14 April 2024

MARS Modding the IC-705

Yesterday I decided it was time to do the MARS mod - wide-band  HF transmit modification - to my IC-705. There was nothing special about yesterday, other than the fact that I finally screwed up the courage to open up the little radio and git 'er done!

I like to do the MARS mod on as many of my HF radios as possible. I'm a MARS and SHARES operator, and doing the mod gives me the knowledge that I can use this very expensive and capable radio outside of the ham bands. I've done MARS mods on the IC-7100, 7200 and 7300, Yaesu FT-891, the 991 and the Elecraft KX2. The process differs from manufacturer to manufacturer. Icom's process is the most destructive - you have to carefully remove very small diode(s) from one of the boards in the radio. Yaesu's is the least destructive - you create a solder bridge across one or more open pads on one of the boards. Elecraft's is the most elegant - you simply do a firmware update. 

There are several good on-line resources for IC-705 mod. Of course you won't find anything official from Icom on the subject, but it doesn't take long for the info for any radio, from any reputable manufacturer, leak out. So it was with the IC-705. Within a few months of release, word was already circulating on how to do the modification.

Before going further, I need to say this - if  you want a MARS modified radio your best and safest bet is to buy a new one from the major distributors like HRO or GigaParts. They are authorized by the manufacturers to do the mods, have all the technical data, equipment and experienced personnel to do the job, and your radio retains the original manufacturers warranty. Yes, you'll pay extra, but it is the safest route to take if you want a new ham radio with this modification. I only do this mod on radios that are out of warranty, and I do it only on radios I own - I don't do this as a service for others. 

OK, back to the resources. There are several videos on YouTube showing how to do the mod. All follow the same steps, but in each the mod is done with varying levels of expertise. In one or two I'm surprised the radio survived the surgery. The best video I've found, and the one I watched several times before doing my mod, is the one put together by TRX Lab:

There are also modification instruction sheets posted to the mods.dk website. Mods.dk is a paid subscription website, but they do allow the download of one document per day to those who are not paid members. If you go there, look for the document dated 26 March 2023.

The mod involves removing one very, very small surface mount diode from a portion of the main board that is very crowded. This implies finesse, and the right tools. Of course you'll need heat. Most use a soldering iron. However, I've invested in a quality hot air station specifically designed for electronics use. The model I bought is the Quick 861DW. The Quick is considered a basic 'pro' unit, but it gets generally excellent reviews from people I trust. Honestly, I don't even look at my soldering iron when doing this kind of work. The hot air station is a much better tool.

All the other tools are pretty run-of-the-mill for electronics hobbyists:

  • screwdrivers (I use JIS standard screwdrivers when working on Japanese manufactured gear)
  • forceps and tweezers 
  • heat resistant tape (for masking components on the board)
  • static-safe prying and opening tools (commonly called spudgers)
  • wrist grounding strap
  • static free work surface
Magnification is your best friend. I don't care how good your eyesight it, unless you are the Six Million Dollar Man with bionic vision, you are going to need lots of magnification. The diode that needs to be removed is about the size of a speck of ground pepper! I use a combination of a swing-arm LED lamp with a built-in magnifier and an OptiVisor headband magnifier with a separate magnifying loupe and LED illumination. Often it requires using all of these in conjunction to properly see the board components I'm working on

So let's get to the radio. The radio comes apart like a bit of a puzzle box, but overall it's not too bad. Honestly, one of the biggest pains was getting the six screws out that hold the two halves of the radio together. Everything is tight, and two of the screws are, I suspect, set with thread locking compound. They were a PITA to get out, even with the correct JIS screwdriver, and I buggered a few of them up. But once the radio is open, it's pretty straight forward. You have to remove the front panel and the two connecting ribbons, the sheet metal RF shield and another smaller ribbon connector (at the bottom in the photo below). There are two small antenna cables to disconnect. Once everything is unscrewed and disconnected, wiggle the main board out and rotate it so the bottom of the board is facing up. 

The front panel removed and flipped face down (note the speaker in the lower left corner of the panel).
The main board is underneath the RF shield. It has to be removed and flipped over to
access the diode that needs to be removed. This requires disconnecting the two large ribbon cables,
the smaller ribbon cable at the bottom, the RF shield, and then disconnecting two small antenna
cables (underneath the shield). After that the main board can be removed and flipped over

Here are the two black and gray antenna wires on the main board that have to be removed before the main board can be taken out and flipped over. One is the HF connection, the other is the VHF/UHF connection. Not sure which is which.


Here's the main board removed and flipped over. The diode to be removed is in that 'field' of diodes at the bottom center of the board (outlined in yellow). Luckily the diode in a good location at the bottom left corner of the field. (Sorry for the fuzzy quality of the image, I think the camera was stuck on macro mode.)


According to the instructions downloaded from mods.dk, on US versions of the IC-705 only the diode in the lower left corner needs to be removed (circled in yellow below). Other sources say a diode on the second row also needs to be removed (circled in white). However, this diode seems to be related to 60 meter capability, and since the US version of the 705 already has 60 meter capability (enabled in firmware?), I decided to leave it in place. If future testing reveals this second diode does need to come out, I'll tackle that later.


The next step is to apply heat resistant (Kapton) tape to mask out just the diode that needs to be removed (circled in yellow, below), and protect surrounding components. It's even important to mask open component pads, to avoid melting the solder on the pads and accidentally creating a solder bridge.


Next comes the steady hands part. Apply heat from the hot air station to the diode for just a few seconds, grab it with a set of tweezers, and it should lift right off the board, leaving an open pad that doesn't need any clean-up. Some sources say you should add extra lead solder and flux to each end of the diode pad, to lower the melt temperature of the lead-free solder Icom uses when it builds the boards, but I don't find that necessary if I properly mask out the component using the heat resistant tape. 

Gone, gone, gone...

Once the diode is off the board and you've checked the pad to make sure everything is clean, the only thing left to do is put it all back together and test. The 705 goes back together in reverse order, with a little wiggling to make sure all the ribbon cables are routed properly.


Once that's done, test on various ham and non-ham frequencies (into a dummy load, of course) to ensure the radio does in fact transmit outside of the ham bands and at the correct power levels. Everything looks good!


In all, the process was easier than I thought it would be. The little rig really isn't that hard to open up and navigate around in. Just take the usual precautions - use an anti-static wrist band, work on an anti-static work surface, use the appropriate tools, and you should be all right. Oh, and take lots of pictures to document your process in case you forget what board, ribbon cable or screw goes where.

The radio is a very neat, trim and compact design on the inside. Hey, it's an Icom, right? It's also a very rugged build; everything inside the case is very well secured - literally screwed down tight. There's no wasted space and nothing is flopping around in there. It's a brick. Honestly, with everything so tightly packed in and with no airflow it's a wonder these radios run as cool as they do. 

So that's it! If you have any questions or comments please post them below or contact me at w8byh@arrl.net, and I'll be happy to respond.

W8BYH out

24 March 2024

The Acceptance Phase

Over the years I've posted here a few times about my adventures with my Elecraft KX2. Recently I wrote about upgrading it with the new Elecraft KXIBC2 board, which allows charging of the lithium-ion battery while still installed in the radio. I've also sung its praises here and on other forms for it's excellent design, modularity, maintainability, manufacturer support and world-class performance on SSB. 

What I've had to finally come to accept, though, is that the KX2's is a lousy digital mode performer. 

I so desperately want this little rig to run things like Winlink and JS8CALL, but I've struggled on-and-off for two years to get it working correctly, with no real success. Lord knows, I've put a few dozen hours into the effort, and have bought no end of USB sound card dongles, Digirig interfaces, cables and assorted bits 'n bobs. All to no end. My last attempt was a few days ago, when a JS8CALL session on three different bands netted only two very weak beacon reports. OK, I was getting out, but not well, and I have no idea why.

I'm no digital mode dummy. The list of radios I've run Winlink, JS8CALL, VarAC, Fldigi, MS-DMT and other digital modes on is extensive. Probably close to a dozen different models across all manufacturers, some with internal sound card interfaces, some requiring external sound card setups like the Signalink. The KX2 is, hands down, the most difficult radio I've ever dealt with on digital modes.

"No Winlink for you!"

This isn't a tragedy, merely an inconvenience. I've got other QRP rigs that do just fine on digital modes, like the Icom IC-705. It's just disappointing that an otherwise great little rig is a stinker on digital. Going forward it'll be relegated to SSB only, and in that use it's at the top of the heap. It's such a cracking good little radio that it'll stay on my 'do not sell' list, along with my Yaesu FT-818 (which, by the way, runs digital modes without breaking a sweat). One of the reasons is that the KX2 has had the MARS mod done to it, and I've actually used it to check into both MARS and SHARES nets. It's usefulness as a sideband rig is beyond measure.

So if anyone out there has a KX2 (or KX3) and runs it successfully on digital modes, I'd desperately love to talk with you. Drop me a line.

Until then, I'm screwing up the courage to do the MARS mod on my IC-705.

W8BYH out

13 March 2024

Thinking Outside The Box

Pet peeve time.

Ham radio is in love with the go-box. You can't attend a hamfest or club meeting without seeing presentations on, or hearing discussions about, go-boxes; what goes in them, how they are built, how to power them, how to connect to them, etc. Suffice to say, ham radio is go-box batty. Proof? Just Google 'ham radio go box'. 

The go-box concept is good, but it can be limiting in both capabilities and scope. Just the mindset that all your capability has to fit into a single box, and if it doesn't fit, then you don't need it, is a silly way to approach a problem. 

I haven't seen too many go-boxes that were built to meet a specific mission or requirement. For example, I once asked a person demonstrating his go-box why he included a VHF packet modem. He admitted there wasn't a clear need for it - it was there 'just in case'. This in a region that hasn't seen any public service related packet activity for over 15 years.

I don't want to disparage the concept of the go-box, but the 'box' mentality and the lack of a requirements-based approach seems to lead to a lot of implementations that look like solutions in search of a problem.

Let's think beyond the go-box and instead think about the concept of a mission-focused communications hub or, as we used to call them in the Army, a 'comms center'. A comms center is just a place - a table, a room, a shelter, a tent. Heck, it can be the tailgate of a pickup truck. But it is the place at which you build out a communications hub in support of an event or incident, and build it out tailored to the mission requirements.

A comm center can be anywhere, even in a sandbagged bunker

I use the term 'mission focus' a lot, and it really is the key to the comms center concept. You build capability to meet a specified mission. Let's use a county-level ARES group as an example. Do a mission analysis and ask yourself (and your EMA) these questions: 

  • What are your served agencies? 
  • What are the missions of these served agencies? 
  • What communications capabilities do they need to meet their missions? 
  • What are their organic communications capabilities?  
  • What are they lacking? 
The answer to 'What are they lacking?' is what should drive your mission focus. Once you identify and understand that gap, and build capabilities to close it, you are on the path to establishing a formal comms center.

The comms center concept is also fluid. In the Army, I've been in situations where the comms center started out as just a single VHF radio mounted in a truck, a map board and a message log. Over time it morphed into a dedicated shelter with multi-channel voice and digital HF and VHF capabilities, a landline switchboard and a SATCOM link. What all this gear wasn't, was stuffed into a single box. That was impractical and unwieldly; each communications system required more elbow room than a boxed enclosure could offer.

Far-fetched for a civilian operation? Not at all. With growing reliance on systems like Winlink and other HF-based digital tools like JS8CALL, Fldigi, VarAC, and use of internet-linked VHF voice and data modes like DSTAR, C4FM, DMR and Echolink, the technology stack in a civilian comms center can easily match that found in military units. And let's not forget the vulnerability of terrestrial-based internet. There's a reason a Starlink package is a standard part of many civilian communications centers.

But a comms center isn't really about comms equipment. The job of the comms center is moving information, and the synchronization of communications across systems, agencies and departments. With this in mind, a comms center's key functions include:

  • Establishing and maintaining communications support as directed by the event director, incident commander or incident communications leader
  • Maintaining the event/incident radio log
  • Conducting an overall 'radio watch'; ensuring all comms systems are up, operating and proactively monitored
  • Interfacing communications systems. For example, establishing radio-wire interfaces, making sure information received via radio is 'hopped' to the appropriate systems like WebEOC, internal chat systems, status boards, etc.
  • On-boarding new personnel, departments or agencies that show up to support the incident, making sure their organic communications systems are integrated into the communications architecture
  • Radio set-up and programming
  • Troubleshooting communications issues
So... while a go-box can serve as a component of a comms center, it should never be considered an all-encompassing solution. For this reason I'm not a big fan of the 'box' solution. It seems to impose conceptual restrictions, trying to force the mission requirements to fit the box, not the other way around.

So let's stop focusing on go-boxes and instead focus on flexible, mission focused comms centers. Start thinking outside the box.

W8BYH out

03 March 2024

A Small KX2 Upgrade

I continue to be impressed by Elecraft and their long-term support for products that other manufacturers would consider 'end-of-life' and not worth investing time or effort on. Case in point is the KX2, introduced in 2016. While eight years isn't really that long for an amateur radio to be in production, it is unusual for a radio to see firmware improvements and factory hardware upgrades this far into its production life. Yet 'obsolete' and 'end of life' don't seem to be in the Elecraft vocabulary; they continue to provide support for rigs that have been out of production for years. There are no orphans in the Elecraft line-up.

Case in point with the KX2 is the recent release of the KXIBC2 internal battery charger board. The KXIBC2 replaces the internal clock board and adds the ability to charge a factory Li-ion battery inside the rig and provides a real-time clock. This is a big improvement, and addresses one of the major complaints many have of the KX2. As designed, the battery pack had to be charged outside of the rig - open the radio and remove the battery, plug it into a charger, when fully charged re-install it in the radio. Elecraft originally designed the radio this way because back in 2015, when the design was finalized, Li-ion charging technology wasn't what it is today, and Elecraft thought it was smarter and safer to require charging outside the radio. Nine years on, Elecraft figured out a power management system that allows the Li-ion pack to be charged safely while inside the radio. The KXIBC2 board is available as a factory option, or a user installed kit.

The kit arrived a week ago, and yesterday I decided it was time to dive in and do the upgrade. In typical Elecraft fashion, the installation instructions are well thought out and easy to follow. It's a simple matter of pulling out the old clock board, popping in the new charger board, soldering two jumpers to the main board and adjusting the radio settings to recognize the new board. In my case I needed to do a firmware update (v3.00 to v3.02). 

The KXIBC2 board installed (right side of the picture. It replaces to old real-time clock 
board, but provides a charge controller plus real-time clock. The red and white pins
will be soldered to the main board. The large open space will be taken up by the Li-ion battery

The KXIBC2 board seen from the 'outboard' side

Jumper wires soldered in place on the main board

Battery pack in place, time to test. The LED on the charger board is a steady
yellow, so the battery is charging and all's good!

A quick firmware update brings everything up to snuff

The little rig is merrily charging away, getting ready for the next radio adventure!

There you have it. A dandy little rig made even better, courtesy of a company that actually listens to and engages with its customers.

W8BYH out

04 February 2024

So Close, Yet Still Oh So Far

I got bored yesterday and decided to put together yet another one of my ham radio transceiver evaluation spreadsheets. This time I wanted to evaluate QRP and 100 watt HF rigs against the same criteria, but not have them compete in the same space. So I decided to take a look at 100 watt rigs and QRP rigs separately.

My evaluation criteria change around the margins from year-to-year, but there are always a core set of requirements I'm looking for. These are MY requirements, the features and capabilities that matter to me. I also only evaluate rigs I've got personal experience with, or rigs that have caught my eye. For example, as kind of a toss-in to see where the market is today I decided to add the new(ish) Yaesu FT-710 to the evaluation. I have no personal experience with the rig, other than about a 15 minute test session at my local HRO showroom, but felt it deserved to be evaluated against some of its older siblings like the FT-897 and the FT-891.

Some of the radios I evaluate are out of production, so their scores really are not relevant to anyone other than me. But, since they are in my radio arsenal, I figured they would serve a useful purpose to highlight how far current rigs have (or have not) improved in terms of features and capabilities.

Let's talk briefly about the evaluation criteria. As I said, these are features that matter to ME. However, I know from talking to a lot of hams that like to operate outdoors that many of you are interested in these features, too. I also weight the evaluation criteria. For example, I consider the a built-in sound card interface to be critically important, so I give it an evaluation weight of 3, as opposed to having back-lit buttons, which only gets an evaluation weight of 1. While I think back-lit buttons are important, I consider a built-in sound card interface to be three times as important. 

Let's review some of the criteria:

  • Built in panadapter. This implies the radio has a real-time panadapter and waterfall display. Over the years I've found this a very useful feature, particularly when doing digital modes. A panadapter isn't absolutely critical; some high performing rigs on this evaluation, like the KX2, don't have them, but if the radio does have one that's a plus
  • Sound card interface. I've already discussed this above. My feeling is this - with a modern rig of any type, if you are a manufacturer and don't include a sound card interface, you are half-stepping it
  • Ease of digital mode configuration. It's one thing to have a built-in sound card. It's another to have a firmware set that makes it easy to configure for and run sound card digital modes. In my experience, Icom clearly excels at this. While no manufacturer's digital mode configuration settings are exactly 'easy', Icom's configurations are the least confusing and aggravating to set up and troubleshoot. 
  • Internal battery. It used to be only QRP rigs came with internal batteries (and not all of them, at that). I can understand 100 watt rigs not having internal batteries due to cost and technical complexity (although that excuse is becoming harder and harder to swallow, given recent improvements in battery chemistries and charging technologies), but there is NO reason today for a QRP rig to not have replaceable, rechargeable internal batteries or, in the case of rigs like the IC-705 and the Lab599 TX-500, a battery holder that securely attaches to and integrates with the main radio body
  • MARS mod. This is important to me, but likely not to many others. I'm a licensed MARS operator, so the ability to do a wide-band TX mod on any radio I own is important. The good news is that just about any radio can take a MARS modification. The challenge is the cost and difficulty. Most radios need some physical modification - either the removal of diodes or, in the case of some Yaesu rigs, adding a solder bridge across two open pads on a board. But the all-time winner is Elecraft. Their MARS mods are done via software - quick, easy, elegant and reversable
  • Tuners. Most tuners built into 100 watt rigs are anemic, handling (at best) a 4:1 antenna mis-match. They'll tweak up an 'almost resonant' antenna, but choke when the SWR crawls above 5:1. But what if you are dealing with some serious mis-matches under something like disaster response conditions? Spare me the talk about only using resonant antennas. I operate in the real world, where I've got one antenna up, and it's got to work on 10 - 40 meters and, if possible, at reduced power on 80 meters. This is why I want a more robust tuner in my radio. I'm OK with a tuner that can handle a 4:1 mis-match, but if you can give me one that'll handle 10:1, and build it into the radio, you get an extra point in my evaluation
  • IP and MILSTD ratings for water/dust resistance and ruggedness. Every rig fails at this, but I keep it as aspirational evaluation criteria. Both Yaesu and Icom know how to build IPX and MILSTD radios - they do it every day for the military, marine, aviation, commercial and land mobile markets the serve, and they also do it for some of the ham radio UHF/VHF handheld radios they currently make, like the Icom ID-52. There is no reason why they can't put just one HF radio in their lineup that meets these standards
  • Factory ruggedized. This is the most subjective evaluation criteria I have. It is different from IP and MILSTD ratings, but the end goal is the same - a radio that offers improved water and shock resistance for field use. There two radios on my list that manufacturers have either implied or outright stated as built to a higher standard - the Icom IC-7200 (now out of production) and the Lab599 TX-500. I've opened up my IC-7200 several times, and I can tell you that radio is about as water resistant as a submarine with screen hatches. It looks rugged, but it's really just a plastic shell surrounding a huge heat sink. A good radio, yes, but in no way water resistant. Icom should be ashamed of itself for implying in their product literature that the IC-7200 was in some way more water resistant than other radios on the market. The TX-500 is a different story. Lab599 proudly states that the radio is built to offer a higher level of water resistance. While the radio doesn't meet IPX or MILSTD ratings, reports from the field are that the radio really does offer serious water resistance in light rain and snow (it's a Russian design so, yeah, snow). The TX-500 is the only radio I give an extra point to for being truly rugged 

What's not in this evaluation criteria? UHF/VHF capability. Since I'm only interested in HF, I don't take into consideration any UHF/VHF capabilities the radio might have. Both the IC-7100 and the IC-705 offer UHF/VHF, but I simply don't care when it comes to what I'm looking at here. I also don't evaluate for CW capabilities. I'm not a CW operator. HF voice and digital only.

So, winners? Here's a few:

  • In the full-size 100 watt category, the IC-7300 is the winner. I've said this many times in the past - if you want an HF radio that works great in the widest number of scenarios, the IC-7300 is it. After over a decade in the market it really hasn't been beat. It's not a perfect radio by any means, but compared to all the others in it's market niche, it is still the best.
  • In the QRP rig category, the IC-705 is the clear winner. Like the IC-7300, it works best in the widest set of circumstances and offers those used to Icom's command and feature set a very similar menu structure. In fact, if you can operate a current Icom HF radio (7300, 7610) you can operate the 705 with ease. Performance on HF digital, with one exception, is a dream. It is hands down the easiest to configure and run digital QRP radio on the market. That one exception? RFI interference via the USB connection. This is a very serious issue, one that Icom has acknowledged, but not likely to address. The way around this is to run the radio on digital modes via wi-fi. There are several apps you can use for this, but I've had the most success with Icom's own RS-BA1 software 
There's no losers, per-se. Just several second place finishers, and a few radios that should have been spared this comparison (like the Yaesu FT-818 and the Xeigu G90). The #2 finisher in the 100 watt category is the Icom IC-7100. Even after 15 years of production, this is still a very viable design, with an excellent feature set and great digital mode performance. Icom kinda' sorta' killed it off in early 2023, then resurrected it for another production run (and with a corresponding price increase). Speculation is that the 7100's replacement has been delayed due to chip shortages (boy, that excuse is wearing thin), and Icom scraped up enough parts to do a final production run or two of the 7100 as a 'gap filler' until the new radio can make it to market. 

Some observations regarding other radios. The Yaesu FT-891 remains the radio that could have been. If  you look at the score it received, a respectable 9, and then consider where that radio would have placed if Yaesu had put a sound card interface in it (giving the rig 3 more points), that would have put the radio in a solid 2nd place, ahead of the IC-7100. But considering Yaesu has a long history of snatching defeat from the jaws of victory. Jeezus guys, just a simple sound card interface!

The Yaesu FT-710 looks like a solid performer, and I have to admit that I quite liked the interface when I played with it at HRO. Far, far better than the awful interface on the FT-991A. But I've also heard some of the same stories regarding digital mode configuration with the 710 that I heard with earlier models. Again, an overly and unnecessarily complex command set. I'll be doing more research on this rig before making a final assessment.

In the QRP category, while the Elecraft KX line remain strong contenders, their single biggest weakness is digital mode operations. The KX2 is a bugger to configure and run on digital modes, and the rig heats up very quickly. It just seems that digital operations were an afterthought with these rigs. On sideband they are unmatched in their class - even better than the IC-705. The venerable old FT-818 is such a simple rig that it's actually easy to configure for digital modes, and it'll run all day long on its 5 watt output. Sometimes simpler is better. Too bad the old girl isn't really competitive in any other category. But hey, it's almost a quarter century old design, so it can be forgiven.

OK, this is it for now. Remember, these are MY selections based on MY criteria. I'm sure many of you will disagree, so let me have your comments!

W8BYH out