Newsgroup: it.hobby.radioamatori
Titolo: Potenza minima dell'FT-857

Salve a tutti,
Tempo fa ho sentito dire che la potenza minima di uscita dello Yaesu FT-857
è di 5W.
Mi chiedevo se fosse possibile ottenere (con o senza modifiche) una potenza
ancora più bassa di 5W.
Grazie
Andrea   IW0HOG

ancora più bassa di 5W.
in quale banda/modo? dai un'occhiata a questo articolo
http://www.mods.dk/view.php?ArticleId=2731
in particolare alle voci da 24 a 44
cercati un po di docum ma tempo fa lessi che si faceva in questo modo
saluti e se fai modifiche comunicale.,.interessa anche me come
informazione.
imho è nata con 5w come minima, lascio 5w (o passo all'817..hi hi)
meki 
icq# 12757256  

 icq# 12757256 

In UHF escono soltanto 2w
beh...in v e in hf mi pare sia 5...
ad ogni modo imho non vale la candela. non è nato per il qrp.
meki 
icq# 12757256  

 is typical for the 857? Thanks for your help! 73, bob/wz0b
SNIP
----- RISPOSTA 1 -----
From:  "wb6mlc" <kac@i...>
Date:  Sat Aug 14, 2004  5:39 am
Subject:  Re: FT-857 qrp current drain - how much?
Hi Bob,
The 3-4 watt power output minimum is about right for the FT-857D
driving a dummy load while measuring with a bird watt meter. I noticed
that at 5 watts out, my FT-857D draws between 4.0 to 4.5 amps. In
receive mode on batteries (SLA or NiMH ) it draws about 440 to 500mA
with the backlite off. About 100ma is consumed by the fans if the rig
is very hot, and the fans must kick in briefly during receive mode.
They dont seem to stay on for very long BTW.
Compared to a FT-817ND, it is not as efficient when running 5 watts.
It makes more sense to run 10-20 watts with this radio
to get the best low power efficiency. If you want to operate at only
the 5 watt level and below, make sure you have a battery of sufficient
capacity.
73,
Ken WB6MLC
----- RISPOSTA 2 -----
From:  "David J Windisch" <davidw@c...>
Date:  Sun Aug 15, 2004  9:46 am
Subject:  Re: [FT-857] Another method of QRP; was: FT-857 qrp current
drain - how much?
Hi, all concerned:
In the old days, one could couple his buffer to the antenna for qrp. One of
these new days, I'll try removing h-f r-f drive, Vcc and bias from the h-f
PA fet's, and moving the driver line at the output of the h-f triplexer to
the PA output filter. This isn't for the faint-hearted. I haven't done any
of this yet, cuz I haven't deciphered whether the driver is part of the
vswr-shutdown ckt, and thus (I hope) protected.
Never met a rig I didn't think I could make better than stock ;o)
My '857 draws about 15 A on h-f with 100W out.
73,
Dave, N3HE

Forse può essere utile questa informazione:
-----------------------------------------
WARNING: changing these will reset all the memories.
  1.. Enter the Servicemenue. I want to warn you do not change these values 
unless you are sure of what you are doing. To get them turn transceiver off. 
Press and hold the A,B,C keys; while holding them in, press and hold in the 
[PWR] switch for 1/2 second to turn the tranceiver On. Now let go of all 
keys. Press F key to finish.
  2.. For this procedure you will need a Dummy Load (or a well matched 
Antenna) and a Wattmeter!
  3.. Locate Menue No
  4.. NO-024  HF1-PO-MAX  165 (set to 255) CW     1.800.00
a.. NO-028  HF2-PO-MAX  159 (set to 255) CW     7.068.19
a.. NO-032  HF3-PO-MAX  158 (set to 255) CW    21.225.13
a.. NO-036  50M-PO-MAX  145 (set to 255) CW    50.000.00
a.. NO-040  VHF-PO-MAX  87 (set to 255)  CW   145.437.50
a.. NO-043  UHF-PO-MAX  112 (set to 255) CW   438.900.00
That?s it!
After this mod I have about 130 Watts on HF and 6 mtr, about 90 Watts on VHF 
and 40 Watts on UHF!
I have done this mode a few month ago and I have no problems (my Final 
Transistor is still ok ;-)) !
IMPORTANT: Before changing any values in the Aligment menue, please write 
down your original settings!
WARNING: DOING THIS MOD MAY EVENTUALLY RESULT IN A DAMAGED FINAL TRANSISTER 
AND/OR REDUCED SERVICE LIFE!!
73 de Alex, HB9TSF, NH7VW
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