Wow, that'll teach me not to read my manual. 1 Watt resolution on the SWR
meter? Someone didn't have his thinking cap on that day.
Scott
--
Scott Johnson (scott@wowpage.com) (s.johnson@klotzdigital.com)
ICQ: 30730876 ICBM: N33 45 50.6 W84 49 31.3 (+- 3dB)
> -----Original Message-----
> From: tentec-bounces@contesting.com
> [mailto:tentec-bounces@contesting.com]On Behalf Of Mark Erbaugh
> Sent: Wednesday, January 29, 2003 3:35 PM
> To: Larry; Ten Tec
> Subject: Re: [TenTec] Jupiter swr
>
>
> Larry,
>
> One of the limitations of the Pegasus (and I assume the Jupiter)
> is that the
> forward and reflected power can only be read to a whole watt (i.e. 0, 1,
> 2 - nothing in between). With lower forward power readings (such
> as in tune
> mode), there may not be enough reflected power to get an
> accurate SWR. For
> example with a forward power of 20 watts and reflected power of 0
> watts, the
> SWR is 1.0:1 (naturally), with a reflected power of 1 watt, the SWR is
> 1.6:1. At 20 watts output, there is no way to get an SWR reading between
> 1.0 and 1.6. As the output power increases, the SWR resolution becomes
> better.
>
> Another way of putting it: Assume that the SWR is 1.4:1. With
> that SWR, the
> reflected power is about 3% of the forward power. With 100 watts out, that
> would be 3 watts. With 20 watts out, that is only 0.6. Since the
> Jupiter can
> only read to the nearest watt, that 0.6 watts gets reported as 1
> watt, which
> gives the swr of 1.6:1. As you increase the power to 100 watts,
> the SWR will
> appear to drop to 1.4:1
>
> Also, any additional line loss that the Jupiter sees that your analyzer is
> not seeing will tend to reduce the SWR. Are you connecting the analyzer at
> exactly the same place in the feedline?
>
> Mark
>
>
> ----- Original Message -----
> From: "Larry" <w5wlb@gbronline.com>
> To: "Ten Tec" <tentec@contesting.com>
> Sent: Wednesday, January 29, 2003 12:35 PM
> Subject: [TenTec] Jupiter swr
>
>
> > I notice after building my 40m dipole that the swr as seen by
> the jupiter
> is lower than the swr as seen by my analyser.The jupiter also
> shows a lower
> swr when speaking into the mike than it does when in the tune position.Its
> not really important to me since its quite a bit below 2to1 but I
> asumed all
> these readings would be some what closer than what they are.Is there a
> simple answere for these differences ?
> > W5wlb Larry
> > _______________________________________________
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> > TenTec@contesting.com
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> >
>
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