Hi, ? If 28dBi isn¡¯t enough gain, you can increase it with an in-line preamplifier. The Z3801A Manual (page 2-4), even mentions it for long cable runs ¨C including cascading them for long runs and lossy cables. ? Vendors used to make amplifiers for CATV and Satellite TV. They are still available dirt cheap - $7.95 USD on ePay. They have a frequency range of 950MHz to 2150MHz. ? They have F Connectors - they¡¯re for TV Stuff, right? I just a Male and Female BNC to F Connector adapters. You just patch it in. I have heard of people cascading them too, dumb ¨C where is that signal now in all of this noise? Grin ¨C contradiction, I guess. ? They say it needs 12V minimum to power it. The Z3801A supplied 5V works fine, you just get less gain of course. It doesn¡¯t seem to over current the Z3801A supply either. I¡¯m sure the 75 Ohm to 50 Ohm mismatch VSWR is relatively poor 1.5:1 or more, it does work. ? I don¡¯t know if you would have success with 3.3V though. It may not bias-up with whatever device they are using with their design. Mine is an RCA brand ¨C got it at Walmart a long time ago. ? I have the Amplifier in line (about 10 feet of cable from the Antenna), plus another 10 foot cable connected to my Z3801A RF Port and it does work. I get around 9dB gain at 1575MHz. It does have kind of a crappy Noise Figure specification, but you still get enough gain to make it worthwhile. My antenna is in the house on the second level and I generally see 4 of 6 satellites all of the time. It goes into ¡°Holdover Mode¡± very occasionally. ? Since the same GPS Engine is probably used for the Z3801A and Z3804A, it should have 5V from the Z3804A. It passes the 5V through to the GPS Antenna for its operation. ? I added the in-line Amplifier in early 2004 and it has been operating without incident since then ¨C 19 years. ? I use GPS-Con for the Console on my main computer. I like it. ? ? HP Z3801A Modifications ---------------------------------- I bought my Z3801A in March 2003. I built a -50V Linear Power Supply for it, put that on a UPS. I have seen it pull over 1A for a short period of time when the OXCO is cold until the Outside Blanket is up to temperature. It draws much less than that afterwards. ? I modified it for the RS232 Interface instead of the RS-422 Interface and connected that to a cable with a USB to RS232 Dongle ¨C the Software Driver doesn¡¯t work with the Dongle Chip on it now. Using direct cabling for now. ? I also made a translator followed by a paralleled 74F38 Driver and Pullup plus series Cable termination for the 1PPS Output. That connector is on the Front Panel with a similar translated and buffered 10MHz TTL Signal Connector as well. ? I also added a 7404 to drive an LED for a Front Panel heartbeat indicator. ? ? Does anyone know of a Dongle that works with the Windows 10 Driver? It used to work but now comes up with a message that the Driver and Hardware Dongle are incompatible. ? ? Ross ? ? ?
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From: [email protected] < [email protected]> On Behalf Of paulswed Sent: Saturday, September 10, 2022 7:57 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP Z3804A ? Power up the unit and check the antenna connector to ground with a dvm. Believe you will see. 5 V. Good to check. However if the z380X is newer maybe 3.3V. That antenna should work as long as the cables not to long and the antenna has a good view of the sky. 28 db gains not all that much. But may be good enough for your check. Best of luck you are making progress. I see Dave answered is a Motorola Oncore receiver.
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Re: Suffering from RIFA anxiety!
On 9/10/22 22:12, Matt Huszagh wrote: Those are the problematic ones. They will fail. The cracking that
you see is the beginning of the failure. We've replaced dozens of them
at LSSM, some having exploded while others had gotten close. They
aren't "horror stories", it's a well-known and understood failure mode. What's your policy on Schaffner filters? As I understand it, these often
contain the same problematic metallized paper in epoxy safety caps and
exhibit the same failure mechanism as standalone RIFAs. But they're a
bit less convenient to replace.
If you replace them, do you choose a mechanically-compatible modern
Schaffner? I guess the alternative would be to open the filter and
replace just the caps, but that doesn't seem so easy.
Actually I don't think we've run into any of those at LSSM, and I've not had any fail in my own test equipment either. I guess I've gotten lucky there. Though most people say that the big problems with Schaffners show up when an instrument that had a previous life in a 115V country is moved to a 230V country. We should probably adopt a replace-on-sight policy for those at LSSM, but most of the hardware on exhibit there mostly predates the existence of IEC connectors, and thus the all-in-one line entry modules. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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If it has been powered down for long enough for the almanac data to become invalid (~6 months), it can take a lot longer than that.
-Dave
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On 9/10/22 23:42, Dave Seiter wrote: Shouldn't take a day; I fire mine up every once in a while, and it usually locks in less than 10 minutes (and that's with an indoor antenna).
-Dave
On Saturday, September 10, 2022 at 08:32:00 AM PDT, paulswed <paulswedb@...> wrote:
Hello to the group well I'll be darned. Never seen one either. But it surely appears to be a Z380X inside of a distribution amplifier.
Very very nice. Thats a great find.
If you power it up, it will need an older 5V GPS antenna. Nothing fancy. Given thats its been off most likely a long time it could take a day to lock. But that depends on what the actual GPS receiver is. I cannot tell. There is a bit of label?over the chip that might give a clue.
But thanks for the hi res pix that was very helpful.
Regards
Paul
WB8TSL
--
Dave McGuire, AK4HZ
New Kensington, PA
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Shouldn't take a day; I fire mine up every once in a while, and it usually locks in less than 10 minutes (and that's with an indoor antenna).
-Dave
On Saturday, September 10, 2022 at 08:32:00 AM PDT, paulswed <paulswedb@...> wrote:
Hello to the group well I'll be darned. Never seen one either. But it surely appears to be a Z380X inside of a distribution amplifier. Very very nice. Thats a great find.? If you power it up, it will need an older 5V GPS antenna. Nothing fancy. Given thats its been off most likely a long time it could take a day to lock. But that depends on what the actual GPS receiver is. I cannot tell. There is a bit of label?over the chip that might give a clue. But thanks for the hi res pix that was very helpful. Regards Paul WB8TSL
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On Sat, Sep 10, 2022 at 06:57 PM, paulswed wrote:
Ozan
Power up the unit and check the antenna connector to ground with a dvm. Believe you will see. 5 V. Good to check. However if the z380X is newer maybe 3.3V.
That antenna should work as long as the cables not to long and the antenna has a good view of the sky. 28 db gains not all that much. But may be good enough for your check.
Best of luck you are making progress. I see Dave answered is a Motorola Oncore receiver.
Regards
Paul
---- Thank you Paul. I will send updates as I find more about ?this box. Ozan
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On Sat, Sep 10, 2022 at 03:24 PM, Dave McGuire wrote:
On 9/10/22 18:15, Ozan wrote:
Looking at it again I think you are right, this unit seems to be a
prototype based on mix of two existing products. Board on the top is
bolted only at 3 places to two bars with large portions unsupported, not
production-HP like. I am not next to the unit but I will check the
serial number and report. It is possible the box and bottom board is an
existing distribution amplifier, top board is an existing GPS receiver,
?likely?59551A. ?ROMs on the top board have stickers that say
59551-8000x. I will check if any of HP distribution amplifiers match to
bottom board.
I see GPS antennas that advertise 3V-5V operation with 28dB gain. Is
there anything particular I should look for?
I attached the picture of what I think is the GPS board.
That's a Motorola Oncore GPS receiver module.
-Dave
--- Thank you Dave. A search returns quite a bit of information about Oncore GPS modules.? Ozan
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Re: Suffering from RIFA anxiety!
"Dave McGuire" <mcguire@...> writes: Those are the problematic ones. They will fail. The cracking that
you see is the beginning of the failure. We've replaced dozens of them
at LSSM, some having exploded while others had gotten close. They
aren't "horror stories", it's a well-known and understood failure mode. What's your policy on Schaffner filters? As I understand it, these often contain the same problematic metallized paper in epoxy safety caps and exhibit the same failure mechanism as standalone RIFAs. But they're a bit less convenient to replace. If you replace them, do you choose a mechanically-compatible modern Schaffner? I guess the alternative would be to open the filter and replace just the caps, but that doesn't seem so easy. Matt
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Ozan Power up the unit and check the antenna connector to ground with a dvm. Believe you will see. 5 V. Good to check. However if the z380X is newer maybe 3.3V. That antenna should work as long as the cables not to long and the antenna has a good view of the sky. 28 db gains not all that much. But may be good enough for your check. Best of luck you are making progress. I see Dave answered is a Motorola Oncore receiver. Regards Paul
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Re: Suffering from RIFA anxiety!
The best time to replace Rifa capacitors is immediately. ;)
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Re: Read frequency list from HP 8510C via HP-IB
Yeah, OUTPFREL is only for reading back a frequency list that you gave it, not a start/stop/count. I struggled with this too and never did figure it out, so when I wrote the HP8510C module for scikit-rf I always just kept track in python before sending the commands to the instrument.
I don't know if you are using python, but if you are, skrf.vi.vna.hp8510c has a few useful abstractions: set_frequency_step() which allows start/stop/npoints with npoints>801, and set_hz() that takes a bag of (possibly >>801) assorted frequencies even if the spacing is mixed / weird. Then two_port() (or .s11, .s21, etc) do the measurements. The returned Network object has both S params and frequencies. No magic is happening for the !=801 point sweeps, it's just breaking down the big sweeps that the 8510 can't handle into little sweeps that it can, it uses the faster FORM2 binary transfer mode and start/stop/n sweeps when it can, it has the correct loop structure to take advantage of 8360 fast-lock, etc. Hope it helps.
Cheers, J
On Saturday, September 10, 2022 at 08:07:32 PM EDT, vk2bea via groups.io <vk2bea@...> wrote:
I looked at the manual and I think my assumption is correct.
At least the HP8510 has a command to read the list segments...? I had to jump through hoops to do it on the 8753 8-( ...?
Michael
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Re: Suffering from RIFA anxiety!
On 9/10/22 19:46, vk2bea via groups.io wrote: I opened up an HP counter of mine and saw the dreaded RIFA X2 & Y2 caps.
Out of an over abundance of caution I replaced them.
Looking carefully at them they appear to be in reasonable shape. There is some minor plastic cracking but it seems at odds with the horror stories you hear. Those are the problematic ones. They will fail. The cracking that you see is the beginning of the failure. We've replaced dozens of them at LSSM, some having exploded while others had gotten close. They aren't "horror stories", it's a well-known and understood failure mode. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Read frequency list from HP 8510C via HP-IB
I looked at the manual and I think my assumption is correct.
At least the HP8510 has a command to read the list segments...? I had to jump through hoops to do it on the 8753 8-( ...?
Michael
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Suffering from RIFA anxiety!
I opened up an HP counter of mine and saw the dreaded RIFA X2 & Y2 caps. Out of an over abundance of caution I replaced them. Looking carefully at them they appear to be in reasonable shape. There is some minor plastic cracking but it seems at odds with the horror stories you hear. (of course I have no idea on how the instrument I have was used before I got it. It may have had a good low use life) Does any one know if there are good guide lines as to when to check the equipment for these problematic caps? You can decode the date from the HP S/Ns. What years were instruments built with the bad RIFA caps? Are there particular models that, as a general rule, are likely to eventually exhibit a failure ? Michael 
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Re: Read frequency list from HP 8510C via HP-IB
That usually indicate there is no data (as you found from the error explanation).
Are you sure the command is doing what you think it's doing?
I've not used the 8510 but with the 8753 you cannot get the discrete source (frequency) values for each point. You must interpolate it from the start/stop (or center/span) data. (or use marker of course)
There is a 'list frequency sweep' mode, where you can enter either discrete frequencies or many start/stop values. This allows you to use your 201 (1601 or whatever) points economically if you have non contiguous areas of interest.
Maybe the 8510?OUTPFREL command is similarly targeted. (all I could find in a quick Google search is "OUTPFREL - Output frequency list".
Michael
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Swapping C1 (100uF) for what I had on hand, 470uF, brought the rails back to somewhere near nominal (+7V is now +7.3V which is out of spec) but it brought the meter back to life so that I can now coarse zero it, etc.
I will need to get an axial to replace the radial I've tacked in but it looks like the unit is on track to being repaired.
TonyG
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And as soon as I posted this, I went back and checked C1:
And previously I swear it tested correctly but now it is testing at 650nF instead of 100uF - Clearly I did something wrong.
Please ignore.
TonyG
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Hey All, I'm currently working on fixing up a non-working HP 432A unit - I've identified that there are several issues with the A2 board that I need to address before moving forward:
- Power rails outside of the spec, and
- 5KHz Multi-vibrator is bouncing around.
I'm taking the approach of addressing the rails first. The DC rails should be:
- +7V nominal - Anywhere between +6.5V and +7.1V - Broken unit 6.4V
- -13V nominal - Anywhere between -12V and -14V - Broken unit -11.1V
The broken unit I have is outside of those values - I started looking at it and eventually settled on looking at A2CR6 (6.2V Zener) as everything is referenced to the +7V rail and sure enough, it is out of spec with only a 5.8V drop. Before changing that though, I put the scope on the rails of the non-working unit and looked at them - These images show what I saw: 7V Rail -13V Rail You can see there is quite a bit of ripple on the rail. I have a working A2 board and swapping that in shows nice clean rails: 7V Rail -13V Rail Has anyone had this problem before and could provide any thoughts/insights/comments on what might be causing the ripple? I know that the issue is contained in the A2 board because I've been using the same chassis, A1 board, and Thermistor mount to test so the only difference between the two cases is the working A2 board and the non-working one. Look forward to any comments the group has. TonyG
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HP5340A intermittent or thermal problem
I have this one 5340A microwave counter that just won't work right despite lots of effort. I have four of these altogether, two Nixie style and two LED. Three work beautifully.. The problem one (LED) would be number two in the lineup, so I'd really like to get it going right. The number four unit (Nixie) is the crappiest in all respects except that it works great - I had to do some major kludge repairs in its power supply many years ago, it has no provision for OCXO, and is worst cosmetically.
The problem one at first couldn't lock onto anything above around 10 GHz. After much swapping of boards from unit four, I thought I had it made. It looked like A7 had problems. After some study of the manual, I put the original A7 back and did some tweaking, and it started working, until it quit again. It seemed like a thermal or intermittent issue somewhere, but after much study, I still can't tell. I even tried swapping all the boards between the units, and ended up with neither working. Swapping them all back put unit four immediately back to excellent working order, while the problem one remained a problem. Then today fooling with the tweaks on A7 and jiggling things around, it suddenly took off working fine again - then not at all. Lots of board jiggling and poking around in the bad one seems to mostly make it worse, even if it happens to start working for a few moments. The same action on unit four has virtually no effect - it just keeps going and going just fine.
This part of the system is quite complicated, with a number of interactive control and phase locked loops that are automatically tweaked and activated according to the counting conditions (mostly frequency), so I think I'll have to build a test thingy like the "K05-5340A Feed-Forward Simulator" described in the manual. I think it will help to isolate the functions somewhat, to figure out WTH is going on in there. One issue with this is that the procedure in the manual is about using it, but some of the steps have ambiguity. For instance, there's a test point marked "DC" on the K05-5340A circuit, where I think you'd take the DC measurement, but the text says get it from the pin 10 on the connector. These two points differ by a 51 ohm resistor, which can result in a 5 percent difference in reported voltage (the load is about 980 ohms). Maybe it's not that critical, but so far it looks like everything is quite sensitive to the adjustments being just right. Has anyone been through a full CAL of a 5340A, and knows the ropes on this procedure?
Anyway, it could be a bad part or connection somewhere, but very hard to tell when everything goes unstable. There are a lot of solid-Ta caps in the analog circuits that potentially could be leaky, but at least HP used the nice hermetically sealed can types, which tend to be quite reliable.
Ed
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On 9/10/22 18:15, Ozan wrote: Looking at it again I think you are right, this unit seems to be a prototype based on mix of two existing products. Board on the top is bolted only at 3 places to two bars with large portions unsupported, not production-HP like. I am not next to the unit but I will check the serial number and report. It is possible the box and bottom board is an existing distribution amplifier, top board is an existing GPS receiver, ?likely?59551A. ?ROMs on the top board have stickers that say 59551-8000x. I will check if any of HP distribution amplifiers match to bottom board.
I see GPS antennas that advertise 3V-5V operation with 28dB gain. Is there anything particular I should look for?
I attached the picture of what I think is the GPS board. That's a Motorola Oncore GPS receiver module. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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On Sat, Sep 10, 2022 at 08:38 AM, paulswed wrote:
One additional comment. This is a prerelease widget. Or its one heck of a hack. Notice the GPSDO LEDs are simply drilled through the front cover. No labels. Also and this may have been someone else. The RS232 hack. A nice unit no matter. But a odd one. Whats the serial number??
Regards
Paul
WB8TSL
---------------- Hi Paul, Looking at it again I think you are right, this unit seems to be a prototype based on mix of two existing products. Board on the top is bolted only at 3 places to two bars with large portions unsupported, not production-HP like. I am not next to the unit but I will check the serial number and report. It is possible the box and bottom board is an existing distribution amplifier, top board is an existing GPS receiver, ?likely?59551A. ?ROMs on the top board have stickers that say 59551-8000x. I will check if any of HP distribution amplifiers match to bottom board. I see GPS antennas that advertise 3V-5V operation with 28dB gain. Is there anything particular I should look for? I attached the picture of what I think is the GPS board.? Thank you for all your comments. Ozan
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Dave McGuire
Jared Cabot
vk2bea
