Because I receive so many tips from readers here on QRPer, I wanted way to share them in a concise newsletter format. To that end, welcome to QRPer Notes, a collection of links to interesting stories and tips making waves in the world of radio!
Field Antenna Survey
Many thanks to Phil (KA4KOE) who shares the results from an informal survey he conducted on the POTA Facebook group. Phil writes:
I’ve let the survey run for about 3 days on the POTA Facebook group. Sample size was 658 votes. I opted to do a “type” survey and not by manufacturer.
I have both the single and double Pico paddle and the KX3 mount. After watching you hand hold your paddles, I came up with a way to make small paddles easier to hold. I have attached a photo. It is a small piece of 3/8 ID pipe insulation to make holding the Pico paddle easier.
Do you usually try to use an isolator or do you often let your wires touch branches by just pulling them over? When you deploy 20m EFHWs, for example, do you try to avoid having an end touch a branch and only have the throw line going over the branch? I tried to go through your videos and look but you don’t often mention how far you pull the wire up and possibly over. Thanks!
This is a great question!
Before I answer, I’d like to add a little context:
I am a QRP operator. The maximum amount of power I use in the field is 10 watts, but 99.5% of the time, it’s actually 5 watts or even much less.
I am answering this as a field operator, meaning I’ll be referring to temporaryantenna deployments.
That said, the quick answer is no, during park and summit activations, I do not worry about my antenna radiator wire touching tree branches.
I do isolate the end of my wire antennas from tree branches and leaves, but I don’t worry about other parts of the radiator touching.
Also, all of my antenna wire has some sort of jacket–I don’t run bare wire in the field.
I recently built a tabletop QRP HF antenna for 17 and 20 meters, in the spirit of the Elecraft AX-1, so I could operate at lunchtime on the campus where I teach. My wants were something small, that would fit in my work bag, that didn’t require a tuner, and could work on a couple of different bands. But on a lark I decided to attempt a POTA activation at Lake Thunderbird State Park (K-2792) pairing this antenna with my Penntek TR-35 QRP CW transceiver. I figured I’d maybe get one or two QSOs and then switch to a long wire in a tree. But what happened amazed me.
I talked to seemingly everyone. Beginning at 9:00 AM September 26th I worked both 17 and 20 meters for an hour and a half and made 37 contacts from across the country. I even had a Swiss guy call me back on 17 but he faded before we could finish. This antenna, at least as a CW POTA activator, works. Granted conditions were very good, but I’ve replicated this multiple times in the past few weeks, just recently at a picnic table in the parking lot of the Route 66 Museum (K-8644) in Clinton, OK (there is quite a thrill in urban activations).
It has also reasonably low profile and very quick to setup and take down. It is also quite a conversation piece when I set it up at school. I elevated the counterpoise by attaching it to a nearby oak and an interested undergrad sheepishly asked if I was listening to the tree!
The build is pretty simple. Physically the antenna consists of a small painters pole from Walmart and an old tabletop camera tripod. I found a nut that fit the screw portion of the tripod and hot glued it into the orange connecting section of the pole. That way the tripod can then be screwed onto the pole. The RF parts of the antenna consist of a 38” telescoping whip that I scavenged from the rabbit ears antenna that came with my RTL-SDR. It connects using the original connector which was hot-glued into a hole I drilled into the top of the painters pole. I found similar small 3 or 4-foot whips from AliExpress for cheap and these would probably work fine.
I then soldered a long length of speaker wire that was wound into two coils: the top for 17 meters (24 turns) and the bottom for 20 meters (25 turns plus the former 24-turn coil). The speaker wire was the soldered to the center of a BNC connector which I hot glued and taped to the pole. I soldered a short piece of wire from the shield of the BNC for the counterpoise and added an automotive spade connector to attach to a 17-foot length of wire. I also included a switch between the coils and the BNC connector to select either just the top coil (17 meters) or both coils (20 meters) using solder, hot glue, and tape. I then covered my shame in silicone tape.
The most time-consuming aspect of the project was tuning the antenna. It required trial and error to first tune the number of turns on the 17-meter coil and then the 20-meters coil. I extended the counterpoise (for me it’s best when slightly elevated) and the telescoping whip. I performed the tuning with the whip not fully extended to give room to tune in the field. Using a nanoVNA was useful here, as was soldering a pin to the wire to poke through the wire at various parts of the coil to find the best SWR.
In use, the antenna can be affected by both body capacitance and how the counterpoise is situated, so I found that an in-line SWR meter was helpful in making sure all was well. Once set up it is easy to fine tune by just adjusting the whip length. 1.5:1 SWR is about how well I can tune on average. Obviously if you have a tuner you would just have to get it close.
There are a million variation on a small base-loaded vertical antenna, and you can definitely improve upon this design. And, besides the super well-built and elegant AX-1, QRP Guys sells an interesting looking kit, and there are some good 3D printed designs I might want to try out. But regardless how you go about it, it might be worth giving a tiny antenna a shot.
Here’s the product description from Elecraft’s website:
The AX2 is small enough to take anywhere – just in time for lightweight field ops during the new solar cycle. Use it HT-style with a hand-held, like the KX2; on a picnic table with an AXB1 whip bipod; or with a tripod and AXT1 tripod adapter. The AX2’s rugged, nylon housing is water-resistant, with low wind resistance and our new anti-wobble design.
Experimenters will love the AX2’s versatile design. A snap-off cover provides access to the high-Q inductor. Simply remove turns and re-solder one wire to cover your favorite band. Clip-off tabs are provided for band identification.
The table below shows how the new AX2 20-meter mini-whip compares to our original AX1 multi-band whip. Both are designed for lightweight portable operation. The versatile AX1 covers multiple bands via a selector switch and can handle up to 30 W continuous TX power.
The ultra-compact AX2 has a new anti-tilt base design that minimizes BNC connector wobble – ideal for hand-held (HTstyle) use. While the AX2 covers 20 meters as shipped, it can be modified by the user to cover any single band from 17 through 6 meters. The base unit includes small tabs that can be clipped off to identify the target band.
NOTE: Both whips are intended to be used with an ATU to compensate for terrain, body capacitance, height, etc.
A reader recently asked if I’d be selling my AX1 after learning about the AX2, but that isn’t going to happen. The AX2 is a 20 meters and up antenna and I see it as being a brilliant SOTA companion since its lightweight, stable design should do well on windy summits.
For POTA and WWFF, however, I really rely on the 40 meter band for most of my contacts. The AX1 covers 40 meters brilliantly (and 20M and 17M) so I’ll still rely on it quite heavily.
I discovered something you might have an interest in for your wire antenna deployment. Years ago when I was a building contractor, we used chalk line for floor layout. It has a very high tensile strength and is very light weight. After reflecting on this, I recently bought a 100’ spool of braided 1 millimeter chalk line and used it for a field deployment. I attached my “throw weight” to it and easily launched it about 60’ into a tree. You can see it in the attached photo holding my homebrew EFHW to my Jeep.
The magnet wire was scavenged from a HUGE transformer from a neighbor’s discarded light fixture.
I did the new installation for him and he gave me the old one. I promptly disassembled it and collected miles of 14 and 20 gauge magnet wire 😊!
I haven’t added the capacitor to this antenna yet because it is sufficiently resonant and broadbanded on 40, 20, 15, and 10 Meters. I did some testing with the capacitors though on my previous build which was the PVC tube EFHW transformer. I believe I may have sent you a photo of that in a previous message. It too was resonant in the same places, but adding the capacitor smoothed and widened the acceptable SWR range.
The attached photos are my complete antenna assembly: matching transformer (49:1), 65.5’ speaker wire, 100’ braided 1MM chalk line, and throw weight (epoxy filled lug nut with short paracord pigtail).
Compact and lightweight.
I love this, Dan! I also like how self-contained and compact it is. What a professional job, too, with heat shrink, proper connection points and tie-offs.
Do you have an antenna or radio project you’d like to share on QRPer.com? Contact me!
Chameleon Antenna has sent me a number of their antenna systems to evaluate in the field over the past few months at no cost to me. I appreciate not only the opportunity to test these antennas, but to provide the company with my frank feedback.
As I’ve mentioned previously, Chameleon antennas are military grade and build here in the US (check out Josh’s tour of their factory). You pay a premium price–compared to imported options–but their gear is built for performance, easy deployment, and longevity.
What has impressed me most about Chameleon gear is how flexible and modular it is. Their antenna systems are adaptable to almost any situation and always built around the idea of emergency communications.
Recently, Chameleon sent me their new CHA TDL or Tactical Delta Loop antenna. This vertical loop antenna has been designed to be portable, and tunable from 3.5 to 54.0 MHz (80-6M), but, as Chameleon points out, “is most effective on the bands from 10.1 to 54.0 MHz (30-6M). ”
If I’m being perfectly honest, I wasn’t sure what to expect this antenna to look like–in terms of size–once deployed, so I set it up in the front yard prior to taking it to the field.
Set up couldn’t have been more simple: attach the 17′ telescoping whips to the stainless steel spike (with one whip attached to the Hybrid Micro), extend the whip sections, then attach the loop wire to connect the tips of both whips.
It might have taken me four minutes to set up the TDL on the first go.
This antenna needs a little space for sure: this isn’t one you could easily deploy in a dense forest, but it has a very flat profile vertically. I can’t think of a single park I’ve activated that couldn’t accommodate the CHA TDL.
I like to try to give gear a fair chance when I do evaluations and thought I’d wait until propagation was at least stable before taking the TDL to the field and making a real-time, real-life video (as I used it for the first time). But, frankly, I’m way to impatient to wait for the sun to play fair! Trial by fire…
Lake Norman State Park (K-2740)
On Monday (March 15, 2021) I packed up the CHA TDL and headed to Lake Norman; one of my favorite parks to play radio.
Propagation left much to be desired that afternoon, but the weather was perfect.
I decided to pair the CHA TDL with my Icom IC-705. Since the CHA TDL requires an ATU, I connected the mAT-705 Plus.
NVIS on the low bands
I had no idea what to expect from the CHA TDL in terms of performance, but Chameleon notes that it provides Near-Vertical Incidence Skywave (NVIS) propagation on 40 and 80 meters. NVIS antennas are very popular for the military and for emergency communications since the propagation footprint is much closer to home than it might normally be.
NVIS is also a brilliant option for park and summit activators, especially if they’re activating in an area with a high density of park/summit chasers. For example, if you live and activate sites in the state of Maryland, employing a NVIS antenna might make your site more accessible to the DC metro area, Pennsylvania, Virginia, New York, Delaware, and New Jersey–regions that might otherwise be in the skip zone of your 40 meter signal.
On the air
Operating five watts CW, I started calling CQ POTA on 20 meters and snagged four stations in about seven minutes.
I was very pleased to work a station in California and one in Montana with five watts. (Though I need to check, this might have been my first MT station logged from a park.)
Next, I moved to 40 meters and was very curious if the TDL would provide me with proper NVIS propagation.
It did! One litmus test for me is when I work stations in Tennessee on 40 meters. Typically, I only log TN stations when on 80 meters or when I’ve configured one of my wire antennas for NVIS coverage.
Here are my logs from this 28 minute activation:
Here’s a QSOmap of the activation–the delineation between my four 20 meter contacts and eight 40 meter contacts is pretty evident:
In a future video, I’ll show how I deploy the CHA TDL.
Unfortunately, I left my tripod at home, so apologies for the viewing angle as I operated the IC-705.
This first test of the CHA TDL really couldn’t have gone better.
I was able to easily deploy it on sloping ground, among trees, in a state park, and snag both locals and QRP DX within a brief window of time on the air. All this, while our local star tried its best to interfere.
In terms of construction, the TDL is what I would expect from Chameleon: military grade.
For park activators and Emcomm purposes, the CHA TDL makes for a convenient, portable NVIS antenna on 40 and 80 meters.
While I have lighter, smaller footprint antenna options for SOTA, I must admit I’m very curious how it might perform on 20 and 17 meters from the summit of a mountain. The idea of being able to rotate the antenna and change the propagation footprint is very appealing. I’ll save this experiment for a summit that doesn’t require hours of hiking, though, and one where I know I can jab the stainless steel spike in the ground (i.e. not on top of a rocky mountain).
Any negatives? When I first deployed the TDL at home, we were having 30+ MPH wind gusts. When the gusts shifted, it did move the antenna. This could be remedied pretty easily by using a bit of fishing line filament to tie off one side of the loop. With that said, I’m not sure I’d configure the TDL as a loop if I expected strong winds. Also, as I mentioned earlier, this might not be the best antenna to pack if you plan to include a multi-hour hike in your activation.
And herein lies the brilliant thing about Chameleon Antennas: If I packed in the CHA TDL and found that winds were strong on site, I would simply configure it as a vertical instead of a loop!
The CHA TDL can easily be configured as a CHA MPAS Lite portable vertical: all it’s missing is a counterpoise wire which you can buy separately from Chameleon or, better yet, just use some spare wire you have on hand!
Or, you could configure it as a random wire antenna by directly connecting a length of wire to the Hybrid Micro transformer.
That’s the thing about Chameleon HF Antennas: they can be configured so many different ways.
If you’re interested in the CHA TDL, I’d strongly encourage you to read though the user manual: it’s chock full of info and ideas. Click here to download as a PDF.
Next time I take the CHA TDL out, I think it’ll be to a summit where I’d like to see how it might perform on the higher bands with the ground sloping away from the antenna site.
Many thanks to Rob Sherwood (NC0B) who notes that Icom has published details regarding their new AH-705 antenna tuner which is designed to pair directly with the Icom IC-705 QRP transceiver.
Many Icom IC-705 owners have been waiting to learn more about the AH-705 before purchasing a dedicated portable ATU for their IC-705. Some of these details may help potential customers make a purchase decision.
Key specifications and features per Icom:
Covers the 1.8 MHz to 50 MHz bands
30 m, 98.4 ft or longer antenna: 1.8 – 54 MHz, 7 m,23 ft or longer antenna: 3.5 – 54 MHz * Depending on operating conditions or environments, the tuner may not be able to tune the antenna.
SO-239 antenna connector for 50 Ω antenna such as dipole or Yagi
“Terminal connector”, binding post socket adapter supplied for a long wire antenna
2-way power sources using alkaline batteries (2 x AA cells) or external 13.8 V DC* * 13.8 V DC should be taken directly from an external power supply, not through the IC-705.
IP54 dust-protection and water resistance construction*
* The connectors should be covered with an adhesive tape or a jack cover to prevent water seeping into the connection.
Full automatic tuning, just push the [TUNER] button on the IC-705
Latching relays used for saving power consumption
190 × 105 × 40 mm; 7.5 × 4.1 × 1.6 in, 450 g; 15.8 oz* compact design
* Battery cells are not included.
45 tuner memories
Of course, I don’t have an AH-705 in hand to test yet, so there’s no way I can comment on performance.
Still, I can’t turn of the reviewer inside so I feel I can make some superficial comments assuming the specs don’t change.
Complete integration with the IC-705
Could (potentially–?) be permanently mounted outdoors at the antenna feed point as a dedicated remote tuner
IP54 dust and water resistant
Power from internal batteries and an external DC source
It’s an Icom product, so I would expect excellent overall quality
Maximum wattage is only 10W, which I suppose is okay if you never put an amplifier between the IC-705 and the AH-705
Based on Icom specs, the AH-705 is larger than other portable ATUs at 7.5 × 4.1 × 1.6 inches. For example:
Some have noted pricing around $350 US price–that’s a premium for a portable ATU considering the Elecraft T1 is $180 assembled and many LDG models are less than $200. Of course, none of those ATUs have an IP54 rating, either.
Speculation here, but the AH-705 might only work with the IC-705 or Icom radios with similar ATU commands. One original pre-production prototype image of the AH-705 shows a power switch; the latest images do not. Like the mAT-705Plus, I’m not sure if the AH-705 can be turned on in order to tune only via RF sensing without essentially modifying a control cable to trick the ATU into powering up.
I was a little surprised to see that the AH-705 “only” has 45 tuner memories. In truth, I never really pay attention to this spec because I’m primarily a field operator. My radio sessions are only an hour or two long and I routinely pair my transceivers with a wide variety of antennas, so a portable ATU never has a chance to develop a complex tuner memory map for any given antenna. But as a reviewer, I try to step in other operators’ shoes so I see where this could be a slight negative for those who plan to use the AH-705 at home and connected to only one antenna. As a point of comparison, the mAT-705Plus has 16,000 tuner memories. Still, memories only help shave off a bit of the auto-tuning time. This would never have an impact on my purchase decision.
Biggest positive for me? IP54 rating
Since the AH-705 is designed to be dust and weather resistant, it could be mounted at the antenna feed point. At home, perhaps it could act like an externally-mounted, remotely-controlled antenna tuner. I’m not sure what the maximum length of the control cable could be, but Icom Japan even lists a 16 foot control cable as an accessory. Of course, you would still need to follow Icom’s guidance about protecting the antenna, transmitter and control cable connection points.
Biggest negative for me? The size.
If the AH-705 specs are correct, it’s a little surprising Icom designed a portable ATU that’s this large. As you can see in the image above, it easily fits in the LC-192, but frankly since I’ve been an Elecraft T1 tuner user, I’ll notice that the AH-705 is 3.1″ longer, 1.6″ wider, and .7″ taller than the T1. It will certainly take up more backpack space.
Of course, unless I build an IC-705 control interface for the Elecraft T1, I can’t directly pair it with the IC-705 like I could with the AH-705. That said? I personally prefer pressing a tune button on the T1 and sending “QRL?” instead of hitting the PTT or CW key and allowing the IC-705 to kick in a continuous tune cycle for a few seconds. You might have noticed in some of my videos that when I tune to a new CW frequency, I’ll listen for activity, then tap the TUNE button on the T1 and send “QRL?” or “QRL de K4SWL”. By the time I’ve sent that string, the T1 has typically already found a match.
How will it perform?
I’ve got to assume the AH-705 will perform well. Icom tends to give their products thorough QC before shipping them to customers. I don’t anticipate any issues with the AH-705 as I did with the original maT-705, for example.
I’ll plan to test the AH-705 after it’s available.
Note: the following post was originally published on the SWLing Post.
Chameleon Antenna recently sent me a prototype of their latest antenna: the CHA MPAS Lite.
The MPAS Lite is a compact version of their MPAS 2.0 modular antenna system and designed to be even more portable.
Chameleon Antenna is a specialist antenna manufacturer that makes military-grade, field portable antennas that are low-profile and stealthy. Chameleon products are 100% made in the USA and their customers range from amateur radio operators to the armed forces.
Their antennas are not cheap, but they are a prime example when we talk about “you pay for what you get.” In all of my years of evaluating radio products, I’ve never seen better quality field antennas–they’re absolutely top-shelf.
I’m currently in my hometown doing a little caregiving for my parents. I’d only planned to be here for a couple of days, but when I saw that the remnants of Hurricane Zeta would pass directly over us with tropical storm force winds and rain, I stuck around to help the folks out.
Zeta struck quite a blow, in fact. No injuries reported, but over 23,000 of us have been without power for over 34+ hours in Catawba county. With saturated grounds, the winds toppled a lot of trees and damaged power lines.
Yesterday, I wanted to take advantage of the power outage and get on the air. I couldn’t really do a POTA activation because I needed to manage things here at my parents’ house. Plus, why not profit from the grid being down and bathe in a noise-free RF space–?
I decided to set it up in their front yard.
CHA MPAS Lite
I had never deployed the MPAS Lite before, so I did a quick scan through the owner’s manual. Although the MPAS Lite (like the MPAS 2.0) can be configured a number of ways, I deployed it as a simple vertical antenna.
Assembly was simple:
Insert the stainless steel spike in the ground,
Attach the counterpoise wire (I unraveled about 25′) to the spike
Screw on the CHA Micro-Hybrid
Screw the 17′ telescoping whip onto the Hybrid-Micro
Extend the whip antenna fully
Connect the supplied coax (with in-line choke) to the Hybrid-Micro
Connect the antenna to the rig
Although I had the Icom IC-705 packed, I wanted to keep things simple by using the Elecraft KX2 I’d also packed since it has a built-in ATU.
Important: the CHA MPAS Lite requires an ATU to get a good match across the bands.
I wasn’t in the mood to ragchew yesterday, but I thought it might be fun to see how easily I could tune the MPAS Lite from 80 meters up.
I checked the Parks On The Air spots page and saw NK8O activating a park in Minnesota in CW:
He was working a bit of a pile-up, but after three calls, he worked me and reported a 559 signal report. Not bad at 5 watts!
I then moved to 40, 18, and 20 meter and called CQ a couple times to see if the Reverse Beacon Network (RBN) could spot me. I like using the RBN to give me a “quick and dirty” signal report. I was very pleased with the bands I tested:
Those dB numbers are quite good for an op running 5 watts into a vertical compromised antenna.
The KX2 very effortlessly got near 1:1 matches on every band I tested.
Of course, after working a few stations in CW and SSB, I tuned to the broadcast bands and enjoyed a little RFI-free SWLing. Noting 13dka’s recent article, I’m thinking on the coast, the MPAS Lite will make for a superb amateur radio and SWLing antenna.
Although the remnants of Zeta had effectively passed through the area three hours prior, it was still very blustery outside. I was concerned gusts might even be a little too strong for the 17′ whip, but I was wrong. The whip handled the wind gusts with ease and the spike held it in place with no problem.
One of the things I have to watch with my Wolf River Coils TIA vertical is the fact it’s prone to fall in windy conditions and many ops have noted that this can permanently damage the telescoping whip (the weak point in that system).
I’m pretty certain this wouldn’t happen with the Chameleon 17′ whip–it feels very substantial and solid.
Ready to hit the field with the CHA MPAS Lite!
I’m a huge fan of wire antennas because I believe they give me the most “bang-for-buck” in the field, but they’re not always practical to deploy. I like having a good self-supporting antenna option in my tool belt when there are no trees around or when parks don’t allow me to hang antennas in their trees.
I’ve got a park in mind that will make for a good test of the CHA MPAS Lite: it’s a remote game land with no real parking option. I’ll have to activate it on the roadside–an ideal application for the MPAS Lite.