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power for qrp-labs dds

 

Ive used the mini360 dc to dc converter to power a vfo 12v down to 5v. Seems to work ok but it use it as an outboard vfo so not in the box with the radio.
 

Or put 2x 7805 regulators in parallel ; I have done that for a router for which I did not have the 7.5V power supply unit ,fitting 2 x 7808 regulators in a small aluminium enclosure ; after 5 years still operational without any problems.

Frank? GM0CSZ / KN6WH


On Tue, Jan 24, 2017 at 4:41 PM, Lawrence Galea <9h1avlaw@...> wrote:
You can use a 7809 or 7808 before the 7805 to spread the dissipation in each regulator.
Lawrence
 

You can use a 7809 or 7808 before the 7805 to spread the dissipation in each regulator.
Lawrence
 

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Frank

Building one today - thanks for your help
73
Art

Sent from my iPhone

On Jan 24, 2017, at 10:44 AM, Frank Dinger,GM0CSZ <gm0csz@...> wrote:

You don't need a buck converter just a 7805 regulator or its lower current sibling 78L05 with input 12V ,output 5V with both up- and down-stream capacitors (electrolytic and ceramic)? to prevent possible oscillation.

On Tue, Jan 24, 2017 at 8:15 AM, Art Olson via Groups.Io <olsonaj6927@...> wrote:

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art
 

You don't need a buck converter just a 7805 regulator or its lower current sibling 78L05 with input 12V ,output 5V with both up- and down-stream capacitors (electrolytic and ceramic)? to prevent possible oscillation.

On Tue, Jan 24, 2017 at 8:15 AM, Art Olson via Groups.Io <olsonaj6927@...> wrote:

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art
Jack Purdum
 

Hi Ryan:?

I think that's my next step. The buck converter worked fine on the Forty-9er, but I think this receiver is more sensitive.

Thanks!

Jack, W8TEE


From: Ryan Flowers <geocrasher@...>
To: [email protected]
Sent: Tuesday, January 24, 2017 1:56 AM
Subject: Re: [BITX20] power for qrp-labs dds

I just used a 7805 regulator connected to 12v. Works fine so far. Yes, you lose a little power in heat, so it's not as efficient as a buck converter, but I don't consider it an issue for my use.
Hope this helps!
Ryan KC7RYS
 

I just used a 7805 regulator connected to 12v. Works fine so far. Yes, you lose a little power in heat, so it's not as efficient as a buck converter, but I don't consider it an issue for my use.

Hope this helps!

Ryan KC7RYS
 

Art,

I am assuming you are building your own;

?

I used an LM7808 ?(8v) regulator into the Nano (Arduino), and use the 5v out of the Nano to power the DDS /LCD (if you're building your own)

?

I have also used these successfully to help eliminate noise;

http://www.xppower.com/pdfs/SF_IV.pdf

to power a noisy OLED display - but they are not cheap and you need to be aware of your power requirements.

Rgds,
Darryl

?

?

On 2017-01-24 11:15 AM, Art Olson via Groups.Io wrote:

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art
 

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Great suggestions. Will give it a try

Thanks

Art

Sent from my iPhone

On Jan 23, 2017, at 7:42 PM, M Garza <mgarza896@...> wrote:

Hi Art,
What is wrong with using a 7805 to provide the 5 volts?? It should not create any noise.

Marco - KG5PRT?

On Jan 23, 2017 6:15 PM, "Art Olson via Groups.Io" <olsonaj6927=[email protected]> wrote:

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art
M Garza
 

Hi Art,
What is wrong with using a 7805 to provide the 5 volts?? It should not create any noise.

Marco - KG5PRT?

On Jan 23, 2017 6:15 PM, "Art Olson via Groups.Io" <olsonaj6927=[email protected]> wrote:

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art
 

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Use a 5 volt 3 pin regulator, powered from the 12 volt rail?


On 24/01/2017 11:15 AM, Art Olson via Groups.Io wrote:

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art
 

开云体育

Art,

I built a small board with a 7805 on it.? Haven't tested it yet.

73,? George


On 1/23/2017 6:15 PM, Art Olson via Groups.Io wrote:

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art
 

the Bitx40 uses 12v natively however the qrp-labs DDs vfo requires 5 volts. I have tried several buck converters but there is a lot of hashing (noisy) when the converter is powered on. Anyone have a suggestion as to anything I might try. If I use an external 5 volt wall wart then the problem (noise)?goes away. I don't want to have a 12 v power connection and have to run a wall wart also.

73

art

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