[RFI] Ultrasonic receivers

[EDWARDS, EDDIE J]

> -----Original Message-----
> From:	Rob Atkinson, K5UJ 
> Has anyone had any experience using an ultrasonic receiver of some
> sort to 
> find an arc?
> 
> American Science and Surplus sells an ultrasonic receiver kit for 18
> or 19 
> bucks.  
> 
	Hi Rob,

	Yes, we use an Ultrasonic parabolic detector (UltraProbe 2000)
here at work to confirm noisy power poles and determine what exact piece
hardware is causing the noise.  They're also used in other industrial
applications without the parabolic dish to check for electrical faults
in switchgear or liquid leaks and the like.  Ours made by UE Systems,
Inc. (Elmsford, NY) and costs $4300 several years ago.  Yes, it's
expensive (in amateur terms, not commercial), but good industrial test
equipment is always expensive if it's well built to take punishment.
It's extremely sensitive with pinpoint precision.  I pointed it at some
birds flying by and picked up flutter off their wings!  In one case I
was able to determine which side of the transformer squirrel guard was
giving me the noise.  That's precise!!!  

	Here's the specs on ours:
	Freq range: 20 khz -- 100 khz
	Transducer type: Piezoelectric
	Transducer config: Septisonic: Phased array of 7 transducers
	Transducer cable is RF shielded
	Parabola is acrylic w/urethane handle
	Whole unit is anodized aluminum about 2.5 lbs.
	Detection range: (5psi thru 0.005" orifice) 100 feet
	Parabola size: 18.25" x 4.125" deep
	Comes with ear-muff headphones, a foam lined instrument case
	Has a sensitivity selector and a meter
	Has 1 year warranty (never needed)
	Comes with a training video
	Info Hotline: 800-223-1325 if you want your power company to buy
one!

	As you can tell, we've been very pleased with this unit.  Spec
sheet also mentions that electrical arcs are generally best heard around
40 khz.

	Looking at the web page you mentioned, I doubt that the unit's
transducer(s) (is it an Array? or only one?) is very sensitive.
Probably good for 5-10 ft range if even that.  It won't help for noise
at the top of a power pole at all.  This is definitely a case of "You
get what you pay for" in my opinion.  But for the money it might be fun
to play with to see if you could make it better by adding better
transducers and a parabolic dish.  

	Tnx for the cool web site link!  Some really neat stuff on
there.

	73,
	de ed -K0iL
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Ed Edwards, Communications Engineer
2-Way & Paging Systems
Omaha Public Power District   
Omaha, NE
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