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Re: Stellex YIGs
John Miles
They're equivalent to these Endwave parts, as far as I can tell:
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The YTOs themselves are nice parts, but the popular synthesizer boards that use them are noisy. The comparison frequency is relatively low (250 kHz), causing a 90-dB in-band PN penalty. With a higher Fcomp you can do quite a bit better. -- john, KE5FX Does anyone has a detailed datasheet of the stellex permanent magnet |
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Stellex YIGs
microwaveengineer1968
Does anyone has a detailed datasheet of the stellex permanent magnet
YTOs that are commonly offered on ebay ? im especially interested in the max current the coil can take without frying. Im in the process of building a 32GHz Synthesizer and want to use one of those YIGs to generate a 8GHz Signal that then will be multiplied to 16GHz and then to 32GHz ,im planing on using a SPD from metelics for this task driven by a 100MHz Crystal oscillator, i know theres better stuff around but im trying to utilize stuff in got in my drawer. Anyway i need a datasheet for the YTO to be able to properly design the loop filter and driver circuitry. |
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Re: DIY: Repair of HP Step Attenuators
Thanks John!
Best George --- In hp_agilent_equipment@..., J Forster <jfor@...> wrote: hour chasing small bits of an assembly because I ignored that precaution. |
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Re: Hp-8443A Tracking Generator Problems
J Forster
They are very likely Sealectro or MicroDot. If you email me a (small ) pic of
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both M and F, off list, I'll see if I can ID them. If they are gold plated with Teflon insulation between center and outer conductors, Sealectro is the most likely choice. -John David C. Hallam wrote: I did call them GOOFY because that is what they are. They are goofy because |
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Re: Hp-8443A Tracking Generator Problems
If you can email me photographs, I'll compare them to
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what's in my 8443A. But it doesn't really matter. The only important one for your present purpose is A6W1, the one from the RF amp to the counter's INT input. All you have to do is scope it long enough to verify that there's RF there; this can be accomplished without an adaptor. Dave Wise -----Original Message----- |
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Re: Hp-8443A Tracking Generator Problems
David C. Hallam
I did call them GOOFY because that is what they are. They are goofy because
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I think the only place in the whole world they were used was the jacks and plugs for the cables of the connections between modules of the 8443A. They are not SMA, SMB, or SMC. I have looked at drawing of each of these types are the are not same as what HP used. I have no idea what they are or where to obtain them. I would certainly appreciate it if anyone could identify them along with a source of supply. As far as I am concerned their official description is "unobtainiun". David KC2JD/4 -----Original Message-----
From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]On Behalf Of David Wise Sent: Friday, November 16, 2007 5:03 PM To: hp_agilent_equipment@... Subject: RE: [hp_agilent_equipment] Hp-8443A Tracking Generator Problems I didn't call them goofy, David Hallam (the OP) did. You and I are referring to what's more commonly called "Hybrid-D" connectors. (From context, I judge that David Hallam is thinking of the SMB (SMC?) plugs on the inter-assembly cables inside the instrument. The hybrid-D of interest in this thread actually has no standard D contacts at all, it's all coaxes. Which by the way are called "Size 8". Not to inundate you with 8's, but the connector pin layout is called "8W8", which predictably means 8 contacts 8 of which are coax. Regards, Dave Wise > -----Original Message----- > From: hp_agilent_equipment@... > [mailto:hp_agilent_equipment@...]On Behalf Of J Forster > Sent: Friday, November 16, 2007 2:02 PM > To: hp_agilent_equipment@... > Subject: Re: [hp_agilent_equipment] Hp-8443A Tracking > Generator Problems > > > Sealectro is a brand. They made SMA, SMB, SMC, and a number > of other miniature > coax connectors. They ALSO made a number of proprietary types > in addition to the > standards. > > As to 'goofy', do you mean the D connectors w/ the mix of > coax and ordinary > pins? > > -John > > > > David Wise wrote: > > > They did call them by an obsolete name, "selectro" (or was > it "sealectro"?). > > > > > > > Yahoo! Groups Links > > > > |
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Re: Hp-8443A Tracking Generator Problems
I didn't call them goofy, David Hallam (the OP) did.
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You and I are referring to what's more commonly called "Hybrid-D" connectors. (From context, I judge that David Hallam is thinking of the SMB (SMC?) plugs on the inter-assembly cables inside the instrument. The hybrid-D of interest in this thread actually has no standard D contacts at all, it's all coaxes. Which by the way are called "Size 8". Not to inundate you with 8's, but the connector pin layout is called "8W8", which predictably means 8 contacts 8 of which are coax. Regards, Dave Wise -----Original Message----- |
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Re: Hp-8443A Tracking Generator Problems
J Forster
Sealectro is a brand. They made SMA, SMB, SMC, and a number of other miniature
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coax connectors. They ALSO made a number of proprietary types in addition to the standards. As to 'goofy', do you mean the D connectors w/ the mix of coax and ordinary pins? -John David Wise wrote: They did call them by an obsolete name, "selectro" (or was it "sealectro"?). |
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Re: HP-8443A Tracking Generator Problems
I said that two sentences later:
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"At narrow RBW settings, you have to fine-tune the TG to be exactly on frequency, that's the screwdriver adjustment on the front panel. Since you don't know that it's spot-on, start with a wide RBW then narrow it down." Said screwdriver adjustment trims the 3MHz LO which mimics the final I.F. of the 8552. Late versions of the 8443A have a "Restore Signal" mode which uses the actual IF signal from the 8552. In that mode, as long as it's within the SA's RBW, the TG puts out exactly the frequency presented to the SA's RF input. Note: This doesn't work with early 8552's, they don't bring their final IF out to the bulkhead. While the mod is conceptually simple, it's physically difficult due to the location of the contacts, so I haven't done it to my 8552A. And another note: When the 8553B is in FULL scan mode, it puts out its own marker in addition to the one from the 8443A. Fortunately they are recognisably different: the former is a dip in trace height while the latter is a change in trace intensity. And a note about that. How much brighter it gets depends on the Marker Intensity control, which adjusts the time the scan is paused at the marker position. Regards, Dave Wise -----Original Message----- |
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Re: HP-8443A Tracking Generator Problems
J Forster
ONLY, if the TG is actually putting out the same frequency as the SA is
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tuned to. I have an AIL 757 and TG. If the tracking control is not tuned right, the YIG in the SA's front end will be tuned to a different frequency than the TG and you see little to nothing on the SA. -John David Wise wrote: You don't even have to select zero span. The function and |
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Re: HP-8443A Tracking Generator Problems
J Forster
Take a look at the Wiltrons. The advantage is that the marker accuracy is independent of the GHz/Volt calibrations. In fact, I have a little home brew unit in a Tek TM-500 PI that does just that... mixer, LPF, detector, comparator.
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-John lothar baier wrote: this is another way but i havent seen anyone using this in centuries, the last time i saw it was on a old jerrold sweeper, everything i had ever since was using the approach i described, problem with the RF method is that its quite expensive to realize, a directional coupler, sampling mixer and the oscillator and frequency counter costs money and space and also takes away from the RF power, another factor is that whenever you use a comb generator you run the risk of finding your peaks "everywhere" even in places you dont want them :) |
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Re: DIY: Repair of HP Step Attenuators
J Forster
FWIW, do it over a tray w/ turned up edges. I just spent over an hour chasing
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small bits of an assembly because I ignored that precaution. Best, -John g47g wrote: Thanks. I'll try to disassemble the unit, then I hope I'll see the |
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Re: Hp-8443A Tracking Generator Problems
They did call them by an obsolete name, "selectro" (or was it "sealectro"?).
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-----Original Message----- |
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Re: Hp-8443A Tracking Generator Problems
lothar baier
usually HP used SMC and SMB on the inside of most instrument, i havent seen anything special in any of the HP Gear
Dan Rae <danrae@...> wrote: David C. Hallam wrote: IDavid if you do look for another one, try to find a later one with LED displays rather than nixie tubes, they are a little bit more reliable. But they are pretty easy to work on, all in all, given a modicum of test gear. I'd bet it is probably something very minor wrong with yours. And it's probably ten years since I had the lid off mine, but I don't remember anything odd about the coax connectors inside, SMC I think. Good luck, Dan --------------------------------- Be a better pen pal. Text or chat with friends inside Yahoo! Mail. See how. |
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Re: Hp-8443A Tracking Generator Problems
David C. Hallam wrote:
IDavid if you do look for another one, try to find a later one with LED displays rather than nixie tubes, they are a little bit more reliable. But they are pretty easy to work on, all in all, given a modicum of test gear. I'd bet it is probably something very minor wrong with yours. And it's probably ten years since I had the lid off mine, but I don't remember anything odd about the coax connectors inside, SMC I think. Good luck, Dan |
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Hp-8443A Tracking Generator Problems
David C. Hallam
Thank you to all who replied to my request for help. I now understand more
about the operation of this piece of test gear and also believe the solution to my problem is more complex than I originally thought. Given the investment in time, money, and effort it will take to acquire and/or fabricate things like circuit board extenders and jumper cables with those goofy (Yes I still think HP used "goofy" connectors, they aren't SMA, SMB, SMC, or SM* anything) connectors on one end and BNC on the other, I believe it might be more expeditious to find another 8443A I can purchase, only after verification that it is working properly, than to attempt the repair of mine. I will do what trouble shooting I can without those items before writing this one off. David KC2JD/4 |
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Re: DIY: Repair of HP Step Attenuators
Thanks. I'll try to disassemble the unit, then I hope I'll see the
reason of the failure. --- In hp_agilent_equipment@..., lothar baier <microwaveengineer1968@...> wrote: cam in place is missing homepage. |
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Re: HP-8443A Tracking Generator Problems
You don't even have to select zero span. The function and
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purpose of a TG is to output, at all times, whatever frequency the SA is listening to. As the SA scans, so does the TG. In all scan modes, the SA should show a horizontal line at a height determined by the TG's output amplitude. So just route the TG RF out to the SA RF in. If the trace rises, you have RF, if it doesn't, you don't, and either the TG is not outputting or it's off frequency. At narrow RBW settings, you have to fine-tune the TG to be exactly on frequency, that's the screwdriver adjustment on the front panel. Since you don't know that it's spot-on, start with a wide RBW then narrow it down. You could also view the TG output on your scope, at low frequencies. If the SA is on low band, the TG will be between 100kHz and 11MHz. However, the counter is tapped off at a different point so it's possible for the TG to output RF without counting, even if the counter works in EXT mode. Check the condition of A6W1 (Service Sheet 3) and scope it for RF. You've received good advice when it comes to checking the connections; with their inadequate brackets, those bulkhead-mounted hybrid-D's are notorious for "signalus interruptus". A couple of minor corrections to earlier postings: 1. The 8552 47MHz LO is not fixed; it's tuned by the Fine Tuning control, and swept on spans narrower than 50kHz. The 8443A's predecessor, the 8601A Option <mumble>, used with the 8553L, did not input the 47MHz LO. The 8601A generates its marker with RF blanking. 2. The marker is not necessarily at the SA center frequency, it can be moved side-to-side with the Marker Position control. Regards, Dave Wise -----Original Message----- |
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Re: HP-8443A Tracking Generator Problems
I cant be bothered to look at the manual as it it out of reach, but has it
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occured that you are assuming that the marker and RF output are connected......they may not be. Check you actually have a RF output on a scope or an RF voltmeter. The marker could be generated from the scan and the RF signal could get lost before the counter take-off and the output terminal. Like all fault finding you need to go round the loop checking for signals with an independent piece of gear. Dont just make assumptions about how it works. Things that "must" be working usually arn't from my experience, until proved otherwise !! Alan ----- Original Message -----
From: "David C. Hallam" <dhallam@...> To: <hp_agilent_equipment@...> Sent: Friday, November 16, 2007 6:09 PM Subject: RE: [hp_agilent_equipment] Re: HP-8443A Tracking Generator Problems Since I have demonstrated the counter portion of the 8443A is functionalas it will count an external signal from my signal generator and the RFoutput the 8443A is functionalNO not necessarily....measure it ! since there is a marker on the CRT display, the problem is in the counting of RF output frequency at the point where the |
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Re: DIY: Repair of HP Step Attenuators
lothar baier
most likely the cam is worn out or the little ball that locks the cam in place is missing
g47g <g47g@...> wrote: Hi Lothar, I have a 8495A manual step attenuator, and though it has the correct attenuations on every step(?), but it needs force to switch the attenuator in different positions, and also the well known "click" cannot be heard, when turning (with some force) the knob. Could you help me with some idea and procedure, as you did with the electronic controlled equivalent ? Thanks George Galambos --- In hp_agilent_equipment@..., "microwaveengineer1968" <microwaveengineer1968@...> wrote:
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