question about Yaesu FT-857D
Steve
station. I want something that won't break the bank, but that will
give me room in which to "grow" as I upgrade my license. I have my eye
on the Yaesu FT-857D right now and it's gotten some good reviews on
the web.
I notice that the FT-857D's current consumption is a maximum of 22
amps, but I'm guessing that this is when transmitting with maximum
power on HF, correct? For operating on VHF and UHF, would my Astron 20
amp power supply suffice? I can always upgrade power supplies later,
if necessary, when I upgrade my license, but I'd like to think that,
if I buy the FT-857D now, I won't also have to buy another power
supply right away.
Thanks,
Steve
Highland Ham
> amps, but I'm guessing that this is when transmitting with maximum
> power on HF, correct? For operating on VHF and UHF, would my Astron 20
> amp power supply suffice? I can always upgrade power supplies later,
> if necessary, when I upgrade my license, but I'd like to think that,
> if I buy the FT-857D now, I won't also have to buy another power
> supply right away.
That 22 Amperes max is highly likely for more than 100 Watts RF PEP
(Peak Envelope Power) You rarely need that peak current ; the average
current being approx 8 Amperes on transmit (even with audio compression)
If you are worried that your PSU can't handle brief excursions above 20
Amperes , causing your PSU (perhaps) to shut down or the supply voltage
to drop (when your unit has a voltage fold back facility) ,you can
simply put a (sealed )12 v lead acid battery with a capacity of say 10
Amperes*Hours (AH) parallel to the PSU. The battery will then take care
of the peak current.
With a battery of say 18AH (golf trolley variety) your power supply
unit (PSU) won't need a capacity higher than 8-10 Amperes since the
battery will supply the higher current.
On receive the current will be approx 2 Amperes ,with the PSU having
sufficient excess capacity to charge the battery .
Frank GM0CSZ / KN6WH
Steve
wrote:
Thanks. I doubt I'll have any problem in that case. I have an Astron
13.8 volt, 20 amp supply and my guess is that it'll be all I need for
now, for VHF / UHF work.
Steve
KC2SIZ
Bryan
Hi Steve,
Welcome to HF! I'm guessing your power supply is the RS-20, the same as
mine. It has a *peak* current capability of 20A. In continuous duty, it's
rated at 16A: http://www.astroncorp.com/linear.shtml. My old Kenwood TS120S
transceiver (approximately equivalent in terms of maximum current demand)
will dim the pilot lamps on hard voice peaks and keydown CW at 100W output.
I like Frank's idea as an interim solution, though a heftier supply is a
better long-term solution.
73,
Bryan WA7PRC
Cecil Moore
> I like Frank's idea as an interim solution, though a heftier supply is a
> better long-term solution.
I run an RS-20 paralleled with a deep discharge
marine battery. I not only run my IC-756PRO from
that configuration but I run my SG-500 amp at
the same time - never had any problems.
--
73, Cecil http://www.w5dxp.com
Rick Frazier
Don't worry about it... If the power supply doesn't handle the peak
current, you can always add a parallel battery. Even a small 7MAH
(motorcycle size) would help.
I've got an 957 (before D, but with the DSP option) in my truck and it's
provided very faithful service despite the typical voltage variations of
a vehicle. Yaesu doesn't recommend running it below 12.0 volts, and
there used to be warnings from newsgroups and such that it could lose
the factory settings if you try to run it below that, but I've seen dips
as low as 10.5 volts with the radio on while cranking the motor to start
the truck, and never lost the settings. Just in case, I'd google the
three button "secret" menu that shows the factory settings and write
them down (Can't recall, but it's something like hold down abc while
pressing the on button.). I've got them somewhere, but it's been so
long I doubt I could find them, and I've not had a problem anyway. The
rig gets great reports and does fine, even on a pickup truck with either
an ATAS-120 or Ironhorse hamstick antennas... It's a great choice of
radio, versatile and sturdy. The worst issue is mounting the head where
I can reach it without stretching while I drive, but that won't be an
issue for you if you're going to use it at your QTH. It certainly
doesn't have some of the choices and options of a big rig like an Icom
756Pro2, but doesn't cost that much either... Because it is a small
rig, you will need to bet used to selecting various menus, but most of
your operating will likely center on three or four, at most, with only
rare use of the others (except for fine adjustments for maximum power
out of a linear, who ever changes the power output, for example? I know
the one in my truck has only been below 100 watts when someone once bet
me I couldn't get across the state on less power, and that was sitting
still. Running mobile, you want something you can operate without
looking, and the 857 has fit the bill there very well.
Astron supplies are pretty hefty, compared to a lot of them, and it
should do just fine in normal service. On the other hand, if you intend
to run high duty-cycle rtty or similar, get the bigger supply or add a
battery in parallel right away. For voice (ssb) or CW, you shouldn't
have much of a problem, if my experience with the 857 is any indication.
Good Luck and 73.
--Rick AH7H
Scott
and 6M will draw 20 Amps or so. One thing you can do...power it from a
car battery in the ham shack. Take the battery out to the garage and
charge it every couple days (depending on how much you use the radio for
TX)...that would get you by until you upgrade to a bigger power supply.
Or...go into the setup menu and set the RF Power adjustment to
something like 50 (about half power) when you're on HF or 6M.
Scott
N0EDV
Steve wrote:
--
Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)