This past year, Joyce/\K0JJW and I did quite a few Summits On The Air (SOTA) and Parks On The Air (POTA) activations, often as part of an RV camping trip. During this time, we made some improvements to our portable gear. For SOTA, we primarily use the VHF/UHF bands but we have been sprinkling in a bit more HF activity. For POTA, we often don’t have a Height Above Average Terrain advantage, so we definitely use the HF bands.
Our main goal was to have a backpack portable station for SOTA and POTA that can cover HF through 70 cm, on the most popular bands/modes including CW, SSB, FM and FT8.
Using The IC-705
The Icom IC-705 is a great transceiver for covering most HF, VHF and UHF bands. With an external battery, the transceiver puts out 10 watts of RF power. (This is a bit less than the 50 watts from our Yaesu FT-90, which is our default choice for 2m and 70 cm SOTA.) We have accumulated a number of Lithium Iron Phosphate batteries from Bioenno. They are all set up with PowerPole connectors and are easily interchanged. See a previous post, My SOTA Battery Journey.
Arguably the biggest weakness of the IC-705 is the lack of an internal antenna tuner for the HF bands. Of course, you can operate without a tuner by making sure your antenna is always 50 ohms. I find that limiting, especially under portable conditions where the antenna configuration might be compromised. Also, some common end-fed antennas that cover multiple bands are not a good match for all bands. There are external automatic antenna tuners available for the IC-705, so initially those looked like a good solution. Then I remembered that I had a small MFJ-902 Travel Tuner that could do the job. The MFJ-902 is a classic T-network with two variable capacitors and one variable inductor. I gave it a try and was impressed with how easy it was to tune using the SWR meter of the IC-705. This thing is simple and it works.
The rear panel of the tuner has two SO-239 connectors, one for the transceiver and one for the antenna. I put a BNC adapter onto the transceiver port and used a short BNC cable to connect to the IC-705.
The Travel Tuner is compact and not very heavy, so it works out well for backpack portable use. It can handle up to 150 watts, which is overkill for the IC-705 but it may come in handy when used with a higher power transceiver. Still, I am on the lookout for an even more compact (probably lower power) manual antenna tuner.
We have collected a variety of HF antennas, focused mostly on 20 meters and higher. These are typically end-fed, including single-band half-wave designs as well as multiband random-length antennas. These are used in the classic SOTA configuration with one end of the wire supported by a lightweight fishing pole and the coax connection on the ground, fed by a 25-foot length of RG-8X coaxial cable.
With the popularity of FT8 on the HF bands as well as 6 meters, I figured we should include that mode in our portable kit. My first thought was to use a compact Windows computer running the standard WSJT-X software. Ultimately, I chose the SDR Control app for the Apple iPad (by Marcus/DL8MRE), which supports specific Icom radios. The iPad connects to the IC-705 via its WiFi connection, which simplifies the connection/cabling challenge. The SDR Control app does cost $49.99, so it is not your inexpensive iOS app but I have found it to be worth the price. Because this app is focused only on iOS and certain Icom radios, it is well-tuned to be a no-fuss solution. I am currently using the app only for FT8 but it has other features and modes for me to explore.
The Powerwerx PWRbox is shown in the photo above, which we often use for operating POTA. (This box is a bit heavy for hiking.) The PWRbox holds a 20 Ah battery as described here. Also shown in the photo is a handy little stand for the IC-705, the NEEWER Folding Z Flex Tilt Head. It does a great job of holding and stabilizing the radio at a variety of angles. (Hat tip to Kyle/KD0TRD.) It is also a little heavy for backpack portable, so it usually gets left behind on a hike.
For a protective case for the IC-705, we use the Maxpedition 12-Inch X 5-Inch Bottle Holder. I’ve seen other IC-705 users recommend it and OH8STN mentioned it on his blog. At first glance, the case seems a bit large but this provides enough room inside to stow a small Bioenno battery and other accessories. The side pouch is a good place for storing the microphone and power cord.
This post shares some new equipment configurations we are using for SOTA and POTA, mostly focused on the IC-705. I really like that radio for portable ops as it is the best solution for operating HF through UHF. The SDR Control software on an iPad has also turned out to be a win for us.
What are you using for your portable station?
Do you have any tips or other operating ideas?
73 Bob K0NR