Date   

Re: Characterized my new v6

 

That is in fact how I first characterized my attenuator when I built it.

My test equipment is:
   VNA:        Agilent E5071B
   SA:           Agilent E4407B
   SigGen:   HP 8648C
Really, it's my company's R&D test lab equipment, but I like to pretend it's mine :-)

The SA's max input is 30dBM, so with 40dB attenuation at 0dBM, I'm nowhere near saturating it.

I did spend some time with my  attenuator and VNA today to measure it on all
the ham bands and then every 5 MHz up to 400 MHz.  I should have done this ages
ago.

I didn't realize it was so far off. From 160 to 6m it varied from 40.2 to 37.1 dB.
From 50 to 300MHz it was pretty flat staying between 37.0 and 37.4
and then from 300 to 400MHz it went from 37.2 to 36.1.

Refiguring the numbers showed less power than before, but no wins for the third harmonics for 15 or 30m  (40.4 and 39.5 down).

My test procedure is:
  1. Set Tx frequency
  2. Set SA frequency to match & span 100K Hz
  3. Set trace hold
  4. Key Tx for 1 second
  5. Measure peak on held trace

Next time I get a chance, I'll try reducing the bias and fiddling with the LPF torroids.

I did install a kit-projects AGC Sunday.  I seemed to not have broken anything, but
It took about an hour to install.  I used two cuts in the RF line to get rid of
the stubs under the AGC PCB.
I don't notice any difference with it on or off yet.
I guess that's what the weekends are for. 

John
K6JDS

On 6/20/2020 7:46 AM, Evan Hand wrote:
Is it not possible to verify the distortion of the SA input with a step attenuation on the input?  Drop the input by some amount (like 3 or 6 db) and verify that all signals are reduced by the same amount.  If all drop, then the input is not distorting.

Please let me know if this test is not valid, still somewhat new to SA use.
73
Evan
AC9TU


Re: Power supply

Bob Lunsford
 

Good info, Raj. Thanks.

Also, the SGM type lead-acid batteries, generally referred to as Deep Cycle, have a larger space than most regular batteries below the lead peroxide and pure sponge lead plates because it takes much longer for the residue from the plates to accumulate and build up to short out the plates. Many battery rebuild companies flush out the bottoms of batteries to get rig of that residue and then, after drying, they refill with acid and sell them as "reconditioned" batteries.

When I worked in the foreign car garage, half the batteries need not have been replaced if only the owners had removed the terminals every year and cleaned the battery and cable terminals. When they build up carbon at the terminals, that carbon acts like a resistor and develops a voltage across the carbon and the dells are not able to obtain a full charge. On average, auto batteries last only about five or six years but with proper cleaning, terminal care and water level maintenance, they can last much longer.

Bob — KK5R

On Tuesday, June 23, 2020, 1:01:32 AM EDT, Raj vu2zap <rajendrakumargg@...> wrote:


Bob,

I was told that the Toyota Camry handles charge between 20-80% only and they warranty the cells for the life
of the car I think.

Raj

At 23/06/2020, you wrote:
>The Army airfield battery techs also said that the way to avoid a nicad developing a memory was to not fully charge them. They develop the memory (where they have shorter times for supplying current) when they are forced to hold a maximum charge. Charging them to 80-90% of full design charge levels eliminates the memory.





Re: Power supply

 

Bob,

I was told that the Toyota Camry handles charge between 20-80% only and they warranty the cells for the life
of the car I think.

Raj

At 23/06/2020, you wrote:
The Army airfield battery techs also said that the way to avoid a nicad developing a memory was to not fully charge them. They develop the memory (where they have shorter times for supplying current) when they are forced to hold a maximum charge. Charging them to 80-90% of full design charge levels eliminates the memory.


Re: Beta Readers, closed!

Bob Lunsford
 

Reminds me of the old question: "Oh, say can you C...?" (snicker)

On Monday, June 22, 2020, 10:52:58 PM EDT, Jeff Debes <jeff.debes@...> wrote:


Best of luck ......but  its a very tall order to write anything on that subject  that everyone can understand.
 People have different minds, abilities  and very different styles of learning .
Have you considered that the design of ‘C’ itself is cryptic and may never be easy for most to learn?   
I never encountered any programming language book ( C or otherwise) that I thought was self-standing.
Most products made today put ease-of- learning and use as a nice-to-have option.
But again, good luck with the effort.

Jeff Debes
AC2JB 






On Jun 21, 2020, at 8:00 AM, Jack, W8TEE via groups.io <jjpurdum@...> wrote:


All:

Is this a great group of people or what? Almost 100 individuals offered their time to help read my new intro C book. To everyone one, thank you!

There is no way that I can read and do justice to the comments from 100 readers, so I need to shut down the volunteer Beta readers appeal and consider it closed. I will likely thin the number to perhaps a dozen or so readers. I'll do this in the next two days.

Again, thank you for your support...it is sincerely appreciated.

73,
Jack, W8TEE

--
Jack, W8TEE

--
jeff.debes@...


Re: Power supply

Bob Lunsford
 

The Army airfield battery techs also said that the way to avoid a nicad developing a memory was to not fully charge them. They develop the memory (where they have shorter times for supplying current) when they are forced to hold a maximum charge. Charging them to 80-90% of full design charge levels eliminates the memory.

Also, a ham named Peter Stark (now probably SK) had articles in QST and 73 Mag about "zapping nicads" when they short out, to zap the short they develop when the nicad plates form a link that grows between the plates. Does not work in all cases but it can restore some of them to service. I have used it and can vouch for the fact that some can be "repaired" but not all. You charge a big cap and use the charge to "zap" the shorted cell. Otherwise, the battery/cell is worthless so trying it may lead to success.

Bob — KK5R

On Monday, June 22, 2020, 10:46:00 PM EDT, Bill Cromwell <wrcromwell@...> wrote:


Hi Bob,

With appropriate transistors and heat sinks we can pick whatever charge
or discharge current we want. All the energy is converted to heat in the
transistor and it's heat sink and a small amount in the battery.

In your case somebody observed that the lights went out. In my case the
arduino (or other controller) watches for the "lights out". That
controller doesn't get distracted like the guy in the lab coat with
pocket saver and bow tie can. We also have to be careful not to get the
coffee mug to close to the 'data' on the clipboard. It is hard to read
on coffee damaged paper:)

73,

Bill  KU8H

bark less - wag more

On 6/22/20 5:07 PM, Bob Lunsford via groups.io wrote:
> I worked at Fort Hood in avionics for six years. Repaired some battery
> analyzers that would rejuvenate the NiCads used in the aircraft.
> Periodically, they'd discharge the batteries and recharge them to kill
> the memory that NiCads developed. They used aircraft landing lights for
> the load (we'd probably use brake lights) and when they got down to no
> light output, they'd clip shunts between the cells and leave 'em
> overnight. Then the analyzer would recharge the batteries and if they
> failed the test, they'd go through the discharge cycled again. The
> batteries could be recycled this way countless times.
>
> Today, lithium batteries are the name of the game. I've even wondered
> about putting three or four cell phone batteries in series to try them
> out. For their size and power possibilities, they interest me for QRP rigs.
>
> Bob — KK5R
>
> On Monday, June 22, 2020, 4:45:36 PM EDT, Jerry Gaffke via groups.io
> <jgaffke=yahoo.com@groups.io> wrote:
>
>
> I've been planning to build an arduino based battery evaluator as well.
>
>> My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage.
>
> Be aware that a lead acid battery (SLAB = sealed lead acid battery) has
> a very low internal impedance.
> A short could be hundreds or even thousands of amps, and may cause the
> battery to explode.
>
> I'd put some sort of load resistor on the output of that power
> transistor, an incandescent automotive tail-light
> as suggested by JohnR seems ideal for the small batteries typically
> lugged around with a radio.
> Here's the specs for the dual filament 1157 builb:
> http://www.run-n-lites.com/bulbspec.html
> So the brake filament burns 26.8 Watts at 12.8 Volts, the tail-light
> filament burns 8.3 Watts at 14 Volts.
> Why the brake filament is assumed to run at a lower voltage I have no
> idea, but current draw from
> a 12.0 Volt supply should be roughly 2 Amps for the brake filament and
> 0.66 Amps for the tail-light filament.
>
> We're off grid, for our really big lead acid batteries I use solid
> copper wire from old house wiring.
> For example, 14 awg solid copper wire is 2.5 ohms per 1000 feet, so 100
> feet is 0.25 Ohms,
> and across a 12 Volt battery will draw around 12/0.25 = 48 Amps,
> dissipating 12*48=576 Watts.
>
> An old car battery is worth about $10 at a scrap yard, as the lead can
> be recovered.
> The smaller batteries that JohnR described are worth a little bit as well,
> hence his statement of "If you had an old one to swap fantastic".
> Some outfits may consider batteries to be hazardous and have policies to
> prohibit
> giving them away, trading in an old one would keep their numbers lined up.
>
> Jerry, KE7ER
>
>
> On Mon, Jun 22, 2020 at 08:47 AM, Bill Cromwell wrote:
>
>    Hi John,
>
>    I have rolled my own and have considered additional sophistication
>    like what you describe. I have only four of those SLABs and I just
>    pay attention to how long they run the radios before a swap is
>    required. My idea was to use a power transistor as a current sink
>    into a dead short and draw it down to the low set point while
>    monitoring and recording the voltage. All while *I* do more
>    interesting things. Pencils and graph paper on a clipboard with a
>    clock demand a lot of attention. Been there- done that. An arduino
>    controller would be ideal. They don't seem to get bored:)
>
>    73,
>
>    Bill KU8H
>
>    bark less - wag more
>    Hide quoted text <#quoted-167966190>
>
>    On 6/22/20 11:33 AM, JohnR wrote:
>
>        I work for a phone company in maintenance. The fire alarm
>        batteries get swapped out every 3 years need it or not. All of
>        the batteries I use have been used for 3 years before I use them
>        on the radios. If you know of a fire system company or
>        maintenance people of buildings these are the people to ask. The
>        batteries are scrap at that point and some people are strict
>        about there scrap but the fire alarm people I deal with don't
>        care that much, if you want one or two no problem. If you had an
>        old one to swap fantastic. I have also found that battery AH
>        tester at Aliexpress for a couple of dollars, I forget but under
>        5$. I use a tail light off of a car as a load. It runs the
>        battery down to a certain voltage and cuts off. It then tells
>        you how many amp-hours the battery will produce and give you an
>        idea of how long it will last..Great for used batteries and to
>        know what you have for field day
>        73, John
>        This is the one I use.
>        New ZB2L3 Li-ion Lithium Lead-acid Battery Capacity Meter Discharge
>        Tester Analyzer Measurement Analysis Instruments
>        https://www.aliexpress.com/
>        --
>        “A single light can banish the darkness”
>        /Lux e tenebris
>        "A fool stares at the finger that points at the moon"
>        I Ching/
>
>




Re: Beta Readers, closed!

Jeff Debes
 

Best of luck ......but  its a very tall order to write anything on that subject  that everyone can understand.
 People have different minds, abilities  and very different styles of learning .
Have you considered that the design of ‘C’ itself is cryptic and may never be easy for most to learn?   
I never encountered any programming language book ( C or otherwise) that I thought was self-standing.
Most products made today put ease-of- learning and use as a nice-to-have option.
But again, good luck with the effort.

Jeff Debes
AC2JB 






On Jun 21, 2020, at 8:00 AM, Jack, W8TEE via groups.io <jjpurdum@...> wrote:


All:

Is this a great group of people or what? Almost 100 individuals offered their time to help read my new intro C book. To everyone one, thank you!

There is no way that I can read and do justice to the comments from 100 readers, so I need to shut down the volunteer Beta readers appeal and consider it closed. I will likely thin the number to perhaps a dozen or so readers. I'll do this in the next two days.

Again, thank you for your support...it is sincerely appreciated.

73,
Jack, W8TEE

--
Jack, W8TEE

--
jeff.debes@...


Re: Power supply

Bill Cromwell
 

Hi Bob,

With appropriate transistors and heat sinks we can pick whatever charge or discharge current we want. All the energy is converted to heat in the transistor and it's heat sink and a small amount in the battery.

In your case somebody observed that the lights went out. In my case the arduino (or other controller) watches for the "lights out". That controller doesn't get distracted like the guy in the lab coat with pocket saver and bow tie can. We also have to be careful not to get the coffee mug to close to the 'data' on the clipboard. It is hard to read on coffee damaged paper:)

73,

Bill KU8H

bark less - wag more

On 6/22/20 5:07 PM, Bob Lunsford via groups.io wrote:
I worked at Fort Hood in avionics for six years. Repaired some battery analyzers that would rejuvenate the NiCads used in the aircraft. Periodically, they'd discharge the batteries and recharge them to kill the memory that NiCads developed. They used aircraft landing lights for the load (we'd probably use brake lights) and when they got down to no light output, they'd clip shunts between the cells and leave 'em overnight. Then the analyzer would recharge the batteries and if they failed the test, they'd go through the discharge cycled again. The batteries could be recycled this way countless times.
Today, lithium batteries are the name of the game. I've even wondered about putting three or four cell phone batteries in series to try them out. For their size and power possibilities, they interest me for QRP rigs.
Bob — KK5R
On Monday, June 22, 2020, 4:45:36 PM EDT, Jerry Gaffke via groups.io <jgaffke=yahoo.com@groups.io> wrote:
I've been planning to build an arduino based battery evaluator as well.

My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage.
Be aware that a lead acid battery (SLAB = sealed lead acid battery) has a very low internal impedance.
A short could be hundreds or even thousands of amps, and may cause the battery to explode.
I'd put some sort of load resistor on the output of that power transistor, an incandescent automotive tail-light
as suggested by JohnR seems ideal for the small batteries typically lugged around with a radio.
Here's the specs for the dual filament 1157 builb: http://www.run-n-lites.com/bulbspec.html
So the brake filament burns 26.8 Watts at 12.8 Volts, the tail-light filament burns 8.3 Watts at 14 Volts.
Why the brake filament is assumed to run at a lower voltage I have no idea, but current draw from
a 12.0 Volt supply should be roughly 2 Amps for the brake filament and 0.66 Amps for the tail-light filament.
We're off grid, for our really big lead acid batteries I use solid copper wire from old house wiring.
For example, 14 awg solid copper wire is 2.5 ohms per 1000 feet, so 100 feet is 0.25 Ohms,
and across a 12 Volt battery will draw around 12/0.25 = 48 Amps, dissipating 12*48=576 Watts.
An old car battery is worth about $10 at a scrap yard, as the lead can be recovered.
The smaller batteries that JohnR described are worth a little bit as well,
hence his statement of "If you had an old one to swap fantastic".
Some outfits may consider batteries to be hazardous and have policies to prohibit
giving them away, trading in an old one would keep their numbers lined up.
Jerry, KE7ER
On Mon, Jun 22, 2020 at 08:47 AM, Bill Cromwell wrote:
Hi John,
I have rolled my own and have considered additional sophistication
like what you describe. I have only four of those SLABs and I just
pay attention to how long they run the radios before a swap is
required. My idea was to use a power transistor as a current sink
into a dead short and draw it down to the low set point while
monitoring and recording the voltage. All while *I* do more
interesting things. Pencils and graph paper on a clipboard with a
clock demand a lot of attention. Been there- done that. An arduino
controller would be ideal. They don't seem to get bored:)
73,
Bill KU8H
bark less - wag more
Hide quoted text <#quoted-167966190>
On 6/22/20 11:33 AM, JohnR wrote:
I work for a phone company in maintenance. The fire alarm
batteries get swapped out every 3 years need it or not. All of
the batteries I use have been used for 3 years before I use them
on the radios. If you know of a fire system company or
maintenance people of buildings these are the people to ask. The
batteries are scrap at that point and some people are strict
about there scrap but the fire alarm people I deal with don't
care that much, if you want one or two no problem. If you had an
old one to swap fantastic. I have also found that battery AH
tester at Aliexpress for a couple of dollars, I forget but under
5$. I use a tail light off of a car as a load. It runs the
battery down to a certain voltage and cuts off. It then tells
you how many amp-hours the battery will produce and give you an
idea of how long it will last..Great for used batteries and to
know what you have for field day
73, John
This is the one I use.
New ZB2L3 Li-ion Lithium Lead-acid Battery Capacity Meter Discharge
Tester Analyzer Measurement Analysis Instruments
https://www.aliexpress.com/
--
“A single light can banish the darkness”
/Lux e tenebris
"A fool stares at the finger that points at the moon"
I Ching/


Re: Power supply

Bill Cromwell
 

Hi,

You missed the part about the transistor. It *IS* the load resistor. If I set the transistors up to only allow 100 mA and feed that 100 mA to a dead short then the battery has a 100 mA load on it. The only way there could be more current (100 amps for example) flowing through the battery load is if the transistor fails short. I have been using this exact approach to charge my SLABs (and other batteries). There is a fuse to shut it down if the transistor fails short. It has been in use 25 years for lead-acid batteries. The NiCads and more recently the NiMH are charged the same way but with lower currents. The units all still have their original fuses in place. The NiCads gave me well over ten years service minimum and some even longer. The charge circuit works in reverse of the configuration I described. As an aside, "rapid charging" kills batteries.

I expect to use the same approach to charge Lithium batteries with a source voltage set to taper off the current when the battery approaches full charge. The arduino would be used to assure the charge is turned completely off when it is done. In this case the charging source is both current and voltage limited giving the taper charge. The controller would also chart A-H of charge and A-H of discharge. A 7 A-H battery requires more than 7 A-H of charge to get to to "full charge". Before the battery "fails" that difference will start to increase.

My use of the arduino would simply manage/record the whole process.

My SLABs are 7 A-H pulls you have mentioned. I got them from another ham. Good stuff.

73,

Bill KU8H

bark less - wag more

On 6/22/20 4:45 PM, Jerry Gaffke via groups.io wrote:
I've been planning to build an arduino based battery evaluator as well.

My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage.
Be aware that a lead acid battery (SLAB = sealed lead acid battery) has a very low internal impedance.
A short could be hundreds or even thousands of amps, and may cause the battery to explode.
I'd put some sort of load resistor on the output of that power transistor, an incandescent automotive tail-light
as suggested by JohnR seems ideal for the small batteries typically lugged around with a radio.
Here's the specs for the dual filament 1157 builb: http://www.run-n-lites.com/bulbspec.html
So the brake filament burns 26.8 Watts at 12.8 Volts, the tail-light filament burns 8.3 Watts at 14 Volts.
Why the brake filament is assumed to run at a lower voltage I have no idea, but current draw from
a 12.0 Volt supply should be roughly 2 Amps for the brake filament and 0.66 Amps for the tail-light filament.
We're off grid, for our really big lead acid batteries I use solid copper wire from old house wiring.
For example, 14 awg solid copper wire is 2.5 ohms per 1000 feet, so 100 feet is 0.25 Ohms,
and across a 12 Volt battery will draw around 12/0.25 = 48 Amps, dissipating 12*48=576 Watts.
An old car battery is worth about $10 at a scrap yard, as the lead can be recovered.
The smaller batteries that JohnR described are worth a little bit as well,
hence his statement of "If you had an old one to swap fantastic".
Some outfits may consider batteries to be hazardous and have policies to prohibit
giving them away, trading in an old one would keep their numbers lined up.
Jerry, KE7ER
On Mon, Jun 22, 2020 at 08:47 AM, Bill Cromwell wrote:
Hi John,
I have rolled my own and have considered additional sophistication
like what you describe. I have only four of those SLABs and I just
pay attention to how long they run the radios before a swap is
required. My idea was to use a power transistor as a current sink
into a dead short and draw it down to the low set point while
monitoring and recording the voltage. All while *I* do more
interesting things. Pencils and graph paper on a clipboard with a
clock demand a lot of attention. Been there- done that. An arduino
controller would be ideal. They don't seem to get bored:)
73,
Bill KU8H
bark less - wag more
Hide quoted text <#quoted-167966190>
On 6/22/20 11:33 AM, JohnR wrote:
I work for a phone company in maintenance. The fire alarm
batteries get swapped out every 3 years need it or not. All of
the batteries I use have been used for 3 years before I use them
on the radios. If you know of a fire system company or
maintenance people of buildings these are the people to ask. The
batteries are scrap at that point and some people are strict
about there scrap but the fire alarm people I deal with don't
care that much, if you want one or two no problem. If you had an
old one to swap fantastic. I have also found that battery AH
tester at Aliexpress for a couple of dollars, I forget but under
5$. I use a tail light off of a car as a load. It runs the
battery down to a certain voltage and cuts off. It then tells
you how many amp-hours the battery will produce and give you an
idea of how long it will last..Great for used batteries and to
know what you have for field day
73, John
This is the one I use.
New ZB2L3 Li-ion Lithium Lead-acid Battery Capacity Meter Discharge
Tester Analyzer Measurement Analysis Instruments
https://www.aliexpress.com/
--
“A single light can banish the darkness”
/Lux e tenebris
"A fool stares at the finger that points at the moon"
I Ching/


Re: Power supply

Bob Lunsford
 

I worked at Fort Hood in avionics for six years. Repaired some battery analyzers that would rejuvenate the NiCads used in the aircraft. Periodically, they'd discharge the batteries and recharge them to kill the memory that NiCads developed. They used aircraft landing lights for the load (we'd probably use brake lights) and when they got down to no light output, they'd clip shunts between the cells and leave 'em overnight. Then the analyzer would recharge the batteries and if they failed the test, they'd go through the discharge cycled again. The batteries could be recycled this way countless times.

Today, lithium batteries are the name of the game. I've even wondered about putting three or four cell phone batteries in series to try them out. For their size and power possibilities, they interest me for QRP rigs.

Bob — KK5R

On Monday, June 22, 2020, 4:45:36 PM EDT, Jerry Gaffke via groups.io <jgaffke@...> wrote:


I've been planning to build an arduino based battery evaluator as well.

> My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage.

Be aware that a lead acid battery (SLAB = sealed lead acid battery) has a very low internal impedance.
A short could be hundreds or even thousands of amps, and may cause the battery to explode.

I'd put some sort of load resistor on the output of that power transistor, an incandescent automotive tail-light
as suggested by JohnR seems ideal for the small batteries typically lugged around with a radio.
Here's the specs for the dual filament 1157 builb:  http://www.run-n-lites.com/bulbspec.html
So the brake filament burns 26.8 Watts at 12.8 Volts, the tail-light filament burns 8.3 Watts at 14 Volts.
Why the brake filament is assumed to run at a lower voltage I have no idea, but current draw from
a 12.0 Volt supply should be roughly 2 Amps for the brake filament and 0.66 Amps for the tail-light filament. 

We're off grid, for our really big lead acid batteries I use solid copper wire from old house wiring.
For example, 14 awg solid copper wire is 2.5 ohms per 1000 feet, so 100 feet is 0.25 Ohms,
and across a 12 Volt battery will draw around 12/0.25 = 48 Amps, dissipating 12*48=576 Watts.

An old car battery is worth about $10 at a scrap yard, as the lead can be recovered.
The smaller batteries that JohnR described are worth a little bit as well,
hence his statement of " If you had an old one to swap fantastic".
Some outfits may consider batteries to be hazardous and have policies to prohibit
giving them away, trading in an old one would keep their numbers lined up.

Jerry, KE7ER


On Mon, Jun 22, 2020 at 08:47 AM, Bill Cromwell wrote:
Hi John,

I have rolled my own and have considered additional sophistication like what you describe. I have only four of those SLABs and I just pay attention to how long they run the radios before a swap is required. My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage. All while *I* do more interesting things. Pencils and graph paper on a clipboard with a clock demand a lot of attention. Been there- done that. An arduino controller would be ideal. They don't seem to get bored:)

73,

Bill KU8H

bark less - wag more
Hide quoted text

 

On 6/22/20 11:33 AM, JohnR wrote:
I work for a phone company in maintenance. The fire alarm batteries get swapped out every 3 years need it or not. All of the batteries I use have been used for 3 years before I use them on the radios. If you know of a fire system company or maintenance people of buildings these are the people to ask. The batteries are scrap at that point and some people are strict about there scrap but the fire alarm people I deal with don't care that much, if you want one or two no problem. If you had an old one to swap fantastic. I have also found that battery AH tester at Aliexpress for a couple of dollars, I forget but under 5$. I use a tail light off of a car as a load. It runs the battery down to a certain voltage and cuts off. It then tells you how many amp-hours the battery will produce and give you an idea of how long it will last..Great for used batteries and to know what you have for field day
73, John
This is the one I use.
New ZB2L3 Li-ion Lithium Lead-acid Battery Capacity Meter Discharge
Tester Analyzer Measurement Analysis Instruments
https://www.aliexpress.com/
--
“A single light can banish the darkness”
/Lux e tenebris
"A fool stares at the finger that points at the moon"
I Ching/


Re: Power supply

Jerry Gaffke
 

I've been planning to build an arduino based battery evaluator as well.

> My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage.

Be aware that a lead acid battery (SLAB = sealed lead acid battery) has a very low internal impedance.
A short could be hundreds or even thousands of amps, and may cause the battery to explode.

I'd put some sort of load resistor on the output of that power transistor, an incandescent automotive tail-light
as suggested by JohnR seems ideal for the small batteries typically lugged around with a radio.
Here's the specs for the dual filament 1157 builb:  http://www.run-n-lites.com/bulbspec.html
So the brake filament burns 26.8 Watts at 12.8 Volts, the tail-light filament burns 8.3 Watts at 14 Volts.
Why the brake filament is assumed to run at a lower voltage I have no idea, but current draw from
a 12.0 Volt supply should be roughly 2 Amps for the brake filament and 0.66 Amps for the tail-light filament. 

We're off grid, for our really big lead acid batteries I use solid copper wire from old house wiring.
For example, 14 awg solid copper wire is 2.5 ohms per 1000 feet, so 100 feet is 0.25 Ohms,
and across a 12 Volt battery will draw around 12/0.25 = 48 Amps, dissipating 12*48=576 Watts.

An old car battery is worth about $10 at a scrap yard, as the lead can be recovered.
The smaller batteries that JohnR described are worth a little bit as well,
hence his statement of " If you had an old one to swap fantastic".
Some outfits may consider batteries to be hazardous and have policies to prohibit
giving them away, trading in an old one would keep their numbers lined up.

Jerry, KE7ER


On Mon, Jun 22, 2020 at 08:47 AM, Bill Cromwell wrote:
Hi John,

I have rolled my own and have considered additional sophistication like what you describe. I have only four of those SLABs and I just pay attention to how long they run the radios before a swap is required. My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage. All while *I* do more interesting things. Pencils and graph paper on a clipboard with a clock demand a lot of attention. Been there- done that. An arduino controller would be ideal. They don't seem to get bored:)

73,

Bill KU8H

bark less - wag more
Hide quoted text

 

On 6/22/20 11:33 AM, JohnR wrote:
I work for a phone company in maintenance. The fire alarm batteries get swapped out every 3 years need it or not. All of the batteries I use have been used for 3 years before I use them on the radios. If you know of a fire system company or maintenance people of buildings these are the people to ask. The batteries are scrap at that point and some people are strict about there scrap but the fire alarm people I deal with don't care that much, if you want one or two no problem. If you had an old one to swap fantastic. I have also found that battery AH tester at Aliexpress for a couple of dollars, I forget but under 5$. I use a tail light off of a car as a load. It runs the battery down to a certain voltage and cuts off. It then tells you how many amp-hours the battery will produce and give you an idea of how long it will last..Great for used batteries and to know what you have for field day
73, John
This is the one I use.
New ZB2L3 Li-ion Lithium Lead-acid Battery Capacity Meter Discharge
Tester Analyzer Measurement Analysis Instruments
https://www.aliexpress.com/
--
“A single light can banish the darkness”
/Lux e tenebris
"A fool stares at the finger that points at the moon"
I Ching/


Re: Power supply

Bob Lunsford
 

I remember working in a foreign car garage in the late '60's and the cars there were Renaults and Peugeots among a few Japanese cars. The French cars recommended setting the mechanical voltage regulators at between 13.8 and 14.2 volts for charging purposes but this was also to compensate for the batteries frequently being placed at one end of the car and the motor starter/generator at the other end. Therefore, it was to compensate for voltage drop in the battery cable. Also, if the voltage was too high, it tended to boil out the water in the battery but when this happened, you could smell it.

Bob — KK5R

On Monday, June 22, 2020, 9:38:42 AM EDT, Bill Cromwell <wrcromwell@...> wrote:


Hi,

The direct answer to your question is *yes*. Not even a qualified yes. I
operate *all* of my "twelve volt" gear on thirteen point eight volts (or
a little more. That includes my uBitx.

More info - The "12" volt automotive electrical voltage specification
allows up to 15 volts (it did when I was young) and still gets up to 14
volts (or so). It can drop to around 10 volts at discharged. That 13.8
number is a "nominal" which means a "name" for the average charging
voltage. That 15 volts was the recommended limit for adjustment of the
mechanical voltage regulators. We used to run with the headlights on -
not for safety - but to pull the system voltage down from that 15 (or
more) volts. Voltages that high were hard on some of the parts including
the battery. The battery need a drink of water frequently. 13.8 volts is
trivial.

Now doomsday people can list all the "12 volt" radios that die instantly
from 13.8 volts so I can make a list of radios to *never* buy (or even
accept as a gift).

73,

Bill  KU8H

bark less - wag more

On 6/21/20 10:45 PM, Bob Lunsford via groups.io wrote:
> Keep in mind that those batteries that are lead-acid when fully charged
> are closer to 13.6V but that comes down to closer to 12V after some
> current draw. Therefore, a better question, for my part, is whether the
> V6 can be run with confidence with 13.6V or should it be run only at
> about 12V? This is an important question to me since I will either be
> using a cheap batter like for a lawn mower that runs about $25 at Wally
> World or an emergency light gell cell which is about the same except
> without the liquid in the cells like in a simple lawn motor battery.
>
> On a uBITX for 40M I had before, I had some series 1A diodes to lower
> the applied voltage to the main board while keeping the two amplifier
> transistors at the higher 13.6V (brown wire) which may not have been
> necessary.
>
> In my case, perhaps a better way to get to the meat of the matter is to
> ask, what is the maximum voltage that can be safely applied to a V6...?
>
>
> On Sunday, June 21, 2020, 3:34:25 PM EDT, Gordon Gibby
> <docvacuumtubes@...> wrote:
>
>
> a 7amp hr sealed lead acid 12 volt battery with a 2 or 3 amp fuse does a
> very nice job.
>
> Gordon
>
>
> On Sun, Jun 21, 2020 at 2:57 PM thomas.adair <thomas.adair@...
> <mailto:thomas.adair@...>> wrote:
>
>    Can someone tell me what DC power supply and maps per hour to use
>    for the Bitx v6? Does 12 volts need to be stepped down to a certain
>    value?
>
>




OT - Arduino Related Terms - Crossword Puzzle

Dennis Zabawa
 

Need a break?  Try this puzzle: ARDUINO Crossword Puzzle


Re: Power supply

Dean Souleles
 

I have a v5 with the 2.8" Nextion screen.

I run off a 13.8V desktop supply at home with no problems.

For portable operation I use 12V rechargeable 3 Amp hour batteries from Talentcell..

https://www.amazon.com/TalentCell-Rechargeable-3000mAh-Lithium-External/dp/B01M7Z9Z1N/ref=sr_1_1?dchild=1&keywords=talentcell+rechargeable+12v+3000mah&qid=1592842699&sr=8-1

I can run a whole day SSB on one charge.

73,
Dean
KK4DAS
Dean


Re: Power supply

Bill Cromwell
 

Hi John,

I have rolled my own and have considered additional sophistication like what you describe. I have only four of those SLABs and I just pay attention to how long they run the radios before a swap is required. My idea was to use a power transistor as a current sink into a dead short and draw it down to the low set point while monitoring and recording the voltage. All while *I* do more interesting things. Pencils and graph paper on a clipboard with a clock demand a lot of attention. Been there- done that. An arduino controller would be ideal. They don't seem to get bored:)

73,

Bill KU8H

bark less - wag more

On 6/22/20 11:33 AM, JohnR wrote:
I work for a phone company in maintenance. The fire alarm batteries get swapped out every 3 years need it or not. All of the batteries I use have been used for 3 years before I use them on the radios. If you know of a fire system company or maintenance people of buildings these are the people to ask. The batteries are scrap at that point and some people are strict about there scrap but the fire alarm people I deal with don't care that much, if you want one or two no problem. If you had an old one to swap fantastic. I have also found that battery AH tester at Aliexpress for a couple of dollars, I forget but under 5$. I use a tail light off of a car as a load. It runs the battery down to a certain voltage and cuts off. It then tells you how many amp-hours the battery will produce and give you an idea of how long it will last..Great for used batteries and to know what you have for field day
73, John
This is the one I use.
New ZB2L3 Li-ion Lithium Lead-acid Battery Capacity Meter Discharge
Tester Analyzer Measurement Analysis Instruments
https://www.aliexpress.com/
--
“A single light can banish the darkness”
/Lux e tenebris
"A fool stares at the finger that points at the moon"
I Ching/


Re: Power supply

Mick
 

I also run my V6 from a 13.8 Vdc switching power supply (jet stream jpts32mab) and I have not had any issues.
--
 

73
Mick VA3EPM 


Re: Power supply

Bill Cromwell
 

Hi,

I have a V3 here and I do run from a lead-acid battery. Some of mine reach above 13 at full charge. I do NOT charge while I am actually using any of the batteries. That can go higher than 14 volts sometimes and will affect the load (the radio). My V3 has one of the more robust versions of the audio amp IC. Some were junk. If mine does die a different IC will be hired:) I also used the lead-acid battery to power a few uBitx radios I have fixed for some other hams (varied models). It has never been a problem.

In the end the owner must decide. This thread has been in response to a question about power supplies and "12 volts". I think we all covered it.

73,

Bill KU8H

bark less - wag more

On 6/22/20 11:11 AM, Allen Hill via groups.io wrote:
Don't forget the V3 which had power supply issues with audio amp. V4 was changed to a discrete audio amp to mitigate this. V5 was changed to a more voltage tolerate audio amp.
Thanks!
On June 22, 2020, at 10:55 AM, Evan Hand <elhandjr@...> wrote:
Everyone seems to forget the LM78L05ACZ regulator, however, for this discussion, it is rated at 30 volts input, so also not an issue.
In the pre v6 kits, having to wire the separate power lines, I always put in a diode to drop the voltage to the mainboard. This was done as much for reducing the voltage drop across the Raduino 5 volt regulator as any of the other components.
With the way that the power is supplied to the v6, it is now much harder to split off the power, so I would not do it for those rigs as N0YWB is suggesting.
YMMV
73
Evan


Re: Power supply

JohnR
 

I work for a phone company in maintenance. The fire alarm batteries get swapped out every 3 years need it or not. All of the batteries I use have been used for 3 years before I use them on the radios. If you know of a fire system company or maintenance people of buildings these are the people to ask. The batteries are scrap at that point and some people are strict about there scrap but the fire alarm people I deal with don't care that much, if you want one or two no problem. If you had an old one to swap fantastic. I have also found that battery AH tester at Aliexpress for a couple of dollars, I forget but under 5$. I use a tail light off of a car as a load. It runs the battery down to a certain voltage and cuts off. It then tells you how many amp-hours the battery will produce and give you an idea of how long it will last..Great for used batteries and to know what you have for field day
73, John
This is the one I use.

New ZB2L3 Li-ion Lithium Lead-acid Battery Capacity Meter Discharge Tester Analyzer Measurement Analysis Instruments

--

“A single light can banish the darkness”

Lux e tenebris 

"A fool stares at the finger that points at the moon"
I Ching




Re: Power supply

Allen Hill
 

Don't forget the V3 which had power supply issues with audio amp. V4 was changed to a discrete audio amp to mitigate this. V5 was changed to a more voltage tolerate audio amp.

Thanks!



On June 22, 2020, at 10:55 AM, Evan Hand <elhandjr@...> wrote:


Everyone seems to forget the LM78L05ACZ regulator, however, for this discussion, it is rated at 30 volts input, so also not an issue.

In the pre v6 kits, having to wire the separate power lines, I always put in a diode to drop the voltage to the mainboard. This was done as much for reducing the voltage drop across the Raduino 5 volt regulator as any of the other components. 

With the way that the power is supplied to the v6, it is now much harder to split off the power, so I would not do it for those rigs as N0YWB is suggesting.

YMMV
73
Evan 


Re: Power supply

Evan Hand
 

Everyone seems to forget the LM78L05ACZ regulator, however, for this discussion, it is rated at 30 volts input, so also not an issue.

In the pre v6 kits, having to wire the separate power lines, I always put in a diode to drop the voltage to the mainboard. This was done as much for reducing the voltage drop across the Raduino 5 volt regulator as any of the other components. 

With the way that the power is supplied to the v6, it is now much harder to split off the power, so I would not do it for those rigs as N0YWB is suggesting.

YMMV
73
Evan 


Re: Power supply

N0YWB
 

The TDA2822 audio amplifier integrated circuit on the original uBITx V6 is limited to 15 Volts. 
The LM386-N audio amplifier IC used later can tolerate 22 Volts. 
The maximum input voltage of the LM7805 voltage regulator is rated for 35 Volts no load, 
but is heat-limited to 20 Volts input at 1 Ampere rated output. 
The output power amplifier transistors are rated for 24 Volts. 
I do not recommend operating at more than 15 Volts input. 
My uBITx will draw 2.7 Amperes key-down at 13.8 Volts, and still operates at 9 Volts (with reduced output power). 
 
Note that healthy lead-acid batteries can rise to 14.2 Volts during rapid charging,  
and are typically 13.8 Volts during normal charging. 
Fully charged no-load voltage at room temperature is typically 12.7 volts, 
dropping to 12.2 Volts at 50 percent capacity, and 12.0 Volts at 25 percent capacity. 
Repeatedly discharging below 50 percent will significantly shorten the life of a lead-acid battery.