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Yaesu FT-857D / MP1 Antenna / Battery ... Question

Hi Guys

Who Using a YAESU FT-857D in SOTA ?

What power do you use ? and with what type of battery?

Does one of you used the MP1 antenna with 100w ?

I use now with 5 w actually, and I think next days I use with 100w…

Any problems

Thanks for answers

73 Laurent F8BBL

In reply to F8BBL:
Hi Laurent

I use the FT-857 when the distance and ascent to summits is not too great, otherwise I take the FT-817 and 3.3 AH LIPO battery. I wouldn’t contemplate using the FT-857 with less than a 7 AH SLAB when running 50w or more. I don’t run 100w as it isn’t necessary, except maybe on 160m on the few occasions I have used topband from a summit. It makes such a difference having the extra power - with 5w I may make 30 QSOs if I am lucky but with 40w or more 80+ QSOs are possible over say two bands on CW/SSB. I have carried and used a 13 AH SLAB on a few occasions but find that this weight is too much for me unless the distance to the top is very short.

I do not know the MP1 antenna is - I use a link dipole or long wire myself on HF. I like using the FT-857 and think it to be a very underated rig.

73 Phil

In reply to G4OBK:

Hi, Laurent, I use the 857 with a homebrew tuner, a W3EDP antenna and a 12 or 13 Ah slab (the 12 Ah Yuasa is significantly lighter) and use between 20 and 100 watts (20 and 50 on 2 metres!) I’m with Phil, it’s a great little rig. One tip: since a larger battery gives you more freedom to use power, I have selected from the second menu bank the option to have the display colour change with the selected mode, and pressing MFi and DISP in the first menu bank doubles the size of the frequency display but sacrifices the mode indication. This makes the display easier to read on a hill top.

I’ve never used the MP1 so can’t comment.


Brian G8ADD

In reply to G4OBK Phil and G8ADD Brian

Hi Phil and Brian

Thank you very much for fast and interesting reply.
How long with this 12 Ah battery for 50w output ?
For the MP1 Antenna, the constructor said 150w maxi, but 150w HF ? or PEP ?
see you next days from TK Corsica SOTA
73 Laurent F8BBL

In reply to F8BBL:

Hi, Laurent: I activated last week for over an hour at 50 watts and did not run the battery flat, my guess is that it would be good for at least 90 minutes on SSB or CW, perhaps shorter on FM.


Brian G8ADD

In reply to G8ADD:
Ok Brian Thank you veru much for infos, I think also around 90mn or 2h with 50w.73 Laurent F8BBL

In reply to F8BBL:
Morning Laurent
I have been using the 857D for several years as my /p radio. It is my radio of choice for SOTA as it has the advantage of 100w power output if needed. I also have an 817 but find it frustrating to use as it is only 5w, and very fiddly to adjust with gloves on. I usually run the 857 at 45w on the HF bands, 35w 2m SSB, 25w 2m FM, and the full 20 watts on 70cm any mode. I use a 7Ah SLAB battery, sometimes two. It does make a heavy pack though so be warned. I have not managed to totally flatten a battery on any activation to date including multiple peak and band activations. Like the majority I also use a link dipole for HF, a homebrew ultralight yagi for 2m and 70cm (DK7ZB design) and a delta loop for 6m. The Li-po batterys can save a lot of weight but at a price. I have used cheap li-po’s in model helicopters and they do not give good life at high discharge rates (20A), stay with a recognised supplier, and a high discharge rate (30C) to give good life. Kokam make good cells, but at twice the price of the Chinese imported cells it made better financial sense to me to use the very cheap SLAB’s. I justify the extra weight of SLAB’s in my pack as training weight for fell running so it is not so bad, if a little painful at times!
Hope this helps.

In reply to F8BBL:

Hi Laurent

I have an 857 but have never used it on a summit so can’t comment on battery life. But I do occasionally use the MP1 Chapstick.

I have found it to be very effective on 20 metres (and higher) when I’ve been in very restricted locations, such as Schilthorn (HB/BE-048) where big dipoles wouldn’t be practical.

Most people who had experience with the MP1 have improved its performance by adding extra ¼ wave radials for the bands required replacing the very poor system that comes with the antenna. I’ve found the radials (3 cut for each band I use) can be bent to fit the location with out causing too many vSWR problems. Looking at its construction it will handle 100 Watts easily (the full output from a 857/897). The MP1 works well but is no match for full sized dipoles or ¼ wave verticals though.

Until recently the maximum power I had available was 20 Watts from a 897 on its internal batteries, which I found I could use for over 2 hours if I stayed on ssb.

The system I have now settled on is an FT-817 feeding a HF packer amp which produces 40 Watts on 80/60 and 40 metres, 50 Watts on 20 and 17metres and drops to 15 Watts at 10 Metres. The amp is powered from a 7 Ah SLAB and have managed over 3 ½ hours with it. I think it is one of the best weight to power out compromises that I’ve used.

Carolyn (G6WRW) now over 100 activations :o)

Congrats on the 100+ activations Carolyn.

On occasion that I have got to use an FT-857, I have never really liked it, and always felt more ‘comfortable’ going back to my 817. My 897 at home seems very similar to the 817 to operate, so I do like that too, although too bulky for SOTA despite it being marketed as a “trans-portable”.

I don’t think any of this is to do with pros-cons of each model, just my personal taste and embedded operating style.

I think HF SSB really benefits from the extra power, especially on 40m. We have only really done well on 40m SSB with 5 watts from Northern Scotland, or near the South Coast of England. 80m SSB with 5 watts is normally reliable in winter, or early mornings. 20m SSB is sometimes exceptional good, and sometimes difficult! CW is easy on all bands at (nearly) all times with 5 watts.

I haven’t yet properly counted up how many (on average 1 hour) activations I get out of my 7Ah SLAB, while operating 5w CW from the 817. It is quite a lot! I don’t use an amp.

Steve G1INK would be a good person to ask about the power consumption where FT-857 running some power and SLABs are concerned, because that is Steve’s usual MO and he gets great results.


i use the mp-1 antenna with an ic-703 (10 watts), never used it with more power. i think it’s a good antenna for sota, especially when i have to walk far or climb steep mountains.

some pictures are on the sota-section of my homepage:


vy73 de martin

In reply to OE5REO:

Hi Carolyn, Tom, Martin

I’ve a problem with internet and I send this msg by my cellular/p
Thanks to all for nice infos, I looking again next time when the internet connexion is OK next days only
73 Laurent F8BBL

In reply to F8BBL:

Hi Guy’s

Thank you very much for all answer
see you next time on the SOTA Pile up
Next weeks (1er to 15 august) I go on Corsica Island, I activate 1 SOTA… with FT-857 + MP1 antenna (and also 2 IOTA)
See you
73 Laurent F8BBL