Keyboard Shortcuts
Likes
- HP-Agilent-Keysight-Equipment
- Messages
Search
|
Re: HP 8484A Power Sensor find
开云体育Hi Phil I assume you are in the USA? but please consider me for any wave guide power sensors above 20 Ghz Wanted 100 Ghz plus power measurement ? Regards Paul B From:
[email protected]
[mailto:[email protected]]
On Behalf Of Phillip Potter ? Hello all, No virus found in this message. |
|
Re: HP 8484A Power Sensor find
I just bought another 8484A but if you have other types I would be interested.
toggle quoted message
Show quoted text
Peter On May 24, 2019, at 1:22 PM, Phillip Potter <p.potter@...> wrote: |
|
Re: HP 8484A Power Sensor find
Hi Bruce,
toggle quoted message
Show quoted text
Well, four others pulled the trigger on email to me before you, BUT, I think ? I’ve got some more here, somewhere, and I’ve already told two others that I would go diving this afternoon to find them. If I can suss them out of my “box catastrophe” I will get back to you next week. I’m pretty sure that I have some more. I’m asking $80 for the sensor, 25 for the cable, plus $7.90 shipping. I’m open to negotiation, if you think my asking prices are out of line. Oh, yeah I think there are 30db attenuators, too, if your interested, for $40. Now, I just have to find them. Ill get back to you, when I round them up, if your still interested. Thanks, Phil, N6OMM On May 23, 2019, at 9:58 PM, Bruce <bruce@...> wrote: |
|
Re: 8566 to measure 100W FM transmitter
Bob Albert
One comment.? +30 dBm isn't a half Watt.? It's one Watt.? Thirty dB above one milliwatt by defninition. Bob
On Friday, May 24, 2019, 9:28:48 AM PDT, <j.kernkamp@...> wrote:
You are right! The listing was titled misleadingly, and it looked like the one that I have, but - my mistake. Here's the right one - an RF Industries model RFA-4059-A - about $50 from https://fieldcomponents.com. |
|
Re: 8566 to measure 100W FM transmitter
I am not sure that the FXR HW-15N you have referenced
toggle quoted message
Show quoted text
does what you think it does. The FXR HW-15N is a bias Tee, and its purpose is to AC couple the RF signal from the N male to the N female, and to AC block, but DC couple, the BNC that goes to the N female. It is used to inject DC into a coax so you can drive a remote preamp, or other device. An example where such a device is used would be a remote antenna/preamp that is mounted up an antenna tower. -Chuck Harris j.kernkamp@... wrote: A good way to to this is with an RF Signal Sampler, such as the one here - eBay item number: |
|
Re: 8566 to measure 100W FM transmitter
A good way to to this is with an RF Signal Sampler, such as the one here - eBay item number:
173890076938.
Use a signal generator and your SA to adjust it for 40 dB loss at your transmitter frequency. Then you can safely use it to see the 100W signal and the harmonics or spurs on the SA. ? |
|
Re: 8566 to measure 100W FM transmitter
Clue, if your attenuator doesn't have fins, or water cooling
toggle quoted message
Show quoted text
ports, it isn't rated for 100W. Even 10W attenuators are usually quite large... maybe an inch and a quarter in diameter, and several inches long... -Chuck Harris Don Bitters via Groups.Io wrote: Please do not attempt to pump 100W signal into the input of the 8566 spec analyzer. Calculate the power drop necessary to get it to a safe level to input the signal. The max signal into the 8566 is +30 dBm = 0.5 watt. The attenuator in the 8566 is only rated at 0.5 watt also. I am willing to bet your 90 dB step attenuator is also rated at max 1 watt or less. Start with at 20 to 50 dB attenuator rated at 100W or more at the transmitter (if you are hooking up to the output directly). |
|
Re: 8566 to measure 100W FM transmitter
Please do not attempt to pump 100W signal into the input of the 8566 spec analyzer. Calculate the power drop necessary to get it to a safe level to input the signal. The max signal into the 8566 is +30 dBm = 0.5 watt. The attenuator in the 8566 is only rated at 0.5 watt also. I am willing to bet your 90 dB step attenuator is also rated at max 1 watt or less. Start with at 20 to 50 dB attenuator rated at 100W or more at the transmitter (if you are hooking up to the output directly).
If you are using a loop coupled antenna, calculate the coupling factor to calculate the power applied to the 8566 and attenuate the coupled signal as required to get it to a safe level for the max input. To repeat the obvious every 3 dB drop in signal is half the power, calculate the required attenuator pad power for each attenuator added to the input path to the 8566. If you overpower the input to the 8566 by greater than the +30dBm stated (input attenuated internally), the damaged will be catastrophic. If you are on the low band you will take out the attenuator and low band mixer - pricey, if the 8566 resets and you are on the high band you will take out the attenuator and the YTX (YIG tuned mixer/filter) - really pricey. I had a customer once that did something similar and got both high and low bands - to the tune of more than $15k (full realign required), when parts were readily available. Good signal hunting. Don Bitters |
|
Re: TE FS -
开云体育Good eye. It is a Lowenstein early spark key. I have about 500 or more rare telegraph keys along with early wireless equipment like coherer and spark stuff. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 848-245-9115 ? From: [email protected] <[email protected]> On Behalf Of radioconnection@... ? Mike |
|
Re: 8405A Vector Voltmeter...reference for the amplitude meter?
If it’s a 50 ohm resistor in each leg, it will have 6 dB loss to each side.
The other configuration is a star made up of three 16.667 ohm resistors. Also 6 dB loss. An ohmmeter will tell you which it is. If the ohmmeter doesn’t confirm one of those configurations, then it’s some sort of transformer, not intended to be an equal split, or it’s damaged. From Tom Holmes, N8ZM |
|
Re: TE FS -
开云体育Hi – ? The 11970K has been sold and paid for. Now looking for offers on the other two. 73 – Mike ? ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 848-245-9115 ? From: [email protected] <[email protected]> On Behalf Of Mike Feher
Sent: Thursday, May 23, 2019 12:09 PM To: [email protected] Subject: Re: [HP-Agilent-Keysight-equipment] TE FS - ? Obviously I took on more than I can handle. I was hoping a few interested fellows would come over and we could work out some deals. That does not seem to be happening. I am overwhelmed by emails, only a few with offers and the others asking how much, even though I asked for offers. Also, most are interested in the smaller items like horns and so on. This essentially means that I need to go through all of the small stuff to find specific requests. If I am going to do that, I might as well start selling items as I go through them. More than likely I will strip all of the heavy stuff and sell the essential pieces. So, here are three items for sale to start that are easily mailable. ? HP Harmonic mixers – ? 11970K $200 11970A $250 11970U $550 ? If you want all three, I will accept $800 plus shipping. I will also consider offers on the others. As soon as these sell, I will list other items or wait a week and list other items. Thanks & 73 – Mike ? ? ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 848-245-9115 ? From: Mike Feher <n4fs@...> ? Hi all – ? Since I hardly ever use my lab any more, I decided to sell most of its contents. Unfortunately I am unable to ship heavier items due to physical limitations here. Consequently, if you would like to get something it is best if you pay me a visit. The more you take, the better the price, HI. Small items I can ship or even place on eBay. PP is fine with me. Any interest then please call or send me a direct email at n4fs@... . You can also try calling on the number below, however I do not have an answer machine set up on it. At the following link you can see 64 pictures, some not that great, taken inside the lab. In addition I also have a 2000 sq. foot basement, a 600 sq. foot garage and a 1000 sq. foot shed all full of stuff including loads of TE. Looking for offers until I place the smaller stuff on eBay. Thanks & 73 – Mike ? ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 848-245-9115 ? |
|
Re: 8566 to measure 100W FM transmitter
开云体育Dear DW,If you need to prove an inherent transmitter fault, then you need to measure the signal in the feed-line to a dummy load. The resistive potential divider approach is tricky, because all resistors have parasitic inductance and capacitance. To calibrate, you would need to measure the transmission from main line to sampling port over the range of frequencies required. Once the basic transmitter is verified to be working correctly, repeat the measurement in the feed line to the antenna. As others have said, great care is needed to ensure that the combination of signals cannot overload the mixer. It is often necessary to reduce the carrier level using a cavity notch filter. If there are multiple transmitters on-site, as is often the case, you may find intermodulation products generated in the transmitter output stage due to signals from other transmitters picked up by the antenna. This is why hybrid couplers/circulators/filters in the feed line are often required. Finally, intermodulation in feed-lines, antennas and support structures can also be a problem. Measurements with a receive antenna, a short distance from the site are the usual method for investigating this. Happy testing. Regards, Alwyn _____________________________________________________ Alwyn Seeds, Director SynOptika Ltd., 114 Beaufort Street, London, SW3 6BU, England. Tel.: +44 (0) 20 7376 4110 SynOptika Ltd., Registered in England and Wales: No. 04606737 Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom. _____________________________________________________
|
|
Re: 8566 to measure 100W FM transmitter
Hi.
What is the intended "Purpose" of the measurement? If it's to check some aspect of the modulation, then you can use any means (a simple wire antenna) to get enough signal to see, without frying your SA.?? Hint, always start on the highest attenuation (lowest sensitivity) setting with unknown signals, especially when connecting to equipment you don't have all the info for... If however, they are asking you to check for harmonics, and if they are within specification, take care.? Simple solutions will not do, as they will not have a flat response from the TX frequency out to the third and beyond harmonic.?? You can pre-calibrate simple pic-off's, but that takes care too, and you have to insert them into the TX to antenna feeder somewhere. Ideally, there would be a broadband directional coupler permanently in line for such checks, but they cost, so I guess get left out of the build spec'.?? Or, one kept on site and calibrated, so that it can be inserted when needed.? (Obvious TX down time needed of course.) Using any (even a formally calibrated) antenna to make such measurements needs the calibration/correction data, as you will need to correct for the antenna factor, to get the true "in-the-air" signal levels. If the TX has a sample port, ask to see the calibration data, so you know what sort of level comes out of that.?? Also, if it has data out into the land of harmonics.?? Make sure too, that the sample port is actual RF (not rectified RF just used as a power level check.) If it's a harmonic check that is wanted, and even if the sample port shows it's clean, any "off air" received harmonics could also be caused by "rusty bolt" effects, on other structures near the affected RX, or even on the TX's own antenna/and support. Though, if it's own antenna (the antenna itself that is) is that bad, some harmonic energy will come back down the feeder, and in turn be reflected back up, so should show up in any Forward Power Sample signal. Transmitter (especially broadcast TX) checks, need to be done carefully, and with a documented method, so you know you are getting a "true" measurement, comparable to those when it was first commissioned.?? Even for quick n dirty checks, you need to know quite a bit of detailed info before you begin. Sadly, even with the kit I have available, and my job is high power RF (up to 30kW at present) & I'd hesitate to do such checks on any broadcast TX, without a lot of background info, and data first. Plus, a written agreement to pay for any damage caused to your SA, by their equipment! Lastly, an 8566 is a large heavy beast (as I'm sure you know!)? I would not want to cart one into a small Broadcast TX hut.? A 8591 or similar is much better, and some versions have the ability to be programmed up with correction factors for antennas and couplers before the event via the memory card.? But that's another kettle of fish... Best Regards. Dave B G0WBX. -- Created on and sent from a Unix like PC running and using free and open source software. :: |
|
Re: WTB AMI/Mostek MK6220N RAM Chip
开云体育e: WTB AMI/Mostek MK6220N RAM Chip Once I took a flash photo (cameras used to have a
flash that used special bulbs with magnesium filaments, and the
camera spat out a picture on paper that appeared in about a
minute) of a friend as he worked on a, probably 8080 or Z80,
computer circuit that he had just got working.
Immediately his circuit released a cloud of smoke before he
could turn it off. After repairing the power supply the circuit
still did not work and it was time to go home. The next morning
the circuit was back to working.
The cause was an open EPROM window and apparently the flash
turned on elements that shorted the power supply. After a rest
the chip recovered. I have seen other chips recover from abuse
but replace them if possible. Yours may last another 20 years.
Hmmm.. Unexpected EMP event (sort of!)? Nice...
At a guess, as no permanent damage was done to the EPROM
(though I used to use an old style rechargeable Xenon flash gun
to erase EPROM's) that the flash caused the parasitic diodes
between the power rails to conduct, and the chip substrate just
latched on as a sort of crowbar device!?? I'm also guessing that
whatever smoked, saved the chip!
Or your unexpected(?) flash made him jump and short
something?
Probably lots of other gadgets / systems out there
that could be similarly problematic...
Have Fun!
Dave B G0WBX.
-- Created on and sent from a Unix like PC running and using free and open source software. :: |
|
Re: HP 8484A Power Sensor find
Quoting Phillip Potter <p.potter@...>:
Hello all,I may be interested - what are you looking for them Please contact me off list, if you are interested at p (dot) potter (at) sbcglobal (dot) net. |
|
Re: 8405A Vector Voltmeter...reference for the amplitude meter?
The HP spec sheet says it is a "nominal 6 dB insertion loss".
toggle quoted message
Show quoted text
This is a power splitter not a power divider. 73 Gary K4FMX -----Original Message----- |
|
Re: 8566 to measure 100W FM transmitter
tmillermdems
开云体育This could also be intermod. Can you (op) provide a list of
frequencies at the transmit site as well as the frequency of the
victim? On 5/23/2019 7:08 PM, Stephen Hanselman
wrote:
Hmmmm, the spur complaint is it an “all the time” or intermittent? ?We had a 2M repeater that was plagued with spurs, turned out to be a paging transmitter turned up to allowed +25% mixing with somebody else in our final. Crowded mountain tops can be very interesting.? |
|
Re: 8405A Vector Voltmeter...reference for the amplitude meter?
On Thu, May 23, 2019 at 08:19 PM, Dave Brown wrote:
No worries, and thanks for your input. :o) I just wanted to make sure it's in the ballpark at least. On a similar note, does anyone know of a place where I might find the datasheet for the parts in this set? Keysight lists the set but has no documents available. Haven't had much luck elsewhere either. Thanks! Sean |
|
Re: 8405A Vector Voltmeter...reference for the amplitude meter?
开云体育So I don’t think you have anything to worry about. Mind you, I reserve the right to retract my original statement at any time, given ?my mental arithmetic ain’t that marvellous these days! DaveB, NZ ? ? From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] ? On Thu, May 23, 2019 at 08:11 PM, Dave Brown wrote: 5 db would be about right if its just a? 50 ohm resistor from common to each downstream port. Measure the ‘port-to-common’ resistance? for each downstream port. DaveB, NZ Just slightly more than 50 ohms, same both sides. |
Paul Bicknell
Phillip Potter