Clearly Sherpas are the way to go.
I love my FT818 and it’s reliability. I have a Pelican case knock-off I keep everything in that is then kept within my backpack. My total pack weight is @18lbs for a all day SOTA hike. I like the workout aspect of it all.
As far as modifying to make lighter. I wouldn’t want to tinker with the radio and find out my tinkering has mucked something up on a summit.
When I transition over to using HF bands also (1001 points!) I will lighten up the pack by using the MTR4BV2 and my FT60R HT.
Erik
Damn the tuning knob has a dirty big lump of brass, and weighs 18g.
3D printed replacement: 3g
( p.s. grubscrew under the rubber)
Currently using 3x18650 battery pack with bms & balancer: 154g
I have measured the various rx currents of my '817
On 11.5V battery, 40m SSB, Squelch on, No backlight 320mA, unsquelched 350mA
5V 194mA
6V 59mA (actually 6.7V)
9V 17mA (HF)
CPU 5V regulator in 46mA (35mA+Green RX led 10mA)
Backlight 30mA (from 12V)
My first cut puts smps modules on the 5V and 9V supplies, and run the 6V regulator from the 9V smps.
The relays are spec’d to 6.75 volts, so I have set the 9V rail to 7.6V. The audio runs off the 9V supply, so at higher volumes I should win vs smps on the 6V rail.
Idle current is now 170mA running CPU regulator from the 7.6V @ 12V, 182mA without.
The rx led and backlight are adding 40mA!
The two backlight LED’s are in parallel and could be put in series. However I can get LED’s that are >10x brighter, so I think I will replace all the leds and reduce the current right down, and then the backlight can stay on too.
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Interesting results, but what is meant by these measurement 5v 6v 9v. Does the current drawn really go down as the voltage goes up? What’s the 17mA at 9v mean? Sorry if it should be obvious.
73 Andrew VK1DA/VK2DA
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The radio has multiple rails:
Unswitched 12V (panel and finals)
Switched 12V to 9,6,5V radio regulators
switched 12 to panel & backlights
9V (audio and and relays)
6V (actually 6.7V) mixers and some rf analog
5V radio digital and most analog
5V panel CPU and Display only
The biggest current is 5V radio supply, so a switchmode will reduce this most, moreso with a lithium battery
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I beefed up the seals on my FT817 and have filled it with compressed helium. Its now amazingly light. The downside is that it has a tendency to blow away in a light breeze.
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Ok that makes more sense now. Thanks.
So the smps is quite a game changer. Just needs to be quiet enough.
73 Andrew VK1DA/VK2DA
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Helium is light but a vacuum is lighter. Pump a vacuum in and hold onto the radio.
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Believe it or not, i know an activator that weighed his underpants and wore ones that only weighed a few grams. We did an activation together once and the weight of my M&S undies really held me back. I never considered compensating by lightening my rig. 
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i know an activator that weighed his underpants and wore ones that only weighed a few grams.
And that, your honor, is how I came to be wearing lacey undies and carrying a stainless steel whip , when the troop of girl guides arrived at the top of the mountain.
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Would a more sensible idea be to wear a Bibendum suit and fill that with Helium. Then you and what you carry will feel lighter and there’s no need to play “butcher the 817” ? 
Roll on the invention of antigravity! Wouldn’t it be nice to cancel 90% of your weight and nonchalently skip up 10-point summits? 
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Cancel 10% would make my doctor smile!
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