patents@dx0man.prestel.co.uk wrote:
> I'm intrigued by your query about the OMNI-V J310's. I have an OMNI-V
> and its now quite ancient. Are there any symptoms associated with
> J310 ageing ?? I feel, but cannot verify, that I've recently been
> getting more intermod than I used to get when the rig was newer,
> especially on 40m. Could be that the European QRM is a lot louder now
> I use ladder line instead of 100ft of coax, but it has occurred to
> me that I might also have a front end problem developing. The front
> end sensitivity on the HF (20 and up) bands appears to be low,
> although I can hear signals way down to the antenna noise if I crank
> up the RF gain. I cannot crank up the audio gain without getting
> noise of the wrong sort - not from the antenna. (My RF gain is usually
> well up, at 3-4 PM; audio stays down at 9-10 PM).
>
> The J310 is easily obtainable here, but I'm not sure how to set about
> matching a set of four. I think any replacement must use a well
> matched set, or it will defeat the object of sharing the work load.
>
> Incidentally, I replaced all the front end switching diodes with
> locally obtained pin diodes (not necessarily the best ones for the
> job - see recent comment on Paragon diode swap). This was before I
> discovered the obvious - I had a stuck reed relay !! There was no
> noticable performance improvement, even when I fixed the relay
> (with the help of the TT service dept).
>
> But I wonder if I should really be considering a complete re-alignment
> (is there any info on that available ?) after so much heavy use.
>
> 73 John G3JAG
>
> On 20-Jan-99 Steve Baron wrote:
> >
> > A few years ago I noticed that the voltage on a few of the J10's
> > was
> > significantly lower (0.5 to 1 V) than the others which were up
> > around 1.5
> > (1.7 ?) or so. Replaced some and all were 'balanced'.
> >
> > Recently had the covers off and checked them again and saw that a
> > few had
> > dropped again.
> >
> > Would appreciate any input on the effect of reduced voltage - and
> > perhaps a
> > number for the lowest that should be tolerated.
> >
> > Thanks.
> >
> >
> >
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>
> ----------------------------------
> E-Mail: patents@dx0man.prestel.co.uk
To: <tentec@contesting.com>
> Date: 22-Jan-99
> Time: 14:03:35
> John Crux
> Consultant in product forgery - Asia and
> Africa
>
> ----------------------------------
>
> --
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All you have to do is vary the value of the 100 ohm source/drain
resistor for each J310 until each device draws the same current. You
really don't have to match them otherways.
Bill Cook N4WC
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