 13 foot drag wire, and walked out onto the balcony. I was soon having a SSB conversation on 12 meters with a W7 in Oregon (from Illinois). A great first QSO.
Subsequent tests confirmed that the MFJ-1898 was reasonably effective on all bands from 10 -30 meters - it's great to have all the bands open to test !
There was no problem adjusting the antenna to an SWR of less than 2:1 on any band without the tuner. With the KX2 it really is as simple as adjusting the coil slider for maximum noise, hitting the tuner button, and Bob's your uncle.
But What About BNC and UHF Connector Antennas?
No problem.
Accommodating a BNC antenna like an AX-1, MFJ single bander, or the old ATX was almost an afterthought but a happy one.
Same goes for UHF-base connector antennas. Admittedly these are less common, but my Outbacker Joey is one, as are some Yaesu and Icom antennas.
I probably should have mentioned earlier that the stud and mounting hardware are just the typical CB mirror mount hardware you can find almost anywhere.
The picture below shows mocked up bracket set-ups for BNC and UHF connector antennas.
On the left, the UHF set up requires inverting a UHF to 3/8-24 stud connector - it's now upside down compared to how it is normally used in a mirror mount. By turning the connector upside down, the 3/8-24 stud sticks out the bottom and can be secured with a 3/8-24 nut. You can mount the coax ring connector top or bottom so long as it stays insulated. The UHF connector sticks up to receive the antenna.The BNC set-up is easier yet, as no insulation is required. That is just a BNC bulkhead connector with flanges or washers of sufficient diameter to allow mounting through the existing 1/2 inch hole. Then just use a BNC to BNC jumper.
Why a bracket for a BNC antenna? I've had to rework an FT-817 front BNC socket after a poor choice of antenna. Don't need to do that again. Taking the stress off the radio's antenna connector is well worth the trouble if you never use the bracket for anything other than BNC-based antennas.
I was asked to provide some more detail about the stud mounting hardware for the options just discussed. Hopefully this picture will provide the needed detail.
Conclusion - bet you're glad we're here.......
OK, I'll admit to being a bit of an Elecraft fanboy, especially for portable ops. You cannot have operated a KX1, 2 and 3 for several years and not be a big fan.
But even a fan boy has to draw a line somewhere. I just can't go along with the notion that an AX-series antenna is the only antenna for handheld KX2 ops.
Theoretically, doubling the antenna length quadruples the radiation resistance, and that should add in the nature of 6 dB to your signal. I can't prove that, but I've operated a number of 4- and 5-foot antennas on the KX2 (ATX, Joey, single band MFJ's to name a few) and believe that the Buddistick and MFJ-1898 perform better.
And between the slider coil MFJ and the tapped coil Buddistick, there is simply no comparison in ease of adjustment. It was definitely worth the spendy price of the 1898 IMHO.
A few bucks of metal and an hour of your time in exchange for a potential 6dB of signal. It's true that both longer antennas only knock down to about a foot, rather than a little more than half a foot. If that really bothers you, no worries.
It's a little heavier than I'd like, especially with the MFJ-1898. Yet I've comfortably used it in hand-held mode for several minutes at a time. And it's easy to rest the radio case on a tabletop or fence rail to make protracted operating easier. Whether you find it comfortable to use will depend on the size of your hand, and arm and grip strength. And the shape of the KX2 isn't a great ergonomic match for hand-holding, and this gets worse with progressively larger and heavier antennas. A decent glove, with a grippy surface, can go a long way toward making handheld operation more fun.
Your opinion may be different, and that's what's great about ham radio. But the small weight and length penalty of having a much longer handheld antenna is an investment I'll make every time I go out. 😎
The Fine Print
As author Jean Shephard W9QWN once wrote, "You'll shoot your eye out!!!"
Probably not, but be careful.
This is a description of what I've done. You need to make your own decisions about suitability and safety. Observe RF exposure guidelines, stay a safe distance from other people and pets, and objects, especially electrified ones. And watch out for yourself whether building or operating, Keep ham radio fun.
72 Scott KA9P/ZF2SC
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