Re: [time-nuts] Modified Extron DA [WAS: Rb video]

A cap marked 82pf might indeed be 79pf or any value 15-20% either side of the marked value. Depends upon what cap type you use. If you really need 79pf, buy a couple dozen 82 pf caps and select one based upon measurement. Be aware that the measure may be off by 10% too. Regards, Brian On 8/9/

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Hi Since you have a handle on the Q (and thus the peaking width) you can come up with a pretty good mental picture of what a value shift will or won't do. For those who can't stand changing out / padding one cap (that's all that you would ever need to do in the is case) LTSpice is indeed your f

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Thanks. Might end up more useful than the Pi-network approach I've used a few times before. I appreciate knowing of more tools that can be called upon to help with a design. I just wish the calculators had some way to deal with standard values (like TI's FilterPro). Its frustrating getting a 79p

Re: [time-nuts] Rb video

Hi, In this case the fan is the primary cooling method. The heatsink may help a bit, but the fan appears to have done most of the work since the base is not that hot even without the heatsink. For testing the 5680's I got on their PCBs, I just had a tiny fan on standoffs stuck on top of them wh

Re: [time-nuts] Rb video

Hi Without seeing his heat sink, there's no way to know how big he intended to make it. If it was the size of the rest of the box (X, Y and Z) then it's a fine solution that will work well. It'll also cost more than all of the rest of the box. If it's a 1/2" thick heat sink that almost matches

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Hi For a reasonable standard distribution, you probably want one input and many outputs. One in / eight out or one in / 12 out are fairly common. At least the video gizmo we've been dissecting has trouble past one in / 4 out. If you cascade them you are at one in to 3 useful outputs. to get to

Re: [time-nuts] Rb video

On 08/09/2013 03:09 PM, Bob Camp wrote: > Hi > > A few observations: > > 1) He talks about using a heat sink on the front panel, but then never shows > it / does it. The fan inside the box is not going to cool that Rb the way it > needs to be cooled. You either need a pretty massive heat sink on

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Bob wrote: I still think that a distribution amp based on logic ic's is cheaper / simpler / lower power / higher performance. A pair of NC7SZ125's will dump 20 dbm into 50 ohms all day long running at 5.5 volts. Good isolation as well. Do the lowpass filter right and the harmonics are not an

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Hi The simplest way to design it is to do a T matching network. Two inductors in the top of the T and one cap to ground. Weather it's a filter or a match, it's the standard three element T lowpass. The logic gate wants to "see" an inductor at high frequency. The T has an input inductor and th

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Bob, I need some education. For a low-pass filter I think series L and shunt C. For two inductors that normally means 2-3 capacitors.  If you use only one shunt capacitor is the second L in series with it (as a harmonic trap)? Can you point me to a design tool (or equation set) somewhere that sh

[time-nuts] RB video

I believe the subject video does a nice job introducing viewers to the construction and potential of EXTRON's extensive of NTSC video equipment housed in nice, reusable cabinets. The cabinets that I am familiar with have slide-in front and back panels of 1/16-inch aluminum that can easily be

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Hi I still think that a distribution amp based on logic ic's is cheaper / simpler / lower power / higher performance. A pair of NC7SZ125's will dump 20 dbm into 50 ohms all day long running at 5.5 volts. Good isolation as well. Do the lowpass filter right and the harmonics are not an issue. Two

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Bob wrote: The original design with 3x75 ohm outputs would be driving a 50 ohm load rather than a 33 1/3 ohm load. That would put it "in spec" for the CLC409 as opposed to just out of spec current limit wise. Right. Analog video generally ranges from 0 to +1 V, so as a DC-coupled video amp

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Hi The original design with 3x75 ohm outputs would be driving a 50 ohm load rather than a 33 1/3 ohm load. That would put it "in spec" for the CLC409 as opposed to just out of spec current limit wise. Bob On Aug 9, 2013, at 2:48 PM, Charles Steinmetz wrote: > Bob wrote: > >> Ok, each op-am

Re: [time-nuts] 9390-55108 IRIG

Paul, You've notice this too. Steaks on the grill go from raw to well done in a few milliseconds. Brian On 8/9/2013 17:48, paul swed wrote: You just never know when you need accurate time in the basement or garage and definitely insures you don't over do the steaks on the grill. Regards Pa

Re: [time-nuts] Modified Extron DA [WAS: Rb video]

Bob wrote: Ok, each op-amp drives three loads. Each load has a 50 ohm resistor in series with it. Each output could be terminated in 50 ohms. If they all are terminated, the op amp is driving three 100 ohm loads in parallel. The op amp sees 33 1/3 ohm at it's output in that case. That's way

Re: [time-nuts] 9390-55108 IRIG

The value of the am over dc was the ease that it could be sent over ac coupled amplifiers and distribution. These things drove numbers of clocks and data recorders typically. IRIB B I believe came about roughly in 1957-59. I had used it for my clock distribution until I ran across numbers of video

Re: [time-nuts] 9390-55108 IRIG

That is exactly what I did about 7 or 8 years ago with one of my 9390's. I have the 9390 in the lab and I bought a very large TRAK display which is in my office. This 9390 has old firmware so the day of year number is wrong, but the time is right as it is running off of GPS. I just have a long run

Re: [time-nuts] 9390-55108 IRIG

alw.k...@gmail.com said: > What in practical terms is the IRIG-B (AM, not DC) good for? There is nothing magic about it. It's been around a long time and lots of gear uses it. The AM version works over long twisted pairs, telephone lines. http://en.wikipedia.org/wiki/Inter-range_instrumentat

Re: [time-nuts] 9390-55108 IRIG

It was originally designed to put on magnetic tape for time tagging telemetry data from the White Sands missile testing base. It can be used for a number of applications where you need to send time via coax cable to other devices i.e. time displays, synchronising other timing devices. Google IRIG-

Re: [time-nuts] 9390-55108 IRIG

Hi If you are trying to pass timing around a large area (factory / test range / base) on telephone lines, time on an audio tone is a pretty good idea. Bob On Aug 9, 2013, at 1:38 PM, Al Wolfe wrote: > The TrueTime GPS receiver and frequency standard I have puts out IRIG-B as > well as 4 ea

Re: [time-nuts] 9390-55108 IRIG

The TrueTime GPS receiver and frequency standard I have puts out IRIG-B as well as 4 each 10 Mhz. signals. What in practical terms is the IRIG-B (AM, not DC) good for? Al, K9SI The DC code was usually TTL compatible PWM and the IRIG-B would be 3V pk-pk AM. Marker 8 cycles, "1" 5 cycles an

Re: [time-nuts] 9390-55108 IRIG

Good luck! Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: 09 August 2013 13:42 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 9390-55108 IRIG Rob, that's it - IRIG-B. Then I

Re: [time-nuts] Rb video

Hi Yes, we are better off with his video that without it. It takes a brave individual to show all the zigs and zags along the way in a project. My comment was aimed at those simply looking to understand what he did, why he did it, and duplicate the effort. Bob On Aug 9, 2013, at 10:24 AM, Da

Re: [time-nuts] Rb video

On Aug 9, 2013, at 9:41 AM, Dr. David Kirkby wrote: > On 9 August 2013 14:09, Bob Camp wrote: >> Hi >> >> A few observations: >> >> 1) He talks about using a heat sink on the front panel, but then never shows >> it / does it. The fan inside the box is not going to cool that Rb the way it >>

Re: [time-nuts] Rb video

Hi A few observations: [] 9) There are many examples out there of why video editing is a good idea. You could have chopped a *lot* out of that video …. [] Bob == Whilst I agree that the video could have been trimmed slightly, overall I don't think it w

Re: [time-nuts] Rb video

On 9 August 2013 14:09, Bob Camp wrote: > Hi > > A few observations: > > 1) He talks about using a heat sink on the front panel, but then never shows > it / does it. The fan inside the box is not going to cool that Rb the way it > needs to be cooled. You either need a pretty massive heat sink on

Re: [time-nuts] Rb video

Hi A few observations: 1) He talks about using a heat sink on the front panel, but then never shows it / does it. The fan inside the box is not going to cool that Rb the way it needs to be cooled. You either need a pretty massive heat sink on the front panel with no fan or something smaller wi

Re: [time-nuts] 9390-55108 IRIG

Rob, that's it - IRIG-B. Then I must look at the O/S / sound driver/codec. ALSA has replaced OSS which the driver was written to use. There is ALSA OSS emulation, which I am using. That is perhaps, the problem. I just have to find an older distribution that uses OSS and install it. Thanks for your

Re: [time-nuts] 9390-55108 IRIG

Re: [time-nuts] 9390-55108 IRIG

The refclock utilises AGC and winds the mixer input up to full volume. It is supposed to be a mic input so it would be over loaded. I think its AM as there is a carrier with peaks. Perhaps a picture from an oscilloscope would be a better way to describe it? Listening to it, I hear 1KHz and 50(100

Re: [time-nuts] Rb video

On 9 August 2013 03:50, Mark Sims wrote: Hi Mark, I'm not sure why you needed to start a new thread - why not just add to the old one? > I also use a blinking status LED controlled by an ATTINY13 AVR chip. It also > reads a temperature sensor and controls a PWM'ed fan. The LED blinks out the

Re: [time-nuts] 9390-55108 IRIG

Mark, What is your ref clock driver 6 expecting to see? IRIG-B can be in a modulated or un-modulated form (Datum called this DC code) The DC code was usually TTL compatible PWM and the IRIG-B would be 3V pk-pk AM. Marker 8 cycles, "1" 5 cycles and "0" 2 cycles wide. Spaces 1V pk-pk. Rob -O

Re: [time-nuts] 9390-55108 IRIG

That one is about 10 years younger than this one :) I don't know why they called everything 9390, when the difference between generations is substantial. Probably a marketing decision.. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of

Re: [time-nuts] 9390-55108 IRIG

Didier has the 9390-6000 manual that has details of the IRIG ouputs for that, I wouldn't expect there to be too much difference, if any _http://www.ko4bb.com/manuals/index.php?dir=05%29_GPS_Timing/Datum_ (http://www.ko4bb.com/manuals/index.php?dir=05)_GPS_Timing/Datum) Regards Nigel G

[time-nuts] 9390-55108 IRIG

I am trying to get a Datum 9390-55108 to work with NTPD using refclock driver 6. So far I have been unsuccessful. The output looks like IRIG-B (modulated 1Khz with 50% greater amplitude pulses) I can't get it to work with NTPD. Unless of course, my NTPD version is broken! Does anyone have informa