MFJ-1820T Whip

I made an impulse buy this week. After reading an old Elecraft mailing list post from Wayne Burdick N6KR where he made a strong recommendation, I ordered an MFJ-1820T whip antenna. I need another portable antenna like I need a hole in the head but I figured it might be fun to give this little whip antenna a try.

If you aren’t familiar with it, the MFJ-1820T is a 4-foot, telescopic, loaded whip for the 20M band. It collapses down to a tiny 10-inches. It will handle 25 watts but my whip will never see that much power. It sells for around $30 (U.S.).  Wayne recommended using at least one 13-foot radial with it. I went with two 13-foot radials made from some cheap speaker wire I had on hand.

MFJ-1820T Collapsed
MFJ-1820T Collapsed

This morning, while operating from a local park, I connected the whip to my KX3 with a BNC right angle adapter. I connected my radials to one of the knurled nuts on the KX3 with an alligator clip. To keep the whip from swiveling, I used a small, plastic spring clamp.

The MFJ-1820T whip connected to my KX3. The plastic spring clamp was used to stabilize the whip. You can also see the alligator clip for the radials.
The MFJ-1820T whip connected to my KX3. The plastic spring clamp was used to stabilize the whip. You can also see the alligator clip for the radials.

The KX3’s internal tuner loaded up the whip with no problems. I heard W8SVC calling CQ from Michigan and gave him a call with 5 watts. He got my callsign on the first call but he wasn’t sure he had copied it correctly. I upped my power to 10 watts (gasp!) and called again. He gave me a 559 and we exchanged our basic information. Unfortunately, I lost him when the band faded.

Moving up to the 20M QRP calling frequency, I called CQ a couple of times. AA8WQ (QRP at 5W) responded from Ohio and gave me a 569 report. Again, we were able to exchange our basic info before I lost him completely.

Frankly, I wasn’t really expected much from a 4-foot whip but I was surprised that I was able to make two contacts this morning. It certainly isn’t the best antenna for 20M but, when the band is in good shape and you need something that sets up in an instant, the MFJ-1820T is certainly a usable antenna. I’ll probably be carrying the MFJ-1820T in the field as a backup antenna.

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

Antenna Testing in the Park

Today was fun. I had a little time this afternoon, so I headed out to a nearby park to test a new antenna and ended up making a couple of interesting contacts.

I spent a couple of hours in Towpath Park, a nice little park along the Schuylkill River. It’s usually not very crowded, so it’s been one of my favorite places to test new antennas. Today, I was doing some initial testing and tuning on a Tri-Band Vertical from QRPGuys.

My "outdoor shack" overlooking the Schuylkill River
My “outdoor shack” overlooking the Schuylkill River

I set up the antenna and spent some time taking SWR plots on the antenna. The 20 and 30 meter bands were great without any adjustments. The 40M band is resonating too low, so I need to do some tweaking on one of the loading coils. I’ll do a separate post on this antenna when it’s finished.

My antenna today. My $9 telescopic pole from eBay is mounted on a screwdriver shoved in the ground.
My antenna today. My $9 telescopic pole from eBay is mounted on a screwdriver shoved in the ground.

I put the antenna analyzer away and got out my KX3. I made a few “CQ SKCC” calls on 20M and was answered by CT7AFN in Portugal. There was some QSB but we managed to exchange SKCC numbers. A few minutes later, I got a call from another station in Portugal, CT1BQH. Wow! Back-to-back Portuguese SKCC stations. This new antenna definitely has some mojo.

I worked stations in Texas and Florida before wrapping up. I neglected to bring gloves today and the wind chill was taking a toll on my fingers. I packed up my equipment and headed out happy with the contacts I made in a short period of time.

I have a little work to do on this new antenna but so far it looks like a keeper.

72, Craig WB3GCK

Pre-Holiday QRP Portable

I wanted to get out and do a little QRP-portable before all the holiday festivities get started. I hadn’t operated from Black Rock Sanctuary in a while, so I headed over there. It was dreary and drizzly today, so it was a good day to operate from the truck and give my homebrew 19-foot vertical another workout.

The vertical antenna in use at Black Rock Sanctuary
The vertical antenna in use at Black Rock Sanctuary

Since the last time I used the 19-foot vertical in the truck, I found a way to ground the antenna to the body of the truck. It was a simple matter of backing out one of the screws that hold the bed liner in place and using it to attach a small L bracket. This now provides a convenient spot to attach my ground lead.

Ground connection for the vertical antenna.
Ground connection for the vertical antenna.

I was using my little MS2 straight key with the KX3 today. The bands were in pretty decent shape and the antenna seemed to be working great. I made a half-dozen SKCC contacts on 40 and 20 meters with some respectable signal reports. One SKCC’er in California called me on 20 meters but the frequency was taken over by other stations. I wasn’t able to complete the QSO but at least I was being heard on the West Coast.

Operating position in the truck
Operating position in the truck

I also had some nice two-way QRP QSOs. W4UV in North Carolina had a great signal on 40M with his Ten Tec QRP rig. Jim N0UR was really pounding in from Minnesota on 20 meters. My favorite QSO of the day was with Dirk W8IQX. Dirk was running 2 watts from his FT-817 to an AlexLoop on 20 meters. If I copied correctly, he was in Florida. QRP never ceases to amaze me!

Happy Holidays to you and yours.

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