power supply interference with radio broadcast

Chris Soucy · July 16th, 2011, 01:16 AM

Geez, and there was me thinking 88 - 108 Mhz (a la the UK) was sacrosanct for the music stations, just goes to show, you learn something every single day.

No nearer to solving your problem though, sorry to take the thread off at a tangent.

What's it to be -

another linear regulatr attached to the spare one you have?

A new LR that O/P's what you need?

A total rebuild of the workflow?

Where are you in NZ BTW, 1 Watt doesn't get you far on the West coast of the South island?

CS

Renton Maclachlan · July 16th, 2011, 02:29 AM

Just had a brain wave tonight... about a guy who I know can help and would love to...and I know has knowledge re ipods...

Greg Miller · July 16th, 2011, 05:29 AM

Glad to hear you finally thought of someone local with some knowledge of electronics.

Anyone with more than a basic high school knowledge of electronic circuits could solve this for you in about an hour. No smoke. No mirrors. No magnets. Just good old elementary electronics.

Brian P. Reynolds · July 16th, 2011, 08:18 AM

I was in my local second hand store this morning "Cash Converters" they had a box full of old phone chargers, computer power supplies, and plug packs from toys and video games etc.
Voltages range from 3v AC to 24v DC and every thing in between and several at 5v DC and by the weight some had transformers in them. and ALL............. $2 EACH.

Renton Maclachlan · July 16th, 2011, 02:30 PM

Quote:

Originally Posted by Brian P. Reynolds

I was in my local second hand store this morning "Cash Converters" they had a box full of old phone chargers, computer power supplies, and plug packs from toys and video games etc.
Voltages range from 3v AC to 24v DC and every thing in between and several at 5v DC and by the weight some had transformers in them. and ALL............. $2 EACH.

Hmmm...now that is an idea. We have a 'Cash Converters' just down the road...Thanks!

Greg Miller · July 16th, 2011, 08:36 PM

Just be absolutely sure the output voltage is regulated! You don't want to fry your iThing.

Take a digital voltmeter with you when you dig through those old, relatively unknown, power supplies. If the output is much more than 5.1 or at worst 5.25 volts, don't buy that one.

And if you're going to wire a USB connector to it, it goes withotu saying that you need to be very careful of polarity and correct pinout.

Brian P. Reynolds · July 22nd, 2011, 02:06 AM

I don't know how your going, but had another thought is get a plug in 12v car lighter adaptor for the ipod. It would have an inbuilt regulator to cope with varying car voltages 12-13.8v then feed it from a 12v DC transformer power adaptor that should be easy to find.

Renton Maclachlan · July 22nd, 2011, 05:22 AM

Quote:

Originally Posted by Brian P. Reynolds

I don't know how your going, but had another thought is get a plug in 12v car lighter adaptor for the ipod. It would have an inbuilt regulator to cope with varying car voltages 12-13.8v then feed it from a 12v DC transformer power adaptor that should be easy to find.

Thanks Brian. I haven't got there yet. Have talked to a friend with clues and contacts and hope to talk to someone tomorrow. I'll mention your idea.

Renton

Greg Miller · July 22nd, 2011, 06:47 AM

Quote:

Originally Posted by Brian P. Reynolds

another thought is get a plug in 12v car lighter adaptor for the ipod. It would have an inbuilt regulator to cope with varying car voltages 12-13.8v then feed it from a 12v DC transformer power adaptor that should be easy to find.

Well, the car lighter adapter most likely has a switch-mode regulator in it. And most 12V "transformer power adapters" these days have switch-mode regulators in them. So you're trading his present problem (one switch-mode regulator) for twice as much potential problem (TWO switch-mode regulators). I fail to see any advantage in that approach!

One NZ vendor (tradetech) told me that NZ has power efficiency regulations in place, which prevent them from selling anything except switch-mode regulators at this point in time (with very few exceptions apparently).

So I think the previous suggestion of going to a used-stuff store (or yard sales, or wherever) with a voltmeter in hand, might be the only option *IF* he wants to buy locally.

Of course other countries might have other regulations, if he wants to import. I have a box of old linear supplies here, but they have the wrong input specs: USA is 120v/60Hz, whereas NZ is 230v/50Hz. He might find something appropriate from another European country. In that case, he'd have to change the original AC input plug for one of the NZ style... I doubt if he has the technical expertise to do that.

The OP apparently hasn't done anything about this in a week's time, so it doesn't appear to be terribly urgent.

Renton Maclachlan · July 22nd, 2011, 04:05 PM

I certainly don't have technical expertise in this area, but I am pursuing it with people here who do. I am in their hands.

While it is not crashingly urgent, I want to resolve it as quick as possible because of the PR with the owner of the house where the gear is.

Brian P. Reynolds · July 22nd, 2011, 05:51 PM

The 12v adaptor would have only a 3 pin voltage regulator and some resistors in it as you are only working with low voltage DC volts. (not switch mode)

Just a little off subject... but are you transmitting music or chat type radio or some other, what is the range of the transmission and have you had copyright problems with music content (if any).

Renton Maclachlan · July 22nd, 2011, 06:23 PM

Quote:

Originally Posted by Brian P. Reynolds

The 12v adaptor would have only a 3 pin voltage regulator and some resistors in it as you are only working with low voltage DC volts. (not switch mode)

Just a little off subject... but are you transmitting music or chat type radio or some other, what is the range of the transmission and have you had copyright problems with music content (if any).

I've finally connected with someone who knows exactly what is needed and why, and is prepared to fix something up for me - a 5v linear power supply, which some here have suggested, which he has some of apparently. So problem may be solved next week.

RE your off topic question...I run a prerecorded 82 hour program (at the moment - though I have about 15 more hours available to go on to the program). The program is looped so runs 24/7/52. It sounds just like a conventional station though without time or geographic indicators. I'm the host and the program consists of serious documentaries about life the universe and everything focused on origin issues. I have about 480 music tracks without repeats of a wide variety of genre, most played in blocks of four back to back, between docos. I'm covered for copyright through paying a special annual fee to APRA, for low-powered non-commerial radio stations. NZ has several parts of the fm band set aside for low power (max 1w) free to air broadcasting. Range is about max of 10km...I have been on the web and need to get back on...

Greg Miller · July 22nd, 2011, 07:27 PM

Quote:

Originally Posted by Brian P. Reynolds

The 12v adaptor would have only a 3 pin voltage regulator and some resistors in it as you are only working with low voltage DC volts. (not switch mode)

You might think so, but that's not necessarily the case. I have seen some (marketed for use with cellphones) that seemed (based on the parts I saw inside) to be some sort of switcher. No transformer, mind you, but apparently some sort of PCM switcher that ultimately charged the output cap to the desired voltage (I don't recall whether it was +5 or something else) by use of variable pulse width.

Even though the input is +12 and not +180, I suppose it still runs cooler and is more efficient than a linear, although it may seem like a minor point at that low a voltage.

Greg Miller · July 22nd, 2011, 07:30 PM

Quote:

Originally Posted by Renton Maclachlan

NZ has several parts of the fm band set aside for low power (max 1w) free to air broadcasting. Range is about max of 10km.

What a great opportunity! Too bad the FCC didn't think of that when they allocated the FM broadcast frequencies here in the USA.

Rick Reineke · July 23rd, 2011, 09:39 AM

The FCC has Low-Power FM. (LPFM) One still needs a license to broadcast legally though of coarse. In fact I worked (audio) on a news show piece about it about eight or so years ago for NBC when the classification was still in congress. One of the main supporters was Sen. John McCain R-AZ . I don't recall the max. transmission wattage or other technical details though but I think with all favorable conditions, the range was about 5 miles at best.

July 16th, 2011, 01:16 AM	#46
Chris Soucy Inner Circle Join Date: Feb 2007 Location: Fairfield, Dunedin, New Zealand Posts: 3,691 Images: 18	Re: power supply interference with radio broadcast Geez, and there was me thinking 88 - 108 Mhz (a la the UK) was sacrosanct for the music stations, just goes to show, you learn something every single day. No nearer to solving your problem though, sorry to take the thread off at a tangent. What's it to be - another linear regulatr attached to the spare one you have? A new LR that O/P's what you need? A total rebuild of the workflow? Where are you in NZ BTW, 1 Watt doesn't get you far on the West coast of the South island? CS

July 16th, 2011, 02:29 AM	#47
Renton Maclachlan Trustee Join Date: Jul 2007 Location: New Zealand Posts: 1,180	Re: power supply interference with radio broadcast Just had a brain wave tonight... about a guy who I know can help and would love to...and I know has knowledge re ipods...

July 16th, 2011, 05:29 AM	#48
Greg Miller Trustee Join Date: Jan 2011 Location: Pennsylvania Posts: 1,791	Re: power supply interference with radio broadcast Glad to hear you finally thought of someone local with some knowledge of electronics. Anyone with more than a basic high school knowledge of electronic circuits could solve this for you in about an hour. No smoke. No mirrors. No magnets. Just good old elementary electronics.

July 16th, 2011, 08:18 AM	#49
Brian P. Reynolds Major Player Join Date: Jan 2010 Location: Adelaide, South Australia Posts: 466	Re: power supply interference with radio broadcast I was in my local second hand store this morning "Cash Converters" they had a box full of old phone chargers, computer power supplies, and plug packs from toys and video games etc. Voltages range from 3v AC to 24v DC and every thing in between and several at 5v DC and by the weight some had transformers in them. and ALL............. $2 EACH.

July 16th, 2011, 08:36 PM	#51
Greg Miller Trustee Join Date: Jan 2011 Location: Pennsylvania Posts: 1,791	Re: power supply interference with radio broadcast Just be absolutely sure the output voltage is regulated! You don't want to fry your iThing. Take a digital voltmeter with you when you dig through those old, relatively unknown, power supplies. If the output is much more than 5.1 or at worst 5.25 volts, don't buy that one. And if you're going to wire a USB connector to it, it goes withotu saying that you need to be very careful of polarity and correct pinout.

July 22nd, 2011, 02:06 AM	#52
Brian P. Reynolds Major Player Join Date: Jan 2010 Location: Adelaide, South Australia Posts: 466	Re: power supply interference with radio broadcast I don't know how your going, but had another thought is get a plug in 12v car lighter adaptor for the ipod. It would have an inbuilt regulator to cope with varying car voltages 12-13.8v then feed it from a 12v DC transformer power adaptor that should be easy to find.

July 22nd, 2011, 04:05 PM	#55
Renton Maclachlan Trustee Join Date: Jul 2007 Location: New Zealand Posts: 1,180	Re: power supply interference with radio broadcast I certainly don't have technical expertise in this area, but I am pursuing it with people here who do. I am in their hands. While it is not crashingly urgent, I want to resolve it as quick as possible because of the PR with the owner of the house where the gear is.

July 22nd, 2011, 05:51 PM	#56
Brian P. Reynolds Major Player Join Date: Jan 2010 Location: Adelaide, South Australia Posts: 466	Re: power supply interference with radio broadcast The 12v adaptor would have only a 3 pin voltage regulator and some resistors in it as you are only working with low voltage DC volts. (not switch mode) Just a little off subject... but are you transmitting music or chat type radio or some other, what is the range of the transmission and have you had copyright problems with music content (if any).

July 23rd, 2011, 09:39 AM	#60
Rick Reineke Inner Circle Join Date: Aug 2008 Location: New York Posts: 2,039	Re: power supply interference with radio broadcast The FCC has Low-Power FM. (LPFM) One still needs a license to broadcast legally though of coarse. In fact I worked (audio) on a news show piece about it about eight or so years ago for NBC when the classification was still in congress. One of the main supporters was Sen. John McCain R-AZ . I don't recall the max. transmission wattage or other technical details though but I think with all favorable conditions, the range was about 5 miles at best.