Ham Radio EMCOMM Go Kit – Version 2

Last year I put together both VHF/UHF and HF go kits. While functional, neither of these was as capable or robust as I ultimately wanted my go kit to be. My new goal was to build an all-in-one station in a box that was not overly bulky or heavy.

Design

If you look around the internet you will see a lot of people building go kits in rack cases. I always liked the sturdiness and modularity of this type of case, but not the bulk. Most builders us a full size 6 unit case, which is not compact (roughly 24″ square and 13″ tall) nor lightweight (over 18lbs). After evaluating the equipment I planned to use in the kit I realized that I did not need a full depth case. Using a shallow case saves me 8″ of depth and cuts the weight as well. I laid out several possible equipment arrangements in CAD and found that if I kept the kit fairly barebones (no SWR meters or external antenna tuners, only one external speaker) I could also move from a 6 unit case to a 4 unit and still fit everything I needed. The 4 unit shallow case I used is 22.4″ x 16.2″ x 9.1″ and weighs 12.8lbs.

The general design philosophy for this project was to have all of the equipment mounted to two shelves (one on the bottom and one at the top). After my experiments in CAD I found that a good organizational layout was achieved with the power supply, power distribution, and HF transceiver mounted on the bottom. As part of the power distribution system I wanted to incorporate an automatic backup power switch. This allows the power system to seamlessly change from AC wall/generator power to battery power. While not necessary, this is a nice feature to have because it prevents your radio from turning off while operating if there is an interruption of power (which can easily happen in emergency and field operations).

This left the VHF/UHF transceiver, speaker, and two SignaLinks for the top shelf. The SignaLinks are separated by the speaker to easily differentiate which unit is connected to which radio. I went with multiple digital interfaces because while I will most likely never be transmitting on both V/U and HF simultaneously, it can be very handy to be able to monitor both at the same time or to monitor one while transmitting on the other. Having two units also allows me to never worry about changing radio and SignaLink wiring to operate on the band I need to.

In order to simplify the cabling between the SignaLinks and my laptop I decided to us a powered USB hub and to make the USB hub accessible on the back of the case. This makes it very convenient when in the field since I don’t have to reach into the case to plug in the interface cables. The addition of a rear mounting plate gave me a place to pull out the V/U transceiver’s antenna connection for easier access as well.

I decided one external speaker would be adequate based on the layout I settled on. In this layout there is a fair amount of space below the V/U radio’s speaker to allow for sufficient sound output. The HF radio, however, has much less space above its top mounted speaker. Another consideration I made was that FM audio on V/U is generally very clean, especially compared to SSB audio on HF. Based on this I chose to use the speaker with the HF radio.

Parts

Construction

The Powerwerx power supply is perfect for go kits. It is very compact (6″ x 5″ x 2″), has convenient Anderson powerpole connections on the front (in addition to terminals on the back), and can be secured with mounting brackets.

The Yaesu 450D offers a lot of bang-for-your-buck and is relatively compact and lightweight as well (9lbs). The built-in automatic antenna tuner does not have the widest range (3:1), but I don’t plan to use it with non-resonant antennas so it should be more than adequate. Making use of the internal tuner also allowed me to eliminate an external tuner from the design, which was one of the key reasons I was able to fit everything inside a 4 unit case. The 450D was mounted using 2.5″ steel brackets along with M4 machine screws and 1/8″ nylon spacers to prevent the brackets from rubbing against the radio’s enclosure. I had originally intended to use Yaesu’s mobile mount for the 450D, however, it took up too much space and would have affected my layout. This arrangement lifts the radio about 1/2″ off of the shelf which should provide plenty of ventilation.

In the preliminary layouts I had planned to use a West Mountain Radio PWRgate and Rigrunner for backup power switching and power distribution. This plan proved impractical due to space restrictions, however, I found the perfect substitution in the Low Loss PWRgate. It is about half the size of the other backup power switch and it provides 3 output powerpoles which eliminates the need for a Rigrunner or other distribution block. While the LLPG is rated for 25 amps vs the 40 amps of the other unit, this should still be adequate for my purposes. The LLPG is very lightweight and was mounted using heavy duty double stick tape.

The Kenwood V71A was mounted using it’s mobile mounting bracket. The voltage converter for the USB hub was screwed to the shelf using its mounting tabs. The other equipment on the upper shelf was mounted using either heavy duty velcro (SignaLinks, USB hub) or double stick tape (speaker). I also added some rubber strips to the bottom of the speaker because I found in test fittings that the clearance between the speaker and the HF radio was only about 1/8″ and I didn’t want any inadvertent contact between them when the case is moved.

Cable Management

Part of eliminating the Rigrunner from my build meant that I had to provide some protection for the power wiring and radios. This was done using inline fuse holders with ATC style fuses. I also had a fair amount of radio interface and USB cables to manage. The shelves I chose are vented which makes them perfect for using wire ties to secure everything in place. I also wanted to make the go kit as straightforward as possible to assemble and disassemble. Part of this goal was limiting the wire tying of cables to individual shelves. This means that if I want to remove a shelf, I only need to disconnect the handful of cables that are connected between the two shelves (two power, one speaker audio, one SignaLink), then unscrew the shelf and pull it out. No cutting of wire ties is necessary.

I really wanted to be able to stow the radio microphones inside the go kit and I found that I could velcro the V/U radio’s mic to one of the HF radio’s mounting brackets and the microphone’s cable would then fit nicely between the power supply and HF radio. This is especially convenient since the microphone jack is in a position that makes disconnecting it a bit of a pain.

The HF radio’s mic is stowed using velcro and a strap to the inside of the front case lid. The lid has enough depth that the mic can fit without contacting the front of the power supply. The power supply AC power cord is stowed using a similar strap method as the HF mic, except it is in the rear case lid.

Weight

Part of the goal of using a smaller rack case was to cut down on weight as well as bulk. I had estimated that I could build the go kit and keep the weight around 35lbs. In the end the kit weighs 40.5lbs. I think the lesson I took from this is that wire and mounting hardware add up to more weight than you might realize.

Operation

The kit is very straightforward to setup. Once the lids are off I simply unstrap the microphones and power cord. Then I can either plug in AC power or a battery, hook up my antennas, connect USB to my laptop, and I’m on the air. I am very happy with how little bulk this kit has; with the lids removed the case is only 12″ deep and easily fits on a small table. The kit is small enough to integrate perfectly into my home station, which makes it very convenient to make sure everything is fully functional for field operations. I am very pleased with how this kit turned out and I learned a lot of along the way, especially about case layout and parts fitment.

QRP Go Kit

After assembling a solid set of QRP gear this year I wanted to put everything into an easy to transport package. To house and protect the kit I used a Monoprice 13″ x 12″ x 6″ Weatherproof Hard Case. This case is the perfect size to fit my mcHF transceiver, and Elecraft T1 autotuner, along with a 3″ external speaker, hand microphone, and power cable. All together the case and equipment weigh a little under 7.5lbs.

With this kit, all I need is 12VDC power and an antenna and I am on-the-air. This should pair perfectly with a small battery and either my random wire or end fed half wave antennas that I built recently.

HF Random Wire Antennas

Resonant antennas have a lot of advantages: they are efficient, impedance matched to your transmitter and require minimal tuning. The main disadvantage of resonant antennas is that they are nearly always only usable over a single frequency band. Non-resonant antennas do not present a match on any band by default, however, they can be easily matched to a wide range of frequencies. One of the most common ways to match a transmitter to a non-resonant antenna is to use a 9:1 UnUn combined with an antenna tuner.

100W Random Wire

I built this version for field use and wanted to make the design as flexible as possible. To this end I built the antenna such that I can easily lengthen it when extra room is available. The default length is 53 feet and the antenna can be extended to 124.5 feet. These lengths were chosen because they are not resonant on any ham band. The 9:1 UnUn for this antenna uses a FT240-K ferrite toroid wound with 18AWG enamel wire. The UnUn is mounted to a DX Engineering Balun Bracket to provide a mounting point and antenna wire strain relief. The antenna extension was made by using two DX Engineering Wire End Insulators that are be bolted together for strain relief and Anderson Powerpoles for the electrical connection of the 14AWG antenna wire. For a counterpoise I made two 50 foot lengths using 24AWG speaker wire. I can also use the shield of the feedline coax and then isolate the antenna from the transmitter using a 1:1 Balun/Choke. I have used this antenna using only the 53 foot section of wire and was able to tune all of HF and made a few contacts using my HF Go Kit, although some bands required adjustment of the counterpoise length in order to be in range of the Yaesu FT-450’s antenna tuner.

QRP Random Wire

After experiencing some success with my high power version I decided to build a QRP version. The QRP 9:1 UnUn uses a FT140-43 ferrite toroid and is wound using 24AWG enamel wire. This combination should easily handle 10 watts. The physical construction of the UnUn itself uses the same strain relief technique as my End Fed Half Wave Matchbox, where 1/8″ acrylic is epoxied to the enclosure used to house the toroid. For this antenna I used 26AWG stranded copperweld and cut it to 29.5 feet with an additional extension to 53 feet. This should allow for quick and easy field deployment using my 31 foot lightweight fiberglass mast. I did some experiments with my QRP transceiver and my QRP Autotuner and was able to tune all of HF using this configuration and two 50 foot counterpoises.

Overall I think these random wire antennas are a good addition to my antenna arsenal. They are not necessarily the best option, however, they are very versatile and can prove useful when a simple multi-band antenna is required.

End Fed Half Wave Antennas

Half wave dipole antennas are generally considered the reference point for all antennas in ham radio, especially on HF. When fed from the center, a dipole makes for an easy impedance match to 50 ohm coax. When fed off-center at an appropriate location (typically the 1/3 point) and fed with a 4:1 balun, the dipole becomes a solid multi-band antenna. Feeding a half wave antenna from the end, however, presents additional challenges because the impedance is in the thousands of ohms. In spite of this, end feeding antennas can be an incredibly convenient configuration because you only need one support (like a tree) and you can easily place your operating position at or very near to the feedpoint of the antenna. This has led to this antenna design to being very popular with portable operators and others who want an antenna that is easy to erect quickly.

QRP Matchbox

While researching this type of antenna I found a couple of blogs (here and here) that have a lot of good information regarding end fed half wave antenna designs. These designs rely on the principles used by the PAR Endfedz which consist of an impedance transformer between the antenna and transmitter as well as a capacitor across the feedpoint. Based on this design I made an impedance transformer using a FT140-43 ferrite toroid (this size toroid is overkill for a QRP application) with 27 turns on the secondary and 3 turns on the primary (24AWG enamel wire). This is then wired such that the start of both the secondary and primary are connected to the coax connection shield. The other side of the primary is connected to the coax center pin. The remaining secondary connection is the attachment point for the antenna. A 150pF is then wired across the coaxial connection. I used a 1000V mica capacitor since very high voltages are present at the feedpoint.

The matchbox was constructed using a 3.25″ x 2.125″ x 1.5″ ABS plastic box and 8-32 stainless steel hardware. To provide strain relief I epoxied a piece of 1/8″ acrylic to the back of the matchbox enclosure. I also made a strain loop at the end of the antenna wire for attachment to the acrylic sheet using an S hook. This allows the acrylic to carry the load of the antenna, not the antenna connection point. I also used pieces of acrylic for the end insulators since it is the perfect material to weave small wire through and lock it in place.

I wanted to experiment with the effectiveness of this matchbox with different antenna designs. I also wanted to test the antennas in a typical field installation configuration; in this case they were erected as a sloper with one end in a tree about 25 feet in the air and the feedpoint about 5 feet off the ground.

40/20 Meter Half-Wave

This antenna is a full size 40 meter half-wave with a tuning stub in the center to adjust the resonance of the antenna as a 20 meter full-wave. The tuning of this antenna was very straightforward; I simply tuned the main element for the center of the 40 meter band and then adjusted the 20 meter stub for the center of the 20 meter band. With the 26AWG stranded copperweld wire that I used the antenna ended up being about 62 feet long with a 2 foot long stub in the center. This antenna exhibits great bandwidth and easily covered both bands with under 2:1 SWR.

40/30 Meter Loaded Half-Wave

This antenna is a full size 30 meter half-wave with a loading coil/choke and tuning stub at the end of the antenna to provide resonance on 40 meters as well. The loading coil/choke consists of 55 turns of 24AWG enamel wire on a piece of 3/4″ PVC pipe. This coil is approximately 47uH of inductance, which should have an impedance of almost 3000 Ohms at 10MHz. The purpose of the coil is to choke off the current flow and electrically shorten the antenna on the 30 meter band while providing the necessary inductance to resonate the full antenna on the 40 meter band since it is shorter than a full half-wave on that band.

Tuning this antenna required a fair amount of trial and error because the 30 meter element and tuning stub length interact and affect the resonance on both bands. I initially trimmed the main element without the loading coil and had a good match with 42.5 feet of wire. After attaching the loading coil and several feet of tuning stub I found that the antenna appeared to be too short for 30 meter resonance and too long for 40 meter resonance. Eventually after several trimmings I found that a stub length of about 3 feet resulted in the 30 and 40 meter resonances tracking each other when I adjusted the length of the main element. I then added wire to the main element until I achieved a good match on both bands, in this case a main element of 48 feet works well. 30 meters is a narrow band and this antenna easily covers the entire band with under 2:1 SWR. Because of the loading coil, this antenna does not exhibit particularly high bandwidth on 40 meters, however, the purpose of this antenna is for QRP digital operation which does not involve a lot of tuning around, so it was trimmed to provide the best match at the low end of 40 meters and should have plenty of bandwidth for PSK and JT65 operation.

100W Matchbox

After my successful experiments with the QRP matchbox I wanted to build a more robust version for higher power applications. This requires the use of thicker gauge wire and a larger toroid to handle the higher currents and and more powerful magnetic fields. In this case I used 18AWG enamel wire wound on a FT240-43 ferrite toroid, which should easily handle 100 watts of power. A 27:3 turns ratio was used again as well as the same 150pF 1000V mica capacitor. I mounted the completed toroid in a 4″ x 4″ x 2″ NEMA 4X box and mounted it to a DX Engineering Balun Bracket. For the antenna connection I used 10-32 stainless steel hardware.

80/40 Meter Loaded Half-Wave

This antenna is constructed similarly to the 40/30 meter version described above. This time, however, the loading coil consists of 67 turns of 20AWG enamel wire on a piece of 1″ PVC pipe. This coil has an inductance of about 66uH which is required to achieve an appropriate amount of current choking at 7MHz. For strain relief I used 1/4″ Lexan sheet to make the connection points for the antenna and coil wires. I then epoxied the Lexan to the PVC coil form and bolted the connections using 10-32 stainless steel hardware.

I found this antenna to be easier to tune than the 40/30 meter version. This is most likely due to the larger difference in frequency ratio between the 80 and 40 meter bands vs the 40 and 30 meter bands. After trimming I found that a main element length of about 67 feet gave a good match across the 40 meter band. As anticipated this antenna has a limited amount of bandwidth on the 80 meter band (about 90KHz). I decided to construct a way around this by adding a tuning stub to the end of the 80 meter section to allow for adjustment of which portion of 80 meters I wanted to operate in. Since the primary usage of this antenna would be for field deployment and emergency communications I would most likely need to be able to use it in the digital portion of the band (3.583MHz or so) as well as the higher end of the band (3.983-3.99MHz) where the ACS nets in my area take place. After some experimentation I found that the antenna was resonant in the voice section I wanted with an 80 meter stub 9 feet in length. I then made an additional 3 foot length of wire that I can add to the end using Anderson Powerpoles that shifts the resonance of the antenna to the digital portion of the band. This allows me to easily change the section of the 80 meter band I want to use by simply adding or removing this small section of wire. This additional wire has a very minimal effect on the 40 meter resonance of the antenna (around 10KHz) and does not prevent the antenna from achieving an SWR of under 2:1 across the entire band whether it is installed or not.

I did a few side by side comparisons between this antenna and my 80 meter loop skywire. My first comparison involved observing the signal strength when listening to the local ACS net on 80 meters. I found that I could copy everyone easily with the end fed half-wave, however, they were generally an S-unit or two weaker than with my loop. This was as expected since the end fed is both lower and smaller than the loop. I also made a QSO on 40 meter SSB using 100W and got a good signal report from the station I contacted in Michigan (about 300 miles away). Overall I think this antenna is a very solid semi-compromise antenna for field use and will definitely be part of my HF Go Kit going forward.

Elecraft T1 QRP Autotuner Kit

img_0841In the months since I completed my mcHF SDR transceiver kit, I have thought about building a QRP antenna tuner to go along with it. After some investigating I came across the Elecraft T1 which is available assembled or as a kit and can handle 10W of continuous power. While I have never owned any Elecraft gear, they have a very good reputation and several people in my ham radio club swear by their equipment. The kit looked like a fun project and a perfect match for my QRP gear so I decided to order one.

img_0842The kit took about a 4.5 hours to complete. The included instructions are very detailed and do a good job of emphasizing critical parts of the build. The biggest issues arise in regard to several components that need to be mounted in a very specific way in order for the case to fit properly. The circuit boards are fairly tightly packed, but anyone with good soldering experience should have no problem assembling this kit.

img_0844img_0843The finished product is very compact and incredibly simple to operate. I really appreciate that the instructions are printed on the front label in case you forget. So far I have used it to tune a couple different antennas of various designs and it performs very well. It finds matches quickly and the relays aren’t annoyingly loud like some autotuners. I look forward to getting a lot of use out of this and my mcHF.

Manual Antenna Tuner

Manual Tuner (10)Manual Tuner (9) Automatic antenna tuners are incredibly convenient devices. They also require power, interface cables, and many have a limited impedance matching range. Manual tuners, on the other hand, feature a simple design and can have a very wide matching range.

Manual Tuner (6)Manual Tuner (4)After deciding that I wanted to build a T-match type of tuner, I needed to find some high voltage air variable capacitors. I looked around at what was available and found this great pre-made assembly that features two 22-360pF variable capacitors (rated for 1kV) and a 12 position rotary switch (rated for 5A). This should be able to handle 100W when properly matched. After deciding on this component I selected an 8″ x 6″ x 3.5″ aluminum enclosure for the tuner.

Manual Tuner (2)The next part of the tuner is the inductor. In order to make use of the 12 position rotary switch I needed to make a coil with taps. I also had to keep the coil relatively small so that it would fit in the enclosure I was using. After doing some research I found that an inductance of 30-40uH is typical for a T match antenna tuner and should be able to match a good range of impedances from 160M – 10M. K7MEM has a great single layer air core inductor calculator that uses common PVC pipe as a coil form. For the coil I decided to use 18AWG teflon insulated wire since it should be large enough to handle 100W and the teflon insulation is both easy to work with and very heat resistant. Using the calculator I found that 46 turns of wire on a 1.25 inch PVC pipe resulted in a 35uH inductor that would fit nicely in the enclosure.

Manual Tuner (5)To wind the coil I used a ring terminal to secure the starting end and started winding. At every tap point I separated the insulation and soldered a jumper to the exposed wire. Then I continued winding until the next tap point and so on until I finished the coil with another ring terminal. I tapped the coil at turns 2, 4, 6, 8, 12, 16, 20, 24, 30, 36, and 42. The finished coil was then bolted on top of nylon spacers to the enclosure.

Manual Tuner (3)Manual Tuner (1)To finish the tuner I wired the taps in the order they were wound to the rotary switch. The start of the coil should be wired to the point where the variable capacitor rotors are connected together. The end of the coil should be grounded to the enclosure along with the common point on the rotary switch. Each variable capacitor stator is wired directly to the center of a SO-239 connector, one to the input and one to the output of the tuner. Finally, I added a ground stud to the enclosure.

Manual Tuner (8)Manual Tuner (7)When using a tuner of this design it is good to keep in mind that the most efficient match occurs when the capacitance is at a maximum and the inductance is at a minimum. Therefore when adjusting the tuner I always start with the capacitors at close to their maximum setting (fully meshed) and the inductor on the first tap. I then click through the inductor taps until I see a dip on the SWR meter and adjust the capacitors to achieve the lowest SWR I can.

I have used this tuner with a couple different antenna designs and it performs fairly well. When used with various dipoles and other wire antennas I have been able to achieve matches the majority of the time. However, I may need to adjust the design of the coil since it seems that I never make use of the later taps and may not require such a large coil.

Ham Radio EMCOMM Go Kit – Antennas

Having a bunch of hardware and the power to run it is all fine and good, but if your antennas aren’t capable of getting the signal out all of those radios are useless.

Mast System

Like with my go kits, my first priority was to have a good VHF/UHF antenna system. A magmount on the roof of your car is OK, but for local line-of-sight communications the gain and height of your antenna are very important. I also wanted something that I could easily transport and erect by myself.

Antenna Mast (2)After some investigations I decided to aim for a simple lightweight mast system that I could mount to the trailer hitch on my car. The base for this setup is a hitch mount flagpole mount. For the mast I chose the MFJ 1904H. This mast solves a lot of potential problems for a portable mast system:  it is 5 feet long when collapsed making it easily transportable in my car, it is non conductive and will not interfere with any antennas mounted on it, and despite being made of fiberglass it is fairly sturdy (each tube wall is 1/8″ thick). I don’t intend to heavily load this mast so this should serve my needs well. In order to achieve a tight fit between the flagpole mount and the mast I used a section of 2″ PVC pipe as a spacer. When fully extended the top of the mast is about 21 feet high.

I also purchased a 33 foot version of this mast design from Max-Gain Systems. While this version requires some guying, it allows for considerable more antenna height and consequently performance.

VHF/UHF

Antenna Mast (3)Antenna Mast (1)For the VHF/UHF antenna I chose the Two Way Electronix Dual Band Slim Jim. As someone who uses a J-Pole antenna as my base VHF antenna, I am very familiar with how well these antennas perform. The Slim Jim is a J-Pole made from 450 Ohm ladder line so that it can be rolled up for easy storage and transport. I mount the antenna to the mast using a nylon bolt and wingnut the passes through the insulation at the top of the antenna and a hole drilled in the top fiberglass section. This setup is very light weight and has virtually no wind loading which makes guying the mast unnecessary (under average wind conditions).

HF

For HF I did considerable research regarding what type of antenna is appropriate for emergency communications. A lot of ham radio is focused on making contacts at great distances (DX). This necessitates a low angle of radiation from the antennas being used. For a dipole this means that the antenna should be at least a half wavelength above ground. The most common HF EMCOMM bands are 40 & 80 meters (one half wavelength on 40 meters is about 66 feet, double that for 80 meters). For EMCOMM purposes, however, we only want to communicate within a couple hundred mile radius of our location. This requires a Near Vertical Incident Skywave (NVIS) propagation path. It turns out that this makes our lives a lot easier since a dipole can be used for NVIS when it is mounted much lower than it would typically be. Instead of trying to get a dipole very high, mounting it at 15 feet is ideal for this application. Another benefit of this approach is that at this height the dipole loses almost all of its directionality and is essentially omnidirectional.

Hamsticks

Antenna Mast (4)In an effort to maximize portability and reduce both setup time the footprint of the EMCOMM station I decided to try MFJ’s hamstick dipoles (MFJ-2240, MFJ-2275). These are loaded antennas that use a base section coil wound on a fiberglass rod with a stainless steel whip on the top. While a small loaded antenna will not have the efficiency, or the bandwidth of a full size antenna, it is considerably smaller (15 feet vs 66 & 133 feet). The hamstick dipoles actually perform fairly well. I was able to tune them for the digital portion of the bands and using the antenna tuner in my Icom 703 I can tune either dipole across their entire respective band. The dipoles are also fairly light weight and my fiberglass mast seemed plenty strong enough to support their weight. I would still like to try stacking the dipoles on the mast simultaneously in a cross configuration and seeing if that effects anything.

Folded Skeleton Sleeve Dipole

Field Setup (1)Field Setup (2)After exploring a few different designs I think that my 75/40 meter Folded Skeleton Sleeve Dipole will make an excellent EMCOMM antenna. It is resonant on both bands, making it easy to tune up and operate on the two most common HF bands used during emergencies. It is also over 20 feet shorter than a typical 80 meter dipole, making it somewhat more space efficient.

End Fed Half Wave

Similar to the Folded Skeleton Sleeve Dipole, my 80/40 End Fed Half Wave antenna is resonant on the two most common EMCOMM bands. It is also only 76 feet long (58% of a typical 80 meter dipole) and is quick and easy to deploy as a sloper.

Performance

While I haven’t done much operating with the Hamsticks, I have done a fair amount of testing with the Folded Skeleton Sleeve Dipole and it is a very competent antenna. My Ham Radio club used it during Field Day and made over 350 contacts with this antenna. The End Fed Half Wave is also a solid performer and works quite well for regional communications.

Ham Radio EMCOMM Go Kit – HF

HF Kit (1)After some thought I decided that I wanted to treat this as more of a HF Field Kit than a true Go Kit. I had heard good things about the Yaesu FT-450D and after seeing sale prices and mail-in rebates drop the price to $600 I decided to buy one. The Yaesu (9”W x 3.3”H x 8.5”D, 8.8 lbs) is not as compact as some HF rigs, but it is nowhere near as unwieldy as my Kenwood TS-590SG  (10.6″W × 3.8″H × 11.5″D, 16.3 lbs) which serves as my main HF transceiver in my station. For such a compact radio it contains many comparable features to my larger and considerably more expensive Kenwood.

Features

The Yaesu 450D is an entry level transceiver, however, it includes a lot of features that give you considerable bang for your buck.

  • HF/6M Coverage
  • 100W Transmitter
  • IF DSP Filtering (Width, Shift, Contour, Notch, Noise Reduction, etc.)
  • Backlit Buttons (perfect for field use at night)
  • Voice Keyer (perfect for contesting and Field Day)
  • Built-in Antenna Tuner

Field Case

HF Kit (2)To house the Yaesu I used a Monoprice 22″ x 14″ x 8″ Weatherproof Hard Case. This should keep the radio, SignaLink, and microphone secure. Less damage prone items like the power cable can be transported in my backpack. For additional capability I decided to add a second case to the kit.

Accessory Case

This case is the same model used to house the Yaesu 450D. In this case it contains my Manual Antenna Tuner, a MFJ 4125P 22A switching power supply, and a MFJ 822 cross-needle SWR Meter. This case greatly expands the capabilities of my HF kit. The manual tuner has a much wider tuning range than the autotuner inside the 450D, the switching power supply allows me to power the radio from line or generator power if available, and the small SWR meter is perfect for station monitoring in the field.

When line or generator power is not available I will rely on my Go Kit Battery Box. I think that this setup will prove to be versatile and the Yaesu 450D provides many modern conveniences as well as 100W output in a compact package.

Ham Radio EMCOMM Go Kit – Laptop & Software

Asus (2)Asus (1)I had a few key priorities for an EMCOMM laptop: adequate performance, decent screen size, full size keyboard, lightweight, good battery life, low price. After looking around at the laptops available I decided to get the Asus VivoBook E403A-US21.

Specs

  • CPU – Intel Pentium N3700 (Quad-Core, 1.6 GHz)
  • RAM – 4GB
  • SSD – 128GB
  • Display – 14″ (1920 x 1080)
  • Wireless – Wifi (AC), Bluetooth (v4.0)
  • Ports – USB 3.1 Type C, USB 3.0, USB 2.0, HDMI, Audio
  • SD Card Reader, Webcam, Microphone
  • Battery – 57 Wh
  • Weight – 3.3 lbs
  • Price – $400

Asus (4)Performance

The Asus VivoBook easily runs Windows 10 and all of the ham radio applications that I need (N3FJP log, FLDIGI, FLWRAP, FLMSG, FLAMP, WJST-X, etc), which allows me to use it as my main station computer. Consequently, if I need to grab my equipment and hit the road I can just disconnect a couple of cables and take my laptop with me, armed with the knowledge that it is up to date, functional, and that the battery is fully charged. By using one laptop for everything it allows me to not worry about maintaining a secondary machine just for my Go Kit.

Asus (5)Power Usage

The VivoBook is fairly miserly when it comes to power usage compared to higher powered laptops and is well suited to field use.

  • Idle Maximum Brightness – 8W
  • Idle Minimum Brightness – 6W
  • FLDIGI, FLMSG, FLAMP, File Browser Open, Maximum Brightness – 11W
  • FLDIGI, FLMSG, FLAMP, File Browser Open, Minimum Brightness – 9W
  • Charging Battery – 33W

While this extremely low power usage provides the benefit of great battery life it also means that the VivoBook can run for hours and hours on an external battery pack like the Energizer XP18000 or the Intocircuit 32000mAh battery pack. Starting with a fully charged laptop and battery pack this laptop could easily run for over 24 hours without needing to plug into 120V. Being low power also means that the system doesn’t get hot, there’s not even a fan for the processor.

Overview

Asus (3)The VivoBook is thin and light and the keyboard and touchpad are excellent. It has a good selection of ports and the build quality is very solid for such an inexpensive machine. The high display resolution is also nice to have especially for a laptop in this price range. The display’s contrast and viewing angles are not very good as was expected for this price range. I was, however, able to improve the color reproduction using my Datacolor Spyder screen calibration tool. Overall this is a fantastic laptop for the money and it is a good addition to my Go Kit setup.

Folded Skeleton Sleeve Antennas

Skeleton Sleeve Dipoles (4)I am always interested in trying different antenna designs, especially if they are simple to construct and provide increased functionality. While perusing some old issues of QST magazine online I found a series of articles that discuss a design called the Folded Skeleton Sleeve. The design is a unique way to build a dual-band resonant dipole or groundplane vertical. The articles appear in the May 2011, October 2011, October 2012, December 2013, and March 2015 issues of QST magazine.

I was particularly interested in this antenna design because a simple resonant dual-band antenna could be very useful for deployment at Field Day or for EMCOMM purposes. Other multi-band antenna designs exist and can perform quite well (windoms, off-center-fed dipoles, G5RVs, non resonant end feds, dipoles fed with window line, etc.), however, these require an antenna tuner to achieve a decent SWR. Other designs, such as trap dipoles, can be heavy and cumbersome with multiple points of failure. The folded skeleton sleeve design exhibits non of these limitations.

Design

Folded Skeleton Sleeve AntennaThe folded skeleton sleeve at first looks like a standard folded dipole, however, the top radiator is not continuous. Two notches are cut along the top of the window line to create the parasitic element that allows for operation on the higher frequency band.

A 75M / 40M antenna should be perfect for both EMCOMM (these are the most common HF bands used for emergency communications) and Field Day. A 40M / 20M antenna is equally perfect for Field Day and the combination of the two provides a lot of operating versatility from two simple antennas that cover the three busiest Field Day bands. I also decided to construct a 40M / 30M antenna for use as a portable antenna for digital communications.

Construction

Skeleton Sleeve Dipoles (2)Skeleton Sleeve Dipoles (3)I built the antennas using 18AWG stranded copper-weld 450 Ohm window line (Wireman #553) and folded dipole insulator kits (Wireman #804) which make fantastic strain reliefs for securing the window line. I also made my own 1:1 baluns in a similar design to what I have done before, except this time I used FT-150A-K toroids and 18AWG wire which allowed me to make the baluns smaller in size while still being adequate to handle 100W. To house the baluns I used Bud Industries PN-1322-DGMB NEMA 4X enclosures. These are well made boxes and they feature convenient mounting tabs that are easily bolted to the center insulator.

75/40 Bandwidth

75 Meter Band

  • 2:1 SWR:  3.68-3.785
  • 3:1 SWR:  3.63-3.86

40 Meter Band

  • 2:1 SWR:  7.18-7.238
  • 3:1 SWR:  7.1-7.3

While the bandwidth of this antenna is not particularly wide, it is easily matched to the radio’s 50 ohm output with practically any antenna tuner.

My ham radio club used the 75/40 at our Field Day site for the duration of the event. While obviously intended for use on 75 & 40 meters, the antenna was used on the higher bands as well with the help of a wide range antenna tuner. Over the course of field day this setup resulted in over 350 CW contacts.

40/30 Bandwidth

40 Meter Band

  • 2:1 SWR:  7.158-7.33
  • 3:1 SWR:  7.073-7.448

30 Meter Band

  • 2:1 SWR:  9.93-10.24

This antenna exhibits better bandwidth than the 75/40 and even reaches an SWR of 1.1:1 on 30 meters.

40/20 Bandwidth

This antenna is by far the best design of the bunch. This configuration results in an SWR of under 2:1 across the entirety of both the 40 and 20 meter bands.

Antenna Winders

Skeleton Sleeve Dipoles (5)Since ladder line can be annoying to work with since it doesn’t coil easily, I decided to build some winders from 1/2 inch PVC pipe to keep the finished antennas organized. I built a larger one for the 75/40 antenna and smaller ones for the 40/20 and 40/30 antennas. I am really pleased with how these turned out and plan to build more for use with other antennas; they are a fantastic way to avoid a tangled mess.