[time-nuts] 4 KV Power Supply Recommendations

[Stanley Reynolds]

I think the marketing term is "Inverter" for the switching microwaves. Have one in the Kitchen but I'm not allowed to disamble it till it's replaced. Label says 120V 12.7 amps made in china 2006.

Stanley



----- Original Message ----
From: Didier Juges <didier at cox.net>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Mon, January 18, 2010 4:10:19 PM
Subject: Re: [time-nuts] 4 KV Power Supply Recommendations

I could not resist, so I checked my relatively expensive Sears/Kenmore
microwave oven.
The results are there:
http://www.ko4bb.com/Test_Equipment/Microwave_oven_leakage/

In one word, dismal. Almost 1W peak power leakage at 1 foot, and almost
100MHz occupied bandwidth.

I looked with a crystal detector driving a scope, and it is obvious the unit
is driven from a 60Hz transformer with half wave rectification, and has no
filtering whatsoever, like the first Microwave oven I have ever opened (a 20
years old model long dead).

Didier KO4BB


> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Chuck Harris
> Sent: Monday, January 18, 2010 8:28 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] 4 KV Power Supply Recommendations
> 
> As I understand it, the supplies are 100KHz, and have no 
> significant filtering at HV.  They modulate the magnetron 
> with the 100KHz PWM mess.  As long as the signal doesn't 
> leave the rather wide ISM band, they are under no obligation 
> to filter anything.... routers, etc. are squatters on the IMS 
> band, after all.
> 
> I am sure that some brands are better than others, but then 
> some brands are only $50.
> 
> I don't have any of the new ovens as yet... My old beaters 
> from the early '90s are still running strong.  I have no 
> neighbors, so their choices are not an issue.
> 
> -Chuck Harris
> 


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