> On Wed, 25 Oct 2017 09:51:39 -0700, Joerg <news@analogconsultants.com>
> wrote:
>
>> On 2017-10-25 08:57, John Larkin wrote:
[...]
>>> Mo is a speech therapist. She occasionally gets an old guy who had a
>>> stroke or something and can't talk or understand speech, but can still
>>> communicate in code.
>>>
>>
>> That could very well happen to me some day. I haven't done ham radio in
>> over 25 years but code is as ingrained as the ability to ride a bicycle.
>> Not at the old speeds but that would come back.
>>
>> It's like the NATO alphabet spelling "Alpha, Bravo, Charlie, Delta ..."
>> which is so ingrained from ham and military days that I instantly use it
>> on noisy phone connections. If the guy at the other end is ex-military
>> or a pilot that instantly works and reduces comm errors to about zero.
>
> I hate conference calls about tech issues. Some of my customers are
> always requesting those dreadful group call-ins. People show up late,
> have to leave, don't identify themselves, and are unintelligible. I
> have to assume that everyone is taking the same notes. Tech stuff
> should be email.
>
Video conferencing works great IME. If I am the initiator I usually
start at the assigned time even if some aren't there yet. Same as I did
with real meetings. That has a teachable effect because now the late
comers have really missed stuff and often must shamefully admit it at
some point.
Zoom works best IMO, next up is GoToMeeting. Some others are sub-par
though. If needed the whole thing can be recorded.
What I found really nice is the ability to tie in an oscilloscope or
other gear as a "participant" or it can be viewed and operated via
someone's screen. That has made a lot of business trips unnecessary.
Probably the only entities online conferencing isn't good for are
airlines, rental car companies and hotels.
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by John Larkin●October 25, 20172017-10-25
On Wed, 25 Oct 2017 20:57:33 -0400, Michael A Terrell
<mike.terrell@earthlink.net> wrote:
>John Larkin wrote:
>> On Wed, 25 Oct 2017 18:44:23 -0400, Michael A Terrell
>> <mike.terrell@earthlink.net> wrote:
>>
>>> John Larkin wrote:
>>>>
>>>> Reed relays are terrible. I like the Fujitsu FTR-B3GA4 series. They
>>>> are good RF switches, too.
>>>
>>>
>>> Any recommendation for a dual coil 12VDC DPDT relay with a low
>>> insertion loss? I need to make a couple replacement attenuator boards
>>> for HP 3325A/B function generators. I have several that were supposed to
>>> be complete, but the boards were missing.
>>
>> The latching version of the Fujitsu has a single coil, but some simple
>> circuit could translate the drive.
>>
>> Since it transmits a clean 100 ps edge, it's a nice 3 GHz switch. Some
>> of that 100 ps is probably loss on my PCB.
>
>
> What is the insertion loss form DC to say 100 MHz? It has to be
>flat, since there is no way to compenstate for variations.
Probably close enough to zero that it doesn't matter.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
Reply by Michael A Terrell●October 25, 20172017-10-25
John Larkin wrote:
> On Wed, 25 Oct 2017 18:44:23 -0400, Michael A Terrell
> <mike.terrell@earthlink.net> wrote:
>
>> John Larkin wrote:
>>>
>>> Reed relays are terrible. I like the Fujitsu FTR-B3GA4 series. They
>>> are good RF switches, too.
>>
>>
>> Any recommendation for a dual coil 12VDC DPDT relay with a low
>> insertion loss? I need to make a couple replacement attenuator boards
>> for HP 3325A/B function generators. I have several that were supposed to
>> be complete, but the boards were missing.
>
> The latching version of the Fujitsu has a single coil, but some simple
> circuit could translate the drive.
>
> Since it transmits a clean 100 ps edge, it's a nice 3 GHz switch. Some
> of that 100 ps is probably loss on my PCB.
What is the insertion loss form DC to say 100 MHz? It has to be
flat, since there is no way to compenstate for variations.
Reply by Michael A Terrell●October 25, 20172017-10-25
George Herold wrote:
> On Wednesday, October 25, 2017 at 6:44:26 PM UTC-4, Michael Terrell wrote:
>> John Larkin wrote:
>>>
>>> Reed relays are terrible. I like the Fujitsu FTR-B3GA4 series. They
>>> are good RF switches, too.
>>
>>
>> Any recommendation for a dual coil 12VDC DPDT relay with a low
>> insertion loss? I need to make a couple replacement attenuator boards
>> for HP 3325A/B function generators. I have several that were supposed to
>> be complete, but the boards were missing.
>
> I'd troll digikey, with a long list you can order by number in stock
> which limits your choices to something popular with others.
That doesn't reflect reliability, or other issues. Just what Digikey
sells. The original relays lasted for over 20 years, but they are NLA.
The board was through hole, a SMD board would be about 1/4 the size.
Reply by John Larkin●October 25, 20172017-10-25
On Wed, 25 Oct 2017 18:44:23 -0400, Michael A Terrell
<mike.terrell@earthlink.net> wrote:
>John Larkin wrote:
>>
>> Reed relays are terrible. I like the Fujitsu FTR-B3GA4 series. They
>> are good RF switches, too.
>
>
> Any recommendation for a dual coil 12VDC DPDT relay with a low
>insertion loss? I need to make a couple replacement attenuator boards
>for HP 3325A/B function generators. I have several that were supposed to
>be complete, but the boards were missing.
The latching version of the Fujitsu has a single coil, but some simple
circuit could translate the drive.
Since it transmits a clean 100 ps edge, it's a nice 3 GHz switch. Some
of that 100 ps is probably loss on my PCB.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
Reply by George Herold●October 25, 20172017-10-25
On Wednesday, October 25, 2017 at 6:44:26 PM UTC-4, Michael Terrell wrote:
> John Larkin wrote:
> >
> > Reed relays are terrible. I like the Fujitsu FTR-B3GA4 series. They
> > are good RF switches, too.
>
>
> Any recommendation for a dual coil 12VDC DPDT relay with a low
> insertion loss? I need to make a couple replacement attenuator boards
> for HP 3325A/B function generators. I have several that were supposed to
> be complete, but the boards were missing.
I'd troll digikey, with a long list you can order by number in stock
which limits your choices to something popular with others.
George H.
Reply by Michael A Terrell●October 25, 20172017-10-25
John Larkin wrote:
>
> Reed relays are terrible. I like the Fujitsu FTR-B3GA4 series. They
> are good RF switches, too.
Any recommendation for a dual coil 12VDC DPDT relay with a low
insertion loss? I need to make a couple replacement attenuator boards
for HP 3325A/B function generators. I have several that were supposed to
be complete, but the boards were missing.
Reply by John Larkin●October 25, 20172017-10-25
On Wed, 25 Oct 2017 09:51:39 -0700, Joerg <news@analogconsultants.com>
wrote:
>On 2017-10-25 08:57, John Larkin wrote:
>> On Wed, 25 Oct 2017 07:22:42 -0700, Joerg <news@analogconsultants.com>
>> wrote:
>>
>>> On 2017-10-24 17:22, John Larkin wrote:
>
>[...]
>
>>>> Here's a tester board:
>>>>
>>>> https://www.dropbox.com/s/t2bpkuq3uxpno0y/P951_E1.JPG?dl=0
>>>>
>>>> which is used to test other boards. That has about 270 of those
>>>> relays.
>>>>
>>>
>>> IME such relays work fine no matter how often used. They failed once
>>> they reached 15 years or older, sometimes over 20 years. When that
>>> happened then usually a lot of them in the same box had erratic contact.
>>> Where you had to exercise all of them numerous times and then they'd
>>> work fine for the day. A month later, same spiel.
>>
>> We use them in products for BIST and occasionally for gain switching,
>> so they don't operate often. I sure hope they don't start dying one of
>> these years.
>>
>
>By the time major problems might arise you and I could be in a elder
>care facility, possibly not remembering Ohm's law :-)
>
>
>> They switch fast stuff nicely:
>>
>> https://www.dropbox.com/s/x0qd4als1s7tco3/Fujitsu_FTR.zip?dl=0
>>
>
>That sure is fast. Most notably no bounce at all.
Those pics are TDR of settled relays. I think I have some bounce pics
somewhere. They do bounce on closure, for less than a millisecond as I
recall. They do not bounce or twang as much as reeds.
>
>
>> We are running an experiment right now, using that giant test board.
>> We will test the switch matrix for leakage current, then run a couple
>> of boards through increasingly nasty reflow and wash processes, and
>> see if we have relay problems. I've been insisting on solvent wash,
>> but people want to see if a lead-free reflow profile followed by water
>> wash is safe.
>>
>
>The relay datasheet says "plastic sealed" amd that moisture sensitivity
>is "not applicable" but I'd get Fujitsu's blessing on that anyhow.
We used some second-source Omron parts that had bad sealing and got
water inside. If a couple of the giant boards are OK, I might let
people use water wash on the Fujitsus.
The spell checker wants to turn Omron into Moron.
>
>>>
>>>>>
>>>>> I have bench gear with similar relays in there. Receivers used for EMC
>>>>> work and such. Everything was fine for about 15 years and then the first
>>>>> ones started not always making contact and I had to swicth back and
>>>>> forth. Maybe the gold layer had worn off.
>>>>>
>>>>> With Reeds I so far didn't have much trouble. They are nice in a hostile
>>>>> environment because of encapsulation. I did wear one out but that was
>>>>> using it to drive a transmitter for fast morse code transmissions. I
>>>>> probably exceeded the maximum number of cycles big time.
>>>>
>>>> I've found reeds to be unreliable. And they are expensive. The
>>>> Fujitsus are DPDT, too, which is handy.
>>>>
>>>> Morse code? Isn't that a variety of smoke signal?
>>>>
>>>
>>> Sort of.
>>>
>>> http://lowres.cartoonstock.com/history-smoke_signal-smoke_sign-smoke_communication-communication-native_americans-ndw0220_low.jpg
>>>
>>> I never got past 25 letters per minute, probably because I have no
>>> musicla talent which is supposed to be linked to it. I have used morse
>>> code a lot.
>>
>> I never got a ham license, partly because I couldn't learn to receive
>> code (and partly because I don't much like to talk to people.)
>
>
>It's a matter of practice. I learned it by listening a whole lot.
>
>
>> ... I also
>> have zero, or negative, musical ability; music mostly annoys me.
>>
>
>Not so for me. I even have MP3 on my road bike and the mountain bike,
>for boring sections of trail. Bluegrass, African Reggae and so on. What
>can instill instant goose bumps with riders I am about to pass is when I
>switch to the theme melody of "The Good, the Bad and the Ugly". Saw that
>movie again yesterday.
>
>https://www.youtube.com/watch?v=h1PfrmCGFnk
Clint was great.
>
>
>> Mo is a speech therapist. She occasionally gets an old guy who had a
>> stroke or something and can't talk or understand speech, but can still
>> communicate in code.
>>
>
>That could very well happen to me some day. I haven't done ham radio in
>over 25 years but code is as ingrained as the ability to ride a bicycle.
>Not at the old speeds but that would come back.
>
>It's like the NATO alphabet spelling "Alpha, Bravo, Charlie, Delta ..."
>which is so ingrained from ham and military days that I instantly use it
>on noisy phone connections. If the guy at the other end is ex-military
>or a pilot that instantly works and reduces comm errors to about zero.
I hate conference calls about tech issues. Some of my customers are
always requesting those dreadful group call-ins. People show up late,
have to leave, don't identify themselves, and are unintelligible. I
have to assume that everyone is taking the same notes. Tech stuff
should be email.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
Reply by Joerg●October 25, 20172017-10-25
On 2017-10-25 08:57, John Larkin wrote:
> On Wed, 25 Oct 2017 07:22:42 -0700, Joerg <news@analogconsultants.com>
> wrote:
>
>> On 2017-10-24 17:22, John Larkin wrote:
[...]
>>> Here's a tester board:
>>>
>>> https://www.dropbox.com/s/t2bpkuq3uxpno0y/P951_E1.JPG?dl=0
>>>
>>> which is used to test other boards. That has about 270 of those
>>> relays.
>>>
>>
>> IME such relays work fine no matter how often used. They failed once
>> they reached 15 years or older, sometimes over 20 years. When that
>> happened then usually a lot of them in the same box had erratic contact.
>> Where you had to exercise all of them numerous times and then they'd
>> work fine for the day. A month later, same spiel.
>
> We use them in products for BIST and occasionally for gain switching,
> so they don't operate often. I sure hope they don't start dying one of
> these years.
>
By the time major problems might arise you and I could be in a elder
care facility, possibly not remembering Ohm's law :-)
> We are running an experiment right now, using that giant test board.
> We will test the switch matrix for leakage current, then run a couple
> of boards through increasingly nasty reflow and wash processes, and
> see if we have relay problems. I've been insisting on solvent wash,
> but people want to see if a lead-free reflow profile followed by water
> wash is safe.
>
The relay datasheet says "plastic sealed" amd that moisture sensitivity
is "not applicable" but I'd get Fujitsu's blessing on that anyhow.
>>
>>>>
>>>> I have bench gear with similar relays in there. Receivers used for EMC
>>>> work and such. Everything was fine for about 15 years and then the first
>>>> ones started not always making contact and I had to swicth back and
>>>> forth. Maybe the gold layer had worn off.
>>>>
>>>> With Reeds I so far didn't have much trouble. They are nice in a hostile
>>>> environment because of encapsulation. I did wear one out but that was
>>>> using it to drive a transmitter for fast morse code transmissions. I
>>>> probably exceeded the maximum number of cycles big time.
>>>
>>> I've found reeds to be unreliable. And they are expensive. The
>>> Fujitsus are DPDT, too, which is handy.
>>>
>>> Morse code? Isn't that a variety of smoke signal?
>>>
>>
>> Sort of.
>>
>> http://lowres.cartoonstock.com/history-smoke_signal-smoke_sign-smoke_communication-communication-native_americans-ndw0220_low.jpg
>>
>> I never got past 25 letters per minute, probably because I have no
>> musicla talent which is supposed to be linked to it. I have used morse
>> code a lot.
>
> I never got a ham license, partly because I couldn't learn to receive
> code (and partly because I don't much like to talk to people.)
It's a matter of practice. I learned it by listening a whole lot.
> ... I also
> have zero, or negative, musical ability; music mostly annoys me.
>
Not so for me. I even have MP3 on my road bike and the mountain bike,
for boring sections of trail. Bluegrass, African Reggae and so on. What
can instill instant goose bumps with riders I am about to pass is when I
switch to the theme melody of "The Good, the Bad and the Ugly". Saw that
movie again yesterday.
https://www.youtube.com/watch?v=h1PfrmCGFnk
> Mo is a speech therapist. She occasionally gets an old guy who had a
> stroke or something and can't talk or understand speech, but can still
> communicate in code.
>
That could very well happen to me some day. I haven't done ham radio in
over 25 years but code is as ingrained as the ability to ride a bicycle.
Not at the old speeds but that would come back.
It's like the NATO alphabet spelling "Alpha, Bravo, Charlie, Delta ..."
which is so ingrained from ham and military days that I instantly use it
on noisy phone connections. If the guy at the other end is ex-military
or a pilot that instantly works and reduces comm errors to about zero.
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by John Larkin●October 25, 20172017-10-25
On Wed, 25 Oct 2017 07:22:42 -0700, Joerg <news@analogconsultants.com>
wrote:
>On 2017-10-24 17:22, John Larkin wrote:
>> On Tue, 24 Oct 2017 16:00:05 -0700, Joerg <news@analogconsultants.com>
>> wrote:
>>
>>> On 2017-10-24 15:44, John Larkin wrote:
>>>> On Tue, 24 Oct 2017 15:21:24 -0700, Joerg <news@analogconsultants.com>
>>>> wrote:
>>>>
>>>>> On 2017-10-24 14:49, John Larkin wrote:
>>>
>>> [...]
>>>
>>>>>> A relay would probably have worked there too, to switch the PD between
>>>>>> TIA inputs.
>>>>>>
>>>>>
>>>>> Only Reeds. With others that might result in customer calls such as "It
>>>>> only works if I hit it with a ballpeen hammer a few times".
>>>>
>>>> Reed relays are terrible. I like the Fujitsu FTR-B3GA4 series. They
>>>> are good RF switches, too.
>>>>
>>>
>>> They do spec a min load though which usually means that long term issues
>>> can result if used for zero-current signal path switching:
>>>
>>> http://www.mouser.com/ds/2/164/Fujitsu_05192016_FTR-B3-938760.pdf
>>
>>
>> We've used 61,000 so far, most for switching low-level signals, like
>> thermocouples. They seem fine.
>>
>
>That's good, more than 10 times the number as most clinical trial.
>
>
>> Here's a tester board:
>>
>> https://www.dropbox.com/s/t2bpkuq3uxpno0y/P951_E1.JPG?dl=0
>>
>> which is used to test other boards. That has about 270 of those
>> relays.
>>
>
>IME such relays work fine no matter how often used. They failed once
>they reached 15 years or older, sometimes over 20 years. When that
>happened then usually a lot of them in the same box had erratic contact.
>Where you had to exercise all of them numerous times and then they'd
>work fine for the day. A month later, same spiel.
We use them in products for BIST and occasionally for gain switching,
so they don't operate often. I sure hope they don't start dying one of
these years.
They switch fast stuff nicely:
https://www.dropbox.com/s/x0qd4als1s7tco3/Fujitsu_FTR.zip?dl=0
We are running an experiment right now, using that giant test board.
We will test the switch matrix for leakage current, then run a couple
of boards through increasingly nasty reflow and wash processes, and
see if we have relay problems. I've been insisting on solvent wash,
but people want to see if a lead-free reflow profile followed by water
wash is safe.
>
>>>
>>> I have bench gear with similar relays in there. Receivers used for EMC
>>> work and such. Everything was fine for about 15 years and then the first
>>> ones started not always making contact and I had to swicth back and
>>> forth. Maybe the gold layer had worn off.
>>>
>>> With Reeds I so far didn't have much trouble. They are nice in a hostile
>>> environment because of encapsulation. I did wear one out but that was
>>> using it to drive a transmitter for fast morse code transmissions. I
>>> probably exceeded the maximum number of cycles big time.
>>
>> I've found reeds to be unreliable. And they are expensive. The
>> Fujitsus are DPDT, too, which is handy.
>>
>> Morse code? Isn't that a variety of smoke signal?
>>
>
>Sort of.
>
>http://lowres.cartoonstock.com/history-smoke_signal-smoke_sign-smoke_communication-communication-native_americans-ndw0220_low.jpg
>
>I never got past 25 letters per minute, probably because I have no
>musicla talent which is supposed to be linked to it. I have used morse
>code a lot.
I never got a ham license, partly because I couldn't learn to receive
code (and partly because I don't much like to talk to people.) I also
have zero, or negative, musical ability; music mostly annoys me.
Mo is a speech therapist. She occasionally gets an old guy who had a
stroke or something and can't talk or understand speech, but can still
communicate in code.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics