[time-nuts] Re: Query about List and about 10 MHz Distro

Sun Aug 29 17:29:26 UTC 2021

Andrew Sureflex (FSJ) is a lot more flexible then the LDF4 Healix, which 
is what you find a
lot of on ebay and at hamfests.

Here is some 1/4"  Sureflex, new:

Andrew Type N Male to Type N Male Sureflex Cable 30 feet 
F1RNA-PNMNM-30-L1 NEW!
https://www.ebay.com/itm/173863049072
US $30.00 + $13.02 Shipping.  For two pieces shipping goes to $16.33, 
for three $22.90

You can cut it with a hacksaw, do NOT use wire cutters.  Connectors can be
installed with just hand tools.

If you move the test equipment around it's not very practical, but if 
it's setup on
a bench or in a rack it will work.

Robert

On 08/29/2021 09:51 AM, Bob kb8tq wrote:
> Hi
>
> Skin depth is what gets you with most coax at 10 MHz, even with the â€œdouble
> shieldâ€ stuff. Hardline with a nice heavy outer would do better. Itâ€™s not terribly
> practical around the typical lab. Might not be a bad choice for a â€œburry in the yardâ€
> setup though. With normal cable, the losses from the soil at normal burial
> depths make a good shield, that makes dealing with it questionable even there â€¦.
>
> Bob
>
>> On Aug 29, 2021, at 9:36 AM, Robert DiRosario <ka3zyx at comcast.net> wrote:
>>
>> What about double shielded RG-223, or Thinnet ethernet cable?
>> Most Thinnet has both a braided shield and a foil wrap.
>>
>> Robert
>>
>> On 08/28/2021 08:26 PM, Bob kb8tq wrote:
>>> Hi
>>>
>>> Anything you do that has a bunch of 10 MHz cables running out from here or there
>>> will impact your ability to listen to WWV at 10 MHz :)  Other than killing all the sources,
>>> there is no silver bullet.
>>>
>>> Bob
>>>
>>>> On Aug 28, 2021, at 7:57 PM, Dana Whitlow <k8yumdoober at gmail.com> wrote:
>>>>
>>>> Bob, my own motivation  for going to fiber was entirely different.  I
>>>> simply wanted to
>>>> run 10 MHz all over the place from reference sources in disparate
>>>> locations in the
>>>> house, and I quickly discovered that cable leakage was embarrassingly
>>>> severe.  So
>>>> I shut down and began contemplating a fiber link.  But then reality set in
>>>> and I realized
>>>> that running fiber across the house had its own big problems, so I set the
>>>> project aside.
>>>>
>>>> Dana
>>>>
>>>>
>>>> On Sat, Aug 28, 2021 at 3:32 PM Bob kb8tq <kb8tq at n1k.org> wrote:
>>>>
>>>>> Hi
>>>>>
>>>>> With a whole variety of pretty good OCXOâ€™s going for cheap money
>>>>> on eBay, itâ€™s likely less expensive to do cleanup oscillators on the link
>>>>> compared to going crazy with low noise optical this or that. Yes, you
>>>>> will be getting something in the high 150â€™s for noise, but still pretty
>>>>> good
>>>>> for $10.
>>>>>
>>>>> If you need better, spend $50 or so on a 10811. Still less money than
>>>>> some of the crazy fiber stuff.
>>>>>
>>>>> With either one, send over a high enough frequency that the loop isnâ€™t
>>>>> dealing with reference spurs in any significant way. Given the clock rates
>>>>> Ethernet runs at these days, that part should be fairly straightforward.
>>>>>
>>>>> This *assumes* that there is a crossover somewhere practical between
>>>>> the fiber noise and the noise on the optical gear. You should be able to
>>>>> work out what it is with some fairly normal phase noise or ADEV testing.
>>>>>
>>>>> Bob
>>>>>
>>>>>> On Aug 28, 2021, at 3:03 PM, Dana Whitlow <k8yumdoober at gmail.com> wrote:
>>>>>>
>>>>>> I was looking for something similar about 18 months or so ago.  Although
>>>>> I
>>>>>> haven't taken any
>>>>>> action yet, I concluded that one could do a nice job for under $200 per
>>>>>> segment, including the
>>>>>> transmitter and receiver modules and lots of connectorized multimode
>>>>>> fiber.  What I *don't* know
>>>>>> is what the phase noise performance would be, except that I do know that
>>>>>> the fiber's VF *is*
>>>>>> materially influenced by temperature.
>>>>>>
>>>>>> I was looking primarily at the HFBR-2416 for the fiber receiver, and the
>>>>>> HFBR-1412 (standard
>>>>>> power) or the HFBR-1414 (high power option) for the transmitter   Unlike
>>>>>> most of the available
>>>>>> models, these are fundamentally analog devices, meaning that you can
>>>>>> transmit sinewave
>>>>>> 10 MHz through them.  At the time I was looking, Mouser was selling these
>>>>>> for about $20 each.
>>>>>>
>>>>>> See the datasheet at
>>>>>>
>>>>> https://www.mouser.com/datasheet/2/678/AV02-0176EN_2019-02-15-1827546.pdf
>>>>>> with particular attention to page 21 regarding the HFBR-2416 receiver.
>>>>>>
>>>>>> I was also looking at Fiber Instrument Sales for patch cords.  We bought
>>>>> a
>>>>>> lot of fiber stuff from
>>>>>> them at Arecibo, and I was always happy with them.  See:
>>>>>>
>>>>> https://www.fiberinstrumentsales.com/catalog-cable-assemblies?gclid=Cj0KCQjwvaeJBhCvARIsABgTDM7eNTkP2nQbyFzhcwDE38VnSEP879MBKV1ZyDq2YrnEtOn7_VfzjbkaAtpfEALw_wcB
>>>>>> Somebody had pointed out yet another source of connectorized fibers
>>>>> ("patch
>>>>>> cords") to me, but I cannot find the name
>>>>>> at the moment.
>>>>>>
>>>>>> Dana   K8YUM
>>>>>>
>>>>>>
>>>>>> On Sat, Aug 28, 2021 at 11:52 AM AC0XU (Jim) <James.Schatzman at ac0xu.com>
>>>>>> wrote:
>>>>>>
>>>>>>> I am hoping that you can help me about a couple of things:
>>>>>>>
>>>>>>> 1) My time-nuts summaries sometimes appear unformatted and unreadable.
>>>>> All
>>>>>>> the text from all the postings is crammed together without spacing. How
>>>>> can
>>>>>>> I fix it?
>>>>>>>
>>>>>>> 2) I want to distribute 10 MHz references by fiber. There are
>>>>>>> RF-over-Fiber products available, but too expensive for me (thousands of
>>>>>>> $$$ per xmit/rcv set).  I am thinking that it should be possible to use
>>>>>>> fiber Ethernet components to do this. I don't mean IEEE 1588 but a much
>>>>>>> simpler, no-computer-required, solution. Possibly just converting sine
>>>>> wave
>>>>>>> (coax) to square wave (fiber) to sine wave (coax). I am looking for a
>>>>> low
>>>>>>> cost solution. Any thoughts or recommendations??
>>>>>>>
>>>>>>> Thanks!
>>>>>>>
>>>>>>> Jim
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