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Author Topic: Digital mode isolation needed?  (Read 9872 times)

2E1CLS

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Digital mode isolation needed?
« on: January 11, 2013, 11:33:55 AM »

Hi, I read somewhere that you don't really need to isolate your radio from the pc and can simply connect the leads straight up? Can someone let me know if this is right or wrong?


Many thanks Carl.
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N4CR

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RE: Digital mode isolation needed?
« Reply #1 on: January 11, 2013, 01:19:45 PM »

It's right if it doesn't cause any problems.

A 600:600 ohm transformer stolen from an old computer modem is a fine example of free isolation. I tell everyone I want their old modem cards and I liberate the transformers.
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73 de N4CR, Phil

Never believe an atom. They make up everything.

AA4PB

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RE: Digital mode isolation needed?
« Reply #2 on: January 11, 2013, 04:07:55 PM »

Isolation (transformers or optical isolators) are often used to ensure that you don't have any issues with ground currents flowing in the connecting shields between the radio and the computer grounds. Often it is not needed (I've done it several times) but you must run some tests to ensure that you are transmitting a clean signal (no hum, etc).
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Bob  AA4PB
Garrisonville, VA

KE4DRN

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RE: Digital mode isolation needed?
« Reply #3 on: January 22, 2013, 06:28:39 PM »

hi Carl,

Take a look at this page

http://www.qsl.net/wm2u/interface.html

73 james
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K5TED

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RE: Digital mode isolation needed?
« Reply #4 on: January 29, 2013, 08:27:58 PM »

Buy an inexpensive stereo "ground loop isolator", for anywhere between $5 to $35, depending on your shopping skills. Use the Left channel line for transmit, the Right channel line for receive. Enjoy your newfound peace of mind and clean signal. No soldering required.

These are commonly used in car audio and sound reinforcement applications. You might need a couple of phono to mini stereo plug adapters as well.
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