Re: Circular polarization antenna question
Have you tried Paul Wade's W1GHZ on-line antenna handbook? I am afraid I
dont have a clickable link. Amateur EMEers use circular polarization I
believe.
Alan G3NYK
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----- Original Message ----- From: "microwaveengineer1968" <microwaveengineer1968@...> To: <hp_agilent_equipment@...> Sent: Saturday, November 03, 2007 9:25 PM Subject: [hp_agilent_equipment] Circular polarization antenna question Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
Yahoo! Groups Links
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Circular polarization antenna question
Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
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11792 and 11722A repair !
If you have a 11722 or 11792 thats bad, you can use the cartridge out
of a 8482A to fix a 11722A or a 8485A cartridge will work for the
11792A !
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DIY Build yourself a 8487A !
8487A are still quite expensive on ebay, usually the go for $1200-1700
money i didnt wanted to spend so i was looking for a alternative.
Taking some sensors apart while working in the lab of a T+M Repair
facility i noticed a striking similarity of the cartridges used in
the R8486A/Q8486A and 8487A ! after running into a blown 8487A i used
a cartridge out of a R8486A to fix it, i send the sensor off for
calibration and it passed ! later conversation with a coleague at
agilent revealed that the cartridge used in the 8486 and 8487 are in
fact idendical !
So the idea was conceived to study what it would take to build up a
8487A !
First of we need a HP8486A R or Q will do just fine, the cartridge,
bellow case, nut and PCB can be reused, be carefull not to lose the
bellow when removing the cartridge !
Next obtain the Service manual of the 8487A (Download from agilent)
page 76 gives you a nice exploded view of the sensor bulkhead, order
MP1/2/3/4/5/6/7/8/10/11/12 total parts cost about $400
Assemble all parts, be carefull not to squish the bellow its very
small (MP9) put your sensor back together, remove the old label and
affix a new one and there you have a 8487A , same goes for the
D !
If you get a waveguide sensor for $300 and add $400 for the parts,
add another $100 for calibration (cypris) can do those, agilent wont
because the sensor wont have a S/N !
you got a 8487A for well below the average ebay cost !
Just remember, this is for your own use only, if you sell the sensor
you will have to let the new owner known that it is a clone,
otherwise it would be considered piracy !
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DIY: Repair of HP Step Attenuators
Since Agilent continiously ups the spare part prices and discontinues
parts it has become more and more important to go past normal repair
practices.
Step Attenuators for example can be repaired without any special
tools or cleanroom enviroment !
Lets take a look at the failure modes first, there are a few:
1.) Blown pads
Usually common with spectrum analyzers if a level past the damage
level of the attenuator was applied
2.) Cracked pads, pad has developed a hairline crack due to
mechanical stress !
3.) Improper contact, the contact in between the attenuator and
contact fingers is disturbed.
4.) Stuck solenoid
Quite common if attenuator hasnt been used in awhile
After we remove the attenuator from the instrument the first step is
to obtain the pinout and build us a little test bench consisting of a
powermeter and a signal generator, the good old 8481D or 8484A will
do nicely, if you dont have a sig gen use the 50MHz calibrator output
of the 435 or 436 or similar model, connect the cal output to the
30dB pad connect the sensor and zero and calibrate meter, the meter
will read -30dBm.
Disconnect the sensor from the attenuator and insert the Step
Attenuator, set step attenuator to 0dB, note the level on the
powermeter, now switch in the attenuator sections one by one measure
and note the level, 70dB attenuators are comprised of a 10 20 and
40dB Pad while 110dB Attenuators normally comprise of a 10 20 and two
40dB pads !
check every section individually, you should hear a click as you
enable each section, if you find a bad section note the value it
should have if all sections appear to be good repeat the test at a
higher frequency using a sig gen, if everything appears to be ok at
low frequency then most likely you have attenuator that just needs
cleaning.
Now lets take the attenuator apart, looking at the top you will see a
nut on each SMA connector, remove this nut this will allow for you to
remove the nameplate, under the plate you will see a wealth of allen
screws, remove those but note that the screws close to the SMA
connector are shorter than the other ones.
Now look at the small sideplate, not the one with the ribbon cable
but the other side - there are 4 small allen screws, remove those and
then remove the sideplate, careful not to lose the little wire mesh
here ! now slide out the u shaped cover and remove the top side.
You now have two parts, one beein the bottom side containing the
solenoids and the other one beein the top part containing the
attenuator pads.
First lets inspect the pads, you can measure them with a ohm meter,
they should measure in the vicinity of 50ohms , except of the 10dB
pad which can measure up to 70ohms or more.
Inspect the pads visually, are there any burned or cracked pads ? if
all pads look ok and check out at DC take a surgical swab and
isopropilic alcohol and carefully clean the contacts pads on the
attenuators.
Next look at the contacts, enable all solenoids and observe the
position of the contact tongues, they should be slightly above the
surface of the block, carefully clean the contact tongues with
alcohol, be careful not to bend them.
next put the solenoids back into the 0 position and look at the top
of the solenoids, you will see two little white plastic rods where
those meet the solenoid you should see little rubber rings , there
are 4 of those on each segment, usually over the years they go
briddle and then disappear, with those rings gone the attenuator wont
make contact anymore, you can buy the rings from watchmakers supply
stores as they are beein used for sprocket gaskets !
Now if your gaskets are there put the attenuator back together after
you cleaned everything and it should work now.
If you have a broken or burned pad dont stress over it the pads are
used in all HP attenuators so just find a attenuator on ebay and take
the pad you need out of it, you can also buy pads from agilent
however be prepared to pay $100-150 per
piece
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Re: 419A Chopper Replacement
At 04:22 PM 11/3/2007, you wrote: I don't know about the alignment. My experience was with the opto-chopper in
the 410C. Mine was replaced as a unit by the company cal lab.
There are only a very few wire pigtail Ne's made. I think there was a means of
ID'ing which is in there by looking very carefully at the glass pinch area.
There is something stamped into the glass as I remember. You might ask someone
like BulbDirect that specializes in lamps. Or ask on the NEON-NIXIE Yahoo group, a lot of expertise and experience there too. John Best,
-John
Christian A Weagle wrote:
--- In <mailto:hp_agilent_equipment%40yahoogroups.com>hp_agilent_equipment@...,
J Forster <jfor@...> wrote:
Many Ne bulbs have minute amounts of radioactive material in them to
stabilize the firing point. As the radioactive emission rate decays, the
bulbs become erratic. Put in new bulbs, if you can.
That was my first impulse; however, the manual (paragraph 5-27) states
that "physical alignment and selection of the neon bulbs are critical"
and that replacement of the entire assy is the only thing to do.
Can you speak to this at all? If I _do_ replace the neons, are
standard NE-2 bulbs the right thing to use?
Thanks for your help!
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Re: 419A Chopper Replacement
I don't know about the alignment. My experience was with the opto-chopper in
the 410C. Mine was replaced as a unit by the company cal lab.
There are only a very few wire pigtail Ne's made. I think there was a means of
ID'ing which is in there by looking very carefully at the glass pinch area.
There is something stamped into the glass as I remember. You might ask someone
like BulbDirect that specializes in lamps.
Best,
-John
Christian A Weagle wrote:
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--- In hp_agilent_equipment@..., J Forster <jfor@...> wrote:
Many Ne bulbs have minute amounts of radioactive material in them to
stabilize the firing point. As the radioactive emission rate decays, the
bulbs become erratic. Put in new bulbs, if you can.
That was my first impulse; however, the manual (paragraph 5-27) states
that "physical alignment and selection of the neon bulbs are critical"
and that replacement of the entire assy is the only thing to do.
Can you speak to this at all? If I _do_ replace the neons, are
standard NE-2 bulbs the right thing to use?
Thanks for your help!
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Re: 419A Chopper Replacement
--- In hp_agilent_equipment@..., J Forster <jfor@...> wrote:
Many Ne bulbs have minute amounts of radioactive material in them to
stabilize the firing point. As the radioactive emission rate decays, the
bulbs become erratic. Put in new bulbs, if you can.
That was my first impulse; however, the manual (paragraph 5-27) states that "physical alignment and selection of the neon bulbs are critical" and that replacement of the entire assy is the only thing to do. Can you speak to this at all? If I _do_ replace the neons, are standard NE-2 bulbs the right thing to use? Thanks for your help!
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Re: 419A Chopper Replacement
Many Ne bulbs have minute amounts of radioactive material in them to
stabilize the firing point. As the radioactive emission rate decays, the
bulbs become erratic. Put in new bulbs, if you can.
Best,
-John
Christian A Weagle wrote:
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Good morning,
I have a 419A Nulling Voltmeter that I just finished replacing all the
electrolytic capacitors in. This cleared up my 'after warming up no
operation' problem. However, I also had to really have my way with
both the chopper freq adj and neon current adj pots to get them to
fire _something_ like reasonably. I can't get the frequency to be
correct (too slow by close to half), and the waveform is pretty
distorted over most of the range, and just _somewhat_ distorted over
the rest. This makes me think I probably need new choppers. I assume
these are unobtainum.
1. is my logic sound, or is there more likely a problem with the
driver instead?
2. what will a somewhat slow, distorted chopper waveform do to the
correct operation of this otherwise-excellent meter?
Thanks very much!
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Good morning,
I have a 419A Nulling Voltmeter that I just finished replacing all the
electrolytic capacitors in. This cleared up my 'after warming up no
operation' problem. However, I also had to really have my way with
both the chopper freq adj and neon current adj pots to get them to
fire _something_ like reasonably. I can't get the frequency to be
correct (too slow by close to half), and the waveform is pretty
distorted over most of the range, and just _somewhat_ distorted over
the rest. This makes me think I probably need new choppers. I assume
these are unobtainum.
1. is my logic sound, or is there more likely a problem with the
driver instead?
2. what will a somewhat slow, distorted chopper waveform do to the
correct operation of this otherwise-excellent meter?
Thanks very much!
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Re: Schematics for 1661cs and other info
On Sat, 03 Nov 2007 18:12:17 +1100, you wrote: HI Group,
Just wondering if anyone has seen schematics for this series of logic
analysers/scopes and if anyone has any info on programming these units.
What OS do they run? Can one write programs for them? Which
compiler/libraries etc Basing my replies on what's available for the 16500 and 165x series: 1) Don't think you'll find schematics, they may have existed only as internal documents never to be released. Tektronix did about the same thing with some of their later units. Programming, well, you have access to the functions over IEEE-488, RS-232 or network if so equipped. Writing a program specifically for it and running that program, I haven't heard of such. Would be interesting though. The 16500 and 165X run a version of HP Unix, IIRC. Whatever they run, it's likely to be custom. You'd be more likely to grab data on the fly, and post process it in another computer with resources you can actually get to. That'll be what I'll do. Harvey
Thanks
Tim
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----- Original Message ----- From: "Chuck Lippmeier" <chuck@...> To: <hp_agilent_equipment@...> Sent: Saturday, November 03, 2007 5:56 AM Subject: [hp_agilent_equipment] Re: ESR Meter Design List,
You may want to have a look at this link
I've been thinking of building this one myself. Yes, I've seen that one, but this latest offering holds more interest for me. I'm not sure what it is that draws me to it, but I like the approach. Best Regards, Bob Groschen Monument, CO
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----- Original Message ----- From: "konnylagarde2002" <alagarde@...> To: <hp_agilent_equipment@...> Sent: Friday, November 02, 2007 1:50 PM Subject: [hp_agilent_equipment] Re: ESR Meter Design In reply to your comment below: The test voltage across the leads is
under 100 mv and capacitors do NOT need to be out of the circuit to
test.... ac power does not in any compromise the functionality of the
instrument and has some advantages as explained in the description. The choice of battery only power is mine. I simply don't want an AC powered ESR meter. End of story. However, I'm glad to see that the excitation is kept at the 'traditional' 100 mV level. That will indeed allow in-circuit testing. While I can't see what this will do that my Dick Smith ESR meter doesn't, the all-analog approach is interesting. I may build one anyway, just to play with it. Best Regards, Bob Groschen Monument, CO
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List, You may want to have a look at this link I've been thinking of building this one myself. Chuck Lippmeier --- In hp_agilent_equipment@..., "Bob Groschen" <rpgroschen@...> wrote:
----- Original Message -----
From: "konnylagarde2002" <alagarde@...>
To: <hp_agilent_equipment@...>
Sent: Thursday, November 01, 2007 1:48 PM
Subject: [hp_agilent_equipment] ESR Meter Design
I can also provide a schematic.
A schematic would be necessary because I would not want
an AC powered ESR meter.
Also, the implied "high current test signal" has implications, like
necessary removal of the cap-under-test from the circuit.
I don't have to do that with my current ESR meter.
Nevertheless, I believe a tester with
a high current capability has merit.
Best Regards,
Bob Groschen
Monument, CO
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Schematics for 1661cs and other info
HI Group,
Just wondering if anyone has seen schematics for this series of logic analysers/scopes and if anyone has any info on programming these units. What OS do they run? Can one write programs for them? Which compiler/libraries etc
Thanks
Tim
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Nice Job!
Cheers!........................................................Don C.
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----- Original Message -----
From: konnylagarde2002
To: hp_agilent_equipment@...
Sent: Saturday, November 03, 2007 6:15 AM
Subject: [hp_agilent_equipment] ESR Meter details
Here are links to the circuit and construction details:
This third item may open too small.... click on image and it should
enlarge. Let me know if you are not able to download any of these
items and I will try again.
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----- Original Message ----- From: "lothar baier" <microwaveengineer1968@...> To: <hp_agilent_equipment@...> Sent: Friday, November 02, 2007 6:47 AM Subject: Re: [hp_agilent_equipment] Re: 70000 vs 8566B they are all the same nowadays but at least you can get the part even if its pricey
i always looked at the powerswitches first usually they were obtained from a supplier , and then check digi key, mouser or newark usually the switch has the name of the manufacturer and sometimes even the part# still on it, i saved many $$$ over the years by doing so Normally I would go straight to the supplier but in this case the switch was to be part of a larger order of Fluke unique parts such as feet, knobs, handles etc. Ironically all the Fluke-unique parts were cheap. The switch, which can be had from generic suppliers, was not. Go figure. Best Regards, Bob Groschen Monument, CO
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I recently got laid off at my job and decidet to go out on my own as
RF/Microwave consultant, if anyone has a need for consulting work in
this area including microwave T+M contact me at
microwaveengineer1968@...
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This a very long shot, but if anybody can help me getting a piece of
the trigger hybrid for a 54121A.
HP part number 1NB7-8130
I recently got a 54120B with the 54121A but they took a the triggering
hybrid. Well for $300 and as is....I do not complain.
But any help is appreciated
or complete 54121A
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9000 calculators are not all that big, most sweepers like the 8350 and wiltron boxes and even the old 8620 has GPIB (on the 8620 as option) the software requires certain equipment but since its HP basic you can go in there and change the programming codes to adapt to any source or equipment you please ! I know the issues with the 2784 first hand, you need a software called lotus measure and its long gone so outside of tek no one can cal this box, this applies to all members of the family ! Many equipment pieces you need for the 8566 can also be used for the 70000 and for some there is not really a subsitute, a good example is the 3335A thats used for several tests. By the way there is also a automated adjustment software for the 8566. Lets face it most home labs dont give a ... about calibrated equipment, adjusments are only to be made if you repair something. The problem i have with parts units is to find one that doesnt have the exact same bad part as the one you are trying to fix, lets face it usually you always encounter the same "offenders" if it comes to t+m so you would have to buy two good working units and keep one for spares. Generally with the 70000 beein newer vintage i would not expect to see as many problems as with an old unit such as the 8566, the other thing is that the cooling system on the 70000 is so ver dimensioned that the box simply runs cooler and cooler temp always translates into higher reliability. Last but not least you get more bang i.e frequency for your buck with the 70000 and if you use a 70908 you have a noise floor thats unmatched. My alltime favorite analyzers though you cant touch or even think about them unless you hit the lottery is R+S stuff, they really got some nice stuff and superb specs, large Display and color but unfortunatly not affordable even used ! John Miles <jmiles@...> wrote:
they aint cheap - i agree but at least you can get them , maybe
its time to start scanning them and put them on the newsgroup ! :)
John makes it sound so easy on the 8566B where it is not, most
custom parts on the HP analyzers are RF/Microwave related and
they are custom on the 8566 as well as the 70000
the only analyzer i have ever seen that did not have any custom
parts was a old AIL757 Dinosaur !
Fact is if the mixer breaks you are in a world of hurt no
matter if you own a 8566 or a 70000, the mixer for the high band
on the 8566 includes also the YIG filter and this sucker is not cheap.
Well there is one downside of the 70000 however i forgot about,
in order to adjust or calibrate a 70000 you need the service
software which is available fairly cheap but requires a 9000
series calculator, those however have gotten cheap nowadays so
its not really a biggy !
Well, it's a big deal if I don't have room for a 9000-series calculator. :) And doesn't it need a GPIB sweeper, too? Or are there manual workarounds? You're right, in that servicing either model can be a pain. None of them are getting any younger. But the great documentation on the 8566 will allow you to work around just about any problem with substitute parts, if necessary. The YTX is about the *only* thing I couldn't replace with surplus microwave parts off of eBay, or out of the Mini-Circuits catalog, if I had to. They seem pretty reliable in my experience, but that's always a concern for anyone who doesn't have (or can't afford) a parts mule. -- john, KE5FX __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around
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