RAST Forum

Ham Radio in Thailand => Other => Topic started by: hs0zfe on March 10, 2012, 04:54:10 PM

Title: OT: NTSC in Thailand's 50 Hz / 220 Volts AC system
Post by: hs0zfe on March 10, 2012, 04:54:10 PM
Those gaming consoles are half price in America. But NTSC uses 60 cycles.  ???
A voltage converter might not be enough to make this work.
Apologies for this very off topic question. The modern TVs like a SHARP Aquous can handle both, PAL and NTSC and the JA standard.

Visitors from JA with their rigs with built in power supplies might have issues over here as well.

73 de Chris HS0ZFE
Title: Re: OT: NTSC in Thailand's 50 Hz / 220 Volts AC system
Post by: HS0ZED on May 12, 2012, 08:37:51 AM
Hi Chris,

It's a non issue, mostly.
TV's that work on multiple systems, or games consoles similarly configured should play well together here since all of the frequency specific stuff is generated or recovered internal to the unit. It makes no use of the mains frequency.

About the only 2 things I can think of where there might be a problem are electrical clocks that reference the AC supply for timing, these are largely historical items so little concern. The other item might be of interest to the high power ham since a majority of large vacuum tube linear amplifiers use synchronous motor driven blowers. These rotate 20% slower on 50Hz compared to 60Hz with a corresponding reduction of airflow. In a country not known for its cooler climes this can exacerbate the issue.

A related  issue that might apply to all is where power transformers, again big linears with large transformers are generally more of an issue here, are designed for 60Hz. Using such a transformer on a lower frequency supply will increase the losses and heat.

JA domestic market equipment is generally designed for 100 volt working. Many use such equipment with a typical 220 to 110 step down transformer, but this needs care. An example is the TS930 and TS940 JA market model radios. These have a power supply whose output is already close to the limit as to what the connected PA driver transistors can withstand. Add to that the fact that many domestic supplies in Thailand show 230 volts rather than 220 volts and now our 110 is 115. Thankfully we have probably seen the last of these failures since theses radios are falling out of use.

Cheers
Martin, HS0ZED