Battery Source

Udo Rumpf wrote:

It's possible you have a problem not related to the voltage; e.g.,
maybe the voltage is dropping well below the 11.8 volts when the
transmitter is keyed, or the radio is not functioning within
specifications.

Eric Greenwell


I have a 720A Dittle radio
Power requirements;
Receive .1 - .4 amps
Transmit (tone) 1.4 amps (.8 amps unmodulated)
The 11.8 volts I was referring to is before transmit.
If I remember correctly when the battery is fully charged
and I hit the transmit button the voltage drops from 12.7 to 12.2.
Udo

With the battery run down to 11.8 volts, measure the voltage right at
the radio connector while keying the transmitter for 5-10 seconds. If it
drops more than it does when the battery is fully (or nearly so)
charged, the problem might be the battery.

However....
I found a German manual for the ATR720A (and ATR70C in English) on the
Filser site (I think they took over the radios from Avionic Dittel).
The specifications don't make any mention of what voltage range the
radio will function over, so I suspect 12 volt battery operation wasn't
on their minds when it was designed. This appears to be an older design
radio, and likely is one that would benefit from 14 volt operation.

So, if it's not the battery, your choices seem to be a modern radio
(like the Walter Dittel FSG 2T I mentioned) or going to a 14 volt
battery pack. Or waiting till you get closer to the airfield to make
your call :^)

--
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Eric Greenwell
Washington State
USA

I have a 720A Dittle radio
Power requirements;
Receive .1 - .4 amps
Transmit (tone) 1.4 amps (.8 amps unmodulated)
The 11.8 volts I was referring to is before transmit.
If I remember correctly when the battery is fully charged
and I hit the transmit button the voltage drops from 12.7 to 12.2.
Udo

With the battery run down to 11.8 volts, measure the voltage right at
the radio connector while keying the transmitter for 5-10 seconds. If it
drops more than it does when the battery is fully (or nearly so)
charged, the problem might be the battery.

However....
I found a German manual for the ATR720A (and ATR70C in English) on the
Filser site (I think they took over the radios from Avionic Dittel).
The specifications don't make any mention of what voltage range the
radio will function over, so I suspect 12 volt battery operation wasn't
on their minds when it was designed. This appears to be an older design
radio, and likely is one that would benefit from 14 volt operation.

So, if it's not the battery, your choices seem to be a modern radio
(like the Walter Dittel FSG 2T I mentioned) or going to a 14 volt
battery pack. Or waiting till you get closer to the airfield to make
your call :^)

Eric Greenwell

I have this Radio now for many years.
Based on what you and Tim are saying, I concluded that
this radio does not perform very well at lower voltage.
Only in the past couple of years while flying a glider with restrictive
space for a batteries (the standard 12v 7amp) have I noticed any
deficiency at low voltage even with fresh sets of batteries.
also this radio seem to eat more on stand by.
Prior to this I had no restriction in capacity and the problem never
came up. Other then that the radio works fine and has good range
when the voltage is up.
Thanks
Udo

Paul Remde mentioned that he replaces his batteries after two years of use.

The sealed lead acid batteries we use, start life with a given capacity,
rated in amp hours. After manufacture, and during the first several
charge/discharge cycles, these batteries will actually gain a small amount
of capacity. After that, it's all downhill, with the battery losing capacity
over time and discharge cycles.

In the alarm industry, we replace the batteries at 5 year intervals. At this
point, most of the batteries will be down to about 70% of capacity. However,
these batteries have a pretty easy life, rarely being called upon to provide
power and generally not bieng discharged deeply.

In a glider, life for a battery is tough. Deep discharge cycles and wild
temperature swings being the norm. Generally, discharging a lead acid below
80% charge will have an impact on its remaining life, below 50% is not
recommended. So life will be short, so to speak.

I agree with Paul, replacing batteries often is cheap insurance. I change
mine at 3 years and always store them fully charged.

all the best,

bumper (12 volts and proud of it!)

Udo Rumpf wrote:

So, if it's not the battery, your choices seem to be a modern radio
(like the Walter Dittel FSG 2T I mentioned) or going to a 14 volt
battery pack. Or waiting till you get closer to the airfield to make
your call :^)

Eric Greenwell


I have this Radio now for many years.
Based on what you and Tim are saying, I concluded that
this radio does not perform very well at lower voltage.
Only in the past couple of years while flying a glider with restrictive
space for a batteries (the standard 12v 7amp) have I noticed any
deficiency at low voltage even with fresh sets of batteries.
also this radio seem to eat more on stand by.
Prior to this I had no restriction in capacity and the problem never
came up. Other then that the radio works fine and has good range when
the voltage is up.

It's possible the radio is not performing as well at low voltages as it
did when new. Electronic parts do age, particularly capacitors. If this
is the problem, a clever and determined technician might be able to
discover the correct parts to replace. A couple calls to people that
repair these would be worth the effort - perhaps there are common
problems that are cheaply fixed.


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Eric Greenwell wrote:
Udo Rumpf wrote:

It's possible you have a problem not related to the voltage; e.g.,
maybe the voltage is dropping well below the 11.8 volts when the
transmitter is keyed, or the radio is not functioning within
specifications.
Eric Greenwell


I have a 720A Dittle radio
Power requirements;
Receive .1 - .4 amps
Transmit (tone) 1.4 amps (.8 amps unmodulated)
The 11.8 volts I was referring to is before transmit.
If I remember correctly when the battery is fully charged
and I hit the transmit button the voltage drops from 12.7 to 12.2.
Udo

With the battery run down to 11.8 volts, measure the voltage right at
the radio connector while keying the transmitter for 5-10 seconds. If it
drops more than it does when the battery is fully (or nearly so)
charged, the problem might be the battery.

However....
I found a German manual for the ATR720A (and ATR70C in English) on the
Filser site (I think they took over the radios from Avionic Dittel). The
specifications don't make any mention of what voltage range the radio
will function over, so I suspect 12 volt battery operation wasn't on
their minds when it was designed. This appears to be an older design
radio, and likely is one that would benefit from 14 volt operation.

Absolutely true. But if you look hard enough, you'll see Filser claims
10.5 to 16 volts as an input voltage range for this radio. The same or
better as the current generation of super radios, which according to the
experts on RAS, supposedly were redesigned to work on lower voltage.



So, if it's not the battery, your choices seem to be a modern radio
(like the Walter Dittel FSG 2T I mentioned) or going to a 14 volt
battery pack. Or waiting till you get closer to the airfield to make
your call :^)


Or, he could get three or four large 12 volt batteries, and keep switching
between them, like a lot of people do. Certainly works for a while.
Particularly if you swap out batteries every year or two so you're using
only really fresh ones.

The FSG 2T very specifically says don't try to transmit with less than 11
volts, so I think that would be an expensive option that really wouldn't
help out. I suppose he could get a new Becker, but it's supposed to have
have at least 12.4 volts. Wonder where all these new super-radios are that
people keep talking about???? When you look at the facts, they just turn
out to be figments of some rather active imaginations.


-Dave

Microair M760 Transceiver.

"Input Voltage 10 - 16 Volts Warning damage will occur above 16
Volts"

"The operator should remember that the minimum operating voltage is 10
volts. This is the loaded voltage (ie the voltage when the radio is
transmitting). For battery operators, check the battery voltage level,
then press the PTT briefly to note the voltage drop. If the voltage
dips by more than 0.5 volts, change the battery before flying."

I enjoy my active imagination but I can also read a spec sheet.

Andy wrote:
Microair M760 Transceiver.

"Input Voltage 10 - 16 Volts Warning damage will occur above 16
Volts"

"The operator should remember that the minimum operating voltage is 10
volts. This is the loaded voltage (ie the voltage when the radio is
transmitting). For battery operators, check the battery voltage level,
then press the PTT briefly to note the voltage drop. If the voltage
dips by more than 0.5 volts, change the battery before flying."

I enjoy my active imagination but I can also read a spec sheet.


You must have missed the part where it says "Input Voltage: Normal 13.8 Volts"
and "Emergency Min: 10.7"

http://www.microair.com.au/admin/upl...heet190905.pdf

The 10.7 emergency min was quoted for all revs of the radio up through
rev M.

The "Normal" 13.8 is what most people call Nominal. It's the only voltage
where the specs on power, distortion, etc are valid.

It's funny you should trot out the Microair as an example of some great
new radio supposed designed for 12 volt operation. In reality, it's been
one of the worst performers at low voltage transmit operation, regardless
of what the specs say.

It's just another radio designed for 14 volt operation, which works poorly
at low voltage, particularly on transmit. Same as we've had for at least
the last 20 years. Quoting specs of 10-16 volts with 13.8 nominal isn't
what I'd call news.

-Dave

David Kinsell wrote:

The FSG 2T very specifically says don't try to transmit with less
than 11 volts, so I think that would be an expensive option that
really wouldn't help out.

Contrary to what Dave writes, here is what the FSG 2T operation manual
says on page 50 of the FSG 2T Installation and Operation manual,
available on Wings&Wheels or Dittel's web site:

6.13 Emegency Operation

Without degradation the FSG 2T can be operated on a dc source between
11 Vdc and nearly 9 volts. This however will NOT reduce the TX
output level, RX sensitivity, and audio output power, due to internal
supply regulation. Below 11 volts the dc indicator flashes
continuously as low supply warning. Since the current drawn from the
battery will increase with lowered Dc supply voltage, the automatic
shut-down will speed-up.

If the supply voltage drops below 9 Vdc the FSG 2T swithces OFF
itself. This automatic feature avoids battery damage due to deep
discharging, even if the radio is left switched ON for months! This
is true for all types of 12 Vdc batteries.

If the battery recovers and voltage exceeds approximately 10.5 Vdc,
the radio returns to operation with the last used setting.

The above clearly shows why pilots have good experiences with Dittel
radios operating on 12 volt battery systems.

I suppose he could get a new Becker, but it's supposed to have have
at least 12.4 volts. Wonder where all these new super-radios are
that people keep talking about???? When you look at the facts, they
just turn out to be figments of some rather active imaginations.

I think I have found the explanation for the super-radios that we have
today. I stumbled across this reference recently:

Here’s the operating voltage matrix right out of DO-160 . . .

Voltage Category B

Maximum 15.1
Nominal 13.8
Minimum 11.0
Emergency 9.0


Modern avionics should operate over the voltage ranges cited for each
category of performance commensurate with the applicable system
voltage.

The table shows operation from 11.0 volts to 15.1, with emergency
operation down to 9 volts, essentially what the Becker and Dittel radios
(and probably others) specify. My short Google search for the standard
came up with an index

http://www.tuvamerica.com/industry/a...ce/emctest.cfm

and this

http://www.aeroelectric.com/articles/do160.html

that shows this specification is just one of many in the standard. I
don't know when the standard came into being, but I'm guessing it (or
the rationale behind it) is what drives manufacturers to produce radios
with a wide voltage tolerance. It's been around for a long time, as the
Dittel FSG 60 manual (March 1981) references the standard.

--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

Eric Greenwell wrote:
David Kinsell wrote:

The FSG 2T very specifically says don't try to transmit with less than
11 volts, so I think that would be an expensive option that really
wouldn't help out.

Contrary to what Dave writes, here is what the FSG 2T operation manual
says on page 50 of the FSG 2T Installation and Operation manual,
available on Wings&Wheels or Dittel's web site:


Utter baloney. The brochure for the radio, also available at the
W&W site, says:

"Is onboard supply sufficient? Observe onboard supply indicator
particularly during transmit, at least 11.0 Vdc must be shown!"


http://www.wingsandwheels.com/FSG2T%20Brouchure.pdf

Exactly which part is utter baloney; the manual or the brochure?

Tom