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 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.
I’ve been in touch with Steve (WG0AT) recently. He happened to be selling his FT-817 at the same time I was looking for a narrow CW filter. The stars aligned and I now have a 500 Hz Collins CW filter in my FT-817ND. Thanks, Steve!
Steve also took delivery of his Icom IC-705 recently so we’ve been trading notes about this fine rig. He and I both have a fear of the ‘705 falling off our laps when using it in the field for SOTA and POTA activations.
Steve, being the king of ham radio customization, started working on a portable desk. He shared iterations along the way and his final product seen in the photo above.
The desk is a brilliant design: it’s lightweight, sturdy, has holes for managing wires/cables, a strap to hold it your leg, and even a cup holder. The cup holder is a bit of genius because he likes a good cuppa tea in the field just like I like a good cuppa joe.
The IC-705 will be able to bolt directly to the lap desk so there’ll be no fear of it falling off a cliff in the field.
Of course, the desk will work with any field-portable radio. Steve shared a few more photos:
I’m going to attempt to build a similar desk for my IC-705. The great thing about it is it’ll easily fit in a backpack, too.
Thanks again for letting me share your photos, Steve! We look forward to seeing this desk in action at a summit near you!
On Tuesday (Nov 17, 2020), I decided to activate South Mountains State Park (K-2753) for the Parks On The Air (POTA) program. As with my activation at Lake James the day before, it was impromptu. Basically, the weather was beautiful, so I couldn’t resist.
In fact, the weather was so nice, on my way to South Mountains I passed by Bakers Mountain County Park and hiked their full trail including the summit. While on that hike, I ran into Kenneth (W4KAC) who had just activated Bakers Mountain for Summits On The Air (SOTA). This was a bit of serendipity because I, too, plan to activate Baker’s Mountain for SOTA and Kenneth provided some great details for finding the summit (which is not actually on the park grounds). It was great running into a fellow QRPer and talking shop, too! I hope to meet Kenneth again in the field.
I arrived at South Mountains State Park mid-afternoon and set up near one of their large covered picnic shelters.
Although I’ve activated South Mountains State Game Land numerous times in the past, I’ve never activated the actual park. The last time I popped by the park, there was already another ham there in the middle of an activation, so I moved to the adjoining game land that day.
South Mountains State Park is a very popular park–indeed, it’s currently the second most activated park in North Carolina. Although I didn’t realize it at the time because I had no internet access, there was actually another operator somewhere at the park on the air at the same time I was.
Once again, I set up the Chameleon CHA MPAS Lite vertical antenna for this quick activation.
Besides being such a quick and easy antenna to deploy, I love how stealthy it is, essentially disappearing against a background of trees.
As you might imagine, activating a park while someone else is also activating it is not ideal. At the time, I couldn’t figure out why contacts were coming in so slowly, but no doubt many hunters probably thought they’d already worked me because they worked the other activator.
In the end, though, my biggest problem at South Mountains was the fact my battery died in the Elecraft T1 ATU after finding a match on the 20 meter band. A 9 volt battery should last months in the T1, but the battery I put in it several weeks ago had already been used in another device for a few months. I had meant to replace it with a fresh cell. I actually packed a new 9V battery in my main radio pack, but I didn’t have it with me on this trip because both South Mountains and Lake James were unplanned activations.
I spent a good half an hour on the 20 and 30 meter bands where I had a decent match, but only logged three or four hunters. Conditions were not ideal on the higher bands.
I really needed to move down to the 40 meter band knowing it would be more productive, but I had no way to find a match for the IC-705. (Lesson learned: I’ll never again leave home without my Emtech ZM-2 as a backup!).
Fortunately, I remembered I had the Elecraft KX1 field kit. The KX1 now permanently lives in my car so I know I always have a complete radio kit for impromptu field activations.
The KX1 has a built in ATU, but it’s not as robust and versatile as the T1 or the internal ATUs in the KX2 or KX3.
I tried loading 40 meters and got a 2.5:1 match. I’m sure the KX1 would have plugged along, but I don’t like pushing much over 2:1 when I don’t have to.
After tinkering with the CHA MPAS Lite counterpoise for ten minutes, I finally found a length that, if half suspended, allowed the KX1’s internal tuner to achieve a 1.9:1 match. Good enough!
I started calling CQ on 40 meters and within a few minutes, I logged a total of 12 contacts.
The KX1 saved my bacon that Tuesday!
All in all, I really enjoyed the time at South Mountains State Park. It was beautiful weather and I had an idea spot to set up and operate. I’ll certainly come back here in the future.
I’ve also decided that I’m going to start packing a resonant antenna option in the car with my KX1 field kit. It’s only this year that I started using multi-band and random wire antennas that require an ATU; they are mighty convenient indeed, but it’s always nice to have a resonant option on hand as well.
Monday (November 16, 2020), I made a detour to the Catawba River access of Lake James State Park (K-2739) to try a late morning POTA activation.
I didn’t plot this activation in advance, so had to work with what I had in the trunk/boot of the car.
I did a quick inventory and found my Chameleon CHA MPAS Lite vertical antenna packed and ready to deploy. (I always have an antenna tucked away in the car because…well, because!)
In terms of radios, I had the Icom IC-705 and Elecraft T1 antenna tuner packed as well. Woo hoo! A perfect combo! Let’s go!
It was blustery and cold Monday morning due to a front that moved through during the night, so it was no surprise that the picnic area was completely void of (sane) people.
I found a picnic table on the bank that was relatively sheltered from some of the stronger gusts moving across the river. It was still quite windy, though, so I propped the MPAS Lite field pack on the table to provide a bit of a wind break for my log book.
Setup was quick. I don’t think I needed more than 4-5 minutes to have the CHA MPAS Lite deployed. This is one of the advantages of field portable verticals. The disadvantage? Verticals aren’t the most effective antennas in this part of North Carolina where ground conductivity is so poor. Still…I knew I could at least grab my ten needed contacts to have a valid POTA activation.
On the air
I won’t lie: it was slow-going.
For one thing, it was 11:00 local on a Monday morning–not exactly a prime time for a park activation.
I first tried making some SSB contacts on 40 meters and spotted myself on the POTA network. I managed to log 5 hunters in 30 minutes. With patience and time, no doubt, I could log ten SSB contacts, but I didn’t have time to wait, so I moved over to CW.
Oddly, the higher HF bands were in better shape than 40 meters that morning. One of my first contacts was NL7V in Alaska on 20 meters. A most impressive contact with 10 watts into a vertical.
I was on the air a full hour and did manage to log a total of 10 contacts. I’m certain if I would have deployed a wire antenna I would have had even better luck. Indeed, had I thought about it in advance, I could have actually deployed the MPAS Lite as a random wire antenna. (Doh!) That’s one of the great things about this antenna system is that it can be configured so many different ways. Next time…
Still…I thoroughly enjoyed my time at Lake James State Park. I’ll make this detour again in the near future.
The Icom IC-705 continues to prove its worth as a superb little POTA transceiver!
I typically pair my IC-705 with a 6 aH Bioenno LiFEPo battery pack (the blue battery between the transceiver and tuner above).
Many thanks for QRPer reader, Ron, who writes:
Dear Thomas, thank you for the great videos and information on POTA and QRP work. I’m very inspired.
Thomas, I received an Icom 705 recently and I was wondering about power. In your videos, is your battery 12 volts? This works okay? I wonder because of the 13.8 volt requirement in the manual.
Thank you for your time. I’ve already picked out a park that I will try to activate one day when I’m up to speed on POTA. 72 Ron
Thanks for your question, Ron. I’m very happy to hear you find the videos useful.
I almost exclusively use Bioenno LiFePo 12V batteries which actually output closer to 13-13.5 volts in use and can even briefly be a bit higher immediately after charging.
Most amateur radio transceivers (including the IC-705) typically have a bit of voltage flexibility and will operate a below 12 volts and tad higher than 13.8 volts. QRP radios especially. You’re wise, though to always check (the MTR-3B is a notable exception as it prefers a max of 12V).
In fact, I just checked the IC-705 specs and its voltage requirements are 13.8 V DC ±15% (12V – 15.87 volts). The IC-705 can actually run on much lower power because the Lithium Ion pack that is supplied with the IC-705 (BP-272) is only 7.4 VDC when charged.
On Monday (October 19, 2020) I received an inquiry from Dale (KI5ARH) only an hour or so before packing up my radio gear to activate Lake Norman State Park (K-2740).
Dale is interested in using his recently acquired Icom IC-705 to get involved with Parks On The Air (POTA) and play radio in the field.
What’s in my field kit
Dale was curious about all of the components of the field kit I use with the IC-705, so I made this video:
Since I had already set up my phone to record the video above, I decided to make a couple more.
I thought there might be some value in making real-time videos showing what it’s like operating CW and SSB during a POTA activation. The videos have no edits and haven’t been trimmed. It’s as if the viewer were there at the activation sitting next to me at the picnic table.
Operating CW with the IC-705
After setting up my station, I first started on the 40M band in CW. I meant to start the camera rolling during tune-up, but forgot to hit record. The video begins after I’d made a few CW contacts, but shows what it’s like changing bands and relying on the Reverse Beacon Network (RBN) to pick me up then the POTA website to auto spot me.
Note: to be automatically spotted by the RBN, you must schedule your activation via the POTA website in advance, or have been already spotted by yourself or someone else, so the system will know to look for you.
My video cut off abruptly due to a low battery message. I had to give my iPhone a quick power charge to make the next video.
Operating SSB with the IC-705
After operating CW for a while, I plugged in the hand mic that ships with the IC-705 for a little SSB action. My main goal with this video was to show how I call CQ and use the voice keyer memories in order to manage the field “work flow” process. I also speak to how important it is to either self-spot or have a friend spot you to the POTA network while operating phone.
I spent so much time setting up and running the camera, I wasn’t actually on the air for very long, but I easily managed to achieve a valid activation and had a lot of fun in the process.
I’m not a pro “YouTuber” as I say in one of my videos. I much prefer blogging my experiences rather than “vlogging,” I suppose.
Still, I think I’ll do a few more “real-time” videos of POTA activations and speak to the various techniques I use to activate parks. Since these videos aren’t edited for time, they may not appeal to the seasoned POTA activator or QRPer–that’s okay, though. My goal is primarily to assist first-time POTA activators.
Have you been activating Parks or Summits lately? Do you have any advice or suggestions I failed to mention? Or do you have suggestions for future topics? Please comment!
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.
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.
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!
While visiting my parents this week in the Piedmont of North Carolina, I took some time Monday afternoon to take the new Icom IC-705 to field and activate Lake Norman State Park (K-2740) for the Parks On The Air (POTA) program.
So far, most of my time with the IC-705 has been in CW mode but a number of my readers have been asking about SSB operation and performance.
My goal for this park activation was to give the IC-705 a proper shake-out on SSB.
Set-up
The activation was very much impromptu–I only decided I could fit it into my day an hour before my start time. In addition, while it wasn’t raining per se, there was a very heavy mist/fog that, at times, felt like a light sprinkle/drizzle.
I packed and planned on using my IC-705, mAT-705 external ATU, and Vibroplex End-Fedz EFT-MTR wire antenna.
I had an issue with the mAT-705 ATU (read more here), so opted for my trusty and incredibly capable Emtech ZM-2.
I did begin the activation in CW and quickly racked up a dozen or more contacts in short order after spotting myself. One of the great things about Lake Norman State Park is it’s one of the few locations I activate these days with proper cell phone coverage for mobile internet so that I can update my own activation spots on the POTA site.
I also moved up to 20 meters and switched over to my recently (re)acquired Elecraft KX1 (FYI, I named her “Ruby” so no way will I sell her again).
I quickly snagged two states (Iowa and Kansas) with 1 watt of power from the KX1’s internal AA cells, then 20 meters fell silent, so I moved to 30 meters to work a few more stations.
SSB on 40 meters
I then moved to the 40 meter band and decided to record a quick video after spotting myself on 7197 kHz. I wasn’t expecting such a productive mini pile-up.
As you can tell from the video, I had my hands full trying to hold my phone/camera, log, and manage the hand mic. Note, too, I prefer not hooking up the speaker portion of the microphone because audio from the IC-705 internal speaker is far superior:
I operated SSB for a good 30 or so minutes and was busy with contacts thanks to all of those excellent POTA hunters.
IC-705 Voice Memory Keyer
Before packing up, I remembered that my buddy Dave had asked me to make a video showing how I use the IC-705’s voice memory keyer, so I moved up to 20 meters (which you’ll see was pretty much dead) and recorded this.
Doh! I had the SSB position in LSB instead of USB! Thanks to one of my YouTube viewers who noticed this. I had been tinkering with mode settings earlier while evaluating the rig. No worries, though, this was more a demo of the memory keyer–check out SSB operation in the video above.
I was actually very relieved 20 meters was dead because I’m terrible at managing a camera, a tablet, and a microphone all at once!
The Icom IC-705 is an SSB champ
Photo taken at South Mountain Game Land last week.
Despite the fact that I was using the default microphone settings and had not even touched the TX EQ or compression, I received no less than three unsolicited compliments about my audio during this activation. That is probably a personal record.
No doubt, the IC-705 is a very capable rig for QRP SSB where audio quality is essential.
On top of that, the eight voice keyer memories are incredibly useful when activating a park, a summit, or even running a contest where you could truly automate your exchanges.
Have you been using the IC-705 in the field? What are your thoughts? Do you have any questions? Please feel free to comment!
UPDATE: Mat-Tuner released the latest updated and upgraded version of the mAT-705 in December 2020. It’s called the mAT-705Plus. Click here to read my initial review of the mAT-705Plus. Note that the following article pertains to the original mAT-705 which is no no longer being produced, but still available for sale (at time of posting) both new and used.
My initial assessment was very positive, but since then the shine has worn off. I’ll explain…
On Monday, I took the IC-705 and mAT-705 to the field for a little Parks On The Air (POTA) fun.
The Par EndFedz EFT-MTR triband (40/30/20M) antenna
Enroute to the site, I thought it would be a good test for the mAT-705 to attempt to tune the excellent EFT-MTR antenna (which is resonant on 40, 30, and 20 meters) on all bands above 40 meters.
After arriving on site, I very quickly deployed the EFT-MTR antenna using my throw line. I then hooked the EFT-MTR up to the mAT-705 ATU and connected the ATU to the IC-705.
After turning on the IC-705, I opened the menu screen and tried to engage the mAT-705 ATU. Unfortunately, the ‘705 didn’t recognize the tuner. I double-checked to make sure the control cable to the mAT-705 was secure–it was. After some head-scratching, I realized I must have left the ATU’s mechanical power switch in the “on” position while using it a few days prior.
This evidently depleted the mAT-705’s internal 9V battery. What a bummer!
I bragged about the mAT-705 in a previous post because, frankly, it is a very capable ATU–quickly finding matches from 160 to 6 meters on my random wire field antenna and horizontal loop antenna at home. It also has an incredibly sturdy aluminum enclosure. It’s a very capable ATU in terms of quickly and efficiently finding matches and, superficially smacks of superb build quality.
Issues
But if I’m being honest, my love affaire with the mAT-705 ended Monday due to a number of discoveries.
9 volt batteries
The mAT-705 next to the IC-705
According to Mat-Tuner’s product description, the mAT-705:
“[I]s powered by an internal standard 9 volt alkaline battery. Power saving technology inside the tuner allows the use of the unit for months without replacement. No battery power is consumed by the unit when powered off.”
Turns out, they mean it saves power only with the mechanical power switch turned “off.”
This, in turn, means that the user must remember each time they use the mAT-705 to flip the mAT-705 mechanical switch off. If left in the “on” position by accident, even with no connection to the IC-705 and while not in use, it will deplete a 9V cell in a matter of a few days.
This is a significant issue, in my opinion, and is compounded by a few other design choices:
Complicated battery removal
There is no “easy access” to the mAT-705 battery. The user must use a supplied (standard) Allen wrench and unscrew the rear panel from the chassis.
As we mentioned in our previous post, Mat-Tuner actually has a procedure for opening the case and replacing the 9V battery in order to prevent the LED illuminators from falling out. I followed this procedure to the letter, yet the illuminators still fell out. They simply aren’t secured properly and would be very easy to lose if replacing a battery in the field.
The LED illuminators
Once open, you discover that the 9V battery’s holder is a piece of double-sided tape. Seriously:
The mAT-705’s 9V battery holder
In addition, the ATU board essentially “floats” in the chassis secured in slide-in slots. The problem is the back panel–which you pull to remove the board–is only secured to the ATU board with three wired solder points.
Even when I lay the board down carefully, gravity will bend those BNC connections.
I can’t imagine this holding up with multiple battery replacements.
No external power port
Given that battery removal will take a user at least 5 minutes, I find it a little surprising that there’s no external power port.
It would be no problem at all for me, if the 9V battery died, to simply hook the mAT-705 up to my portable DC distribution panel like I can do with other external ATUs. But since this isn’t an option, you’re simply out of luck in the field. Better carry spare 9V batteries!
Where the lack of an external power port is really an issue, though, is for mAT-705 users in the shack. If the IC-705 becomes one of your main radios, you’ll have to be very disciplined to turn it on and off each time you use it, else you’re going to be replacing a lot of 9V cells.
Command connection to the IC-705 is basic
It seems to me that if you build an antenna tuner specifically to pair with a radio via a dedicated control cable, the tuner could potentially:
derive power from the transceiver
or at least be told by the transceiver to turn completely off when not actively in use. Especially since once a match is found, it’s locked into position even if the mAT-705 has no power.
The mAT-705 can’t do either.
Is it a good ATU? Yes. But inside it could be better.
As I said above, my original review stands in terms of the mAT-705’s ability to match antennas, I think it’s brilliant.
But I can no longer recommend the mAT-705 until some of these design shortcomings are addressed.
I’ve never owned a portable ATU that required so much discipline from the user in order to preserve the battery. I’ve also never owned one that was so fragile internally. Most portable ATUs *only* turn on when finding a match and then either “sleep” or turn off when not in use.
And portable ATUs like the Elecraft T1, for example? Even have a convenient battery compartment for easy removal. (And, oh yeah, the T1 will run ages on a 9V!)
The Elecraft T1 ATU 9V battery compartment
To add insult to injury, it’s one thing to discover that your mAT-705 ATU eats 9V batteries if left on but not in use, but it’s quite something else to discover your $220 ATU’s 9V battery is held in with a piece of double-sided sticky tape.
How long could this possibly function if you’re replacing batteries frequently in the field?
My hope is that Mat-Tuner will sort out this design and re-introduce the mAT-705 to the market. I’ve heard so many positive things about other Mat-Tuner models which is why I wanted to try one out with the IC-705.
Mat-Tuner ATUs are sold by respected retailers in the ham radio world (like Vibroplex, who loaned this model for review) so I expect they’ll address these concerns in the coming months. I’ll certainly post all updates here on QRPer.
Until then, I have to recommend skipping the $220 mAT-705 and instead purchasing the excellent ($160 kit/$190 assembled) Elecraft T1.
Many thanks to Ray Novak (N9JA) at Icom America who shares photos of the Begali-05 bracket prototype that is being developed for the Icom IC-705 transceiver.
Those who already own a Begali Adventure key will soon be able to mount it on the IC-705 with the Begali-05 bracket.
Ray notes that this is still an early prototype, so the finished product might look quite a bit different.
He also noted, “The plan is for the Begali-05 to be available at Authorized Icom Amateur Dealers.”
I’m a massive fan of Begali keys. Not only do they make some of the best, highest precision keys in the world, but the Begali family are proper ham radio ambassadors. I love supporting them!
Pietro Begali (I2RTF) winner of the 2019 Hamvention Technical Achievement Award.
I’ll attempt to acquire a Belagi-05 bracket and Adventure Key for review with my IC-705. In truth, though, I’m sure it’ll work beautifully. It’ll be a Begali!
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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.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.
