I think you have mistaken the tilde symbol as a negative sign. Tim's 11 dBm
is into the pad.
7 dBm +- 2 dB into 50 ohms is the spec for the mv89 no?
On Saturday, 1 October 2016, Bob Camp wrote:
> HI
>
> > On Oct 1, 2016, at 4:08 PM, Scott Stobbe
HI
> On Oct 1, 2016, at 4:08 PM, Scott Stobbe wrote:
>
> If you used a 6db pad in conjunction with a 50 ohm termination you are spot
> on. If you used a 6dB pad as a 50 ohm load, the effective load will be a
> bit higher than 50 and the attenuation less than 6 dB.
If you used a 6db pad in conjunction with a 50 ohm termination you are spot
on. If you used a 6dB pad as a 50 ohm load, the effective load will be a
bit higher than 50 and the attenuation less than 6 dB. Either way sounds
like the output stage of your OCXO is in spec for 7 dBm into 50 ohms.
On
On Wed, Sep 28, 2016 at 3:30 PM, Scott Stobbe wrote:
> You are certainly no where near -40 dBm into 50 ohms as the blog Bryan
> posted above. Your setup may have 70-80 pF of load (~220 Ohms), if you also
> measured the output voltage with a 10x probe you could work
t;
> >
> > Regards
> >
> > - Original Message - From: "Scott Stobbe" <
> scott.j.sto...@gmail.com>
> > To: "Discussion of precise time and frequency measurement"
> > <time-nuts@febo.com>
> > Sent: Wednesday, Sept
bo.com>
> Sent: Wednesday, September 28, 2016 2:38 PM
> Subject: Re: [time-nuts] Normal operating specs of a Morion MV89?
>
>
>
>> If you used a 10x probe (10 Meg || 10-15 pF) you may have a pretty weak
>> output, but if you could drive a meter of coax or a 1
t;scott.j.sto...@gmail.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Sent: Wednesday, September 28, 2016 2:38 PM
Subject: Re: [time-nuts] Normal operating specs of a Morion MV89?
If you used a 10x probe (10 Meg || 10-15 pF) you may have
If you used a 10x probe (10 Meg || 10-15 pF) you may have a pretty weak
output, but if you could drive a meter of coax or a 1x probe to 800 mVrms
at 10 MHz your probably not too far off spec.
100 pF at 10 MHz is 160 Ohms.
On Wed, Sep 28, 2016 at 12:39 PM, Tim Lister wrote:
From my experience, your best and cheapest approach is to contact the
seller and see if they will just send you a replacement. If the seller
won't cooperate, and insists that you return the item, just close the issue
and try to repair it, or buy another one. If you bought the MV89 from an
On Wed, Sep 28, 2016 at 4:14 AM, Bob Camp wrote:
> Hi
>
> You have one of the many MV89A’s with an output problem. To be absolutely
> sure of the output, you need to have the scope set to 50 ohm input. If it was
> set
> to Hi-Z, the output is likely even lower…..
It seems that
Your oscilloscope fft is plotting single-side amplitude spectrum in V/rtHz
(dBV/rtHz), this is in contrast to a spectrum analyzer which plots power
spectral density W/Hz or (dBm/Hz).
So -2.17 dBv is 10^(-2.17/20) = 0.779 Vrms comparing this to your Vpk-pk
measurement
2.3 / 2 / sqrt(2) = 0.813
Hi
You have one of the many MV89A’s with an output problem. To be absolutely
sure of the output, you need to have the scope set to 50 ohm input. If it was
set
to Hi-Z, the output is likely even lower…..
Bob
> On Sep 28, 2016, at 1:38 AM, Tim Lister wrote:
>
> On Tue,
Take care that the 'scope is not a 50 ohm load: the TDS2024B has not
the 50ohm/1Mohm input selection. So far I wasn't able to get from the
'scope FFT the same measurements that I get from a spectrum analyzer.
On Wed, Sep 28, 2016 at 7:38 AM, Tim Lister wrote:
> On Tue, Sep
On Tue, Sep 20, 2016 at 12:56 PM, Bryan _ wrote:
> May also want to check the output amplitude. If memory serves me correct it
> is very common for a capacitor inside this model number to fail. It can be
> fixed but requires a torch or a pretty heavy duty soldering iron to
http://www.rbarrios.com/projects/MV89A/
-=Bryan=-
> To: time-nuts@febo.com
> From: a...@pcscons.com
> Date: Tue, 20 Sep 2016 15:09:41 -0700
> Subject: Re: [time-nuts] Normal operating specs of a Morion MV89?
>
> Hi Brian
>
> which cap is failing in the MV89 oxco-s?
&g
These have been discussed before at some length. It is not just the
output cap that is easily damaged by rough salvage efforts, which
however are sadly common enough. There is also a frequently seen
problem of bad output spectra with a lot of non harmonic related stuff
in the output, not a
from what I have read they
>> are a good OCXO minus the issue of the one particular cap failing.
>>
>> -=Bryan=-
>>
>>> From: brayn...@gmail.com
>>> Date: Tue, 20 Sep 2016 20:06:59 +
>>> To: time-nuts@febo.com
>>> Subject: Re: [ti
m what I have read they are a
> good OCXO minus the issue of the one particular cap failing.
>
> -=Bryan=-
>
>> From: brayn...@gmail.com
>> Date: Tue, 20 Sep 2016 20:06:59 +
>> To: time-nuts@febo.com
>> Subject: Re: [time-nuts] Normal operating specs of a Mor
bruce.griffi...@xtra.co.nz said:
>> It is possible to check the output level without an oscilloscope ?
> Only with a clasical (diode detector) RF probe (they're still available) or
> an RF power meter.
How about a diode, small cap, and a DC meter? (and a few clip leads)
It won't give an
of the one particular cap failing.
-=Bryan=-
From: brayn...@gmail.com
Date: Tue, 20 Sep 2016 20:06:59 +
To: time-nuts@febo.com
Subject: Re: [time-nuts] Normal operating specs of a Morion MV89?
Yes. This low output due to capacitor failure is a very common failure.
From the last set of MV89a I
+
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Normal operating specs of a Morion MV89?
>
> Yes. This low output due to capacitor failure is a very common failure.
> From the last set of MV89a I got on the bay, all had this issue.
>
> I had good luck opening
On Tuesday, September 20, 2016 01:53:49 PM Tim Lister wrote:
> On Tue, Sep 20, 2016 at 12:56 PM, Bryan _
wrote:
> > May also want to check the output amplitude. If memory serves me
correct
> > it is very common for a capacitor inside this model number to fail. It
> > can be
On Tue, Sep 20, 2016 at 12:56 PM, Bryan _ wrote:
> May also want to check the output amplitude. If memory serves me correct it
> is very common for a capacitor inside this model number to fail. It can be
> fixed but requires a torch or a pretty heavy duty soldering iron to
or a pretty heavy duty soldering iron to get
> the can open.
> http://www.rbarrios.com/projects/MV89A/
>
> -=Bryan=-
>
> > From: lister...@gmail.com
> > Date: Mon, 19 Sep 2016 14:31:06 -0700
> > To: time-nuts@febo.com
> > Subject: [time-nuts] Normal ope
=-
> From: lister...@gmail.com
> Date: Mon, 19 Sep 2016 14:31:06 -0700
> To: time-nuts@febo.com
> Subject: [time-nuts] Normal operating specs of a Morion MV89?
>
> I recently ordered and received what claims to be a 2007 vintage
> Morion MV89 from ebay (I say claimed as that what th
Hi
Compared to some MV89’s that’s a bit cold….It certainly is not alarmingly
hot for an OCXO case.
Bob
> On Sep 19, 2016, at 5:31 PM, Tim Lister wrote:
>
> I recently ordered and received what claims to be a 2007 vintage
> Morion MV89 from ebay (I say claimed as that
I recently ordered and received what claims to be a 2007 vintage
Morion MV89 from ebay (I say claimed as that what the auction item
said, but my unit is missing the identifying label on the top and just
has '2007 MV89A' written on the side in marker). I've powered it up
with a bench power supply
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