David,
I have used Pontis EMC USB converters and they worked meaning they had good
radiated immunity and radiated emissions were below CISPR25 levels even in the
150kHz - 30MHz band.
hvtechnologies is the US distributor.
My first EMC certification test at low frequencies was a humbling experience
due to the noise from the switching power supply. At $7.50 per minute we went
with stacks of AA batteries in parallel.
regards,Jay Cordaro
On Friday, December 6, 2019, 03:48:18 PM PST, David Van Horn via time-nuts
wrote:
It's not shielded, and ferrites are pretty useless down here.
I did try, but the ferrites I have did nothing.
My backup plan arrives supposedly in the next 2 hours
--
David VanHorn
Lead Hardware Engineer
Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO 80301 USA
phone: 303-417-1345 x110
email: david.vanh...@backcountryaccess.com
-Original Message-
From: time-nuts On Behalf Of Dana Whitlow
Sent: Friday, December 6, 2019 10:10 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] USB over optical fiber
Even without any funny business with boost converters (or whatever). those
copper wires make a nice antenna for coupling noise from both ends (PC and USB
accessory) into
the environment inside the chamber. Unless, of course, the cable is
well-shielded, which you did not mention.
I suppose it's too late to ask, but did you perhance try adding some clamp-on
ferrite chokes to the cable?
Dana
On Fri, Dec 6, 2019 at 10:05 AM David Van Horn via time-nuts <
time-nuts@lists.febo.com> wrote:
> This is my backup plan:
> https://industrialcomponent.com/opticis/opm210003.html
>
> The docs are a bit chinglish, but I'm encouraged by the fact that the
> distal end needs external power. I was hoping the corning one was
> powering the distal end by CW laser of maybe 200mW with data carried
> on other wavelengths, or modulation of the power laser, but NOPE, just copper
> wires. That one's packed up and ready to go back right now.
>
> --
> David VanHorn
> Lead Hardware Engineer
>
> Backcountry Access, Inc.
> 2820 Wilderness Pl, Unit H
> Boulder, CO 80301 USA
> phone: 303-417-1345 x110
> email: david.vanh...@backcountryaccess.com
>
> -Original Message-
> From: Scott McGrath
> Sent: Friday, December 6, 2019 6:29 AM
> To: David Van Horn
> Cc: Discussion of precise time and frequency measurement <
> time-nuts@lists.febo.com>
> Subject: Re: [time-nuts] USB over optical fiber
>
> Wow, cost cutting at work I have the corning one but its 3 years old
> Remember when FCC certification meant something for EMC
>
>
>
>
>
> > On Dec 6, 2019, at 3:21 PM, David Van Horn <
> david.vanh...@backcountryaccess.com> wrote:
> >
>
> Well, it arrived, and it is NOISY. ☹ It's pushing out longitudinal
> noise along the cable, and it's deafening my receiver.
>
> After doing some research this morning, it appears that they do the
> DATA optically but power is taken on copper wires, and I'm betting a
> boost switcher to compensate for the voltage drop in the 28 ga wire.
>
> https://www.corning.com/microsites/coc/ocbc/Documents/CNT-075-AEN.pdf
>
>
>
> I have another candidate arriving today which will require a 5V supply
> inside the cage, but I can do that with batteries and a linear
> regulator, much quieter.
>
>
> --
> David VanHorn
> Lead Hardware Engineer
>
> Backcountry Access, Inc.
> 2820 Wilderness Pl, Unit H
> Boulder, CO 80301 USA
> phone: 303-417-1345 x110
> email: david.vanh...@backcountryaccess.com
>
> -Original Message-
> From: time-nuts On Behalf Of David
> Van Horn via time-nuts
> Sent: Thursday, December 5, 2019 6:15 AM
> To: Scott McGrath ; Discussion of precise time
> and frequency measurement
> Cc: David Van Horn
> Subject: Re: [time-nuts] USB over optical fiber
>
> Ok, thanks for the info. My unit should be arriving today or tomorrow.
>
> --
> David VanHorn
> Lead Hardware Engineer
>
> Backcountry Access, Inc.
> 2820 Wilderness Pl, Unit H
> Boulder, CO 80301 USA
> phone: 303-417-1345 x110
> email: david.vanh...@backcountryaccess.com
>
> -Original Message-
> From: Scott McGrath
> Sent: Wednesday, December 4, 2019 9:16 PM
> To: Discussion of precise time and frequency measurement <
> time-nuts@lists.febo.com>
> Cc: David Van Horn
> Subject: Re: [time-nuts] USB over optical fiber
>
> You may still have a problem, That said most of your noise power is
> going to come from your USB device itself and perhaps the power supply
>
> That said ive never really had a problem doing similar testing using
> small chambers from ETS-Lindgren and similar vendors using the Corning
> interface.
>
> That said i’d recommend you go a step up to the Newnex and similar
> devices they are 3x the price but the fiber interlink is just a
> standard fiber LC-LC patch cord.
>
> With the low cost interface crimp its cable once accidentally you are
> buying a new one.
>
> With the newnex you are
