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[XG-2] A little help with math

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Ken Bessler

[XG-2] A little help with math

Here's a quote from a 2006 post W3AB made:
=============================================
A while ago someone asked a question about the above. I
didn't see a reply so I just built a XG2 and checked it with
a HP 8562A spectrum analyzer, the DUT connected directly
into the SA without any cable. I repeated the measurements
three times over the course of 1 hour. They didn't change

Frequencies in MHz and the Po in dBm.

80M - 03.579 = 03.57910 @ -75.00 & -106.3
40M - 07.040 = 07.04015 @ -73.67 & -106.0
20M - 14.060 = 14.05982 @ -73.50 & -105 8
3 X 40M = 21.12052 @ -85.33
4 X 40M = 28.16077 @ -93.67
2 X 20M = 28.11962 @ 81.50
=============================================

I hate to admit it but I'm having trouble with those last 3
values (-85.33, -93.67 & 81.50). Are they Po in mV? Can
anyone convert those to -dBm for me? I tried to e-mail W3AB
but it's bouncing. Help? Thanks!

73's de Ken KG0WX - Kadiddlehopper #11808,
Flying Pigs #-1055, Grid EM17ip

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Don Wilhelm-4

Re: [XG-2] A little help with math

Ken,

I believe those units are already dBm - nothing else makes sense, and
there is a missing minus sign on the last one. +81.5 dBm would be a
very large signal - 141.3 kilowatts into 50 ohms - minus 81.50 dBm does
make sense.

If you want a handy tool for dB calculations, you may want to download
the mini dB calculator by DL5SWB. Google for the website.

73,
Don W3FPR

Ken Bessler wrote:

> Here's a quote from a 2006 post W3AB made:
> =============================================
> A while ago someone asked a question about the above. I
> didn't see a reply so I just built a XG2 and checked it with
> a HP 8562A spectrum analyzer, the DUT connected directly
> into the SA without any cable. I repeated the measurements
> three times over the course of 1 hour. They didn't change
>
> Frequencies in MHz and the Po in dBm.
>
> 80M - 03.579 = 03.57910 @ -75.00 & -106.3
> 40M - 07.040 = 07.04015 @ -73.67 & -106.0
> 20M - 14.060 = 14.05982 @ -73.50 & -105 8
> 3 X 40M = 21.12052 @ -85.33
> 4 X 40M = 28.16077 @ -93.67
> 2 X 20M = 28.11962 @ 81.50
> =============================================
>
>
> I hate to admit it but I'm having trouble with those last 3
> values (-85.33, -93.67 & 81.50). Are they Po in mV? Can
> anyone convert those to -dBm for me? I tried to e-mail W3AB
> but it's bouncing. Help? Thanks!
>
>
> 73's de Ken KG0WX - Kadiddlehopper #11808,
> Flying Pigs #-1055, Grid EM17ip
>
>
>
>
> _________________________________________________________________
> Climb to the top of the charts! Play Star Shuffle: the word scramble challenge with star power.
> http://club.live.com/star_shuffle.aspx?icid=starshuffle_wlmailtextlink_oct_______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>
>

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