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Date
Re: Spectrum analyzer in a high traffic strong signal environment

 

If the analyzer shows the correct level from the calibrator - it's probably fine.? If your instrument requires you to connect a jumper between the calibrator output and the RF input - that is an even higher confidence.

For a more comprehensive verification, connect your signal generator to the spectrum analyzer and measure various frequencies and amplitudes.

When measuring signals in a high RF environment, if you suspect mixer overload, increase the input attenuation.? If the suspect signals decrease by more that the extra attenuation, they were bogus.

Also, most analyzers won't reduce attenuation below 10 dB without extra steps.? That protects the instrument because attenuators aren't as easy to damage (or as expensive) as mixers are.? Zero dB attenuation can give you the most sensitivity for viewing weak signals - but - don't go there unless you are sure it is safe.

0 - Generator field calibration.jpg

Re: Spectrum analyzer in a high traffic strong signal environment

 

Thanks,

I have to confess this happened to me recently with a spectrum analyzer. Currently it seems to work fine where the -10dB calibrator shows -10dB on the display.

Is there ways which I might assess the health of the input to the spectrum analyzer if I might have actually hurt something? Thanks

Ops!
Re: 8516A cable question

 

I have a complete 8516 VNA setup and it was intermittently working with a standard DB25 Thru cable. Right now I am stuck on "NO IF FOUND" error and out of ideas.
Re: 334A Distortion Analyzer, etc.

 

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My quick knee-jerk without studying the schematic is, if it’s in the signal chain, you probably want a high-gain low-noise part like a BC556.? If you only have a 2N3906, it would be okay for debug.

?

Dave Wise

?

From: [email protected] <[email protected]> On Behalf Of Colin Herbert via groups.io
Sent: Wednesday, March 02, 2022 11:10 AM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] 334A Distortion Analyzer, etc.

?

Hi All,
I have been puzzling for a while but I'm not sure that I have got to the truth yet.
I have a H-P 334A Distortion Analyzer which I put away a while ago and now I find that something is not right. When I turn the instrument on, the meter-needle swings to the right and then comes back to zero fairly quickly. Unfortunately, there is still a little movement on the meter-needle but this settles down eventually. Since it looks as though the current isn't passing completely down the A2R44, A2Q8 and A2Q9 components completely, I have ascertained that transistor A2Q9 has probably died on me. This transistor was originally a Motorola SM4713 PNP silicon type. Research tell me that while this transistor is discontinued, an equivalent is probably a 2N3251. However, this is a bit pricey just to check out and I suspect that a?2N3906 will probably suffice just to check. Has anyone else any better ideas? I really want to get this Distortion Analyser working satisfactorily. Thanks is anticipation,
Colin.

334A Distortion Analyzer, etc.

 

Hi All,
I have been puzzling for a while but I'm not sure that I have got to the truth yet.
I have a H-P 334A Distortion Analyzer which I put away a while ago and now I find that something is not right. When I turn the instrument on, the meter-needle swings to the right and then comes back to zero fairly quickly. Unfortunately, there is still a little movement on the meter-needle but this settles down eventually. Since it looks as though the current isn't passing completely down the A2R44, A2Q8 and A2Q9 components completely, I have ascertained that transistor A2Q9 has probably died on me. This transistor was originally a Motorola SM4713 PNP silicon type. Research tell me that while this transistor is discontinued, an equivalent is probably a 2N3251. However, this is a bit pricey just to check out and I suspect that a?2N3906 will probably suffice just to check. Has anyone else any better ideas? I really want to get this Distortion Analyser working satisfactorily. Thanks is anticipation,
Colin.
Re: Spectrum analyzer in a high traffic strong signal environment

 

"...is it possible that although the input levels look fine on screen when in reality the analyzer is actually seeing higher than -30dB at it's input..."
-

Not only is it possible, it is very probable.? Before connecting a spectrum analyzer to any antenna, I like to connect the antenna to an RF power meter.? The broadband sensor will measure the total RF energy that will be incident on your spectrum analyzer's mixer.

In most cases, I believe it is necessary to use some sort of preselector to narrow the spectrum to the area of interest.? I have a complete set of K&L tunable preselectors covering the range from 80 MHz to 1 GHz.? Each covers an octave band.

K_L Filter 2.JPG

Re: Spectrum analyzer in a high traffic strong signal environment

Lothar baier
 

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If the signals are radiated then using cables and adapters with very good shielding can help mitigate the issues but if they are conducted than things become difficult!



On Mar 2, 2022, at 11:23, DW via groups.io <wilson2115@...> wrote:

?There might be cases where a spectrum analyzer is used to measure a particular signal that is surrounded by many adjacent strong signals. Perhaps the signal measured isn't as strong as the adjacent signals and requires and increase in level but unfortunately the adjacent signals are raised as well.

Although none of the strong adjacent signals are overpowering of the analyzer, perhaps they are all somewhere around -30dBm but there are about 10 of them or more, is it possible that although the input levels look fine on screen when in reality the analyzer is actually seeing higher than -30dB at it's input thus staying below the input level limits might not always be so obvious.

Thoughts on this, thanks

Spectrum analyzer in a high traffic strong signal environment

 

There might be cases where a spectrum analyzer is used to measure a particular signal that is surrounded by many adjacent strong signals. Perhaps the signal measured isn't as strong as the adjacent signals and requires and increase in level but unfortunately the adjacent signals are raised as well.

Although none of the strong adjacent signals are overpowering of the analyzer, perhaps they are all somewhere around -30dBm but there are about 10 of them or more, is it possible that although the input levels look fine on screen when in reality the analyzer is actually seeing higher than -30dB at it's input thus staying below the input level limits might not always be so obvious.

Thoughts on this, thanks
Re: HP8640B RF Fails Several Seconds After Power Up

 

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My 8640B came with trashed RANGE and DEVIATION knobs.? Rather than hunt down spares, I cobbled my own.? I took a generic knob and simply attached the old skirt to it.? It looks wrong but works right.

?

FWIW,

Dave Wise

?

From: [email protected] <[email protected]> On Behalf Of Brian via groups.io
Sent: Wednesday, March 02, 2022 2:21 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP8640B RF Fails Several Seconds After Power Up

?

Hello George, from 12,000 miles away.

?

If only I had met you when I lived and worked in the UK.

?

I have a couple of 8640Bs that I’ve managed to keep going – the odd capacitor failing, and those dreaded gears going U/S.

?

A member of the radio club asked me to look at an 8640B that wasn’t working. There was no RF output and gears were so badly cracked you couldn’t turn the knobs. Someone must have tried because one of the wings on the band-change knob is missing. Now that I’ve replaced gears and lubricated bearings, the band change is fine. Unfortunately, even Walter of Sphere Research in Canada can’t help with that knob; can you?

?

I now have reliable RF output, but no frequency readout. I purchased another frequency readout module from a person scrapping an 8640B, who claimed his counter had been working. But, in fact, neither counter works. Can you help?

?

73 de Brian, VK2GCE

?

From: [email protected] [mailto:[email protected]] On Behalf Of george edmonds via groups.io
Sent: Tuesday, 1 March 2022 4:07 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP8640B RF Fails Several Seconds After Power Up

?

Hi

I have repaired a number of HP8640B signal generators with similar faults, the TO3 sockets for the power supply pass transistors go faulty with time resulting in poor Base and Emitter connections.

G Edmonds G6HIG

Re: looking for HP 8340/41B Manual change supplement for 2804A and 2812A Serial# range

 

"Lothar baier" <Lothar@...> writes:

Its the 8516A 40GHz testset !
The manual outlines that FW 11.88 is required and SN 2812A or higher.
Yes there are hardware changes, the CPU and sweep board have different part numbers , the 8516 uses a internal doubler to use a 20GHz source the doubler is controlled over a controll interface on the back of the testset which is connected to the 8410 interface connector on the 8340 , I assume that HP changed the CPU board to be able to control the 8516 and discard the 8410 controll.
I ordered a CPU board on ebay for $75 and will change it out to see if it works, if not i will also change the sweep board
On Mar 2, 2022, at 00:42, Matt Huszagh via groups.io <huszaghmatt@...> wrote:
Interesting, thanks for sharing.

I checked my own manuals. The one I purchased from Artek has the 2812A
component level service manual for the 8340B, but only volume 2. The
copy of volume 1 there is for prefix 2650A. However, I think vol 2 is
the only one you need. This contains the backdating information. There's
more than 20 pages describing the changes from the 2804A prefix,
including changes to the A58 and A60 assemblies.

Matt
Re: HP8640B RF Fails Several Seconds After Power Up

 

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Hello George, from 12,000 miles away.

?

If only I had met you when I lived and worked in the UK.

?

I have a couple of 8640Bs that I’ve managed to keep going – the odd capacitor failing, and those dreaded gears going U/S.

?

A member of the radio club asked me to look at an 8640B that wasn’t working. There was no RF output and gears were so badly cracked you couldn’t turn the knobs. Someone must have tried because one of the wings on the band-change knob is missing. Now that I’ve replaced gears and lubricated bearings, the band change is fine. Unfortunately, even Walter of Sphere Research in Canada can’t help with that knob; can you?

?

I now have reliable RF output, but no frequency readout. I purchased another frequency readout module from a person scrapping an 8640B, who claimed his counter had been working. But, in fact, neither counter works. Can you help?

?

73 de Brian, VK2GCE

?

From: [email protected] [mailto:[email protected]] On Behalf Of george edmonds via groups.io
Sent: Tuesday, 1 March 2022 4:07 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP8640B RF Fails Several Seconds After Power Up

?

Hi

I have repaired a number of HP8640B signal generators with similar faults, the TO3 sockets for the power supply pass transistors go faulty with time resulting in poor Base and Emitter connections.

G Edmonds G6HIG

Re: 8350B *restoration adventure?*

 

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Hi Ruben, sorry, for white/white-red wire, the AC current for “no plugin” is 2.67A, not 267mA…I forgot to multiply by ten for this measurement, my probe was on the scale 100mV/A.

?

?

Yves

De?: [email protected] <[email protected]> De la part de RubenRubio
贰苍惫辞测é?: 1 mars 2022 06:32
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] 8350B *restoration adventure?*

?

Yves, that data is very helpful, thank you so much! Helps a lot indeed ;)

Giving a first sight to your numbers, I noticed in AC current measurement, that my figures are similar to yours except for the white-white/red-white. I have the plugin connected draw figures without any plugin. So weird. Remember the old transformer was destroyed by melted and shorted secondarys. That said, I have the power for two hours last time and no hot heat sink or malfunction of the logic circuitry. The filter caps was tested OK. I bought new extrafine test probes, so next step is measure the DC current using fuse sockets.?

To be continued...

?

PD Lothar, I always look for 'best offer' auctions on eBay, but the shipment and customs still very heavy. It's a disadvantage to live in Europe for this hobby :D

Regards,
Ruben
Re: Newbie to KE5FX

 

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LO that,
My experience would not agree with your thoughts.?
The one I recently bought off eBay seems to work as described in my previous message to Lou.
NI software seems to like it as does at least John’s Timelabs.?

All I can report is my experience.?
Dave
VE7HR?



On Mar 2, 2022, at 12:01 AM, Lothar baier <Lothar@...> wrote:

? Not surprised at all ! Virtually all “NI”
GPIB/USB adapters sold by Chinese vendors on ebay are Fake , unfortunately this also starts to spill over on US sellers as people who bought them from china and couldn’t get them to work are selling them again on ebay !
The best thing you can do is buy from a US seller a unit that is new in box , you can also check the unit to see if it has the little white barcode serial number label on it and run the serial number by NI?



On Mar 2, 2022, at 00:00, Lou Blasco via groups.io <vk3alb@...> wrote:

?

Interesting Dave,

You must have installed NI drivers to get it to work. What version are you using?

Regards

Lou
VK3ALB


On 2/03/2022 16:47, Dave Miller wrote:
I purchased recently from EBL2018 on a NI USB HS and it seemed to recognize fine on time labs.
I can’t say 100% that I did anything else other than plugging it in and seeing software found it   FWIW. It looks exactly like the one I purchased from NI a few years ago. 

Dave
VE7HR 

On Mar 1, 2022, at 9:43 PM, Lou Blasco <vk3alb@...> wrote:

?Thanks All,

It probably won't surprise you as much as it disappointed me to learn that I bought a fake adapter from eBay. The seller gave me all my money back in a heartbeat as soon as I lodged a complaint so I guess he had an idea of what he was doing. 

-- 
Regards

Lou
VK3ALB

Re: looking for HP 8340/41B Manual change supplement for 2804A and 2812A Serial# range

Lothar baier
 

开云体育

Its the 8516A 40GHz testset !?
The manual outlines that FW 11.88 is required and SN 2812A or higher.
Yes there are hardware changes, the CPU and sweep board have different part numbers , the 8516 uses a internal doubler to use a 20GHz source the doubler is controlled over a controll interface on the back of the testset which is connected to the 8410 interface connector on the 8340 , I assume that HP changed the CPU board to be able to control the 8516 and discard the 8410 controll.
I ordered a CPU board on ebay for $75 and will change it out to see if it works, if not i will also change the sweep board?


On Mar 2, 2022, at 00:42, Matt Huszagh via groups.io <huszaghmatt@...> wrote:

?What’s the test set and does it provide any reason why it requires a newer serial number source? I had a compatibility issue with my 8341 and 8510C but it was firmware related and simply fixed by flashing newer firmware (I believe it needed the April ‘92 though I can check to be sure if you’d like to know). I have a copy of this firmware but you can also download it from ko4bb (FYI I found the 8340 and 8341 firmware to be identical). If there are actual hardware changes needed I’d be curious to hear this too.

?Matt

Re: Newbie to KE5FX

Lothar baier
 

开云体育

Not surprised at all ! Virtually all “NI”
GPIB/USB adapters sold by Chinese vendors on ebay are Fake , unfortunately this also starts to spill over on US sellers as people who bought them from china and couldn’t get them to work are selling them again on ebay !
The best thing you can do is buy from a US seller a unit that is new in box , you can also check the unit to see if it has the little white barcode serial number label on it and run the serial number by NI?



On Mar 2, 2022, at 00:00, Lou Blasco via groups.io <vk3alb@...> wrote:

?

Interesting Dave,

You must have installed NI drivers to get it to work. What version are you using?

Regards

Lou
VK3ALB


On 2/03/2022 16:47, Dave Miller wrote:
I purchased recently from EBL2018 on a NI USB HS and it seemed to recognize fine on time labs.
I can’t say 100% that I did anything else other than plugging it in and seeing software found it   FWIW. It looks exactly like the one I purchased from NI a few years ago. 

Dave
VE7HR 

On Mar 1, 2022, at 9:43 PM, Lou Blasco <vk3alb@...> wrote:

?Thanks All,

It probably won't surprise you as much as it disappointed me to learn that I bought a fake adapter from eBay. The seller gave me all my money back in a heartbeat as soon as I lodged a complaint so I guess he had an idea of what he was doing. 

-- 
Regards

Lou
VK3ALB

Re: Newbie to KE5FX

 

Hi Lou,
I believe I have NI-Visa 19.5 64 bit installed. I did an upgrade to the newest version tonight as the tool claimed I had an old version.

I can confirm that both my Old and New NI-GPIB-HS both work with?Timelab
I can look at both of them with the NI Measurement and Automation Explorer tool also.
I don't know if I need the NI tool installed but I have had it there for years but did the upgrade tonight.
The new one is GPIB1

I hope this helps.
Dave
VE7HR



On Tue, Mar 1, 2022 at 10:00 PM Lou Blasco <vk3alb@...> wrote:

Interesting Dave,

You must have installed NI drivers to get it to work. What version are you using?

Regards

Lou
VK3ALB


On 2/03/2022 16:47, Dave Miller wrote:
I purchased recently from EBL2018 on a NI USB HS and it seemed to recognize fine on time labs.
I can’t say 100% that I did anything else other than plugging it in and seeing software found it   FWIW. It looks exactly like the one I purchased from NI a few years ago. 

Dave
VE7HR 

On Mar 1, 2022, at 9:43 PM, Lou Blasco <vk3alb@...> wrote:

?Thanks All,

It probably won't surprise you as much as it disappointed me to learn that I bought a fake adapter from eBay. The seller gave me all my money back in a heartbeat as soon as I lodged a complaint so I guess he had an idea of what he was doing. 

-- 
Regards

Lou
VK3ALB







    

  




  





					


				
				

-- 
72 de Dave
VE7HR

				
				
			

			
				

				

					
						
	
		
			
				
			
		
		

			
				
			
			
			

				
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							Re: looking for HP 8340/41B Manual change supplement for 2804A and 2812A Serial# range
							
						
					

				

				

			
			

				

					


						
							

								
								
							

						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			

				
What’s the test set and does it provide any reason why it requires a newer serial number source? I had a compatibility issue with my 8341 and 8510C but it was firmware related and simply fixed by flashing newer firmware (I believe it needed the April ‘92 though I can check to be sure if you’d like to know). I have a copy of this firmware but you can also download it from ko4bb (FYI I found the 8340 and 8341 firmware to be identical). If there are actual hardware changes needed I’d be curious to hear this too.

?Matt

				
				
				
			

			
			

	

	
			

			

				
					

				
				
			

			

				

					

				

			

			
			
			

			


				
	



		
			
		
			
				
	
		
	

		
			

			
			

			
			
				
				

					

						
							
							

							Re: Newbie to KE5FX
							
						
					

				

				

			
			

				

					


						
							

								
								
							

						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			

				

  
  




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Interesting Dave,

    
You must have installed NI
          drivers to get it to work. What version are you using?

    

    
Regards

      

      Lou

      VK3ALB

      

      

    

    
On 2/03/2022 16:47, Dave Miller wrote:

    

    

				
					
					

					



      
I purchased recently from EBL2018 on a NI USB HS and it seemed to recognize fine on time labs.
I can’t say 100% that I did anything else other than plugging it in and seeing software found it   FWIW. It looks exactly like the one I purchased from NI a few years ago. 

Dave
VE7HR 


      

        
On Mar 1, 2022, at 9:43 PM, Lou Blasco <vk3alb@...> wrote:

?Thanks All,

It probably won't surprise you as much as it disappointed me to learn that I bought a fake adapter from eBay. The seller gave me all my money back in a heartbeat as soon as I lodged a complaint so I guess he had an idea of what he was doing. 

-- 
Regards

Lou
VK3ALB







      

      






    

  


					


				
				
				
			

			
			

	

	
			

			

				
					

				
				
			

			

				

					

				

			

			
			
			

			


				
	



		
			
		
			
				
	
		
	

		
			

			
			

			
			
				
				

					

						
							
							

							Re: Newbie to KE5FX
							
						
					

				

				

			
			

				

					


						
							

								
								
							

						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			

				
I purchased recently from EBL2018 on a NI USB HS and it seemed to recognize fine on time labs.
I can’t say 100% that I did anything else other than plugging it in and seeing software found it   FWIW. It looks exactly like the one I purchased from NI a few years ago. 

Dave
VE7HR

				
					
					

					


On Mar 1, 2022, at 9:43 PM, Lou Blasco <vk3alb@...> wrote:

?Thanks All,

It probably won't surprise you as much as it disappointed me to learn that I bought a fake adapter from eBay. The seller gave me all my money back in a heartbeat as soon as I lodged a complaint so I guess he had an idea of what he was doing. 

-- 
Regards

Lou
VK3ALB





					


				
				
				
			

			
			

	

	
			

			

				
					

				
				
			

			

				

					

				

			

			
			
			

			


				
	



		
			
		
			
				
	
		
	

		
			

			
			

			
			
				
				

					

						
							
							

							Re: Newbie to KE5FX
							
						
					

				

				

			
			

				

					


						
							

								
								
							

						
					

					

						
							


						
						 
						
							
							
						
						
					

				

			

			

			

				
Thanks All,

It probably won't surprise you as much as it disappointed me to learn that I bought a fake adapter from eBay. The seller gave me all my money back in a heartbeat as soon as I lodged a complaint so I guess he had an idea of what he was doing. 

-- 
Regards

Lou
VK3ALB

				
				
				
			

			
			

	

	
			

			

				
					

				
				
			

			

				

					

				

			

			
			
			

			


				
	



		
			
		
	

	
	
	
	


	

		
		
		
		
		
	

	

		
		
		
		
		
	

	
	

		
		
		
		
	



	

		

			
	
		

			
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