If you’ve been here long, you’ve no doubt noticed that I have a sizable collection of QRP radios I take to the field.
Although I have some favorites, I try to rotate all of my radios in the field and even pair them with different antenna combinations as much as possible. If I only owned one field radio, I’d shake things up by pairing my one radio with different antennas deployed different ways during my POTA/SOTA activations.
I get a real thrill out of testing different combinations, actually, and I feel like it keeps me on my toes because I don’t get too comfortable with any one setup in the field.
No doubt, using a wide variety of radios gives me a more informed perspective when beta testing or evaluating new radio models.
That said, there is one radio in my collection that has been overlooked too many times: my Icom IC-703 Plus.
Many of you have noticed this, in fact. I’ve gotten several emails and comments asking, “So Thomas…when are you taking the 703 out again–?” 🙂
When I purchased the ‘703 from my buddy Don a couple years ago, I imagined taking it to the field very regularly. I always thought it was a cool little radio and with its built-in ATU, it’s quite compact for a tabletop-style rig.
Thing is, each time I’ve taken it to the field, I’ve had issues with the electronic keying that I did not have when using it in the shack. It’s quite sensitive to RF, so end-fed antennas seem to create unwanted dits and dashes in the keyer.
The simple fix, I hoped, was simply using an in-line common mode choke to keep the RF away from the radio. Thing is, the IC-703 has an SO-239 antenna port and two of my common mode chokes are BNC. I meant to purchase a BNC-to-PL-259 adapter at the Shelby Hamfest, but picked up the wrong item (I should have been wearing my glasses).
Then I remembered that my Chameleon 50′ RG-58C/U cable not only has an integrated in-line choke, but also PL-259 connectors. This could work!
I packed the IC-703 Plus to take on a two night trip with the idea I might do at least three activations with it. The ‘703 deserved a little outdoors time!
I first attempted to use the ‘703 at Lake James on October 5, 2022. If you watched my (very dark) activation video and read my field report you might recall that I had SWR problems.
During that activation, I thought it might be a fault of the ‘703, so hooked up my Elecraft KX1, then discovered it wasn’t the radio: it was an antenna connection. I thought at the time that the source of the problem was how the radiator was temporarily attached to the EFHW matching unit.
That may have been partially correct.
Fort Dobbs State Historic Site (K-6839)
On the following day (October 6, 2022) a window of opportunity opened in the afternoon and I was ready to give the IC-703 Plus a go again!
I drove to Fort Dobbs State Historic Site in Statesville, North Carolina.
In the past, when I’ve activated Fort Dobbs, I’ve used their excellent picnic shelter. This time, however, when I asked permission to do an activation (I always ask at historic sites like this) they told me it wouldn’t be possible because the picnic shelter would soon be occupied by a community group.
I believe they’re so used to POTA activators only using that picnic shelter site, they thought it was the only viable spot on the property. Of course, I told them “no problem” and that I didn’t want to disturb their guests.
I considered moving on to a different park, but first I asked if there was another spot where I could set up away from the group. They mentioned a picnic area under the trees which I believe gets very little use. I told them that would be ideal and they said, “go for it and have fun!” (Those Ft. Dobbs park employees are top-shelf.)
I found a perfect spot, launched my throw line into a tree, and had the MM0OPX end-fed half-wave deployed in 4 minutes. I hooked up the Chameleon coax to the antenna via an SO-239 to BNC adapter and then plugged the other end (the end with the in-line choke) directly into the IC-703 on the picnic table.
I tuned to 40 meters, found a clear frequency, and keyed down only to discover that the SWR was insanely high. The SWR meter was literally pegged!
Working the problem…again…
I was very confused by this because the previous day I discovered what I thought to be the source of the problem: the antenna radiator was barely connected to the EFHW matching unit.
Once again, I double-checked all of the connections by visually inspecting them, disconnecting them, then re-assembling the components. I even removed the radiator and re-connected it.
I tested and, again, a super high SWR.
I thought back to the previous day how it all played out…
I remembered that when I used my KX1 (thinking incorrectly that the IC-703 had a fault), I switched out the Chameleon coax with a 20 foot RG-316 line that had BNCs on both ends. While reconnecting the coax to the MM0OPX EFHW, that’s when the radiator fell off and I realized just how poorly it was attached (I’ve since soldered the connection). After stripping the radiator and making a secure connection to the antenna, I achieved a 1:1 match on 40 and 20 meters.
Could it be that the Chameleon coax or connectors were faulty? Highly unlikely. It’s a very high quality assembly, has never set out in the rain, and showed no signs of problems.
That left only one suspect and it had no alibi: the SO-239 to BNC adapter. It was the same adapter I used the previous evening at Lake James on the Chameleon coax.
I removed the adapter on that cable and replaced it with a spare I keep in my backpack.
I walked back to the ‘703, hit the key and BOOM…a 1:1 match!
Those ubiquitous BNC adapters
I should have suspected the BNC adapter sooner because this wasn’t the first time I’ve had one of those fail me in the field.
I always try to buy the highest quality components I can afford and last year I searched for a supply of BNC adapters from a quality manufacturer. I discovered it was difficult to find a supply of them that even had a manufacturer name with country of origin listed; instead, most were the same price and the quality via product images looked the same.
If you have any leads on high quality BNC adapters, I’d love your input!
- Icom IC-703 Plus
- Chameleon 50′ RG-58C/U cable
- MM0OPX QRP EFHW (Contact Colin for Availability)
- CW Morse CNC Machined Aluminum Paddle
- Spec-Ops Brand T.H.E. Pack EDC
- Bioenno 15 aH LiFePo Battery (Model BLF-1215A)
- Mini Arborist throw line kit: Tom Bihn Small Travel Tray, Marlow KF1050 Excel 2mm Throwline, and Weaver 8 or 10oz weight
- Tom Bihn Large Travel Tray
- Rite In The Rain Weatherproof Cover/Pouch (affiliate link)
- Moleskine Cahier Journal (affiliate link)
- GraphGear 0.9mm 1000 Automatic Drafting Pencil (affiliate link)
- Camera: OSMO Action Camera with Joby tripod (affiliate links)
With the SWR sorted, I did a little testing to see if the electronic keyer would behave on the IC-703 by turning down the power and calling CQ a couple of times. It performed flawlessly! It seems the in-line choke was working.
Time to start the activation!
On The Air
Fort Dobbs was closing at 17:00 (local) that day, and the time was approaching 16:00. I don’t like to push my luck and finish an activation close to closing time. I suspect doing this would park employees a little nervous that I might not be packed up and driving out of the front gate when they’re ready to check the site, lock up, and go home. I always try to finish an activation about 30 minutes prior to closing time. The last thing I ever want to do is annoy a park ranger because that could paint fellow POTA ops in a bad light.
I decided to start my activation on 20 meters and was very pleased I did.
I worked my first ten stations in 9 minutes–validating the activation in very short order!
I continued working stations on twenty meters which yielded a total of 34 logged in 34 minutes! What fun!
At this point, it was 16:20 local (20:20 UTC)–I was keeping a close eye on the time. I knew if I moved to 40 meters, I could be greeted by a lot of stations since it was in the latter part of the afternoon. I didn’t want to call QRT with a lot of hunters calling me. Instead, I used the IC-703 Plus’ internal ATU to find a match on 17 meters knowing it would be less productive.
I logged two station on 17 meters: WB5MET and W0HL. Then I called QRT right at 16:30 which gave me loads of time to pack up and thank the park rangers before driving off into the sunset.
Here’s what this activation looked like when plotted out on a QSO Map. I found it interesting how 20 meters was incredibly productive, but a little short that day. Save the contact with CT1ETE in Portugal, it was behaving more like 30 or 40 meters:
Here’s my real-time, real-life video of the entire activation. As with all of my videos, I don’t edit out any parts of the on-air activation time. In addition, I have monetization turned off on YouTube, although that doesn’t stop them from inserting ads before and after my videos.
Note that Patreon supporters can watch and even download this video 100% ad-free through Vimeo on my Patreon page:
Click here to view on YouTube.
703 + Fun
It was so much fun performing such a busy little activation with the IC-703 Plus!
I’m happy I was able to sort out the problem with the SWR and not allow that to derail the activation.
Thank you for joining me on this activation! It was heaps of fun to put the IC-703 Plus on the air again!
I hope you enjoyed the field report and my activation video as much as I enjoyed creating them.
Of course, I’d also like to send a special thanks to those of you who have been supporting the site and channel through Patreon and the Coffee Fund. While certainly not a requirement as my content will always be free, I really appreciate the support.
As I mentioned before, the Patreon platform connected to Vimeo make it possible for me to share videos that are not only 100% ad-free, but also downloadable for offline viewing. The Vimeo account also serves as a third backup for my video files.
Thank you so very much!
Cheers & 72,
25 thoughts on “POTA with the Icom IC-703 Plus: Working a serious SWR problem first, though!”
Good sleuthing, Thomas!
Thank you, OM!
These adapters can be a break point so bring back ups. I took my 703 out forPOTA on Saturday to use with my 29ft end fed with the Red LDG 9:1 balun. I got it activated on 40m with a flaky band showing very regional conditions but out of 13 contacts 1 had 9 park to parks. Nothing gets the adrenaline going like ptp as a QRP
Yessir! Actually, I always have two extra BNC adapters tucked away in my pack. If I wouldn’t have had a spare that day, it would have put a damper on my activation for sure! 🙂
That’s a fantastic P2P ration!
Very interesting read. I have used my 703+ for years but in a fixed indoor setting. Last week I decided to take it into the field. Fortunately, I had adapters as I always carry a box of adapters since I do a lot of roving microwave using various rigs for IF’s, but the one thing I forgot was a 1/4″ to 1/8″ adapter for the key. Glad I had an Kx2 for backup. All of my POTA rigs have the same connectors except the 703+. Such a great rig, but it is dated. Now I will make a kit just for the 703. Thanks for your great video’s and activations. I would like to see a comparison of various antennas in your collection.
Yes, I actually keep a 1/4 to 1/2″ plug in the IC-703 kit bag. Besides my Argonaut V, it’s my only field radio with a 1/4″ plug.
Hello. Any suggestions on a brand name bnc adapter? 73
Trouble shooting, trouble shooting, trouble shooting! Thanks! Take extra parts along. What an excellent presentation. A lesson we should all take to heart.
Thank you, John!
I got some of these recently, only used it once with a friend’s 7100. Max Gain Systems was recommended by several in my local club for quality connectors.
Excellent, thank you!
Its good to hear the 703 “came right”. I have a number of field capable radios but my 703 is the one I grab for testing of new antenna builds etc. Only yesterday I had it out in the field helping develop a rapid deployable, multi band , half wave antenna. It was of tremendous help. I have owned this rig since 2003. I was asked, by the RSGB to do a field test of a very early model. The field test was published in the October issue of Radcom ( copies of relevant pages attached). I used the 703 for the work necessary to take part in the “Battlefield Detectives” TV program discussing the Battle of Arnhem. We originally planned to use FT817s for this job but they could fit the bill, however the 703
73/72. Tom G0SBW
Oops I see .pdf files are not permitted. So I have photographed the pages of Radcom referred to above. here they are:-
If you can email me your images, I’ll post them to your comment. WordPress can be so funky about images in comments (even for me!). 🙂 You can get my email from QRZ.
Very cool. I have a 703+ on loan from my elmer and made our QSO with it from my QTH. It’s the most modern rig with bells and whistles I’ve spent time with (CAT control keeps blowing my mind, haha) and it’s a joy to use. Glad you got yours to the field.
Very cool! Yes, CAT control is an amazing thing. Been around for a long time, but so useful when you need a little remote control!
I use these short jumpers (BNC/PL259) with good success. Uxcell seems to be one of the better brands. https://tinyurl.com/55t8cepa
Thanks, Scott! Yes, I *just* took delivery of a new crimper and some supplies to build my assemblies. I’m planning to make some with a female BNC on one end and PL-259 on the other. They’re not quite as small as an adapter, but I feel like they’ll be more reliable.
since you’re at it, why don’t you build those cables as shown here ?
that way, they’ll do double duty 😀 !
Tom… while this wasn’t the case, we often go for chokes and forget about the simplest way to remedy the CMC issue, that is, a piece of wire long 1/4 wave at the desired band, this means that, for example, one may carry some pre-assembled pieces of insulated wire, one with alligator clips at both ends; at that point, just combining the pieces (of different lenghts) it won’t be difficult to setup a quarter wave counterpoise and solve the issue
Yes, a very good point from our resident antenna guru, Andrew! 🙂
A quarter wave counterpoise would certainly bleed off the RF in a very useful way.
Trick with the IC-703–at least my particular model–is that it’s exceptionally sensitive to RF. There’s a mod I need to perform–I just need to make time to do it. 🙂
Thanks as always and hope you’re doing well!
Nice job! My IC-703 (original, non-Plus) is my POTA activation rig of choice and portable rig for years. FYI I enable DSP, NR, NB and F AGC when I operate CW. I disable F AGC on SSB of course. I think I keep DSP on 4, doing from memory, I can check if you’d like. The narrow filter, good deal!
73 Kevin N2TO
Tried to activate Ft. Dobbs last Christmas when I was in the area visiting family. But it was closed for the holidays 🥲
It’s a great site, but I always need a Plan B with Dobbs. I’ve also arrived there to find a massive Revolutionary War Encampment. I had a hunch they wouldn’t want a guy there with technology from the “future”. 🙂
I purchase my connectors from QuickSilver radio. Never had a problem.