[R-390] 8640B

[Ben Loper]

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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