Re: [ot] Characteristic freq of space
At 12:35 AM 20/01/07, you wrote: I spent 46 years as an electronic technician without knowing free space had an impedance of 376.7 ohms. How did that happen? Hi Jerry, I (also) wish I understood fully but, based on equations of primitivity/permeability of free space and has been used practically (afaik) in design of some rather high gain antennas, have to find the article but (iirc) was in UK wireless world some 9 years back. ie In general the 50 or 75 Ohm impedance of coax needs to be matched to that of the antenna and this has a practical exposure to free space of 376.7 ohms, so essentially the antenna does this matching, though this issue seems to have been sidestepped many many times in anything other than Ba Eng courses :( I also recall a lecturer in 1979 or 1980 harping on about it as an important property of space and not to be ignored (at least as background info) for best understanding of RF principles at the most basic and core physics levels but I could not find a rationale behind it for so long ! Suffice it say, my Ba Eng was not in RF but, in digital but have always had a casual interest in the more sophisticated RF issues and recent experience has prompted my interest, hence the question... Regards Mike Massen ps: Interesting that your surname and mine are similar, curious where yours came from ? Jerry
Mike <<mailto:erazmus%40iinet.net.au>erazmus@...> wrote:
Hi Guys,
Apologies for the hugely off topic question but as you guys are so into RF (and its been
a little quiet in last few hours ;) I was hoping someone might be able to answer a simple
question, well fairly simple, with caveats no doubt...
As free space has a characteristic impedance of some 376.7 Ohms (or close to)...
Does free space have any (equivalent) 'characteristic' frequency or resonant frequency(s),
no doubt derived from attenuation/gain factors from RF transmissions etc ?
And if so, can the responder hazard a guess as to why, in terms of equations from first principles
or observations from experiment, that such frequency or even such impedance exists and
practical consequences thereof ?
<cough> Thanks ;)
Regards from
Mike Massen
Network Power Systems
Lab +61 (0) 8 9444 8961
Mb +61 (0) 438 048961
Perth, Western Australia
* USA GMC, Opel and Australian VL/VK Commodore Fuse Rail that wont warp or melt, New model V 2.0
with engine bay illumination timer and relay holder options !
* RB30 Skyline/Nissan/VL Upgraded ignition driver now in long term economy trials
* Twin tyres for most sedans, trikes and motorcycle sidecars
* Industrial grade PolyVinyliDeneChloride (PVDC Copolymer) in bulk, the best
oxygen and water protective barrier you can find for circuit boards.
* Special Equipment for sale: 60KVA 3-phase UPS with large battery cabinet - $12,000
Web site under construction, Ebay and Oztion Auctions <>
Regards Mike * GMC/VK/VL Commodore & Calais FuseRail that wont warp or melt ! * High grade VL/Skyline milspec ignition driver electronics now in development * Twin tyres for most sedans, trikes and motorcycle sidecars
|
[ot] Characteristic freq of space
Hi Guys,
Apologies for the hugely off topic question but as you guys are so into RF (and its been
a little quiet in last few hours ;) I was hoping someone might be able to answer a simple
question, well fairly simple, with caveats no doubt...
As free space has a characteristic impedance of some 376.7 Ohms (or close to)...
Does free space have any (equivalent) 'characteristic' frequency or resonant frequency(s),
no doubt derived from attenuation/gain factors from RF transmissions etc ?
And if so, can the responder hazard a guess as to why, in terms of equations from first principles
or observations from experiment, that such frequency or even such impedance exists and
practical consequences thereof ?
<cough> Thanks ;)
Regards from
Mike Massen
Network Power Systems
Lab +61 (0) 8 9444 8961
Mb +61 (0) 438 048961
Perth, Western Australia
* USA GMC, Opel and Australian VL/VK Commodore Fuse Rail that wont warp or melt, New model V 2.0
with engine bay illumination timer and relay holder options !
* RB30 Skyline/Nissan/VL Upgraded ignition driver now in long term economy trials
* Twin tyres for most sedans, trikes and motorcycle sidecars
* Industrial grade PolyVinyliDeneChloride (PVDC Copolymer) in bulk, the best
oxygen and water protective barrier you can find for circuit boards.
* Special Equipment for sale: 60KVA 3-phase UPS with large battery cabinet - $12,000
Web site under construction, Ebay and Oztion Auctions
|
Diode sensors or thermocouple sensors
Very new to power sensors and was wondering if someone had the time to
explain a few things with me. 1)When and why would you select one type
of sensor over the other? 2)Do both sensors work with the same
wattmeter? 3)Does the wattmeter need to be setup differently according
to the type of sensor used? I am a Ham and work with test equipment and
radios mainly below 1 Gig. Looking at buying HP, Boonton or Marconi
digital wattmeter. I am sure I have more questions but this
information would be of great help. Thank you¡¡..Jim
|
Looking for HP 117A VLF comparator data
Hi all, has anybody some service information, schematic of a HP117A VLF
comparator ?
Any help appreciated.
Regards
Antoon
|
Tks John
You're quite right , of course.- I actually want info on the 2650A for making up a 'modern equivalent' for phaselocking an older klystron generator- the 620B, which covers 10 GHz OK. But in parallel I'm also looking for info re the 8709 to see how I could use the 8690 (plus PI that covers 10GHz) as well. What ever I get first may make the other requirement redundant- will have to wait and see. For whatever reason I telescoped the two requirements--it's been a month or two since I last thought about either.
I think the 8690/8709 combo used special PIs that had factory mods done to interface to the BWO sweep cctry- I need to find out more on that aspect too.
I'm also looking for one or (maybe) two 5255A 12 GHz counter plugins. Both the EIP microwave counters I have don't have GPIB and I need a pair of counters with logging capability that I can use up around 10 GHz.
With a couple of 5245s on hand (and also in regular use!) I can use the BCD outputs to do the logging-but need the 5255As for the frequency coverage.
Meantime - how many pages has the 2650A handbook and are there any large foldouts? I can handle A4 scanning no problem-those large multi-page foldouts can present issues though.
Cheers
DaveB, Christchurch, NZ
toggle quoted message
Show quoted text
----- Original Message ----- From: "John Day" <johnday@...> To: <hp_agilent_equipment@...> Sent: Friday, January 19, 2007 3:16 PM Subject: Re: [hp_agilent_equipment] WG: Mysterious box: At 07:56 PM 1/18/2007, Dave Brown wrote:
DaveB, NZ (Still after a 2650A synchroniser h'book or even the real
thing! - or anything to help get the 8690 + PI phaselocked around
10GHz) Dave, my boy. I never realised you needed a handbook for a 2650A, I
have the very thing, right here in front of me. It is 1964 printing
with the modification data to use various other mixers. The 934A is
the basic harmonic mixer used in these things (same as used in the
540A transfer oscillator as it happens).
But I am not sure that a DY-2650A is the right thing, they were
intended for klystron oscillators, such as the 614, 616, 618, 620 and
the 8614, 8616 units. These were all reflex klystron based. The
DY-2650A takes the reflector voltage (2kV in the standard unit or up
to 3kV with modification M18) and outputs the reflector voltage with
error correction.
The Carcinotron (Backward Wave Oscillator) in the 8690's has
different characteristics. They have an external FM input which is
fairly consistently 6% of band deviation per volt of input (as I
recall). I suspect you would be better off using an 8709 type
synchroniser rather than a DY-2650A. The 8709's (used with the 8620
series and 8350 series sweepers) had a switch selection of
sensitivity, again very much by recollection, and is pretty easy to
modify if need be for other characteristics. Sadly, I don't appear to
have the manuals for the 8709's any more.
The DY-2650A manual is available to a list member if they need it,
provided they agree to have it scanned and the PDF sent to me for uploading.
John
Yahoo! Groups Links
--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.16.14/637 - Release Date: 18/01/2007 13:03
|
hp card extender solution for all 8640b, 8630b/ availble from me
i have found some very cheap sources of 30 pin and 36 pin
genuine cinch solder eyelet connectors "some ever are
genuine card extender types with terminals bent for card
extender applications.
i also have a cheap source that can supply pc cards
for the extenders.
in order to keep prices down id like to have a fairly
large initial run of the pc cards unless
their is great interest in the 36 pin and other sizes
of
extenders it will be just the 30 pin "15 pin double
sided extenders "contacts will not be gold plated but the
connectors will be "
if i can generate enough interest the price will be quite
low.
i woyuld probably just supply a board and connector to
the group and they can solder it on.
you cant troubleshoot boards in an 8640b without a 30
pin extender.
service manual says a 30 pin extender is supplied with
each new unit.
its like trying to find a 432a power meter with a
cable attached to it or a 428b with the probe "ha ha"
there probably is a need for other extenders for hp
scopes and spec analyzers
the double sided 15 pin card will work in older tek
stuff like 5245l counters and 310a wave analyzers
i had to do extensive work on my 310a and without an
extender had to struggle and probably replaced some
capacitors that were still in service limits.
get back to me shortly with your requests so i can
estimate how many boards and connectors i should order in
i think the 1740 scope is a good candidate for cheap
extenders.
im trying to keep this in the $20 range
|
Basically, you have to cannibalize >another unit. I have a 3.7 to 4.2 and 5.9 to 6.5 GHz Communication >Sweep Generator that died. Hmmm, I might have one of those in the basement. What model number is it? I'll look & email you later. > It turns out that HP left a loose screw in >the RF output amp during assembly. The screw was provably NEVER >tightened.... that was clear from a microphotograph I took I complained >bitterly, but they essentially said 'too bad'... it's out of warranty. >They also said I should 'hurry up' and order the replacement module for >ONLY $1400 because the price was about to go up to $2000++. Since then, >I've tried to avoid their newer stuff. Sadly, HP lost sight of the HP way. I know that many of us who were very close to HP back in the 70's regret what happened. I know a lot of the staff did too. But that's the way of the world I am afraid. Well, I think HP got seduced by the Wall Street suits. They came out with so many new products, they could not all succeed, and quality suffered. Now they are producing almost disposable junk IMO.... And an 8620 produces just about as good microwaves as a current unrepairable $$$$$ box. >OTOH, I had a Tek RTD-710A fail. The replacement part was about $2500 >(an amplifier hybrid), but they said there had been a manufacturing >problem. I took it to the local Tek office and they repaired and >calibrated the unit and returned it to me shipping prepaid... at no >charge... ZERO. That sort of thing USED to happen at HP sometimes too. Sadly my last experience with Tektronix was being laughed at when I asked about parts for an AWG2000 series unit about two years ago. Luckily I picked up a parts unit on the big auction for little money and saved the day. That's why I stick with the Tek 7000 and TM500 & TM5000 stuff. It's mostly standard parts. What is special doesn't fail very often and there are plenty of donor units about. The Tek 11000 was just not worth it IMO and the new stuff is just not to my taste. If you think HP had problems, try Keithley! I tried for ages to get manuals for some gear with absolutely no luck at all, I gather that they would not even provide service manuals where they had signed contracts that required them to do so. In one case I know they maintained the equipment free of charge for 13 years rather than provide manuals. John I have some Keithley and like it. If they contracted to provide prints and didn't do it, I'd send the stuff back or not pay the invoice. Almost nothing any instrument maker sells is REALLY sole source. HP makes the 4140B which is just as good as many Keithley toys. This no prints in the manual is silly. If anyone REALLY wants to reverse engineer something, they will. Any protection is in special chips ar PALs with security links blown. I've even seen the operating code in RAM and when the BU battery fails, the code goes and you have to pay for a reload. I've learnt the hard way to ask questions about such things before buying something. Damn lawyers and their suited Harvard Business School buddies. Ya gotta remember, companies are in business for the benefit of their stockholders and the mutual funds. It does not matter to those people if someone makes instruments or sells turnips. It's only the next quarter's profit that matters (and their bonuses, of course) FWIW, -John
|
At 05:53 PM 1/18/2007, you wrote: My gosh! I wouldn't want one of those nowadays!
But I suppose that was what I used before the two rack 8620/9845
based versions. I do recall an automated spectrum analysis system
based on 141T's that took up a couple of racks, darned if I can
remember the controller though. Of course this was in the days when
we still had 524 series counters in racks because the powers that be
thought they were more reliable than 5245's. All the gear tended to
be in racks lined up along the wall and we worked on castored
trolley's that rolled between our individual benches and the test
gear.
The system is NOTHING like a 524 which is all tube. You could not give
me one of those. My reminiscing, I used to have two of these in my house, saved on the heating bill! The system is mostly solid state (it has some BWOs (in the higher
frequency band PIs) and a couple of tubes in the power supply for them
and a CRT) and is largely ICs. In fact, it's a LOT more maintainable
since it has no unobtainable or $$$$$$$$$$ microwave hybrids or ASICs.
Have you tried to fix newer HP stuff? Up until a couple of years ago I maintained all my own gear. My "shack" collection included an 8505A (sorry I sold it now!) 141T system (regret selling that too!) and a complete 8409C system. As well as lots of other 1980's HP stuff. Fortunately much of the gear was either acquired new ( 8620C's and plug-ins, 5345A & PI's, 8505A, 141T (2 complete systems) when I had a consulting practice, or came from sources where I knew the entire history of the unit. In all those years we replaced two output amplifiers in 8640B's and one 8555A mixer. Basically, you have to cannibalize
another unit. I have a 3.7 to 4.2 and 5.9 to 6.5 GHz Communication
Sweep Generator that died. Hmmm, I might have one of those in the basement. What model number is it? It turns out that HP left a loose screw in
the RF output amp during assembly. The screw was provably NEVER
tightened.... that was clear from a microphotograph I took I complained
bitterly, but they essentially said 'too bad'... it's out of warranty.
They also said I should 'hurry up' and order the replacement module for
ONLY $1400 because the price was about to go up to $2000++. Since then,
I've tried to avoid their newer stuff. Sadly, HP lost sight of the HP way. I know that many of us who were very close to HP back in the 70's regret what happened. I know a lot of the staff did too. But that's the way of the world I am afraid. OTOH, I had a Tek RTD-710A fail. The replacement part was about $2500
(an amplifier hybrid), but they said there had been a manufacturing
problem. I took it to the local Tek office and they repaired and
calibrated the unit and returned it to me shipping prepaid... at no
charge... ZERO. That sort of thing USED to happen at HP sometimes too. Sadly my last experience with Tektronix was being laughed at when I asked about parts for an AWG2000 series unit about two years ago. Luckily I picked up a parts unit on the big auction for little money and saved the day. If you think HP had problems, try Keithley! I tried for ages to get manuals for some gear with absolutely no luck at all, I gather that they would not even provide service manuals where they had signed contracts that required them to do so. In one case I know they maintained the equipment free of charge for 13 years rather than provide manuals. John I've thought about changing from the 2100 to a 98xx or PC but rewriting
the SW is just not on my agenda. I mostly use a 8505A these days.
-John
|
At 07:56 PM 1/18/2007, Dave Brown wrote: DaveB, NZ (Still after a 2650A synchroniser h'book or even the real
thing! - or anything to help get the 8690 + PI phaselocked around
10GHz) Dave, my boy. I never realised you needed a handbook for a 2650A, I have the very thing, right here in front of me. It is 1964 printing with the modification data to use various other mixers. The 934A is the basic harmonic mixer used in these things (same as used in the 540A transfer oscillator as it happens). But I am not sure that a DY-2650A is the right thing, they were intended for klystron oscillators, such as the 614, 616, 618, 620 and the 8614, 8616 units. These were all reflex klystron based. The DY-2650A takes the reflector voltage (2kV in the standard unit or up to 3kV with modification M18) and outputs the reflector voltage with error correction. The Carcinotron (Backward Wave Oscillator) in the 8690's has different characteristics. They have an external FM input which is fairly consistently 6% of band deviation per volt of input (as I recall). I suspect you would be better off using an 8709 type synchroniser rather than a DY-2650A. The 8709's (used with the 8620 series and 8350 series sweepers) had a switch selection of sensitivity, again very much by recollection, and is pretty easy to modify if need be for other characteristics. Sadly, I don't appear to have the manuals for the 8709's any more. The DY-2650A manual is available to a list member if they need it, provided they agree to have it scanned and the PDF sent to me for uploading. John
|
Re: HELP!! - 141T / 8555A
zebra strips go bad
toggle quoted message
Show quoted text
----- Original Message ----- From: Chris van Lint To: hp_agilent_equipment@... Sent: Thursday, January 18, 2007 3:46 PM Subject: Re: [hp_agilent_equipment] HELP!! - 141T / 8555A Thanks to all who have replied. It seems that the "junction block" I mentioned may be worth concentrating on. The item in question consists of HP part numbers 00181-04101 COVER: HV CONNECTOR, 00181-47101 GASKET: SIDE, 00181-47102 GASKET: CENTER. Its function is as Pete decribes - it is no more than a connection block, to which on one side the HV is connected and the CRT storage mesh backing electrode (6) and the collector mesh (902) and has no electroics inside it. The other side connects these signals to appropriate points at the face of the CRT via a flat transparent ribbon cable, or as Pete calls it a Zebra strip. The internal connection is made by pressing the contacts on the Zebra cable to against contacts inside the box. Of course anything is possible, but the chances of the Zebra cable being broken are very slim, because it is an integral part of the CRT. The CRT is brand new (NOS), so it is most unlikely that either the CRT or this Zebra cable are at fault. It is difficult o check for continuity at the tube end of the Zebra cable, because it is part of the tube. Assuming that the connection of the Zebra cable at the CRT end is sound, I wonder whether respondents would agree with me, that the "junction box" is the likely culprit. My reason for suspecting the box is that there is no visible change in the appearance of the displayed trace when I disconnect both the CRT storage mesh backing electrode (6) and the collector mesh (902) cables from the pulse circuit board to the box, sugesting that these voltages maybe do not reach the CRT. If there is a consensus that what I am thinking does make some sense and I am not talking through a hole in my head, I will have to bite the bullet and replace the HV tripler and the box. Although the box has is own part number, the HV wire is moulded into it and I cannot just replace the box, without replacing the tripler. This is why I was wondering whether applying some voltage to either of these storage mesh connections should produce a specific result, which would allow me to decide whether or not the connection from the box to the CRT is sound. The other (almost last resort / worst case scenario) would be to put yet another CRT (this one used and of unknown ondition) to see if that will fix it. Cheers, Chris ----- Original Message ----- From: Alan Melia To: hp_agilent_equipment@... Sent: Friday, January 19, 2007 2:29 AM Subject: Re: [hp_agilent_equipment] HELP!! - 141T / 8555A Hi Pete having disassembled the block and cleaned mine some time ago I am pretty sure there is no electronics inside it . It is just a interface from wire to the flat transparent ribbon cable. I cleaned it on the understanding that I have had trouble with "zebra strips" in the past where cleaning was the solution. It is of course possible that one of the traces in the ribbon cable has broken on Chris's tube....they are very thin copper. However if I remember he tried another tube which would mean a different ribbon cable ( I think they are attached to the tube) so that negates that idea. Alan G3NYK ----- Original Message ----- From: Pete <peterawson@...> To: <hp_agilent_equipment@...> Sent: 18 January 2007 16:04 Subject: Re: [hp_agilent_equipment] HELP!! - 141T / 8555A > This problem is tough to get a handle on w/o schematics & I have none. But, > from your shcematics & parts list, what is the P/N > on that "junction" box (I suspect it has some functionality hidden under the > potting compound). I may be able to get some > "inside" help to learn what the gizmo is. > > Pete Rawson > > > > > Yahoo! Groups Links > > >
|
Hey! hey! 'Nuff 'disparagement' for 8690s- still have and use one often! With a set of PIs from 100 KHz to 18GHz as well... But it surely IS heavy.....
DaveB, NZ (Still after a 2650A synchroniser h'book or even the real thing! - or anything to help get the 8690 + PI phaselocked around 10GHz)
toggle quoted message
Show quoted text
----- Original Message ----- From: "John Day" <johnday@...> To: <hp_agilent_equipment@...>; <hp_agilent_equipment@...> Sent: Friday, January 19, 2007 11:21 AM Subject: Re: [hp_agilent_equipment] WG: Mysterious box: At 04:44 PM 1/18/2007, J Forster wrote:
But before the 8620 came out I suppose we MUST have used 8690's!
No question about it. I have two of them (one incomplete). There was the
8690 MF and a PI holder for 3 heads. The systems went from about 100 MHz
to 18 GHz. 4x 6 foot racks of stuff.... 2 for the ANA and sweepers and
test sets, 1 for the 2100, display and keyboard, and 1 for the paper
tape reader and 2315 hard drive.
-John My gosh! I wouldn't want one of those nowadays!
But I suppose that was what I used before the two rack 8620/9845
based versions. I do recall an automated spectrum analysis system
based on 141T's that took up a couple of racks, darned if I can
remember the controller though. Of course this was in the days when
we still had 524 series counters in racks because the powers that be
thought they were more reliable than 5245's. All the gear tended to
be in racks lined up along the wall and we worked on castored
trolley's that rolled between our individual benches and the test gear.
It's funny how much time and effort it took to plot out IF stage
characteristics using a Boonton 250-A RX bridge. How glad we were to
get rid of the GR 1604 bridges, how nice it was to measure crystal
filters without doing it point by point and how totally spoiled we
felt when we got things like 5345A's (replacing 5248M's), 8505A's (to
replace 8405A's and a whole other pile of stuff) and the 8409C
network analyser systems.
Hey does anyone out there remember the old HP803A bridge, I think it
had a super-regen receiver to use as a detector. Or the 434A
Calorimetric power meter? Of course we discoursed on teh 540A
transfer oscialltor some time back.
Sorry, just feeling nostalgic.
|
Re: O/T : MESSEMPFANGER [Rohde & Schwarz ESU2 VHF/UHF Test Receiver
It`s a Rohde & Schwarz VHF - UHF MESSEMPFANGER Test Receiver Model ESU 2, Number 252.0010.52 [further numbers are obliterated] Serial Number : 40.00138. [whew!]
I have posted a photo of THE MESSEMPFANGER [Why does this make me think of a German dentist?] on the groap site.
Cheers!.............................................Don Collie jnr.
toggle quoted message
Show quoted text
----- Original Message -----
From: John Day
To: hp_agilent_equipment@...
Sent: Friday, January 19, 2007 11:22 AM
Subject: Re: [hp_agilent_equipment] O/T : MESSEMPFANGER [Rohde & Schwarz ESU2 VHF/UHF Test Receiver
At 04:32 PM 1/18/2007, you wrote:
>As most of the group appear to be back from holiday, I`m mentioning this
>again.
>I have one of these receivers [what a beauty!], but need service
>information, particularly schematics of the various modules : PLEASE, if you
>can help me get copies of these, email me.
Which model?
Or give us a photo of the unit so we can see which one!
John
>The first group member to do this will receive an autographed photo of
>my wife.
>Thankyou........................................Don C.
>
>
------------------------------------------------------------------------------
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.17.0/639 - Release Date: 1/18/2007 6:47 PM
|
My gosh! I wouldn't want one of those nowadays!
But I suppose that was what I used before the two rack 8620/9845
based versions. I do recall an automated spectrum analysis system
based on 141T's that took up a couple of racks, darned if I can
remember the controller though. Of course this was in the days when
we still had 524 series counters in racks because the powers that be
thought they were more reliable than 5245's. All the gear tended to
be in racks lined up along the wall and we worked on castored
trolley's that rolled between our individual benches and the test
gear.
The system is NOTHING like a 524 which is all tube. You could not give
me one of those.
The system is mostly solid state (it has some BWOs (in the higher
frequency band PIs) and a couple of tubes in the power supply for them
and a CRT) and is largely ICs. In fact, it's a LOT more maintainable
since it has no unobtainable or $$$$$$$$$$ microwave hybrids or ASICs.
Have you tried to fix newer HP stuff? Basically, you have to cannibalize
another unit. I have a 3.7 to 4.2 and 5.9 to 6.5 GHz Communication
Sweep Generator that died. It turns out that HP left a loose screw in
the RF output amp during assembly. The screw was provably NEVER
tightened.... that was clear from a microphotograph I took I complained
bitterly, but they essentially said 'too bad'... it's out of warranty.
They also said I should 'hurry up' and order the replacement module for
ONLY $1400 because the price was about to go up to $2000++. Since then,
I've tried to avoid their newer stuff.
OTOH, I had a Tek RTD-710A fail. The replacement part was about $2500
(an amplifier hybrid), but they said there had been a manufacturing
problem. I took it to the local Tek office and they repaired and
calibrated the unit and returned it to me shipping prepaid... at no
charge... ZERO.
I've thought about changing from the 2100 to a 98xx or PC but rewriting
the SW is just not on my agenda. I mostly use a 8505A these days.
-John
|
Re: O/T : MESSEMPFANGER [Rohde & Schwarz ESU2 VHF/UHF Test Receiver
At 04:32 PM 1/18/2007, you wrote: As most of the group appear to be back from holiday, I`m mentioning this
again.
I have one of these receivers [what a beauty!], but need service
information, particularly schematics of the various modules : PLEASE, if you
can help me get copies of these, email me. Which model? Or give us a photo of the unit so we can see which one! John The first group member to do this will receive an autographed photo of
my wife.
Thankyou........................................Don C.
|
At 04:44 PM 1/18/2007, J Forster wrote: But before the 8620 came out I suppose we MUST have used 8690's!
No question about it. I have two of them (one incomplete). There was the
8690 MF and a PI holder for 3 heads. The systems went from about 100 MHz
to 18 GHz. 4x 6 foot racks of stuff.... 2 for the ANA and sweepers and
test sets, 1 for the 2100, display and keyboard, and 1 for the paper
tape reader and 2315 hard drive.
-John My gosh! I wouldn't want one of those nowadays! But I suppose that was what I used before the two rack 8620/9845 based versions. I do recall an automated spectrum analysis system based on 141T's that took up a couple of racks, darned if I can remember the controller though. Of course this was in the days when we still had 524 series counters in racks because the powers that be thought they were more reliable than 5245's. All the gear tended to be in racks lined up along the wall and we worked on castored trolley's that rolled between our individual benches and the test gear. It's funny how much time and effort it took to plot out IF stage characteristics using a Boonton 250-A RX bridge. How glad we were to get rid of the GR 1604 bridges, how nice it was to measure crystal filters without doing it point by point and how totally spoiled we felt when we got things like 5345A's (replacing 5248M's), 8505A's (to replace 8405A's and a whole other pile of stuff) and the 8409C network analyser systems. Hey does anyone out there remember the old HP803A bridge, I think it had a super-regen receiver to use as a detector. Or the 434A Calorimetric power meter? Of course we discoursed on teh 540A transfer oscialltor some time back. Sorry, just feeling nostalgic. John
|
Re: HELP!! - 141T / 8555A
Thanks to all who have replied. It seems that the "junction block" I mentioned may be worth concentrating on. The item in question consists of HP part numbers 00181-04101 COVER: HV CONNECTOR, 00181-47101 GASKET: SIDE, 00181-47102 GASKET: CENTER. Its function is as Pete decribes - it is no more than a connection block, to which on one side the HV is connected and the CRT storage mesh backing electrode (6) and the collector mesh (902) and has no electroics inside it. The other side connects these signals to appropriate points at the face of the CRT via a flat transparent ribbon cable, or as Pete calls it a Zebra strip. The internal connection is made by pressing the contacts on the Zebra cable to against contacts inside the box. Of course anything is possible, but the chances of the Zebra cable being broken are very slim, because it is an integral part of the CRT. The CRT is brand new (NOS), so it is most unlikely that either the CRT or this Zebra cable are at fault. It is difficult o check for continuity at the tube end of the Zebra cable, because it is part of the tube.
Assuming that the connection of the Zebra cable at the CRT end is sound, I wonder whether respondents would agree with me, that the "junction box" is the likely culprit. My reason for suspecting the box is that there is no visible change in the appearance of the displayed trace when I disconnect both the CRT storage mesh backing electrode (6) and the collector mesh (902) cables from the pulse circuit board to the box, sugesting that these voltages maybe do not reach the CRT. If there is a consensus that what I am thinking does make some sense and I am not talking through a hole in my head, I will have to bite the bullet and replace the HV tripler and the box. Although the box has is own part number, the HV wire is moulded into it and I cannot just replace the box, without replacing the tripler. This is why I was wondering whether applying some voltage to either of these storage mesh connections should produce a specific result, which would allow me to decide whether or not the connection from the box to the CRT is sound. The other (almost last resort / worst case scenario) would be to put yet another CRT (this one used and of unknown ondition) to see if that will fix it.
Cheers,
Chris
toggle quoted message
Show quoted text
----- Original Message ----- From: Alan Melia To: hp_agilent_equipment@... Sent: Friday, January 19, 2007 2:29 AM Subject: Re: [hp_agilent_equipment] HELP!! - 141T / 8555A Hi Pete having disassembled the block and cleaned mine some time ago I am pretty sure there is no electronics inside it . It is just a interface from wire to the flat transparent ribbon cable. I cleaned it on the understanding that I have had trouble with "zebra strips" in the past where cleaning was the solution. It is of course possible that one of the traces in the ribbon cable has broken on Chris's tube....they are very thin copper. However if I remember he tried another tube which would mean a different ribbon cable ( I think they are attached to the tube) so that negates that idea. Alan G3NYK ----- Original Message ----- From: Pete <peterawson@...> To: <hp_agilent_equipment@...> Sent: 18 January 2007 16:04 Subject: Re: [hp_agilent_equipment] HELP!! - 141T / 8555A > This problem is tough to get a handle on w/o schematics & I have none. But, > from your shcematics & parts list, what is the P/N > on that "junction" box (I suspect it has some functionality hidden under the > potting compound). I may be able to get some > "inside" help to learn what the gizmo is. > > Pete Rawson > > > > > Yahoo! Groups Links > > >
|
But before the 8620 came out I suppose we MUST have used 8690's!
No question about it. I have two of them (one incomplete). There was the
8690 MF and a PI holder for 3 heads. The systems went from about 100 MHz
to 18 GHz. 4x 6 foot racks of stuff.... 2 for the ANA and sweepers and
test sets, 1 for the 2100, display and keyboard, and 1 for the paper
tape reader and 2315 hard drive.
-John
|
O/T : MESSEMPFANGER [Rohde & Schwarz ESU2 VHF/UHF Test Receiver
As most of the group appear to be back from holiday, I`m mentioning this again.
I have one of these receivers [what a beauty!], but need service information, particularly schematics of the various modules : PLEASE, if you can help me get copies of these, email me.
The first group member to do this will receive an autographed photo of my wife.
Thankyou........................................Don C.
|
At 02:04 PM 1/18/2007, J Forster wrote: Hmmm, I don't have the documentation handy. But it sounds like the
box used for phase-locking an 8620 series sweeper plug-in to a 3555A
generator in the 8409 network analyser systems. I think I still have
an 8409 manual in the archive, I will see if I can find it.
Sounds close. There is another possibility. It might be for locking the
8690 sweeper in the earlier Phase Lock version of the 8410 that uses the
8660 (??) synthesized generator and 2100 computer. Golly, that goes back! That would be 8410A era in the very late 60's or early 70's. By the early 80's the 8409 systems used the 8350 series sweepers, but I do recall in the 70's having units with the 8327 dual test-set switcher (so we could use a single 8411A sampler), two S-parameter test sets and a pair of 8620 sweepers with appropriate plug-ins - one for each test-set. But before the 8620 came out I suppose we MUST have used 8690's! The 8709B synchroniser box had a meter on the front and the mixer box had 3 BNC sockets on the front. One got input from the 3335A and the other two went to an amplifier, possibly a fairly standard 8447 of some sort. Other cables on the back conected the various boxes to permit the sweepers to be locked to the 3335A. Some switching was handled by a 59307 (VHF switch, I think that is the right model) and the HP-IB A-D converter of the same family was used for digitising. Everything was controlled by a 9845B or C controller. Later on we used 9826 (9000 series 226), the 9836 ( 9000 series 236 ) controllers and later again 9000 series 300's. I have the manuals
somewhere, but not handy. I've not seen a counter associated with either
though. It was also sold as a 'synchronizer' but I forget the number. 8709A and B were the synchroniser boxes, 8709A for 20MHz IF, B for the 8410 IF of about 20.278MHz. In the 80's there was a frequency stability analysis system HP produced that used another 59992 series box. I think over the years I have seen 4 or 5 different 59992's, all with different prefixes and bearing no relationship to each other except that they were used in systems, not sold as products. J06-59992A is a time interval calibrator for the 5370A/B counters K10-59992A is a DC backup for a clock K87-59992A is a video amplifier K08-59992A is an HP-IB bus exerciser (At least I think it was HP-IB) K79-59992A 10MHz mixer with high IF gain (used in 10811A/B manual) I think this was part of the 5390A frequency stability (phase noise) test system. I know this has come up before, possibly in this group. These are all the variants I know of, there are quite likely others. John -John
59992A units were also common in several other systems built around
network analysers and 5345A counters. They can be seen in HP
catalogues in the early 80's but generally only as part of systems.
John
|
Hmmm, I don't have the documentation handy. But it sounds like the
box used for phase-locking an 8620 series sweeper plug-in to a 3555A
generator in the 8409 network analyser systems. I think I still have
an 8409 manual in the archive, I will see if I can find it.
Sounds close. There is another possibility. It might be for locking the
8690 sweeper in the earlier Phase Lock version of the 8410 that uses the
8660 (??) synthesized generator and 2100 computer. I have the manuals
somewhere, but not handy. I've not seen a counter associated with either
though. It was also sold as a 'synchronizer' but I forget the number.
-John
59992A units were also common in several other systems built around
network analysers and 5345A counters. They can be seen in HP
catalogues in the early 80's but generally only as part of systems.
John
|
