Good work and very revealing.
So if I understand this correctly, the Jupiter produces 1.1% of 100 watts as
phase noise therefore you are transmitting about 1 watt of noise and plenty
of dx has been worked on 1 watt so why not continue to filter out that
obnoxious carrier and do some phase noise dxing? Better yet....How about
some MJC dxing (modulated Jupiter case).
Steve Ellington
N4LQ
----- Original Message -----
From: "WA3FIY" <wa3fiy@radioadv.com>
To: <tentec@contesting.com>
Sent: Friday, February 01, 2002 5:09 PM
Subject: Re: [TenTec] [Ten Tec] Pegasus keying...was More About Clix
> On 31 Jan 2002, at 22:56, Steve Ellington wrote:
> >
> > good enough for a code reference but not so for keying. As for the
> > Pegasus...I was refering to the transmitted signal, not the received.
> >
> OK, we have established that the Pegasus [and Jupiter] sound pretty
> good on receive when a decent sound system is used so I decided to
> take a close look or, listen as the case may be, to the transmit signal.
>
> My first test involved running my Peg into a dummy load at 10 watts
> and sending a LONG file via CW. I then went into the workshop
> "shack" at the other end of the house and listened to the signal on
> the following receivers......Collins 75S3, hallicrafters SR-400A
> Cyclone, Drake TR-4, Ten Tec CorsairII and finally Ten Tec
> Paragon. On each receiver, the signal was mid scale on the S meter
> so I was receiving a realistic level. Each receiver was attached to a
> short antenna which prevented any "outside" QRM. In other words,
> I was able to concentrate on my transmitted signal without
> interference .
>
> The signal sounded pretty good, in fact, I thought it sounded very
> good. Yes, some slight phase noise [I think] around the edges as I
> tuned through the signal, but a very nice signal. One I would be [in
> fact I am] proud to put on the air.
>
> OK, that test finished I came into the lab at work and rigged another
> test just to see if my ears were very far off base, and to obtain some
> data as everything up to this point has been pretty subjective.
>
> The test setup consisted of a Jupiter transmitting 10 watts into a
> dummy load with a -20db isolated coupler into a fixed 15db
> attenuator and a step attenuator set at about 66db. The isolated rf
> signal was then fed to a battery powered CRYSTAL controlled
> receiver with no agc and with with very low noise and distortion. I
> don't know the exact bandwidth of the crystal controlled receiver
> but it is somewhere around 2Khz. Output from the crystal controlled
> RX was then transformer isolated and fed to a harmonic distortion
> analyzer. In normal operation, the distortion analyzer is adjusted to
> completely remove the fundamental frequency from the equipment
> under test and anything left is considered harmonic distortion. In
> this case, the crystal controlled receiver distortion products are so
> low as to be insignificant, so anything left after nulling the
> fundamental signal from the receiver is transmitted noise, phase or
> otherwise.
>
> In the following tests, the signal source was set to provide the same
> output from the crystal controlled receiver in each case. I did run
> the power up to full power momentarily to see if it made any
> difference in the transmitted noise. It did not.
>
> Here are the results as indicated on the distortion analyzer:
>
> Jupiter - 1.1%
> Logimetrics analog signal generator - 0.6%
> Ten Tec Paragon - 0.5%
> Omni D C series - 0.4%
> Crystal reference oscillator - 0.09% [This is reaching the limits of
> my measuring ability]
>
> Tapping the Jupiter case caused the distortion measurement to jump
> to a little over 2%. Tapping on the desk where the rig was sitting
> caused little or no change. The signal generator was very bad in this
> respect and the Omni D was very good.
>
> It is clear that the Jupiter [and Pegasus] transmit some phase or
> other kind of noise. It is also clear that the amount of noise they
> transmit is of no consequence in all but the most exacting of
> applications, whatever that means. :-)
>
> It is also understandable that the Jupiter is worse than the Paragon
> because the Jupiter has two VCo's to cover 30 Mhz whereas the
> Paragon has four to cover the same range. So the Jupiter VCO tuning
> sensitivity is twice that of the Paragon. I don't know if there is any
> connection, but with twice as many VCO's the Paragon has
> approximately half the transmitted noise.
>
> But even at 1.1% transmitted noise, the Jupiter is pretty nice. Let's
> see..........that's 0.011 to 1 or about -40db close in........very close
in.
> In the "old days" 30db quieting on an FM receiver was considered
> full quieting. Or put another way, one has to look for the noise
> before it is noticible. In fact that seems to be the case. This does
> not seem to be an issue until someone starts talking about it which
> draws attention to it and then it is an issue. Kind of like a fly speck
> on the ceiling, not noticible until someone points it out. :-)
>
> In closing, I can only say that every day I use either my Pegasus or
> Jupiter, I enjoy them more and I give Ten Tec a great big thank you
> for producing such fine gear at such affordible prices. And to think
> that the best is yet to come!!!!!
>
> -73-
>
> -Lee-
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