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Re: [Amps] wirewound resistor inductance/capacitance parameters

To: <pc5m@xs4all.nl>, <Amps@contesting.com>
Subject: Re: [Amps] wirewound resistor inductance/capacitance parameters
From: Shane Youhouse <kd6vxi@gmail.com>
Date: Mon, 18 Apr 2011 11:29:28 -0700
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I just checked a Dale old school 'sand' wirewound, swept from 1.79 to 4.33.

100 ohms, 3 watts.  R ranged from  100 to  102.   X from 12 to 13.  Swr was 2.1 
to 2.0, all readings from lo to high vs freq.

Next I tried a gold colored encased power resistor w two bolt holes, at 
olpposite ends.

At 1.7625, R=5, X=0, swr = 8.8
At 4.3305, R=7, X=9, swr = 9.1

Marked 8 ohms, 5 percent, 25 watt. 

Didnt have the values you NEEDED, but it would seem that at 1.8-2, 6 or 7 of 
these aluminum encased style would work.

Transistors have ratings, tubes have guidelines!

--Shane  
Kilowatt Delta Six Victor Xray India

-----Original Message-----
From: pc5m, Carel <pc5m@xs4all.nl>
Sent: Monday, April 18, 2011 02:15 AM
To: Amps@contesting.com
Subject: Re: [Amps] wirewound resistor inductance/capacitance parameters



Jim, thanks for your reply, however my goal is to see what can be
done with those low cost chassis mount resistors. The non-inductive
one's (or special thickfilm resistor) are much more expensive....  

So,
I was hoping that someone had taken some data for those low cost ones?
In the meantime I did take some crude RF measurements and two 100 Ohm
50W resistors in parallel gave a 1:1.2 SWR (-20dB RL) at 2 MHz. That is
encouraging...but before I order a massive amount I would like to limit
the risk a bit more... 

73's Carel. 

On Sun, 17 Apr 2011 18:14:31
-0700, Jim W7RY wrote: 

> There are LOTS of non inductive resistors out
there (thick film etc)! 
> Consult the Mouser catalog. Download a Mouser
catalog at
> 
> www.mouser.com [6]
> 73
> Jim W7RY
> 
>
--------------------------------------------------
> From: "pc5m, Carel"

> Sent: Saturday, April 16, 2011 8:37 AM
> To: 
> Subject: [Amps]
wirewound resistor inductance/capacitance parameters
> 
>> Hi, Was
wondering if someone had some RF data (inductance/capacitance, or even
better a spice model..) of the general available low cost aluminum
housed high power (e.g. 50W) resistors for chassis mount? Example are
the Vishay NH series ( http://www.vishay.com/docs/30201/30201.pdf [2])
but also Welwyn and Ohmite run comparable products. Goal would be to
construct some high-power (kW's) dummy oad for 160mtrs (so only
reasonable well reflectionloss needed till 2 MHz..). Did google a bit
but didn't found anything useful. Thanks in advance, Carel
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Links:
------
[1] http://www.vishay.com/docs/30201/30201.pdf
[2]
http://www.vishay.com/docs/30201/30201.pdf
[3]
mailto:Amps@contesting.com
[4]
http://lists.contesting.com/mailman/listinfo/amps
[5]
http://www.avg.com
[6] http://www.mouser.com
[7]
mailto:pc5m@xs4all.nl
[8] mailto:Amps@contesting.com
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