WA8LMF Home Page | Resume | Updated 20 May 2024   

WA8LMF "Studio B"

UPDATE:  Studio B at the 2024 Dayton Hamvention May 17

KM4ACK toured Studio B and made this YouTube video. 

"Studio B" is based on a 12-foot Aliner "Scout" folding a-frame camper.  Unlike the common pop-up tent camper trailers with canvas walls, Aliners have solid walls. The walls are formed of 1" (2.54 cm) thick foam bonded, inside and out,  to skins of a hard melamine plastic similar to kitchen countertops.  Each of the wall/roof panels is surrounded by an aluminum frame.

This construction technique means the walls are excellent insulators (unlike canvas), making it easy to heat or cool the inside efficiently. This particular Aliner has the optional 9000 BTU heat pump installed. It can keep the inside comfortable in almost any weather with about 800 watts of 110 volt AC power.

The  factory-delivered Aliner comes with RV-style 30-Amp 110-volt AC power wiring with a heavy hookup cable that connects to camp-site power pedestals.  It also has a 12-volt system with a 35-amp 12-VDC charger and a 12-volt battery.  The trailer is provided with four standard double AC outlets, a car-type 12 VDC power outlet (a.k.a. "cigarette lighter port") and two 5 VDC USB charge ports powered from the 12 VDC system.  As provided, the 12 VDC system powers two very bright LED lighting fixtures in the ceiling panels and a 12-VDC exhaust fan in the roof.

Since receiving the trailer, I have replaced the old-school externally-mounted lead-acid wet-cell deep-cycle battery with two 100-aH lithium-iron-phosphate batteries mounted internally under one of the bunks. The factory-provided "DC converter" (as RV types persist in calling it -- what hams and telecomms engineers would call a "regulated 12 VDC power supply") is able to "auto-magically" sense and adjust output voltages & charging routines for either flooded lead-acid, AGM,  or lithium batteries. The provided supply can output 30 amps at 13.5 VDC continuously -- providing the equivalent of the 30 amp 12-VDC Astron power supply often seen in ham shacks. It has more than enough 12 VDC current capacity to power the multiple radios, computers and other DC gadgets installed.

I have added solar power and an MPPT charge controller to the 12 VDC system, 2 quad-band HYS  VHF/UHF transceivers, a Yaesu HF transceiver, 2 laptop computers with 12-to-19 VDC "car adapters", 2 soundcard interfaces for digi modes, 5 antennas, 4 Riva Audio "Arena" Wi-Fi speakers in a surround-sound system, and a 35-foot (10 M) telescoping "Spiderbeam" fiber-glass mast that can support multiple HF and VHF/UHF antennas.


The Aliner, folded and ready for travel. Note that the white mast is NOT part of the trailer - It is a street light that "photo-bombed" the shot at a highway rest stop near Clare, Michigan!



Video of Aliner Unfolding  -  Click Anywhere In Picture to Play (Shot with iPhone 6S+ and down-sampled from 1920x1080 Full-HD to 1280x720 Half-HD.)

Factory Floor Plan   (From Aliner.com website)


View of original interior - Sitting in rear looking forward. The vertical surface "soft dormer" pops out after the main sloping a-frame structure is unfolded. The dormer gives you more head room. The table collapses. Then the backs of the two benches fit in the center to become a bed.


Pictures After Outfitting


As seen At Dayton Hamvention "Emergency Comms Vehicles Expo" May 2023  

Antenna at front is the "Kite Loop" all-frequency HF antenna written up in July 2019 QST, tuned with an SGC-230 auto-tuner. It's supported by a Spiderbeam 35-foot (10M) telescoping fiber-glass mast. 
    At the top of the mast, out of the picture, at the top of the loop is a Diamond 770 2m/70cm dual-band mobile whip. This particular antenna is an end-fed half-wave design that does not depend having car-body sheet metal or radials beneath it. it works very well 35 feet (10 meters) up in the air with just a fiber-glass mast beneath it.
    The antenna on the roof line is a Diamond UHV-4  10M-6M-2M-450 quad-bander designed to go with the Yaesu FT-8900 quad-bander and it's Chinese clones.
    The loop at the rear is an MFJ 1736 10-30 MHz "mag loop". 

Note the light-weight folding solar panels on the roof.  The Aliner was special-ordered from the factory, to omit the Plexiglas bubble skylight window normally provided on the roof. This provided the flat surface for mounting the solar panels.


At the Kalamazoo, MI Hamfest & Antique Radio Show October 2024.  "Studio B" was on display directly outside the front door of the Kalamazoo Convention & Expo Center.  The weather alternated between rain and sun all day. I caught this rainbow when the sun suddenly re-appeared. 
   Note that 6 months after the Dayton shot above, that I now have two VHF/UHF antennas on the roof ridge line. The front one is a Diamond 770  2M/70cm  dual-bander.  The rear one is a Comet UHV-4  quad-bander that covers the 10M-6M-2M-70cm bands to match the bands of the Yaesu FT-8900 FM quad-bander transceiver.


Interior view showing some of the added electronics. The 55" TCL "4K" TV is used,  with an HDMI "multi-viewer" screen-splitter,  as four 1920x1080  27" full-HD monitors.   

Click on this picture for far larger more detailed 4000x3000 "4K" annotated version of this picture.  (Opens in new window)  (This picture is 72 separate overlapping shots taken with a Canon Powershot A520 point-and-shoot digi-cam, stitched together with the program "AutoPano Giga".)


The multi-viewer can switch one of the four inputs to a full-screen 4K "UHD" display.  Here the  Geochron display from the upper-left corner in the picture above is zoomed to full screen.


The TV rests face-down on the benches for travel when the trailer is folded. Here you can see the mounting hardware on the back of the TV. The aluminum plate is attached to the standard VESA wall-mount holes of the TV with 9mm screws. The two white PVC pipe risers are U-bolted to the plate. When the screen is lifted to vertical position, the two pipes wedge tightly between the ceiling and the dormer's window frame panel. It only takes about 5 seconds to set up. 
   At the top of the picture are the two control heads for the HYS quad-band FM transceivers and their external speakers.  They are placed so that in a special event activity, two operators seated on the left and right benches could each reach one radio, and one laptop on opposite sides of the table.  In the next row down are the HDMI multi-viewer device and remote controls for the Geochron, the multi-viewer, and the TCL TV attached to the wall with Velcro.


The bottom ends of the PVC pipes have a 45/45-degree miter cut that rests neatly in the V-groove aluminum channel framing the dormer window


Home-made antenna entry panel to allow multiple coax lines from antennas to enter the trailer



A 1.5" x 12" hole was cut through the floor of the trailer, inside a cabinet, to mount the panel. Most of the cables are fitted with type "N" connectors.
    The RF cables are all LMR-195 coax. This cable has the same construction as the well-known LMR-400 cable , but is the diameter of RG-58. It has about 1/3rd the loss of RG-58. Given the short cable runs to the antennas in this project, it is quite usable, even at UHF frequencies.
    Bodies of two HYS TC-9900 FM quad-band transceivers (copies of the Yaesu FT-8900) are at the left .  The control heads of the radios are mounted on the wall under the TV.
    The 8-outlet Tripp-Lite "IsoBar" outlet strip at the right can be plugged into either the trailer's "house power" outlets when an AC hookup is available. Or plugged into a 1 KWh  Jackery Portable Power Station for AC in the field. (AC is only needed for the TV/monitor and the 4  Riva Audio "Arena" WiFi speakers - everything else runs directly from the 12 VDC power system.) 
    The AC power demands are very modest:  The TCL 55" TV was specifically selected because it only consumes 80 watts of 110 VAC power. The Riva "Arena" speakers each contain an extremely efficient  3-channel class-D audio amplifier with a combined maximum power output of 50 watts. The four speakers together consume an average of 15 watts at normal listening levels.
    Unlike most so-called "surge suppressors", Tripp-Lite Isobars contain a true multi-section L/C  RF low-pass filter with large ferrite-core coils and silver-mica RF-grade capacitors.  The filter stops MF-HF-VHF-UHF RF picked up by the AC power line from entering equipment plugged into the outlets. They are invaluable when transmitting antennas are only a few feet from the radios and power supplies. They also stop RF hash from switching-mode power supplies from being radiated by the AC power line into nearby receivers.
    A  "Chunzehui F-1005" 8 Port 40-amp PowerPole panel is located above the IsoBar. It   handles all the 12 VDC power distribution.   Each DC output, and the input, are individually fused with automotive-type ATC fuses - a total of 9 fuses. This DC Powerpole "outlet strip" is available at Amazon.
    4 feet (1.1 meters) of red/black 10 AWG zip cord connects the panel directly to two "Flypower" 12-volt 100Ah lithium-iron-phosphate (a.k.a. "LiFePo") batteries wired in parallel. This particular brand, of the dozens of similar batteries from Chinese vendors on Amazon,  comes with a 200-watt AC charger about the size of a large laptop "power brick".  The charger connects to a charge port on the side of the battery, separate from the main +/- terminals on top. This particular charger is optimized for lithium charging -- it has a programmed charging routine that periodically takes the output voltage up to the 14.6 volts required to fully deep-charge lithium batteries.  (
Normal automotive "12-volt" systems normally produce a maximum of 13.8-14.0 volts which CANNOT fully deep-charge lithium batteries without a voltage booster of some sort. Solar charge controllers can, since "12-VDC" solar panels normally are 19-20 VDC open-circuit.)   The main terminals of these batteries are heavy brass threaded screw holes provided with 6x30mm Allen-hex-socket-in-head bolts, rather than SAE-type posts.  This makes it very easy to stack multiple runs of 10- or 12-gauge red/black zip cord terminated in 1/4-inch ring terminals under each bolt.


The outside of the entry panel, on the underside of the trailer. (The ribbed black material is the under-side of the MDF flooring of the trailer.) The two cables at the left are the RF and power/control cables for the SGC auto-tuner at the front of the trailer. The two cables with "N" connectors at the right are LMR-195; they go to the roof ridge line for the two VHF/UHF antennas. The connector at the far right goes to the MFJ mag loop mounted on a mast attached to the spare-tire bracket at the rear of the trailer.


Antennas on Rear End of "Studio B"

The vertical mast is mounted to the spare tire bracket.  A 10-30 Mhz MFJ magnetic loop antenna and a mini-dipole made from two Quicksilver Radio "QuickStick" hamstick-type mobile whip antennas are mounted to the mast. Normally, a pair of either 30-meter or 60-meter whips are used for HF APRS operation.  The dipole, mounted only about 10 feet (3 meters) above the ground, provides excellent NVIS (Near Vertical Incidence Skywave) propagation for close-in (0-250 miles / 0-400 KM) skywave operation.

Both antennas can be connected in parallel to the same transmission line at the same time with the coax "T" connector shown.   Both antennas are very narrowband and present a nearly infinite impedance except at the frequencies they are tuned to.  This allows instant bandswitching on the attached radio, between 60 meters and 30 meters (or any higher HF band the mag loop might be tuned to).

Note that unlike similar "dipole adapters" for mobile whips, the MFJ-347 has insulated isolated mounts for both whips. This creates a true balanced dipole. (Most other similar adapters have only one insulated antenna mount -- the other whip is connected to the bracket and supporting mast. The Quicksilver Radio current choke balun further improves the symmetry of the dipole.

Click on image for a larger annotated version of this picture showing part numbers. (Opens in new window.)


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