"Brenda Ann" wrote in message
...

"The Shadow" wrote in message
...


Golly Brenda how does
210VA = 95.55W
850VA = 386.75W

wikipedia on volt-ampere
A volt-ampere in electrical terms, means the amount of apparent power in
an alternating current circuit equal to a current of one ampere at an emf
of one volt. It is equivalent to watts for non-reactive circuits.

Are you using peak, rms, or average factors?

I assume the VA figures given by John are rms values

The calculator used assumes a power factor of .70. It is right in line
with the calculations used for USP'es in their V/A to W conversions.

Very good Brenda -- agree if we take into account power factor. I assumed a
resistive load

Also folks note the ICOM 7700 is a 200 Watt Radio and uses a switching power
supply. Finals take 42 Volts

Lamont

In article
,
wrote:

No, it's not a tube rig, it's the latest Icom IC-7700.
See the spec sheet at the end of the brochu
http://www.ab4oj.com/icom/ic7700/IC-7700_pre.pdf

John Plimmer, Montagu South Africa

On Feb 9, 4:42*am, "Brenda Ann" wrote:
"The Shadow" wrote in message

...



wrote in message
...
Thanks for that Lamont.
The device is a transceiver and the power usage on:
Transmit is 850VA and on
Receive is 210VA

Wow John those figures are high -- is it a tube type radio?

210VA = 95.55W
850VA = 386.75W

Does sound like a tube rig.

Tell me you are not buying this transceiver for SWL.

In any event you better be real careful with an inverter powering this
transceiver as it looks to have an auto switching power supply in it.
You would be safe with a 115V inverter but you might see trouble ahead
with a 220V inverter. I've seen inverters hiccup when a load is switched
on, which might cause the auto switching supply to go into the doubling
mode for 115V. When the inverter recovers to 220V you will be lucky if
all that happens is you blow a fuse. Whether or not you have a problem
might depend on timing. Where the inverter is in the AC cycle when you
happen to switch on the radio may determine if a failure event occurs.
Having some load on the inverter like a lamp before you switch on the
radio may help stabilize the situation. Good luck.

--
Telamon
Ventura, California

On Feb 8, 7:11*pm, Telamon
wrote:
In article ,
*"The Shadow" wrote:





wrote in message
...
I would be grateful for the advice of one of our technically minded
members:
The new radio I have coming merely states it's power consumption as
210VA, as it is a multivoltage radio.

What consumption in watts/amps does this translate to at 240 volts AC
mains?
Also. if I used an inverter to drive it off a 12 volt DC battery, what
would the power consumption in amps then be?

POWER CONSUMPTION IS IN WATTS NOT AMPS

A friend who helped me wrote:
Watts = Volts * Amperes so 210VA = 210 Watts
NOT TRUE - WATTS = V*A*COSINE OF THE PHASE ANGLE

210 Watts means 210 / 240 Amps which is .875 Amps.

If you want to use a 12V battery, 210 Watts means 210 / 12 Amps or
17.5 Amps. This assumes the AC supply is as efficient as the DC
supply. It won't actually be quite as efficient, so you're likely to
need fewer Amps, maybe 14 or 15 but that's a guess. Maybe you can ask
as the DC current depends on their design which is not known to us
yet.

Those numbers look very high to me. I suspect they've made a little
mistake.

I replied:
it does seem very high to me for 210VA. at 240 volts AC mains.
As just a poor guess I would estimate
0.5 amps at 240 volts AC mains
and 8 amps at 12v DC
but I cannot calculate it.
_______________________________

So what do the experts out there think?

Would be grateful for your help.

WHAT KIND OF RADIO IS IT -- 210 VA IS TOO HIGH FOR A RECEIVER -- MORE LIKE A
TRANSCEIVER

Volt-Amperes VA usually refers to AC apparent power - it takes into account
reacive components see URL:
http://www.allaboutcircuits.com/vol_2/chpt_11/2.html

True power in an AC circuit is IxE if there are no reactive components
otherwise it is I squared R or ExI x Cos theta

So True Power (Watts) does not equal VA unless the circuit is purely
resistive.

Assuming your device is resisive (or near to it) then see URL:
http://www.sengpielaudio.com/calculator-ohm.htm

which indeed gives 0.875 Amperes

Again using
http://www.sengpielaudio.com/calculator-ohm.htm

which indeed gives 17.5 Amperes

Allowing for efficiencies and loss etc I would allow for 20 to 25 amperes
Most inverters will specify a power rating

As you noted above 210 Watts is to much power for a receiver. Chances
are then the VA the OP refers to is apparent AC power or peak power. In
order to answer the PO's question if we assume AC 210VA peak power I
have found that for most power supplies, which are full wave rectified
followed by larger capacitance a figure of about a third works well.
Then the AC real power would be 74 watts. Then to get to DC we need the
RMS value of the AC real power, which is a factor of 2.828 so about 26
watts RMS. At 12 Volts to drive the inverter would be about 2 amps DC.
I'm making plenty of assumptions here. You will be somewhat more than
2.1 amps depending on the inverter efficiency. Lets use a figure of 80%
so the battery current draw would then be about 2.5 amps. 26 watts and
2.1 amps are rational numbers for todays solid state receivers. A lot of
assumptions but it seems to make sense.

--
Telamon
Ventura, California- Hide quoted text -

- Show quoted text -

Telamon - See I Knew That You Could Do It ! - bravo ~ RHF

Thanks Telemon and all of you for your replies.
The 7700 certainly draws a lot of current on receive mode only.

It will be used for listenig only and I will disable the transmit
through the internal software.
I was hoping to take it to our powerless Seefontein DX site, but the
problems Telemon highlights and the huge 12v DC current draw means I
would need massive batteries, so I wont take it.

Instead I will keep my Icom IC-756PRO III for the DXpeditions.

John Plimmer, Montagu, Souuth Africa

On Feb 9, 7:00*am, Telamon
wrote:
In article
,

Tell me you are not buying this transceiver for SWL.

In any event you better be real careful with an inverter powering this
transceiver as it looks to have an auto switching power supply in it.
You would be safe with a 115V inverter but you might see trouble ahead
with a 220V inverter. I've seen inverters hiccup when a load is switched
on, which might cause the auto switching supply to go into the doubling
mode for 115V. When the inverter recovers to 220V you will be lucky if
all that happens is you blow a fuse. Whether or not you have a problem
might depend on timing. Where the inverter is in the AC cycle when you
happen to switch on the radio may determine if a failure event occurs.
Having some load on the inverter like a lamp before you switch on the
radio may help stabilize the situation. Good luck.

--
Telamon
Ventura, California- Hide quoted text -

On Feb 8, 10:30*pm, wrote:
- Thanks Telemon and all of you for your replies.
- The 7700 certainly draws a lot of current on receive mode only.
-
- It will be used for listenig only and I will disable the transmit
- through the internal software.

- I was hoping to take it to our powerless Seefontein DX site,

ABOUT - Seefontein's DXpedition location in South Africa
-by- John Plimmer - 11-14 September 2007
http://www.dxing.info/dxpeditions/seefontein_2007_09.dx
Nice write-up; good Pictures and an impressive Log.

Plus That Something Extra [ "dX" Rated ]
"Nudists DXpedition" -by- John Plimmer - 4-8 April 2005
http://www.dxing.info/dxpeditions/seefontein_2005_04.dx
Yes It's DXing O-Natural !

wrote:
I would be grateful for the advice of one of our technically minded
members:
The new radio I have coming merely states it's power consumption as
210VA, as it is a multivoltage radio.

What consumption in watts/amps does this translate to at 240 volts AC
mains?
Also. if I used an inverter to drive it off a 12 volt DC battery, what
would the power consumption in amps then be?

A friend who helped me wrote:
Watts = Volts * Amperes so 210VA = 210 Watts

210 Watts means 210 / 240 Amps which is .875 Amps.

If you want to use a 12V battery, 210 Watts means 210 / 12 Amps or
17.5 Amps. This assumes the AC supply is as efficient as the DC
supply. It won't actually be quite as efficient, so you're likely to
need fewer Amps, maybe 14 or 15 but that's a guess. Maybe you can ask
as the DC current depends on their design which is not known to us
yet.

Those numbers look very high to me. I suspect they've made a little
mistake.

I replied:
it does seem very high to me for 210VA. at 240 volts AC mains.
As just a poor guess I would estimate
0.5 amps at 240 volts AC mains
and 8 amps at 12v DC
but I cannot calculate it.
_______________________________

So what do the experts out there think?

Would be grateful for your help.

John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Sangean 803A.
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop, PAORDT Roelof mini-whip
http://www.dxing.info/about/dxers/plimmer.dx






That's key-down CW right? Worst case?

If you're going to be just listening or working SSB your power
consumption will be much less.

"David" wrote in message
...



That's key-down CW right? Worst case?

If you're going to be just listening or working SSB your power consumption
will be much less.

The 210VA is the RECEIVE STANDBY current..

David wrote:

wrote:
I would be grateful for the advice of one of our technically minded
members:
The new radio I have coming merely states it's power consumption as
210VA, as it is a multivoltage radio.

What consumption in watts/amps does this translate to at 240 volts AC
mains?
Also. if I used an inverter to drive it off a 12 volt DC battery, what
would the power consumption in amps then be?

A friend who helped me wrote:
Watts = Volts * Amperes so 210VA = 210 Watts

210 Watts means 210 / 240 Amps which is .875 Amps.

If you want to use a 12V battery, 210 Watts means 210 / 12 Amps or
17.5 Amps. This assumes the AC supply is as efficient as the DC
supply. It won't actually be quite as efficient, so you're likely to
need fewer Amps, maybe 14 or 15 but that's a guess. Maybe you can ask
as the DC current depends on their design which is not known to us
yet.

Those numbers look very high to me. I suspect they've made a little
mistake.

I replied:
it does seem very high to me for 210VA. at 240 volts AC mains.
As just a poor guess I would estimate
0.5 amps at 240 volts AC mains
and 8 amps at 12v DC
but I cannot calculate it.
_______________________________

So what do the experts out there think?

Would be grateful for your help.

John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Sangean 803A.
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop, PAORDT Roelof mini-whip
http://www.dxing.info/about/dxers/plimmer.dx






That's key-down CW right? Worst case?

If you're going to be just listening or working SSB your power
consumption will be much less.

Probably drawing at *least* 2 amps on receive. And, that puppy is capable of 200
W output. With transceivers that put out only 100 W one had best have *at least*
a 20 amp supply. I realize that the '7700 is not capable of DC operation, but
that gives you some idea of power consumption.

Just a thought, but you might peruse the Universal catalogue and look at the
power consumption of *similar* rigs.

dxAce
Michigan
USA

wrote:
Thanks for that Lamont.
The device is a transceiver and the power usage on:
Transmit is 850VA and on
Receive is 210VA

Yikes! That's worse than a desktop computer. Do you generate your own
electricity?

You might as well get an R-390A using 250 Watts to listen to the radio.
Zounds!

In article
,
wrote:

On Feb 9, 7:00*am, Telamon
wrote:
In article
,

Tell me you are not buying this transceiver for SWL.

In any event you better be real careful with an inverter powering this
transceiver as it looks to have an auto switching power supply in it.
You would be safe with a 115V inverter but you might see trouble ahead
with a 220V inverter. I've seen inverters hiccup when a load is switched
on, which might cause the auto switching supply to go into the doubling
mode for 115V. When the inverter recovers to 220V you will be lucky if
all that happens is you blow a fuse. Whether or not you have a problem
might depend on timing. Where the inverter is in the AC cycle when you
happen to switch on the radio may determine if a failure event occurs.
Having some load on the inverter like a lamp before you switch on the
radio may help stabilize the situation. Good luck.


Thanks Telemon and all of you for your replies.
The 7700 certainly draws a lot of current on receive mode only.

It will be used for listenig only and I will disable the transmit
through the internal software.
I was hoping to take it to our powerless Seefontein DX site, but the
problems Telemon highlights and the huge 12v DC current draw means I
would need massive batteries, so I wont take it.

Instead I will keep my Icom IC-756PRO III for the DXpeditions.

The ICOM on receive is not out of line with SWL table top receivers.
My R8B specification states it draws 2 amp at 11 to 16 volts (27 watts)
DC power and the AC power is about 40 watts.

--
Telamon
Ventura, California