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my uBitx Power

Joe Puma
 

Hey guys,

I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.


Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v

band current watts
80 2.18 27.14
60 1.50 18.67
40 1.97 24.52
30 1.42 17.67
20 1.65 20.54
17 1.22 15.18
15 1.15 14.31
10 1.0 12.45

If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
 

Hi Joe,

You could separate the brown wire that feeds the Drains of the finals and measure just that current. It will probably not be substantially different from the way you did it - subtracting the receive current.

The power you are measuring that way is the DC power *input* to your finals. In the olde dayes the TX power and the vacuum tube ratings were defined in terms of *input* power. That is always going to be higher than the RF output power. The difference will be accounted for by the efficiency. If the finals are 50 percent efficient (a reasonable possibility) and you calculated say 24 watts then your RF output power would be about 12 watts. One details that is good to know is the efficiency of your finals. You will need to measure the actual RF output power and calculate the DC input power as you already have done. Dived theout put power by the input power and get a decimal number less than 1. If that number is 0.5 then your efficiency is 50 percent. It could be less. Probably not much more. Some tube amps made greater than 75 percent! But you could not use them for SSB. If you know the efficency then you can calculate output power by measuring that DC input power and leave your fancy, expensive RF wattmeter in the case at home when you take your radio to Field Day.

73,

Bill KU8H

On 11/01/2018 02:07 PM, Joe Puma wrote:
Hey guys,

I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.


Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v

band current watts
80 2.18 27.14
60 1.50 18.67
40 1.97 24.52
30 1.42 17.67
20 1.65 20.54
17 1.22 15.18
15 1.15 14.31
10 1.0 12.45

If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.



--
bark less - wag more
 

You also need to subtract the Tx idle current. You can find this by keying up the mic with no audio input. This current is mainly the bias current in the finals but also the relays and some other things. The Tx idle current will vary with band.


On Nov 1, 2018, at 11:07 AM, Joe Puma <kd2nfc@...> wrote:

Hey guys,

I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.


Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v

band current watts
80 2.18 27.14
60 1.50 18.67
40 1.97 24.52
30 1.42 17.67
20 1.65 20.54
17 1.22 15.18
15 1.15 14.31
10 1.0 12.45

If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
Clark Martin
KK6ISP
Another Designated Engineer on the Information Super Railway.
 

I should have said you need to subtract the Tx idle current instead of the Rx idle current.

Sent from an iPhone, don't ask whose.

On Nov 1, 2018, at 12:13 PM, Clark Martin <kk6isp@...> wrote:

You also need to subtract the Tx idle current. You can find this by keying up the mic with no audio input. This current is mainly the bias current in the finals but also the relays and some other things. The Tx idle current will vary with band.


On Nov 1, 2018, at 11:07 AM, Joe Puma <kd2nfc@...> wrote:

Hey guys,

I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.


Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v

band current watts
80 2.18 27.14
60 1.50 18.67
40 1.97 24.52
30 1.42 17.67
20 1.65 20.54
17 1.22 15.18
15 1.15 14.31
10 1.0 12.45

If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
Clark Martin
KK6ISP
Another Designated Engineer on the Information Super Railway.
Joe Puma
 

Okay on SSB without talking that was .80a

I forgot to mention that my measurements was taking while pressing the CW key.

Joe

On Nov 1, 2018, at 3:13 PM, Clark Martin <kk6isp@...> wrote:

You also need to subtract the Tx idle current. You can find this by keying up the mic with no audio input. This current is mainly the bias current in the finals but also the relays and some other things. The Tx idle current will vary with band.


On Nov 1, 2018, at 11:07 AM, Joe Puma <kd2nfc@...> wrote:

Hey guys,

I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.


Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v

band current watts
80 2.18 27.14
60 1.50 18.67
40 1.97 24.52
30 1.42 17.67
20 1.65 20.54
17 1.22 15.18
15 1.15 14.31
10 1.0 12.45

If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
Clark Martin
KK6ISP
Another Designated Engineer on the Information Super Railway.
Joe Puma
 

Ok got it.

On Nov 1, 2018, at 4:10 PM, Clark Martin <kk6isp@...> wrote:

I should have said you need to subtract the Tx idle current instead of the Rx idle current.

Sent from an iPhone, don't ask whose.

On Nov 1, 2018, at 12:13 PM, Clark Martin <kk6isp@...> wrote:

You also need to subtract the Tx idle current. You can find this by keying up the mic with no audio input. This current is mainly the bias current in the finals but also the relays and some other things. The Tx idle current will vary with band.


On Nov 1, 2018, at 11:07 AM, Joe Puma <kd2nfc@...> wrote:

Hey guys,

I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.


Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v

band current watts
80 2.18 27.14
60 1.50 18.67
40 1.97 24.52
30 1.42 17.67
20 1.65 20.54
17 1.22 15.18
15 1.15 14.31
10 1.0 12.45

If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
Clark Martin
KK6ISP
Another Designated Engineer on the Information Super Railway.
 

I hope your coming wattmeter will come properly set with reliable readings at least for CW keydown or average SSB power. It seems there are many cases they sell stuff non properly set. When I got the licence I too had bought a new swr-power which was showing misleading values. Luckily enough at the local ham radio club my elmers not only found the problem but in few minutes set it right (three trimmers....). I have to say my wattmeter was neither Chinese nor Indian (!!!!) but made in Japan... A reliable and cheap way to measure the power (not the swr) on CW keydown is the RF detector as the one sold by Hendricks.


Il 02/nov/2018 03:11, "Joe Puma" <kd2nfc@...> ha scritto:
Ok? got it.
> On Nov 1, 2018, at 4:10 PM, Clark Martin <kk6isp@...> wrote:
>
> I should have said you need to subtract the Tx idle current instead of the Rx idle current.
>
> Sent from an iPhone, don't ask whose.
>
>> On Nov 1, 2018, at 12:13 PM, Clark Martin <kk6isp@...> wrote:
>>
>> You also need to subtract the Tx idle current.? You can find this by keying up the mic with no audio input.? This current is mainly the bias current in the finals but also the relays and some other things.? The Tx idle current will vary with band.
>>
>>
>>> On Nov 1, 2018, at 11:07 AM, Joe Puma <kd2nfc@...> wrote:
>>>
>>> Hey guys,
>>>
>>> I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.
>>>
>>>
>>> Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v
>>>
>>> band? ? ? ? current? ? ? ? watts
>>> 80? ? ? ? ? ? 2.18? ? ? ? ? ? 27.14
>>> 60? ? ? ? ? ? 1.50? ? ? ? ? ? 18.67
>>> 40? ? ? ? ? ? 1.97? ? ? ? ? ? 24.52
>>> 30? ? ? ? ? ? 1.42? ? ? ? ? ? 17.67
>>> 20? ? ? ? ? ? 1.65? ? ? ? ? ? 20.54
>>> 17? ? ? ? ? ? 1.22? ? ? ? ? ? 15.18
>>> 15? ? ? ? ? ? 1.15? ? ? ? ? ? 14.31
>>> 10? ? ? ? ? ? 1.0? ? ? ? ? ? 12.45
>>>
>>> If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
>>
>> Clark Martin
>> KK6ISP
>> Another Designated Engineer on the Information Super Railway.
>>
>>
>>
>>
>
>
>
>



Joe Puma
 

¿ªÔÆÌåÓý

I do have a device I can use to probe. But max rf voyage is 3v. ?I would have to use resistors with a little trick Jeffery here in the group taught me. I suppose I can try that route and see what it reads.?

Joe



On Nov 2, 2018, at 12:34 PM, iz oos <and2oosiz2@...> wrote:

I hope your coming wattmeter will come properly set with reliable readings at least for CW keydown or average SSB power. It seems there are many cases they sell stuff non properly set. When I got the licence I too had bought a new swr-power which was showing misleading values. Luckily enough at the local ham radio club my elmers not only found the problem but in few minutes set it right (three trimmers....). I have to say my wattmeter was neither Chinese nor Indian (!!!!) but made in Japan... A reliable and cheap way to measure the power (not the swr) on CW keydown is the RF detector as the one sold by Hendricks.


Il 02/nov/2018 03:11, "Joe Puma" <kd2nfc@...> ha scritto:
Ok? got it.
> On Nov 1, 2018, at 4:10 PM, Clark Martin <kk6isp@...> wrote:
>
> I should have said you need to subtract the Tx idle current instead of the Rx idle current.
>
> Sent from an iPhone, don't ask whose.
>
>> On Nov 1, 2018, at 12:13 PM, Clark Martin <kk6isp@...> wrote:
>>
>> You also need to subtract the Tx idle current.? You can find this by keying up the mic with no audio input.? This current is mainly the bias current in the finals but also the relays and some other things.? The Tx idle current will vary with band.
>>
>>
>>> On Nov 1, 2018, at 11:07 AM, Joe Puma <kd2nfc@...> wrote:
>>>
>>> Hey guys,
>>>
>>> I will probably have a watt meter in the coming weeks but I still haven¡¯t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.
>>>
>>>
>>> Voltage is 12.67 Radio idle and 12.45 while Tx¡¯ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v
>>>
>>> band? ? ? ? current? ? ? ? watts
>>> 80? ? ? ? ? ? 2.18? ? ? ? ? ? 27.14
>>> 60? ? ? ? ? ? 1.50? ? ? ? ? ? 18.67
>>> 40? ? ? ? ? ? 1.97? ? ? ? ? ? 24.52
>>> 30? ? ? ? ? ? 1.42? ? ? ? ? ? 17.67
>>> 20? ? ? ? ? ? 1.65? ? ? ? ? ? 20.54
>>> 17? ? ? ? ? ? 1.22? ? ? ? ? ? 15.18
>>> 15? ? ? ? ? ? 1.15? ? ? ? ? ? 14.31
>>> 10? ? ? ? ? ? 1.0? ? ? ? ? ? 12.45
>>>
>>> If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
>>
>> Clark Martin
>> KK6ISP
>> Another Designated Engineer on the Information Super Railway.
>>
>>
>>
>>
>
>
>
>



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