Many thanks to Curt (WU3U) who recently contacted me and mentioned he had built an IC-705 control interface for his Elecraft T1 ATU. This is a homebrew project based on others’ work and uses the FT-817 control port on the side of the T1 tuner.

I asked Curt if he could share a little more about his tuner to post here on QRPer:

Hi Thomas, I can’t take credit for the interface, as a guy in Japan designed it. When I built mine the entire instructions and notes for code for the PIC controller were in Japanese. I used Google translate to translate all of the information and I was able to successfully program the PIC chip and build the circuit. He has since released the details and code in English.

There are two designs: one with an on/off switch, and a newer version without an on/off switch that has auto power save. Both circuits are the same but the software for the PIC chip is different. If you build the one without the on/off switch there is a very specific sequence of connecting and disconnecting the device and it’s my opinion that the one with the on/off switch is the version that makes more sense to build. It shouldn’t matter which order you connect everything up and you simply throw the on/off switch to turn the device on and off.

Building the interface takes an understanding of a fairly simple electronic schematic and acquiring the parts. You also have to have a PIC programmer and the software to write his .hex file into the PIC controller chip.

The parts for the interface are all very common parts. The resistors are standard values. My build cost me about $30 in parts but I had to buy many of them in bulk from Amazon like the enclosures, switches and 3.5mm jacks and circuit boards to name a few. Individually the parts were $30 but my bulk order cost me much more. I also had to buy a PIC programmer for $25 and figure out what software I needed to download to program the PIC chip with the author’s code. It takes an experienced builder about two hours to build the device but it’s not out of the realm of a semi-novice as long as they can get the PIC chip programmed.

Here is the original code using the on/off switch. Everything is now in English:
https://amateur-radio.cocolog-nifty.com/blog/2020/11/post-1eb3cf.html

Here is his newer version with the same circuit design eliminating the on/off switch by using a different PIC program allowing the interface to have auto power shutdown (low power standby) but there is a specific order for connecting and disconnecting the interface. With this version there is still drain on the battery but the designer thinks that drain is less than the normal self discharge of the battery. I feel that any discharge combined with the self discharge of the battery will be more discharge than using the design with the on/off switch.
https://amateur-radio.cocolog-nifty.com/blog/2020/11/post-591d17.html

Video

I think this is a brilliant project and certainly one worth considering for those of us who already own an Elecraft T1 ATU and would like full control from the IC-705.

Thank you for sharing these details, Curt!

On Wednesday, October, 14 2020, the weather was gorgeous so I decided to make an impromptu POTA activation of Pisgah National Forest and the Pisgah Game Land (K-4510 and K-6937). These sites are the closest to my QTH and only a 15 minute drive (in fact, I can even hike up to the same trail network from my back yard).

My canine companion, Hazel, jumped into the car before I could even invite her to come along.

We drove to the trailhead, parked, and hiked a short distance into one of my favorite spots where it’s relatively flat, with lots of tall trees and almost no foot traffic from other hikers.

This activation gave me an opportunity to use the Icom IC-705 in more of a “backpack” setting since I hiked in with only my pack, Hazel, and my folding three-leg stool. Up to this point, I’d only used the IC-705 on picnic tables and flat surfaces since it can’t easily fit on my clip board like my MTR-3B, KX2, and KX1 can.

The activation also gave me a chance to evaluate a new product sent to me by the CW Morse company: their “Pocket Paddle” designed specifically for portable operations.

After reaching the site, I easily deployed the EFT-MTR antenna using my arborist throw line.

I decided to set up the Icom IC-705 much like I did the lab599 Discover TX-500 when I took it on hikes: mount the radio above the front pocket of my Red Oxx C-Ruck backpack.

The arrangement works quite well–I simply sit on the stool in front of the pack and hold my simple logging notepad and paddles on a clipboard.

While this particular site is great because it’s so accessible to me, the negative is it’s deep down in a valley surrounded by high ridge lines. I feel like this does have some impact on how well my signal travels.

Wednesday, it took nearly 50 minutes to rack up a total of 12 contacts in CW mode. I never bothered with SSB/phone because this site had no cell phone service and, thus, there was no way to spot myself on the POTA network.

That’s okay, I felt pretty chuffed about racking up 12 contacts with 5 watts and a wire! This is what field radio is all about, in my opinion.

Loving the Elecraft T1

The Elecraft T1 ATU pairs beautifully with the Icom IC-705.

After a little falling out with the mAT-705, I decided I wanted to try other ATUs with the IC-705. I used to own an Elecraft T1 ATU and loved it, but I eventually sold it for a song to a friend since all of my field rigs at that point had internal ATUs.

I reached out to Elecraft and they sent me a T1 on loan to give it a go. I’d forgotten how much I love this simple, effective ATU.

Even though the EFT-MTR is resonant on 40, 30, and 20 meters, moving to the 30 meter band requires lowering the antenna, pulling off an SMA cap on the coil, then re-hanging it. Not a big deal at all, really, but it’s so much easier to simply press the tune button on the T1 and have it match 30 meters without going through the normal process.

CW Morse Pocket Paddle

I also thoroughly enjoyed using the CW Morse “Pocket Paddles.” I’m not sure when they’ll be available to purchase (perhaps they are already?) but I can highly recommend them.

The paddle action is field-adjustable and even though there’s an Allen wrench built into the paddle base, the machined screws are easy to twist by hand.

They feel very sturdy, too, much like the other CW Morse paddles and keys I’ve used.

I believe the Pocket Paddles are going to permanently pack with my IC-705!