Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Bob kb8tq]

Hi

If you are doing direct measurements on a 10 MHz signal *and* counting on the 
expanded
frequency resolution of a 53131, that’s not going to work. There is an HP app 
note somewhere
that explains why in great detail. The quick read version is that the sampling 
process falls apart.

Bob

> On Jan 21, 2020, at 4:49 PM, Taka Kamiya via time-nuts 
>  wrote:
> 
> I'm not the OP but I was just throwing some ideas about cheap way to 
> distribute.
> But the responses were very timely.  I am, indeed, using HP53132A, RG58, and 
> were doing ADEV measurement of a 10MHz signal.  I have my answers already so 
> I won't go into details but I was seeing some explainable indications.  It 
> might very likely be leak from or into the reference/input.  I will use 
> double shielded and phase stable cables and see if I can eliminate the issue.
> 
> Thanks a-bunch!
> --- 
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
> 
> 
>On Tuesday, January 21, 2020, 4:27:26 PM EST, Bob kb8tq  
> wrote:  
> 
> Hi
> 
> If all you are doing is driving a 5335 and running at 1 second gate times, 
> then there’s not
> a lot to worry about. If indeed you are multiplying this or that up to X band 
> for various purposes
> then  ….. that’s different. Both are in the “hobbyist” range.
> 
> Spurs matter for some things and don’t matter much for others. A spur at -120 
> at 10 MHz 
> may be up around -60 db at 10 GHz. It might matter there … it might not. A 
> -60 db spur 
> at 10 MHz gets into the “yikes” range if directly multiplied. 
> 
> How big is your bench? How long are your feed cables? You are getting into a 
> significant 
> fraction of a wavelength at 10’ of cable. If unterminated (and / or poorly 
> shielded) it will spray
> a bit of RF. 
> 
> Lots of details and no single answer without digging deeper into what you are 
> trying to do.
> 
> Bob
> 
>> On Jan 21, 2020, at 4:06 PM, Bryan _  wrote:
>> 
>> On the point of using a MDA-3V at the hobbyist bench level, any issues that 
>> one needs to be concerned about. A few modification projects online, but 
>> none really comment on any issues or performance.
>> 
>> -=Bryan=-
>> 
>> ________
>> From: time-nuts  on behalf of Bob kb8tq 
>> 
>> Sent: January 21, 2020 7:57 AM
>> To: Taka Kamiya ; Discussion of precise time and 
>> frequency measurement 
>> Subject: Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line 
>> driver options?
>> 
>> Hi
>> 
>> Cross talk between the reference in and the measured signal on the 53131 
>> series can be an
>> issue . The counter drops resolution in the vicinity of 10 MHz as a result. 
>> There is also an  issue
>> with  the sampling process rather than direct feedthrough.
>> 
>> If you are measuring things like phase noise, having a lot of 10 MHz running 
>> around the lab will put a
>> spur in the phase noise plot. It may be close enough in that you don’t 
>> notice it every time. The same
>> sort of spur will play nasties with things like ADEV measurements. Getting a 
>> 10V RMS signal down
>> 120 db is tough …
>> 
>> Finally if you happen to be playing with radios, WWV is at 10 MHz. It does 
>> not take a lot of reference
>> signal to get back into the typical receiving antenna.
>> 
>> ==
>> 
>> If you are daisy chaining counters, there are several ways to do it:
>> 
>> 1) Drive the “ext ref in” and daisy chain off of “ext ref out”. This way the 
>> signal is buffered at each device.
>> It may add a bit of noise, but you can go a long way doing this.
>> 
>> 2) Put a coax Tee connector at each instrument. If the device is high Z in, 
>> this can do ok. If it is a 50 ohm
>> termination all the time … not so much. Even with the high Z input it’s 
>> better for short runs than long ones.
>> 
>> 3) Mix the two approaches. If you have a variety of gear, use the ones with 
>> ref in / ref out as buffers. String
>> the other gear in-between those boxes.
>> 
>> Bob
>> 
>>> On Jan 21, 2020, at 10:27 AM, Taka Kamiya via time-nuts 
>>>  wrote:
>>> 
>>> I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th 
>>> box, it was too weak to reliably drive the 1 pps.  I had a terminator at 
>>> the last tee with short length of RG58s between boxes.  I guess some box 
>>> puts relatively heavy load on the signal?
>>> 
>>> I'd like to know why 10V is a bad idea.  (besides too close to the upper 
>>> limit)

Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Taka Kamiya via time-nuts]

I'm not the OP but I was just throwing some ideas about cheap way to distribute.
But the responses were very timely.  I am, indeed, using HP53132A, RG58, and 
were doing ADEV measurement of a 10MHz signal.  I have my answers already so I 
won't go into details but I was seeing some explainable indications.  It might 
very likely be leak from or into the reference/input.  I will use double 
shielded and phase stable cables and see if I can eliminate the issue.

Thanks a-bunch!
--- 
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
 

On Tuesday, January 21, 2020, 4:27:26 PM EST, Bob kb8tq  
wrote:  
 
 Hi

If all you are doing is driving a 5335 and running at 1 second gate times, then 
there’s not
a lot to worry about. If indeed you are multiplying this or that up to X band 
for various purposes
then  ….. that’s different. Both are in the “hobbyist” range.

Spurs matter for some things and don’t matter much for others. A spur at -120 
at 10 MHz 
may be up around -60 db at 10 GHz. It might matter there … it might not. A -60 
db spur 
at 10 MHz gets into the “yikes” range if directly multiplied. 

How big is your bench? How long are your feed cables? You are getting into a 
significant 
fraction of a wavelength at 10’ of cable. If unterminated (and / or poorly 
shielded) it will spray
a bit of RF. 

Lots of details and no single answer without digging deeper into what you are 
trying to do.

Bob

> On Jan 21, 2020, at 4:06 PM, Bryan _  wrote:
> 
> On the point of using a MDA-3V at the hobbyist bench level, any issues that 
> one needs to be concerned about. A few modification projects online, but none 
> really comment on any issues or performance.
> 
> -=Bryan=-
> 
> 
> From: time-nuts  on behalf of Bob kb8tq 
> 
> Sent: January 21, 2020 7:57 AM
> To: Taka Kamiya ; Discussion of precise time and 
> frequency measurement 
> Subject: Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver 
> options?
> 
> Hi
> 
> Cross talk between the reference in and the measured signal on the 53131 
> series can be an
> issue . The counter drops resolution in the vicinity of 10 MHz as a result. 
> There is also an  issue
> with  the sampling process rather than direct feedthrough.
> 
> If you are measuring things like phase noise, having a lot of 10 MHz running 
> around the lab will put a
> spur in the phase noise plot. It may be close enough in that you don’t notice 
> it every time. The same
> sort of spur will play nasties with things like ADEV measurements. Getting a 
> 10V RMS signal down
> 120 db is tough …
> 
> Finally if you happen to be playing with radios, WWV is at 10 MHz. It does 
> not take a lot of reference
> signal to get back into the typical receiving antenna.
> 
> ==
> 
> If you are daisy chaining counters, there are several ways to do it:
> 
> 1) Drive the “ext ref in” and daisy chain off of “ext ref out”. This way the 
> signal is buffered at each device.
> It may add a bit of noise, but you can go a long way doing this.
> 
> 2) Put a coax Tee connector at each instrument. If the device is high Z in, 
> this can do ok. If it is a 50 ohm
> termination all the time … not so much. Even with the high Z input it’s 
> better for short runs than long ones.
> 
> 3) Mix the two approaches. If you have a variety of gear, use the ones with 
> ref in / ref out as buffers. String
> the other gear in-between those boxes.
> 
> Bob
> 
>> On Jan 21, 2020, at 10:27 AM, Taka Kamiya via time-nuts 
>>  wrote:
>> 
>> I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th box, 
>> it was too weak to reliably drive the 1 pps.  I had a terminator at the last 
>> tee with short length of RG58s between boxes.  I guess some box puts 
>> relatively heavy load on the signal?
>> 
>> I'd like to know why 10V is a bad idea.  (besides too close to the upper 
>> limit)  Cross talk between what/where?
>> 
>> To OP:I have video amplifiers Extron MDA-3V successfully used for this.  1 
>> port in, 3 ports out ones by Extron are very inexpensive at 10 dollars+/-.  
>> I never did formal testing but reading on all counters matched exactly.  
>> They are 75 ohms but it didn't matter in my use case.  You can change/adjust 
>> internal resisters if you are concerned.
>> 
>> ---
>> (Mr.) Taka Kamiya
>> KB4EMF / ex JF2DKG
>> 
>> 
>>  On Tuesday, January 21, 2020, 7:45:22 AM EST, Bob kb8tq  
>>wrote:
>> 
>> Hi
>> 
>> What are you driving?
>> 
>> Most “normal” gear is pretty happy with a fairly wide range of input levels. 
>> Obviously t

Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Bob kb8tq]

Hi

If all you are doing is driving a 5335 and running at 1 second gate times, then 
there’s not
a lot to worry about. If indeed you are multiplying this or that up to X band 
for various purposes
then  ….. that’s different. Both are in the “hobbyist” range.

Spurs matter for some things and don’t matter much for others. A spur at -120 
at 10 MHz 
may be up around -60 db at 10 GHz. It might matter there … it might not. A -60 
db spur 
at 10 MHz gets into the “yikes” range if directly multiplied. 

How big is your bench? How long are your feed cables? You are getting into a 
significant 
fraction of a wavelength at 10’ of cable. If unterminated (and / or poorly 
shielded) it will spray
a bit of RF. 

Lots of details and no single answer without digging deeper into what you are 
trying to do.

Bob

> On Jan 21, 2020, at 4:06 PM, Bryan _  wrote:
> 
> On the point of using a MDA-3V at the hobbyist bench level, any issues that 
> one needs to be concerned about. A few modification projects online, but none 
> really comment on any issues or performance.
> 
> -=Bryan=-
> 
> 
> From: time-nuts  on behalf of Bob kb8tq 
> 
> Sent: January 21, 2020 7:57 AM
> To: Taka Kamiya ; Discussion of precise time and 
> frequency measurement 
> Subject: Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver 
> options?
> 
> Hi
> 
> Cross talk between the reference in and the measured signal on the 53131 
> series can be an
> issue . The counter drops resolution in the vicinity of 10 MHz as a result. 
> There is also an  issue
> with  the sampling process rather than direct feedthrough.
> 
> If you are measuring things like phase noise, having a lot of 10 MHz running 
> around the lab will put a
> spur in the phase noise plot. It may be close enough in that you don’t notice 
> it every time. The same
> sort of spur will play nasties with things like ADEV measurements. Getting a 
> 10V RMS signal down
> 120 db is tough …
> 
> Finally if you happen to be playing with radios, WWV is at 10 MHz. It does 
> not take a lot of reference
> signal to get back into the typical receiving antenna.
> 
> ==
> 
> If you are daisy chaining counters, there are several ways to do it:
> 
> 1) Drive the “ext ref in” and daisy chain off of “ext ref out”. This way the 
> signal is buffered at each device.
> It may add a bit of noise, but you can go a long way doing this.
> 
> 2) Put a coax Tee connector at each instrument. If the device is high Z in, 
> this can do ok. If it is a 50 ohm
> termination all the time … not so much. Even with the high Z input it’s 
> better for short runs than long ones.
> 
> 3) Mix the two approaches. If you have a variety of gear, use the ones with 
> ref in / ref out as buffers. String
> the other gear in-between those boxes.
> 
> Bob
> 
>> On Jan 21, 2020, at 10:27 AM, Taka Kamiya via time-nuts 
>>  wrote:
>> 
>> I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th box, 
>> it was too weak to reliably drive the 1 pps.  I had a terminator at the last 
>> tee with short length of RG58s between boxes.  I guess some box puts 
>> relatively heavy load on the signal?
>> 
>> I'd like to know why 10V is a bad idea.  (besides too close to the upper 
>> limit)  Cross talk between what/where?
>> 
>> To OP:I have video amplifiers Extron MDA-3V successfully used for this.  1 
>> port in, 3 ports out ones by Extron are very inexpensive at 10 dollars+/-.  
>> I never did formal testing but reading on all counters matched exactly.  
>> They are 75 ohms but it didn't matter in my use case.  You can change/adjust 
>> internal resisters if you are concerned.
>> 
>> ---
>> (Mr.) Taka Kamiya
>> KB4EMF / ex JF2DKG
>> 
>> 
>>   On Tuesday, January 21, 2020, 7:45:22 AM EST, Bob kb8tq  
>> wrote:
>> 
>> Hi
>> 
>> What are you driving?
>> 
>> Most “normal” gear is pretty happy with a fairly wide range of input levels. 
>> Obviously things
>> like termination and long lengths of coax can get into the act. For 4 
>> outputs, a passive splitter
>> with 6 db of loss should do just fine. You have only taken the output 
>> voltage down by 2:1 ….
>> 
>> Just for reference:
>> 
>> https://www.avionteq.com/Document/53131A-specification-sheet.pdf 
>> <https://www.avionteq.com/Document/53131A-specification-sheet.pdf>
>> 
>> Calls out a 200 mv to 10V RMS input level as acceptable For a variety of 
>> reasons, 10V RMS
>> is a really bad idea (cross talk ….). Lower is better in this case.
>> 
>>

Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Bryan _]

On the point of using a MDA-3V at the hobbyist bench level, any issues that one 
needs to be concerned about. A few modification projects online, but none 
really comment on any issues or performance.

-=Bryan=-


From: time-nuts  on behalf of Bob kb8tq 

Sent: January 21, 2020 7:57 AM
To: Taka Kamiya ; Discussion of precise time and frequency 
measurement 
Subject: Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver 
options?

Hi

Cross talk between the reference in and the measured signal on the 53131 series 
can be an
issue . The counter drops resolution in the vicinity of 10 MHz as a result. 
There is also an  issue
with  the sampling process rather than direct feedthrough.

If you are measuring things like phase noise, having a lot of 10 MHz running 
around the lab will put a
spur in the phase noise plot. It may be close enough in that you don’t notice 
it every time. The same
sort of spur will play nasties with things like ADEV measurements. Getting a 
10V RMS signal down
120 db is tough …

Finally if you happen to be playing with radios, WWV is at 10 MHz. It does not 
take a lot of reference
signal to get back into the typical receiving antenna.

==

If you are daisy chaining counters, there are several ways to do it:

1) Drive the “ext ref in” and daisy chain off of “ext ref out”. This way the 
signal is buffered at each device.
It may add a bit of noise, but you can go a long way doing this.

2) Put a coax Tee connector at each instrument. If the device is high Z in, 
this can do ok. If it is a 50 ohm
termination all the time … not so much. Even with the high Z input it’s better 
for short runs than long ones.

3) Mix the two approaches. If you have a variety of gear, use the ones with ref 
in / ref out as buffers. String
the other gear in-between those boxes.

Bob

> On Jan 21, 2020, at 10:27 AM, Taka Kamiya via time-nuts 
>  wrote:
>
> I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th box, 
> it was too weak to reliably drive the 1 pps.  I had a terminator at the last 
> tee with short length of RG58s between boxes.  I guess some box puts 
> relatively heavy load on the signal?
>
> I'd like to know why 10V is a bad idea.  (besides too close to the upper 
> limit)  Cross talk between what/where?
>
> To OP:I have video amplifiers Extron MDA-3V successfully used for this.  1 
> port in, 3 ports out ones by Extron are very inexpensive at 10 dollars+/-.  I 
> never did formal testing but reading on all counters matched exactly.  They 
> are 75 ohms but it didn't matter in my use case.  You can change/adjust 
> internal resisters if you are concerned.
>
> ---
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
>On Tuesday, January 21, 2020, 7:45:22 AM EST, Bob kb8tq  
> wrote:
>
> Hi
>
> What are you driving?
>
> Most “normal” gear is pretty happy with a fairly wide range of input levels. 
> Obviously things
> like termination and long lengths of coax can get into the act. For 4 
> outputs, a passive splitter
> with 6 db of loss should do just fine. You have only taken the output voltage 
> down by 2:1 ….
>
> Just for reference:
>
> https://www.avionteq.com/Document/53131A-specification-sheet.pdf 
> <https://www.avionteq.com/Document/53131A-specification-sheet.pdf>
>
> Calls out a 200 mv to 10V RMS input level as acceptable For a variety of 
> reasons, 10V RMS
> is a really bad idea (cross talk ….). Lower is better in this case.
>
> Bob
>
>> On Jan 21, 2020, at 4:19 AM, skipp isaham via time-nuts 
>>  wrote:
>>
>> Hello once again to the Group,
>>
>> May I ask what the current relatively simple options are for
>> expanding a Thunderbolt or equivalent... output for distribution
>> to multiple devices?
>>
>> Although I expect only two or three isolated / buffered outputs
>> will be required in my example. I'm worried about signal level
>> if a passive system (Mini Circuits divider or equivalent type)
>> is used.
>>
>> Would appreciate a few quick opinions on what is practical and
>> seems to work well.
>>
>> thank you in advance
>>
>> regards,
>>
>> skipp
>>
>> skipp025 at yahoo dot com
>>
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to 
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instruc

Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Brian Lloyd]

On 1/21/20 03:19, skipp isaham via time-nuts wrote:
> Hello once again to the Group,
>
> May I ask what the current relatively simple options are for
> expanding a Thunderbolt or equivalent... output for distribution
> to multiple devices?
TAPR TADD-3 for 1pps distribution.
https://tapr.org/?product=tadd-3-pulse-per-second-distribution-amplifier

TAPR TADD-1 for 10MHz distribution
https://tapr.org/?product=tadd-1-rf-distribution-amplifier

There are better solutions but these have a good cost:performance ratio.

-- 


 

Brian Lloyd
706 Flightline
Spring Branch, TX 78070
br...@lloyd.aero 
+1.210.802.8359


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Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Dana Whitlow]

Re cross talk, I'd suggest:

Fairly equal levels on all the used outputs, to minimize the effects of
crosstalk between them.  This is especially important if you're using
RG-58 or similar cable, which leaks like a sieve.  Crosstalk of this
sort will tend to screw up the edges of a PPS pulse, possibly in a way
as to lead to unreliable/unstable triggering of some of your devices.

As high a level as your devices will safely tolerate, unless you're
concerned
about leakage into other systems, like kb8tq's WWV receiver.  Again, I
suggest
avoiding RG-58 and similar single-braid-shielded cables.  This has been a
significant problem for me, receiving WWV at 10 MHz.  I've been able to
some-
what mitigate this with big clamp-on ferrite chokes, but I still have some
issues.

DanaK8YUM

On Tue, Jan 21, 2020 at 9:28 AM Taka Kamiya via time-nuts <
time-nuts@lists.febo.com> wrote:

> I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th
> box, it was too weak to reliably drive the 1 pps.  I had a terminator at
> the last tee with short length of RG58s between boxes.  I guess some box
> puts relatively heavy load on the signal?
>
> I'd like to know why 10V is a bad idea.  (besides too close to the upper
> limit)  Cross talk between what/where?
>
> To OP:I have video amplifiers Extron MDA-3V successfully used for this.  1
> port in, 3 ports out ones by Extron are very inexpensive at 10 dollars+/-.
> I never did formal testing but reading on all counters matched exactly.
> They are 75 ohms but it didn't matter in my use case.  You can
> change/adjust internal resisters if you are concerned.
>
> ---
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
>
>
> On Tuesday, January 21, 2020, 7:45:22 AM EST, Bob kb8tq 
> wrote:
>
>  Hi
>
> What are you driving?
>
> Most “normal” gear is pretty happy with a fairly wide range of input
> levels. Obviously things
> like termination and long lengths of coax can get into the act. For 4
> outputs, a passive splitter
> with 6 db of loss should do just fine. You have only taken the output
> voltage down by 2:1 ….
>
> Just for reference:
>
> https://www.avionteq.com/Document/53131A-specification-sheet.pdf <
> https://www.avionteq.com/Document/53131A-specification-sheet.pdf>
>
> Calls out a 200 mv to 10V RMS input level as acceptable For a variety of
> reasons, 10V RMS
> is a really bad idea (cross talk ….). Lower is better in this case.
>
> Bob
>
> > On Jan 21, 2020, at 4:19 AM, skipp isaham via time-nuts <
> time-nuts@lists.febo.com> wrote:
> >
> > Hello once again to the Group,
> >
> > May I ask what the current relatively simple options are for
> > expanding a Thunderbolt or equivalent... output for distribution
> > to multiple devices?
> >
> > Although I expect only two or three isolated / buffered outputs
> > will be required in my example. I'm worried about signal level
> > if a passive system (Mini Circuits divider or equivalent type)
> > is used.
> >
> > Would appreciate a few quick opinions on what is practical and
> > seems to work well.
> >
> > thank you in advance
> >
> > regards,
> >
> > skipp
> >
> > skipp025 at yahoo dot com
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
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> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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>
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Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Bob kb8tq]

Hi

Cross talk between the reference in and the measured signal on the 53131 series 
can be an
issue . The counter drops resolution in the vicinity of 10 MHz as a result. 
There is also an  issue 
with  the sampling process rather than direct feedthrough. 

If you are measuring things like phase noise, having a lot of 10 MHz running 
around the lab will put a 
spur in the phase noise plot. It may be close enough in that you don’t notice 
it every time. The same 
sort of spur will play nasties with things like ADEV measurements. Getting a 
10V RMS signal down 
120 db is tough …

Finally if you happen to be playing with radios, WWV is at 10 MHz. It does not 
take a lot of reference 
signal to get back into the typical receiving antenna.

==

If you are daisy chaining counters, there are several ways to do it:

1) Drive the “ext ref in” and daisy chain off of “ext ref out”. This way the 
signal is buffered at each device.
It may add a bit of noise, but you can go a long way doing this.

2) Put a coax Tee connector at each instrument. If the device is high Z in, 
this can do ok. If it is a 50 ohm
termination all the time … not so much. Even with the high Z input it’s better 
for short runs than long ones.

3) Mix the two approaches. If you have a variety of gear, use the ones with ref 
in / ref out as buffers. String
the other gear in-between those boxes. 

Bob

> On Jan 21, 2020, at 10:27 AM, Taka Kamiya via time-nuts 
>  wrote:
> 
> I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th box, 
> it was too weak to reliably drive the 1 pps.  I had a terminator at the last 
> tee with short length of RG58s between boxes.  I guess some box puts 
> relatively heavy load on the signal?
> 
> I'd like to know why 10V is a bad idea.  (besides too close to the upper 
> limit)  Cross talk between what/where?  
> 
> To OP:I have video amplifiers Extron MDA-3V successfully used for this.  1 
> port in, 3 ports out ones by Extron are very inexpensive at 10 dollars+/-.  I 
> never did formal testing but reading on all counters matched exactly.  They 
> are 75 ohms but it didn't matter in my use case.  You can change/adjust 
> internal resisters if you are concerned.  
> 
> --- 
> (Mr.) Taka Kamiya
> KB4EMF / ex JF2DKG
> 
> 
>On Tuesday, January 21, 2020, 7:45:22 AM EST, Bob kb8tq  
> wrote:  
> 
> Hi
> 
> What are you driving? 
> 
> Most “normal” gear is pretty happy with a fairly wide range of input levels. 
> Obviously things
> like termination and long lengths of coax can get into the act. For 4 
> outputs, a passive splitter
> with 6 db of loss should do just fine. You have only taken the output voltage 
> down by 2:1 ….
> 
> Just for reference:
> 
> https://www.avionteq.com/Document/53131A-specification-sheet.pdf 
> 
> 
> Calls out a 200 mv to 10V RMS input level as acceptable For a variety of 
> reasons, 10V RMS
> is a really bad idea (cross talk ….). Lower is better in this case.
> 
> Bob
> 
>> On Jan 21, 2020, at 4:19 AM, skipp isaham via time-nuts 
>>  wrote:
>> 
>> Hello once again to the Group,
>> 
>> May I ask what the current relatively simple options are for
>> expanding a Thunderbolt or equivalent... output for distribution
>> to multiple devices?
>> 
>> Although I expect only two or three isolated / buffered outputs
>> will be required in my example. I'm worried about signal level
>> if a passive system (Mini Circuits divider or equivalent type)
>> is used.
>> 
>> Would appreciate a few quick opinions on what is practical and
>> seems to work well.
>> 
>> thank you in advance
>> 
>> regards,
>> 
>> skipp
>> 
>> skipp025 at yahoo dot com
>> 
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>> and follow the instructions there.
> 
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Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Taka Kamiya via time-nuts]

I've tried daisy chaining 4 HP5335A.  By the time signal got to the 4th box, it 
was too weak to reliably drive the 1 pps.  I had a terminator at the last tee 
with short length of RG58s between boxes.  I guess some box puts relatively 
heavy load on the signal?

I'd like to know why 10V is a bad idea.  (besides too close to the upper limit) 
 Cross talk between what/where?  

To OP:I have video amplifiers Extron MDA-3V successfully used for this.  1 port 
in, 3 ports out ones by Extron are very inexpensive at 10 dollars+/-.  I never 
did formal testing but reading on all counters matched exactly.  They are 75 
ohms but it didn't matter in my use case.  You can change/adjust internal 
resisters if you are concerned.  

--- 
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
 

On Tuesday, January 21, 2020, 7:45:22 AM EST, Bob kb8tq  
wrote:  
 
 Hi

What are you driving? 

Most “normal” gear is pretty happy with a fairly wide range of input levels. 
Obviously things
like termination and long lengths of coax can get into the act. For 4 outputs, 
a passive splitter
with 6 db of loss should do just fine. You have only taken the output voltage 
down by 2:1 ….

Just for reference:

https://www.avionteq.com/Document/53131A-specification-sheet.pdf 


Calls out a 200 mv to 10V RMS input level as acceptable For a variety of 
reasons, 10V RMS
is a really bad idea (cross talk ….). Lower is better in this case.

Bob

> On Jan 21, 2020, at 4:19 AM, skipp isaham via time-nuts 
>  wrote:
> 
> Hello once again to the Group,
> 
> May I ask what the current relatively simple options are for
> expanding a Thunderbolt or equivalent... output for distribution
> to multiple devices?
> 
> Although I expect only two or three isolated / buffered outputs
> will be required in my example. I'm worried about signal level
> if a passive system (Mini Circuits divider or equivalent type)
> is used.
> 
> Would appreciate a few quick opinions on what is practical and
> seems to work well.
> 
> thank you in advance
> 
> regards,
> 
> skipp
> 
> skipp025 at yahoo dot com
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.

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Re: [time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[Bob kb8tq]

Hi

What are you driving? 

Most “normal” gear is pretty happy with a fairly wide range of input levels. 
Obviously things
like termination and long lengths of coax can get into the act. For 4 outputs, 
a passive splitter
with 6 db of loss should do just fine. You have only taken the output voltage 
down by 2:1 ….

Just for reference:

https://www.avionteq.com/Document/53131A-specification-sheet.pdf 


Calls out a 200 mv to 10V RMS input level as acceptable For a variety of 
reasons, 10V RMS
is a really bad idea (cross talk ….). Lower is better in this case.

Bob

> On Jan 21, 2020, at 4:19 AM, skipp isaham via time-nuts 
>  wrote:
> 
> Hello once again to the Group,
> 
> May I ask what the current relatively simple options are for
> expanding a Thunderbolt or equivalent... output for distribution
> to multiple devices?
> 
> Although I expect only two or three isolated / buffered outputs
> will be required in my example. I'm worried about signal level
> if a passive system (Mini Circuits divider or equivalent type)
> is used.
> 
> Would appreciate a few quick opinions on what is practical and
> seems to work well.
> 
> thank you in advance
> 
> regards,
> 
> skipp
> 
> skipp025 at yahoo dot com
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.

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[time-nuts] Simple GPSDO Multiple Outputs - buffered line driver options?

[skipp isaham via time-nuts]

Hello once again to the Group,

May I ask what the current relatively simple options are for
expanding a Thunderbolt or equivalent... output for distribution
to multiple devices?

Although I expect only two or three isolated / buffered outputs
will be required in my example. I'm worried about signal level
if a passive system (Mini Circuits divider or equivalent type)
is used.

Would appreciate a few quick opinions on what is practical and
seems to work well.

thank you in advance

regards,

skipp

skipp025 at yahoo dot com

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