Icom IC-703
I recently acquired an Icom IC-703, a QRP rig from yesteryear that I've been seeking out for quite a long time. It came from an estate sale, and subsequently was sold as-in/not working. I didn't know much about it beyond the fact that it came in the original box. Thankfully, when it arrived I was pleasantly surprised to find that it not only worked perfectly - but that it also included the optional 250 Hz CW filter option. The CW filter is a welcome addition, since the native bandwidth of the 703 in CW and SSB modes is something over 5 khz (not exactly contest friendly!).
The 703 will be accompanying me this year to both ARRL Field Day 2026 and a summer camp I'll be volunteering at the following week. I'll be working Field Day from the car (so 1C) with the IC-703 and a 20 meter loaded whip antenna mounted on the trunk lid of my car. As I'm writing this, I just got down driving up and down the local interstate highway testing this exact setup. The Icom performed beautifully, and I made several CW and SSB contacts.
There is one issue with my 703, and it unfortunately is an issue that plagues all of these Icom rigs. That issue is their great susceptibility to EMI and common-mode currents in the RF deck. When using unbalanced antennas I find my 703 likes to malfunction both by latching the keying circuit irregularly and by over-reacting with the ALC circuit when the antenna tuner is engaged. To remedy these issues, I have bypassed the ferrite bead in-line with the key input ground pin (and I'm using a large choke in circuit with the mobile whip). While I had the radio under the knife, I also modified the circuit board to supply the driver transistor with the 8 volt rail rather than the 12 volt rail - something not required by Icom but recommended by 703 enthusiasts as this modification reduces the risk of premature driver failure without a reduction in stage gain or total output power.
I also found that the driver bias potentiometer was set incorrectly. eBay radios often need a once-over with the service manual like this, the 703 wasn't my first "as-is / no returns" purchase and rule #1 will always be to open the chassis before applying power. I have plenty of radios that outperform the 703 on paper, but in actual use it has one of the most sensitive receivers in my shack. What it does well in this category is arguably balanced by what it lacks in selectivity without the optional filter, but I digress. The built-in antenna tuner may not be the most versatile, but for matching the occasional random-wire or tuning up a slight change in SWR, it does fine and is very quick. I often find myself wishing a small built-in tuner like this was something that Yaesu would have incorporated in their FT-891. Oh well!
I'll try and do a write-up of my mobile Field Day experience, and I'll definitely be playing a bit of radio while I'm up at camp. Perhaps I can use my L-match tuner to key up the zip-line as a long wire? :)
2026-06-20