I am an avid user of HF manpack radios, mostly military types in the 20-25w range but also various amateur rigs cobbled into a pack with batteries, antenna tuners, etc. With that I can say the Yaesu FT-857 is one of the best current made amateur radios for making into an HF manpack.
A couple of things make the 857 better than most, first is the reasonable RX current drain around 600ma where lots of other mobile radios draw upwards of 2A on receive. Second is it works well at sub 12v where many other radios get squirrely and it has a feature left over from its battery operated big brother the FT-897 where you can ground or apply power (I forget which) to an additional wire in the power plug and it drops the radio into the 20w mode for better battery life. The 857 is also one of the smallest 100W HF/multiband rigs on the market.
I first started experimenting with amateur radios in a manpack config in the early 80s starting with an Alda 105 100w transceiver with Kenwood 120 portable antenna tuner and 7AH gell cell in a small bakcpack. This radio was similar to the old Atlas 210 series and would literally run for days in receive mode on a single 7AH battery.
One of the first amateur radios I purchased specifically for manpack use was the Yaesu FT-817 when they first came out and I soon learned how frustrating life can be at 5w. I replaced the 817 with the 100W 857, which is only a little bigger and never used the 817 again.
On the military manpack side I've owned or used just about everything ever made and for awhile I lugged around a heavy Cincinatti Electronics PRC-70 manpack, which was a marvel of engineering and covered 2 to 76MHz continuous with internal antenna tuner and about 35w transmit power. It was heavy and around 35lbs for the pack full of junk but it looked cool so I suffered dragging that all over the country in a backpack kit.
I then got a couple of more modern Harris PRC-138 manpacks that cover 1.6 to 60MHz all mode and these were the latest, most high tech DSP/SDR military HF manpack a civilian could purchase at the time. I was in heaven and dragged a 138 all over the place and used the heck out of it. But the pack with radio and antenna kit probably weighed 25lbs.
Then came the Elecraft KX3, which is a tiny 10W radio that outperforms just about any HF rig on the market, weighs 1.5lbs and only draws about 190ma on receive. This rig and a 5AH LiFePO3 battery and antenna system fits in a tiny backpack about 10" X 7" X 4" and all my other manpack radios have been on the shelf for a couple of years since I got the KX3.
I'm considering making an aluminum sheet metal case that fits around the back of the KX3 to hold the battery and a whip socket to make it into a true manpack, but otherwise its the best thing I've every encountered in the manpack category.
If my KX3 was unavailable I would probably grab the PRC-138 as a second choice and the Yaesu 857 as my third choice.
prcguy
Hello,
It is considered for manpack due to it's small size and features. The users likely turn down the power to about 10 watts. SSB and CW are not 100% duty cycle, so it is not a continuous 10 watt draw from the battery.
The greater concern is the current draw during receive (0.6 to 1.0 A) since that is continuous.
73 Eric
