I did a lot of multiop/multiband activations where the usual suspects (FT-817, KX2, KX3, SGC2020, FT857, IC7000, MTR etc) were being used in the same small perimeter on different bands. The only problem I had (twice) with the FT-817 was on 20m SSB RX while a KX3 was transmitting CW on 30m (wideband noise on key). The FT-817 is as clean as any other radio as far as TX is concerned.
Razvan M0HZH / YO9IRF.
I would like to have an rtx as KXā¦ but I still prefer my little 817 (with DSP inside), a little tuner elekraft T1 and a fantastic Norcal Doublet antenna: total 1,36 Kg 
(I add only support dipole where necessaryā¦)
With the ND you also get the internal battery (which is crap) and the upgraded (much more reliable) final board. The non-ND can be used on 60m too, if you wideband it.
There are some tiny differences in between the 817 and 817ND. The plain 817 does 60m fine, you need to enable it with software and it stays enabled until you hard reset the radio. The 817ND only remembers the software mod till the next power cycle. To make it permanent, you remove a solder link.
The 817ND has a 3 colour back light and the final PA FETS were changed as the 817 FETS were obsolete.
But, and you may not feel itās important, the 817 has 2m & 70cms multimode capabiity. The KX2 and KX3 are better receivers and have more power. But you probably wont notice the better RX a lot of the time and the extra power at this level (5W vs 10W) is marginal. I donāt want to be without VHF/UHF multimode capability and that makes the better KX2/3 significantly less desirable to me. YMMV.
I changed from the early 817 to the 817ND and the only difference that I could find was the extra display colour that Andy mentions. I suggest that if you see a vanilla 817 going cheap, check that it transmits OK (that is, it isnāt being got rid of because the PA is dead) and if good then grab it with both hands! Donāt worry about 60 metres, if the FCC grants you the world-wide band you will have to open up the rigs coverage to get it, anyway, but it is an easy job. If it comes with the battery box you can do the green wire mod and put a set of high power NiMH cells in it which will give you enough power for a couple of hours operating.
I purchased my 817ND new in November 2006 already opened up to 60m, so I donāt know any different. I would have thought that the ND is more likely to be available on the secondhand market as it has been in production for a longer period of time than the original version. Mine lives in the backpack more or less on a permanent basis. The only other use it performs other than SOTA is to drive my 23cm transverter when I feel like airing my call on that band. I have been considering buying a second oneā¦ and I know several people who already have two! 
People fear that the KX2 and KX3 are fragile, but that appears to be another internet myth. Iāve been on the Elecraft mailing lists since before the KX3 was introduced and Iāve never heard of one damaged in the field.
Both were designed specifically as trail-ready radios, so they are rugged. My KX3 has fallen off the top of my car twice and is fine. Granted, the car is a Miata, but it still fell four feet.
I do recommend adding the SideKX plates on the ends. I also have the cover. Get the ones from GemsProducts. There are cheaper Chinese copies from Windcamp, but they are made of softer aluminum.
wunder
The KX3 can leak the LO signal at the receive frequency. That is natural for direct conversion receivers. Enable the isolation preamp (10 dB) to take care of that.
People usually discover this during ARRL Field Day.
wunder
I also bought Gems side pannels + cover. Before that I ordered the Chinese Windcamp, but I found them of poor quality - the plastic cover arrived cracked, so I returned the whole thing. For a couple of extra dollars, I bought Gems and this set seems really robust.
Hello Rafael from a fellow Tucson ham!
Iāve been doing SOTA less than a year but I think Iām qualified to say that if you enjoy hiking then yes, this is the Radiosport for you for sure. And just like any sport, part of the fun is the gear. Your HT can get you the 4 QSOās needed to qualify for a summit activation, but itās very likely that you will find HF to be fun enough to justify buying some new gear.
I encourage you to not overthink it. Buy whatever is affordable and get on the air. You wonāt be disappointed whether itās a 817, KX2/3, MTR, or whatever - all of them will be tremendously fun. If amateur radio is a lifelong hobby you will never stop experimenting with new rigs anyway!
My current SOTA station is usually centered on a KX2. I have not done overnight backpacks with it yet but I do some pretty long hikes (last Friday I took it on a 20-miler to Mica Mountain). Iāve made close to 2,000 contacts with it and really canāt complain about anything.
Iāve gone on activations with others who have used MTRās very successfully. I owned an 817 way back when they were new (pre-ND version) and loved it. I would say that pretty much any modern radio will give you plenty of operating joy.
Hope to meet up with you at some point, my QTH is Northwest so I usually am involved with the Oro Valley Amateur Radio Club - they are probably the most vibrant and largest of the Tucson area clubs. And when you do head for the hills, be sure to let us know so we can chase you!
73,
Keith KR7RK
Hello Rafael,
Reading your bio, and seeing that youāll be building a home station as well, consider a KX3 for both SOTA activating and home station use. You could then add to the home station, e.g. the mating 100-W amp, panadaptor, etc. as time and budget allow. That approach would develop familiarity with the same HF radio.
Listening for you on the HF bands!
Ken, K6HPX,
Also Tucson
Happy its a myth as I just bought at 857D.
Paul
That is good news as one of the reasons I purchased an 857D recently was the 70cm and 2m SSB capability.
Paul
Thanks @KR7RK! I know a bunch of OVARC folks from RST & K7UAZ ā and I was actually licensed at the OVARC hamfest in 2015. Good to see another Tucsonan on here. I actually made an āaccidentalā 65-mile FM simplex contact with my HT last weekend ā from Wilderness of Rock on Lemmon to Rio Rico!
@G4OIG and @G8ADD, thanks to you both for the input! This thread has been tremendously helpful so far.
@YO9IRF, Iāve read the same thing about the battery in a number of places, and expect to use external power with whatever rig I buy. When you say the 817NDās final stage is āmuch more reliableā than the 817ās, what do you mean by that?
UHi,
I think the emphasis on radio brands is misleading. Any power between 5 and 15 watts is almost impossible to distinguish at the receiving end. Additional receive sensitivity measured in the lab often does not translate to any observable difference in the field, due to the background noise being far higher than the weakest signal detectable on a test bench. Beyond a certain point, extra sensitivity or RF gain is pointless and in fact weakens the receiverās ability to deal with high interference levels.
Success on SOTA is not due to using the ābest brandā of radio, or ATU, or commercial antenna. The skill of the operator is more important than the radio, in choosing the right band for the conditions, using the right mode, posting alerts sufficiently in advance, using decent antennas that are always the correct length and donāt rely on ATUs, using the right frequency, projecting their voice correctly, speaking clearly, using recognised phonetics and operating consistently, saying just what is needed and not rambling on about rubbish, giving fair treatment to all callers and giving priority to S2S and QRP stations, being flexible and tolerant. These things are not learned from the operating manual and do not flow from buying the ābestā radio. They are learned by doing, watching experts, copying the techniques that work, practicing and repeating. So my advice is be patient, start slow and simple, expect it to be a mixed bag of success and occasional disappointments, remember you are dealing with nature. Conditions vary just like the physical weather.
73 Andrew VK1DA VK2UH
"especially those whoāve taken their equipment on longer trips: is the extra price of the KX2 or KX3 worth it?"
Love the KX3, worked great on 5 day backpack trip, but if you can do without a few of the features and modes, for me, the KX2 is a fantastic rig for backpacking. Its smaller and lighter than the KX3, I got mine last year and took on 7 day trip last summer. It was fantastic. Have since taken on a couple shorter trips, and love it even more. Worth the extra $? Yes! Sold the KX3 soon after.
73, Mark/K6MTS
Your choices sound good. An issue to consider, in high country, operating in snow, you will find water intrusion into the radio is a real possibility. Consider a means of protecting the radio while operating from snow/rain.
N6IZ Brian
The early FT-817 had problems with final power stage (transmit power amplifier) failure, based on Mitsubishi SK2975 transistors. A few years in, they redesigned the power amplifier to use the new Mitsubishi RD07MVS1 transistors, that had much better thermal handling capability (channel dissipation rating 50W vs 10W) and the problems were fixed. Soon after, the ND version was launched and that uses only the new PA design.
This is not a huge problem as Yaesu sells the complete replacement power stage for about US$50 and you can replace it yourself if you have average electronics knowledge.
Razvan.
A āpolyā bag. KISS principle - works for me.
And yes Iām stilling using my FT-817 after 16 years. One of the original. Love this little radio after all this time still looks pristine after many Activations & country visits and operations - including KL & VP8.
And itās longevity in production is a testament as to Yaesuās foresight!
73
Jack(:>)
Oh - and by the way, itās now driving my new 13cms transverter - superbly!!! (70cms IF)
Itās worth being aware, particularly if buying second hand, that thereās more than one version of the FT817ND. The earliest releases that were branded ND could still be widebanded in software and only supported 2 display colours. Those changes came a little later.
Caroline and I own 3 FT817s between us: an original 817, an āearlyā ND, and a ārecentā ND. The middle one is branded as an ND, and is identified as such in software such as FTBasicMMO, but only has 2 display colours and software widebanding sticks. I presume that not many of these were made before the changes to the latest model.
Martyn