Re: BNC that does not have the bayonet lugs
SHVs have bayonet lugs.
-Dave
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On 5/20/25 17:39, Mike via groups.io wrote: SHV?
73, Mike,
Mike Stevens,
G8CUL/F4VRB.
*From:*[email protected] <[email protected]> *On Behalf Of *Paul Bicknell via groups.io
*Sent:* 20 May 2025 22:05
*To:* [email protected]
*Subject:* [HP-Agilent-Keysight-equipment] BNC that does not have the bayonet lugs
Hi all a bit off base? but has anyone ever come across a connector that is the same size and form as a BNC but it does not have the bayonet lugs and uses a locking grove where the lugs would be? it is Made by Radial and there is even a High voltage version with more insulation like the high voltage BNC? as I would like to get hold of a few mating sets
Regards Paul? located in the? UK
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Dave McGuire, AK4HZ
New Kensington, PA
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Re: BNC that does not have the bayonet lugs
SHV? ? 73, Mike, Mike Stevens, G8CUL/F4VRB. ?
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From: [email protected] <[email protected]> On Behalf Of Paul Bicknell via groups.io
Sent: 20 May 2025 22:05
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] BNC that does not have the bayonet lugs? Hi all a bit off base? but has anyone ever come across a connector that is the same size and form as a BNC but it does not have the bayonet lugs and uses a locking grove where the lugs would be? it is Made by Radial? and there is even a High voltage version with more insulation like the high voltage BNC? as I would like to get hold of a few mating sets Regards Paul? located in the? UK
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BNC that does not have the bayonet lugs
Hi all a bit off base? but has anyone ever come across a connector that is the same size and form as a BNC but it does not have the bayonet lugs and uses a locking grove where the lugs would be ?it is Made by Radial? and there is even a High voltage version with more insulation like the high voltage BNC ?as I would like to get hold of a few mating sets
Regards Paul? located in the? UK
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Re: HP 478A Thermistor Sensor. Input return loss and matching
On Mon, May 19, 2025 at 11:54 PM, Jim Ford wrote:
Yes, 1206 is rather large. ?I’ve not opened up the 478A or the other thermistor sensor I have for use with the 432A, one goes to 10GHz and the other to 18 GHz, but I would check into smaller resistors. ?0805, 0603, 0402, 0201, and the near-microscopic 01005 are common. ?I think they even go smaller than 01005. ?Conventional wisdom says smaller ones have lower parasitics. ?Good luck. ?HTH.
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I think some testing of any alternative capacitors would be required because MLCC type caps often have subtle package resonances and they can also develop transmission line type properties when mounted near a ground surface and this can affect the frequency response in subtle ways. In this respect, some high performance COG/NP0 caps are totally unsuitable for wideband use. The classic ATC 100 and 800 range of high Q caps is a good example of a NP0 capacitor type that should be avoided if the aim is to achieve a very flat frequency response across a very wide frequency range. These caps have various package resonances that cause subtle (and very narrow) resonance dips in their frequency response. Often these ATC caps can suffer with several little resonances across VHF and UHF. So these caps would be unsuitable for use in a power meter although I don't think they offer high values in NP0 anyway. The same mini resonance risk applies across all high Q C0G/NP0 MLCC caps although I find that the lower cost ones (with lower Q) tend to give a smoother response but at the expense of higher ESR. Sometimes, mounting the cap on its side can remove a subtle resonance.
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The main risk with selecting really small class 2 (eg X7R) caps is that the capacitance can become very dependent on the applied DC voltage and it also becomes highly temperature dependent. So I don't see the selection of alternative caps as being an easy task. 1206 would probably be OK if they can be made to fit but I'd recommend a very thorough sweep test in very small frequency increments to make sure there aren't any little resonant dips anywhere. These dips can be quite shallow at maybe 0.05dB to 0.3dB and they can be very narrow at maybe 5 MHz wide. It's usually C0G/NP0 caps that suffer in this respect though.
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Regards
Jeremy
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Re: HP 334A distortion analyser problem
Not specific to this device - but check power rails.? Failed capacitors or deteriorated gain transistors in the power supply will cause more noise on the power rail - could be a simple fix . I would start with a PS inspection.? Connect your scope to the rails and look at the signal.? You can look at it with AC mode if the scope cannot provide enough?offset.? ?The ideal?result is a flat line? -? but most likely you will see some 100/120Hz ripple (depending on country) .? If the ripple is going to the filtered DC power rails that can get into the measured signal chain.?? The cold spray might suggest there are failing transistors or diodes but could?also be carbon composition resistors if present.? These? carbon comp. resistors should almost always be replaced with metal film resistors as they don't age well.? Another?reason for hot cold issues is cracked solder joints.? No other way to identify but to? look at the solder joints.? Usually? this happens in areas that?heat up.? The thermal cycling causes the solder to crack.? Take some pictures of the A2 board .?
Also a video here about the unit :?
Maciek?
On Tue, May 20, 2025 at 11:26?AM Goran Parezanovic via <GParezanovic= [email protected]> wrote: I was wondering if someone has the idea about this problem:
In voltmeter mode , just after starting it up, the needle will deflect from zero, for about 5% of the scale ( no input ). This will happen on all the ranges and the deflection is about the same regardless of the range, ( except for two lowest ranges where it gets more than 5 % ). After warming up ( a few minutes ) the needle will go to zero, where it's supposed to be. So I suspected that a warmed up component will go to the good working area. Board A2 has the measuring circuit on itself and transistors Q5 to Q9 form an amplifier that goes to the measuring bridge and then to the meter. I disconnected the input to the measuring circuit and still had the same symptoms, so my conclusion is that the amplifier is inducing the noise. Now comes the puzzling part: I applied "supper cold" spray ( -20 deg)to each transistor in the measuring circuit ( Q5 to Q9) but the voltmeter works fine, stays at zero.?
At the moment I'm looking for advice, the manual reads that the full scale signal is 1 mV ( and has to be measured with 10 Mohm, 10 pF probe ), so for my 5 % deflection the signal would be 50uV, and with my oscilloscope and probes I have I can't trace this level to try to find problem that way ).
Any advice or suggestion greatly appreciated.
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Sorry: maybe I didn't explain myself well: in fact A3A8 is in test mode, as indicated on page 164 of the service manual (Jumper A3A8 TP1 SWP TO A3A9TP3). Anyway I replaced the ACLU module and things have definitely improved: the noise intervals have reappeared and the signal placed at the input is visible again on the CRT. in band "A" things are quite good, while the other bands (2 - 22Ghz) show a signal rather variable in amplitude depending on the frequency.... So the fundamental problem was due to the ACLU module apparently...
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HP 334A distortion analyser problem
I was wondering if someone has the idea about this problem:
In voltmeter mode , just after starting it up, the needle will deflect from zero, for about 5% of the scale ( no input ). This will happen on all the ranges and the deflection is about the same regardless of the range, ( except for two lowest ranges where it gets more than 5 % ). After warming up ( a few minutes ) the needle will go to zero, where it's supposed to be. So I suspected that a warmed up component will go to the good working area. Board A2 has the measuring circuit on itself and transistors Q5 to Q9 form an amplifier that goes to the measuring bridge and then to the meter. I disconnected the input to the measuring circuit and still had the same symptoms, so my conclusion is that the amplifier is inducing the noise. Now comes the puzzling part: I applied "supper cold" spray ( -20 deg)to each transistor in the measuring circuit ( Q5 to Q9) but the voltmeter works fine, stays at zero.?
At the moment I'm looking for advice, the manual reads that the full scale signal is 1 mV ( and has to be measured with 10 Mohm, 10 pF probe ), so for my 5 % deflection the signal would be 50uV, and with my oscilloscope and probes I have I can't trace this level to try to find problem that way ).
Any advice or suggestion greatly appreciated.
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Re: (OT?...) Sticky labels for aluminum and other typical materials panels
Maybe this is the t=right thread to ask if anyone knows of a truly Permanent marker ?
If i write on polythene bags with a Sharpie it rubs off in a few weeks.
A Biro is a little better but too narrow to read easily unless the bag has a white label patch.
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OFF TOPIC - JSR RM3500 automatic modulation meter manual
Date: Mon, 19 May 2025 12:44:52 -03
Does anyone have the manual for the JSR RM3500 automatic modulation meter?
Thank you.
Marcelo F. Ruiz
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Re: (OT?...) Sticky labels for aluminum and other typical materials panels
Custom front panels are a perennial pain, so a lot of people have tried different ways. You may get some useful ideas from this post and the links in that post.
FYI: I haven't tried any of them.
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Looking for manuals for Yokogawa-HP 4255A Universal Bridge
Hi all,
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I am thinking of maybe picking up a 4255A Universal Bridge for some fun, but I can't seem to find a manual for it anywhere.
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Does anyone have a copy of any user or service manuals for this instrument?
I'm happy to buy a paper manual (which I'll scan and upload) or if anyone has a scan they can provide?
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Thanks!
Jared
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Re YIG module power supplies.
Many (most?) "Modern" YIG modules likely protect themselves (but you'd be wise to assume they do not) from incorrect power sequencing.? However...
From personal hard won expensive experience, older units (from the 70's and 80's) are likely to NOT have any such protection built in.
The ONLY way to be sure is to find either the makers data sheet, or consult the detailed schematics of whatever instrument/assembly they were used in, to see how that handles the power distribution and how multiple rails come up from cold.
(One regulator has the voltage reference, other regulators use that output, and/or other regulator outputs as their reference, or enable/disable signals.? Sometimes it is less than obvious.)
The same applies to many modern microwave RF Gain Blocks, that use exotic FET devices.? They too can be instantly destroyed by sequencing the power rails the wrong way...? Again, do not "assume" they have built in protection, unless the makers data sheet says they have.? Even then, that may only protect it when the power is coming up, not if a bias supply fails while in use.
Oh, and yes, "Fine Tune" coils are very fragile.? The YIG may still oscillate if you burn that coil, but if that results in shorted turns, as it might, then the main coil tuning ability, regarding sweep speed will be seriously compromised, or even cause trouble in the main coil driver (over current issues) much as a shorted turn in a power transformer secondary can render it useless.
Take care, and never assume anything, in regards to salvaged RF assemblies of any sort.?? At best, nothing bad happens, but it doesnt work.?? At worst, "Phht"!?? And then more $$$$'s needed.
Regards to All.
Dave 'KBV.
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Created on and sent from a Unix like PC running and using open source software:
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Re: how to convert HP83711B to 83712B!
The 83711A/B was introduced in the early 1990’s or late 1980’s. The Spectrum Analyzer Division (Santa Rosa, CA) had converted the production line to run on 9000/382’s by that time. I would assume that the Network Analyzer/Sweeper Division had also done the same thing by that date.
Don Bitters
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Re: HP 478A Thermistor Sensor. Input return loss and matching
Yes, 1206 is rather large. ?I’ve not opened up the 478A or the other thermistor sensor I have for use with the 432A, one goes to 10GHz and the other to 18 GHz, but I would check into smaller resistors. ?0805, 0603, 0402, 0201, and the near-microscopic 01005 are common. ?I think they even go smaller than 01005. ?Conventional wisdom says smaller ones have lower parasitics. ?Good luck. ?HTH.
Jim Ford Laguna Hills, California, USA?
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On May 19, 2025, at 3:19?PM, jmr via groups.io <jmrhzu@...> wrote:
? Sorry, I made a typo the graph title should say inductance in nanohenries (nH) not uH. The measured Ls for the 1206 capacitor is 1 nH.
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Here's a simulation for the VSWR if the thermistors are not tracking perfectly. This is the case for when one thermistor is 90R and the other is 110R.
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Whilst this still looks really good, the VSWR rapidly degrades to 1.04:1 at 50 MHz if the thermistor tracking degrades to 80R + 120R. I've not show this case as it is probably unlikely to happen unless the sensor has been stressed at some point.
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<H75 VSWR Model_trackingerror.gif> ?
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Regards
Jeremy
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Re: HP 478A Thermistor Sensor. Input return loss and matching
Sorry, I made a typo the graph title should say inductance in nanohenries (nH) not uH. The measured Ls for the 1206 capacitor is 1 nH.
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Here's a simulation for the VSWR if the thermistors are not tracking perfectly. This is the case for when one thermistor is 90R and the other is 110R.
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Whilst this still looks really good, the VSWR rapidly degrades to 1.04:1 at 50 MHz if the thermistor tracking degrades to 80R + 120R. I've not show this case as it is probably unlikely to happen unless the sensor has been stressed at some point.
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Regards
Jeremy
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Re: HP 478A Thermistor Sensor. Input return loss and matching
A couple of people have now mentioned that it's possible to swap the internal caps for 0.1uF parts. I'm still not sure what package will be suitable, especially for the series input cap.
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A 1206 SMD package seems huge to me and it isn't the ideal form factor to achieve low series inductance. However, I put a 100nF 1206 class 2 ceramic cap into an SMD test fixture and measured it from 1 MHz to 2 GHz to look at the package inductance and the ESR.
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See the result below. This is pretty much what I've seen in the past from this capacitor type. The series inductance is about 1nH (seen in the right hand graph) and the ESR slowly climbs from a few tens of milliohms up to about 0.5 an ohm by 1 GHz. Above this, the ESR climbs very rapidly and this is normal.
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I also put this into a simulation of a H75 thermistor head and this predicts the VSWR vs frequency. The series resonance is at about 15 MHz and I would have expected to see this up at maybe 30-40 MHz with a different capacitor package. However, these H75 sensors date back a few decades so I'm not sure what technology HP used for these caps. Has anyone taken one (eg a damaged one) apart?
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I haven't included the tiny package inductance of the thermistors so I think the overall inductance will be slightly higher than my crude model below.
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The model assumes that both of the 100R thermistors track accurately together and this allows a very low VSWR between 10 and 20 MHz. However, if they don't track perfectly when the bridge is balanced, then the VSWR will be a bit higher here in reality. One thermistor might be at 90 ohms and the other one might be at 110 ohms for example where 90 + 110 = 200R. This will degrade the VSWR of the sensor.
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Regards
Jeremy
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I've dumped the three UVPROMs from my counter. The ROMs are attached here in case they could ever be useful to anyone later on.
The versions, as marked on the stickers, are:
U17 - HPIB Controller: 05334-80007 U19 - Executive Controller: 05334-80003 U29 - Measurement Controller: 05334-80006
Ed
I do have a DIY replacement oscillator for the 5334A and 5334B.
If interested contact me off group.
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ed
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If you are new to YIG’s? then you should be very careful about the fine tune / FM coil as it does not take any currant to burn it out And yes you do need a lot of different power supplies to work on a lot of components Not on Yigs but watch out for bias supplies that must be switched on before the main supply otherwise it is sudden death to the device under test ? Paul ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Steve J. Noll, WA6EJO via groups.io
Sent: 19 May 2025 20:20
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] YIG Oscillator Info? ? Yes, thank you. Just found one of the YIGs is shown in one of the files, but the connections shown do not jive with the actual unit PCB. Considering requirements of 40V, 20V, 10V, 5V and one or two more, I now realize these are just not worth the time!
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Yes, thank you. Just found one of the YIGs is shown in one of the files, but the connections shown do not jive with the actual unit PCB. Considering requirements of 40V, 20V, 10V, 5V and one or two more, I now realize these are just not worth the time!
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Re: HP8757A Display Problem (Scalar Network Analyzer)
An update: I've extracted the 1345A display unit and examined the boards we spoke about yesterday; I powered it using a bench supply I designed and built myself years ago which I use for all this kind of work, so the unit was independent from any other elements of the 8757A analyzer, to produce the "pikes peak" test pattern.
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I saw some suspect solder joints on both of the smaller boards on the side, cleaned them and re-soldered them. I also dismounted the PROM and the two static RAM chips and re-seated them; the RAM's are fine (checked on another unit I have).
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The problem persists, I ran out of time last night and have been busy with other matters today, so my next steps are to check both oscillators (20MHz and 19.66MHz) and the divided-down derived frequencies and also examine the "Vector Done" signal path.
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I am also wondering if the tantalum capacitors (those yellow ones on the boards) may be suspect - I have spare caps which I can replace them with but I cannot think of a way they would be causing this problem, the supply rails are exactly as they should be so they are certainly not short-circuit, but maybe open-circuit or high ESR.
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This is taking a lot of time I could be using on other things so I'm also thinking of finding a replacement 1345A to buy, but that would not be a "real" solution!
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Dave McGuire
Paul Bicknell
Marcelo Ruiz
Jared Cabot
Steve J. Noll, WA6EJO
Trevor Gale