FT-817 Power Connection

I’ve seen a lot of discussion on the Internet lately about the FT-817’s less-than-robust DC power connector. Its miniature coaxial power connector has long been recognized as a failure waiting to happen. I thought I’d chime in with my crude, little hack.

Over the years, users have come up with a variety of ways of dealing with the FT-817’s power connector. If you’re brave enough, you can just hard-wire the power cord directly to the FT-817’s main circuit board and eliminate the connector altogether. You can also buy a really slick adapter that gives you an Anderson Powerpole connector on your FT-817.

When I bought my FT-817 almost 15 years ago, I was immediately leary of the little 4.0 x 1.7 mm power connector; there was no way it was going to hold up in the field. I didn’t know of any commercial options at the time, so I raided my junk box to come up with a solution, albeit a crude one.

The power cord with an Anderson Powerpole connector attached to my FT-817
The power cord with an Anderson Powerpole connector attached to my FT-817

I merely attached a small right angle lug to the FT-817’s ground screw. Then, I used a couple of small nylon cable ties to secure the power cable to the lug and provide some strain relief. I installed Powerpole connectors on the other end of the cable. It’s not pretty but it served the purpose.

Close-up of the right-angle lug attached to the ground stud. Two small nylon tie-wraps secure the power cord to the lug. An unused lug is shown in the bottom of the picture.
Close-up of the right-angle lug attached to the ground stud. Two small nylon tie-wraps secure the power cord to the lug. An unused lug is shown in the bottom of the picture.

Although my FT-817 doesn’t see as much field use as it used to, my stupid-simple hack is still going strong after 15 years. While this approach doesn’t eliminate the FT-817’s little DC connector, it has (so far) survived many years of portable use in the field.

72, Craig WB3GCK

Connecting Two Keys to the KX3

When operating in the field, I often like to alternate between a straight key for SKCC contacts and paddles for everything else. I found a quick and easy way to do this, courtesy of an excellent article by Rich AG6QR.

In the past, I would sometimes run an external keyer and connect a straight key in parallel with the keyer’s output. I have often used this as a way to use both computer keying and paddles during Field Day. I have also resorted to putting the CW KEY1 jack into the straight key mode and turning my Palm Mini paddles on their side to simulate a straight key. I could have used the Elecraft paddles designed for the KX3 but that arrangement isn’t very comfortable for me.

I did some searching and found a neat little adapter on the Pignology website. Unfortunately, at the current time, they aren’t accepting orders. A little more searching produced AG6QR ‘s article, which provided a perfectly workable solution. Best of all, I had everything I needed in my junk box.

Inspired by Rich’s article, I assembled a two-pin, female header connector (with standard 0.1-inch spacing) by crimping on a short length of two-conductor wire. On the other end, I soldered on an in-line 1/8-inch stereo jack. (I connected to the tip and sleeve terminals, leaving the ring terminal open.)

This is the 2-pin female header connector. It’s an Amphenol part but, unfortunately, I don’t have the specific part number.
This is the 2-pin female header connector. It’s an Amphenol part but, unfortunately, I don’t have the specific part number.

After setting the CW KEY2 jack to the “HAND” setting, I connected my header connector to the two right-most pins on the front connector and a straight key to the stereo jack. Voila! It worked just fine. As is my usual practice, I used a little Goop sealant/adhesive to add a little extra strain relief and make the connectors more rugged for field use.

This is the straight key adapter connected to my KX3.
This is the straight key adapter connected to my KX3.

So until Pignology reopens, I have a great (cheap) solution for simultaneously connecting a straight key and paddles. Be sure to check out AG6QR’s page for a more detailed description (and better photography).

72, Craig WB3GCK

Quick End Insulator

Here’s another quick hack that took longer to write up than to actually build. I recently built a portable vertical antenna using some #26 Stealth Wire. I needed some sort of end insulator that would facilitate pruning the wire to resonance. Here’s my quick and dirty solution.

Using scissors, I cut a piece of plastic from a used up gift card I had in my wallet. The piece I cut is about 1 inch by 0.5 inches. Then, I drilled 3 holes in it. Two of the holes were just slightly larger than the #26 Stealth Wire (The Wireman Product #534). These holes hold the wire in place. I drilled a larger hole for attaching to a light line or, in my case, a small clip at the top of my telescopic pole. I also rounded off the corners a bit.

The end insulator and the gift card from which it was cut. (Disclaimer: I have no financial interest in the Wawa company, except that I have consumed untold quantities of their coffee over the years.)
The end insulator and the gift card from which it was cut. (Disclaimer: I have no financial interest in the Wawa company, except that I have consumed untold quantities of their coffee over the years.)

So far, this is working out well for my portable vertical antenna. If I was using heavier gauge wire, I would definitely use something more substantial than the gift card. I also wouldn’t use it for a permanent installation. But for an ultralight antenna that is only used for portable excursions, it’s perfect.

If I ever need to replace it, I have enough of the original gift card left to make a bunch more!

72, Craig WB3GCK

Bike Rack Vertical

[This is an updated version of a post that appears on my old website. – WB3GCK]

I do quite a bit of my QRP operating from portable locations. I like to use simple wire antennas but, truth be told, I really dislike spending my limited operating time trying to get antenna wires up into trees.  Also, when activating parks for Parks on the Air (POTA), I often operate from the cab of my truck and need an antenna that is self-contained and quick to deploy.  This set up fits the bill.

What I did was modify my homebrew roll-on mast support so I could use my hitch-mounted bicycle rack to support it. This only required the drilling of two holes in the roll-on mount. Figure 1 shows the roll-on mount clamped into the bike rack. In this case, I was supporting a 31-foot Jackite pole. After extending the pole and removing the bottom cap, I just lower the pole onto the 1-1/4 inch pipe. That’s all there is to it.

Bike Rack Antenna Mount. A 9:1 unun is attached to the Jackite pole with a bungee cord.
Bike Rack Antenna Mount. A 9:1 unun is attached to the Jackite pole with a bungee cord.

By selecting the right size of pipe, I can use this technique to support a variety of masts. For example, I’ve used this type of mount to support two 5-foot sections of TV antenna mast. I used this configuration to support a 1.2 GHz yagi for DStar digital communications during an ARES-RACES drill years back.

My new truck's first QRP-portable outing.
The Bike Rack Vertical in use

When operating QRP-portable, I often use a vertical antenna made from a 30-foot piece of hook-up wire and fed through a homebrew 9:1 unun with an 18-foot length of RG-8x coax. The unun is just attached to the 31-foot Jackite pole using some small bungee cords. No radials are used, which gives this set-up virtually a zero footprint. You can find more information on this configuration on the EARCHI website. I’ve successfully used this antenna in the field over the past few years. It’s a bit of a compromise, as antennas go, but it has always served me well. The extra height using the bike rack mount seems to help performance a bit. (Although I can’t quantify that, I’m sure the extra height doesn’t hurt.) With the internal antenna tuner in my KX3, I can work all bands from 40 through 10 meters.  Heck, I’ve even used it on 80 meters a bunch of times.

I used this particular antenna configuration countless times in recent years.  It was my “go to” antenna for NPOTA activations.  Within 5 minutes of arrival, I can be on the air. When it’s time to leave, tear down is just as fast. Now, that’s what I’m talkin’ about!

73, Craig WB3GCK

“Stationary-Mobile” with My 19-foot Vertical

Earlier this year, I built a lightweight, 19-foot vertical. Intended for tripod or ground mounting, I did the initial tuning and pruning of the vertical in that configuration. Today, I thought I’d see if it would work mounted on my pickup truck.

I have this plastic crate that I keep in the bed of the pickup truck. I use it to hold parts for my drive-on antenna mount, along with some tools and miscellaneous “stuff.” I hold the crate in place using bungee cords attached to a cargo bar that spans the width of the bed. I decided to make use of the crate as a quick and dirty antenna mount.

I took some 1-inch PVC pipe with a female threaded coupler from a previous antenna project and attached it to an inside corner of the crate with heavy-duty zip ties. I kept this part short enough to fit underneath the tonneau cover when traveling. To mount my 20-foot Black Widow pole, I used a 1-inch PVC male coupler and a reducer to go down to a 3/4-inch PVC pipe. The 3/4-inch PVC pipe fits nicely up inside the Black Widow pole. I went with the Black Widow pole rather than the lighter weight pole I normally use with this antenna since I already had all the PVC parts I needed to mount it.

My makeshift mount. The PVC mount is attached to the plastic crate, while the crate is attached to a cargo bar using bungee cords. The random junk I store in the crate keeps things stable.
My makeshift mount. The PVC mount is attached to the plastic crate, while the crate is attached to a cargo bar using bungee cords. The random junk I store in the crate keeps things stable.

I headed out to a local park today to give it a try. It only took a few minutes to get it set up. From the antenna, I ran some RG-8x coax through a window and into the cab of the truck. I connected the antenna ground to the body of the truck using a short piece of braid to a metal plate used to latch the tonneau cover closed.

The Black Widow pole installed on my makeshift mount.
The Black Widow pole installed on my makeshift mount.

I fired up my antenna analyzer and the SWR was off the charts. On closer inspection, I found the plate I was using for my ground wasn’t actually attached to the body of the truck. Instead, I connected two radials and ran them off the back of the truck. This time the SWR on 40 and 30 was much better. The resonant frequencies in this configuration were higher than when ground-mounted but my KX3’s internal tuner easily handled the minor mismatches.

I started out on 20 meters where this antenna operates as a random wire. I heard N5PHT doing a Parks on the Air (POTA) activation (KFF-3023) down in Texas. I gave him a call and exchanged reports. Moving down the band, I worked XE1XR in Mexico. So, the antenna seemed to be working fine. I checked 30 meters but it was devoid of activity.

The 19-ft vertical in operation.
The 19-ft vertical in operation.

Down on 40 meters, I had a nice ragchew with Bernard VE9BEL. Bernard was operating a club station (VE9CRM) in New Brunswick, Canada. He gave me a 599 and said I was “booming” into New Brunswick. Not bad for 5 watts into a 19-foot loaded vertical. I last worked Bernard a few years ago from Mt. Misery in Valley Forge National Park. We had strong signals both ways on that day, too.

So, it looks like this antenna is usable from the truck. I still need to find a way to connect the ground to the body of the truck. If possible, I’d like to avoid drilling holes in my new truck. This antenna is a little easier to deploy than my usual “Bike Rack Vertical.” The downside is I have to exit the truck to change bands. Life is a series of trade-offs, I guess.

73, Craig WB3GCK

The Quickie Whip

This week, my ham radio activity was focused on an emergency communications exercise with my local ARES-RACES group.  I thought I’d do a post about the simple whip antenna I used with a dual-band radio.  I cobbled this  set up together a few years back and it has come in handy on several occasions.

During the exercise, I was operating indoors with easy access to our local repeaters. I was copying digital traffic using the Narrowband Emergency Messaging System (NBEMS), so a handheld radio wasn’t a good option. In this situation, a dual-band mobile radio and this little whip antenna hack were able to get the job done.

The Quickie Whip attached to my old Icom 207-H dual band radio
The Quickie Whip attached to my old Icom 207-H dual band radio

For the whip, I use commercially available, collapsible BNC whip antennas for the 2 meter and 440 bands.  To connect the whip to the radio, I use a UHF-Male to BNC-Female right angle adapter I picked up on eBay. To help improve the efficiency, I attach two 1/4-wave counterpoise wires, one for 2 meters (about 19 inches) and one for 440 (about 6.3 inches).

Quickie Whip Antenna components: telescopic whip antenna, PL-259 to BNC-F right-angle adapter, and the modified 9V battery clip for the counterpoise wires.
Quickie Whip Antenna components: telescopic whip antenna, PL-259 to BNC-F right-angle adapter, and the modified 9V battery clip for the counterpoise wires.

To attach the counterpoise wires, I re-purposed a 9-volt battery holder. I just drilled out one of the mounting holes and used a small bolt and nut to attach the wires. The clip is just about the perfect size to snap onto the right angle adapter.

The antennas I use came from Smiley Antenna. I have 5/8-wave whips for 2 meters and 440, along with a halfwave whip for 2 meters. Although some of the antennas are specified to handle 50 watts, I generally use them only for 10 watts or less (in the interest of RF safety). If I need to run more power, I’ll go with an antenna placed a safe distance away.

I’ve used this simple antenna arrangement in several situations in recent years. It’s become a permanent part of my emergency communications go-kit.

73, Craig WB3GCK

 

A Lightweight Portable Vertical

I bought a lightweight telescoping pole on eBay a while back. It collapses down to 26 inches and weighs less than 12 ounces. Best of all, I only paid around $10 for it. While it was advertised as a 7.2-meter pole (approximately 23.6-feet), I actually measure about 19.5-feet when extended. This pole was just begging for some sort of antenna to support.

After trying different types of non-resonant wires with it, I decided to build some sort of resonant antenna. For quick excursions to the field, I often take the AlexLoop. However, sometimes it’s nice to have something a bit more frequency-agile. I wanted something that is easy to deploy and could cover the 40, 30, and 20-meter bands.

I started off planning to build a vertical with a 16.5-ft radiator to make it resonant on 20 meters. I could then build some loading coils to make it resonant on 40 and 30 meters. In the end, I went a slightly different way with this antenna.

With the lousy band conditions lately, I spend most of my time on 40 meters. I decided to take advantage of the full length of the pole.  So, my concept was to use a 19-foot radiator with loading coils for 40 and 30. On 20M and higher, I would use the radiator as a random wire and use a tuner.

Schematic diagram of the matching network for the 19-ft vertical
Schematic diagram of the matching network for the 19-ft vertical

As you can see in the schematic, I feed the antenna through a 1:1 choke, consisting of 10 bifilar turns of #22 hookup wire on an FT140-61 toroid. I calculated the values for the loading coil using some online calculators (see notes below). From there, I went through several iterations of testing and adjusting to arrive at the final values. For the 40M loading coil, I ended up with 29 turns of #22 enameled wire on a T130-2 toroid. I made a tap at 11 turns for the 30M band.

Interior of the matching unit
Interior of the matching unit

I mounted both coils in a small box and used some small bolts to make the tap points accessible for band changing. I also made a little jumper with alligator clips to short out various portions of the loading coil for the different bands.

The matching network is attached to the pole with a small bungee cord. In this picture, the red jumpers are configured for the 30M band.
The matching network is attached to the pole with a small bungee cord. In this picture, the red jumpers are configured for the 30M band.

The pole won’t support much weight, so I built the 19-foot radiator from #26 Stealth wire (Part #534) from the Wireman. Because the pole is made from carbon fiber, I try to let the top of the pole bend over slightly, to keep the wire away from the pole. I don’t know how much influence the carbon fiber pole would have on tuning but I figure I’d avoid introducing another variable.

For radials, I used a 25-foot roll of cheap speaker wire and used it to throw together four 12.5-foot radials. Again, I grabbed what I had on hand and went with it.  While the four radials seem to be working out OK, I plan to add a couple more for good measure.

I should note that all the materials here were selected based on availability in my junk box. So, there’s certainly plenty of wiggle room here for experimenting.

I made up a little tripod adapter out of some PVC pipe. One end slides over the post on my tripod, while the other end slides up inside the bottom of the collapsible pole. I also found a screw driver with a handle that fits nicely inside the bottom of the pole. So, for ground-mounting, I can just shove the screwdriver in the ground and place the pole on top of it. This works surprisingly well and allows me to leave the tripod at home.

Vertical mounted on a tripod. My backpack is attached to the bottom of the tripod to help stabilize it in the wind.
Vertical mounted on a tripod. My backpack is attached to the bottom of the tripod to help stabilize it in the wind.

After considerable tweaking I ended up with SWRs of less than 2:1 across the entire 40M band and less than 1.5:1 across the 30M band. On 20M and higher, the tuner in my KX3 loads it up with no problems.

The vertical ground-mounted. The pole is light enough to be supported by a screwdriver shoved into the ground.
The vertical ground-mounted. The pole is light enough to be supported by a screwdriver shoved into the ground.

I’ve been very pleased with the results on 40M so far. It seems to radiate pretty well. I’ve also made contacts on 30M and 20M but, honestly, I need to use it more on those bands to get a better feel for the performance.  It’s hard to evaluate antennas when the band conditions are as poor as they have been lately.

Although the antenna works, there are a few things I would do differently, if I were to build another one:

  • My physical packaging could be better.  While the enclosure I used is nice and compact, it’s a little cramped for experimentation.  During development, coil adjustments were tough.
  • Separate coils for 40M and 30M would make the tuning much easier.  The tapped coil was a challenge to adjust.

I like the form factor and easy setup of this antenna.  I can set it up in a few minutes and it is very easy to transport by backpack or bike.  Now to give it some more air time in the field.

Time will tell if it’s a keeper.

72, Craig WB3GCK

 

Notes:

  1. Loading coil calculator:  http://www.k7mem.com/Ant_Short_Dipole.html   (Note:  The calculator I originally used for this project is no longer online.  This calculator should work.  Just use one leg of the dipole.)
  2. Toroid calculator:  http://www.66pacific.com/calculators/toroid-coil-winding-calculator.aspx

Save

Save