[R-390] 8640B

[Mack Rogers]

Both mine are firm but not really what I'd call stiff. I presume it would also depend on how well used each one might be? I bought both mine from a surplus dealer with a good reputation and a very good bench tech.

N4VGB
Mack Rogers



--- On Mon, 1/10/11, Ben Loper <brloper at gmail.com> wrote:

> From: Ben Loper <brloper at gmail.com>
> Subject: Re: [R-390] 8640B
> To: r-390 at mailman.qth.net
> Date: Monday, January 10, 2011, 3:53 PM
> This may be a tough question to
> answer, but how tight should the tuning knob
> on an 8640B be.  I know it shouldn't spin like a well
> adjusted R-390.  On
> mine it's consistent across the range and makes no weird
> noises, but there
> is definite resistance when I turn it and since this is the
> only one I've
> ever had I don't know if that's normal.  I assume the
> know should be fairly
> stiff to avoid it moving after you set it, but I'm just
> curios.  Mine works
> great.  Ben KJ4CC 
> 
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of Doug Massey
> Sent: Monday, January 10, 2011 2:35 PM
> To: Mack Rogers; r-390 at mailman.qth.net
> Subject: Re: [R-390] 8640B
> 
> 
> Amen to both posts!!!!!!!! They are the best....period.
> 
> Doug Massey
> N4ZZT
> Massey Radio Labs
> Johnston SC 29832
> WWW.masseyradiolabs.com
> 
> Mack Rogers <n4vgb at yahoo.com>
> wrote:
> 
> >And here I thought myself as being a bit obsessive
> compulsive when I 
> >purchased my second 8640. Bottom line is it's the
> biggest bang for the 
> >buck out there at this time. It's a very good and
> accurate sig gen with 
> >a super clean output.
> >
> >N4VGB
> >Mack Rogers
> >
> >
> >
> >
> >--- On Mon, 1/10/11, wa4aos at aol.com
> <wa4aos at aol.com>
> wrote:
> >
> >> From: wa4aos at aol.com
> <wa4aos at aol.com>
> >> Subject: [R-390] 8640B
> >> To: r-390 at mailman.qth.net,
> gcbojr at aol.com
> >> Date: Monday, January 10, 2011, 2:45 PM
> >> 
> >>  
> >> 
> >>  Hi Group,
> >> 
> >> I have 4) 8640B's in my electronics lab and use
> them often. I have 
> >> them set up on various benches and that makes
> service, burn-in and 
> >> evaluation all possible with minimal moving units
> around. I bought 
> >> two of the from George Bojr in Texas and he has
> repaired another one 
> >> for me. He has parts for the 8640B and does a
> GREAT job with service. 
> >> The turn around was quick and I was very pleased.
> You can find them
> >> cheaper on ebay but understand you may get a dud
> and or one
> >> with split gears and other issues. George can not
> give you a
> >> NIST sticker but his equipment is calibrated and
> all of my
> >> units are dead on between units. He does sell on
> ebay but
> >> may have inventory for sale at any given time. 
> >> 
> >> Personally, I like the 8640B for receiver work.
> They are accurate, 
> >> dependable and small compared to older units like
> the 606A/B..You can 
> >> also use it's internal counter for external
> measurements, so, it's 
> >> really two pieces of equipment, though, I have
> other counters,
> >> 
> >> Typically, I let them warm up half an hour before
> I do any serious 
> >> alignments as I would no matter what generator I
> use.. Like most HP 
> >> gear, the 8640B accepts and external 10MHz
> reference input should you 
> >> care to do that. I bought one of the 10MHz GPS
> receivers on ebay with 
> >> antenna for around $150 and build an adequate
> distribution unit to
> >> reference a number of HP items in my lab. You can
> also find
> >> pulled Rubidium clocks with a 10MHz out very cheap
> now as
> >> well, under $100. Nothing like knowing you are
> dead on
> >> accurate.
> >> Keep in mind, the 10 MHz external reference is
> just
> >> something I wanted to have; I have a very bad case
> of
> >> gadget-itus. Hi Hi . 
> >> 
> >> The 8640B's calibrated are plenty good enough for
> almost anything you 
> >> will need for working on HF receivers.
> >> 
> >> His email address is
> >> www.gcbojr at aol.com
> >> 
> >> 73,
> >> Glenn Scott WA4AOS
> >> DSM Labs
> >> 
> >> 
> >> 
> >>
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> >
> >      
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