Date   

Re: Low ESR Capacitors

Neil Smith G4DBN
 

$55 when I bought mine on 2017, I emailed him.  Carriage was $9 from Hungary.

Main use is setting up inductors on 136/472 and checking esr of large value caps, but on the resistance range it is pretty much in agreement with my Fluke 8845A using a four-wire Kelvin clip arrangement.

Neil G4DBN

On 27/06/2020 18:40, Michael Scott via groups.io wrote:
Thanks Neill, I assume you have to e-mail him for a price. Roughly how much are they?
 
Mike
 
From: Neil Smith G4DBN
Sent: Saturday, June 27, 2020 5:00 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Low ESR Capacitors
 

I use a Hutale LCR meter from Dr Le Hung. Must put it into a box.  Comes with kelvin clips.  Does all sorts as well as LCR.

Neil G4DBN

http://lcr.is-best.net/en/LCR_eng.pdf

 

 

On 27/06/2020 16:40, Michael Scott via groups.io wrote:
Following the recent discussion on low ESR capacitors ( 7L18 ), what is a reliable method of measurement of ESR? Peak do a meter for around £100, but there are several cheaper multimeters which claim to be able to measure ESR.
 
Has anyone any advice/experience of these devices.
 
I am asking because the subject has come up recently when I have been asked for capacitors from the Chipbank for Sam’s Iceni and other transverters. Many of the capacitors I have in stock were given to me in plastic pots with no information other than the capacitance value. Sam specifies COG/NPO for most of his designs, and in some cases I have reels where the spec or code is given and I can track back to a datasheet, but for the loose ones it is pot luck what you get!
 
73,
 
Mike G3LYP
 


Re: Low ESR Capacitors - Part 2

Michael Scott
 

Thanks Gordon and Chris for the input. There are a few circuits out there so maybe I will try to build one.

73, Mike.

-----Original Message-----
From: Chris Bartram G4DGU
Sent: Saturday, June 27, 2020 6:09 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Low ESR Capacitors - Part 2

However, he says after being tempted away from the computer ... Making
ESR measurements of RF capacitors is a different matter. Probably the
best way is to use a calibrated network analyser, I guess that one of
the £50 Chinese jobbies would be able to do the job, but whatever you
use, it does require _good_ cal. standards to make realistic
measurements. Sadly, you don't get those thrown-in with most affordable
net.ans.

In practice most 1206, 0805 and 0402 SMD capacitors below 100pF can
probably be assumed to be COG/NPO, and probably low loss, but there will
always be exceptions ...

73

Chris G4DGU


Re: 7/8 Hardline Connector

Robin Szemeti - G1YFG
 

And the offending connector:

image.png


On Sat, 27 Jun 2020 at 18:43, Robin Szemeti - G1YFG via groups.io <robin=redpoint.org.uk@groups.io> wrote:
I seem to have acquired a small power amplifier that I intend to use on 70cm ... but it has a 7/8" hardline output for the RF.

I was thinking that 7/16 DIN was probably the connector of choice, but before I get the lathe fired up ... I don't suppose anyone has a suitable 7/8! to *something* adaptor? Or even bright ideas on an easy way to connect it to LDF4-50?

--
Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@...
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the
intended recipient or person responsible for delivering it to the
intended recipient, you have received this communication in error
and must not distribute or copy it.
Please accept the sender's apologies, notify the sender immediately
by return e-mail and delete this communication.

Thank you.


Re: 7/8 Hardline Connector

Reg Woolley
 

Read my e mail before yours my mate has loads

 

De g8vhi

 

Sent from Mail for Windows 10

 

From: Robin Szemeti - G1YFG
Sent: 27 June 2020 18:43
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 7/8 Hardline Connector

 

I seem to have acquired a small power amplifier that I intend to use on 70cm ... but it has a 7/8" hardline output for the RF.

 

I was thinking that 7/16 DIN was probably the connector of choice, but before I get the lathe fired up ... I don't suppose anyone has a suitable 7/8! to *something* adaptor? Or even bright ideas on an easy way to connect it to LDF4-50?


--

Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@...
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the
intended recipient or person responsible for delivering it to the
intended recipient, you have received this communication in error
and must not distribute or copy it.
Please accept the sender's apologies, notify the sender immediately
by return e-mail and delete this communication.

Thank you.

 


7/8 Hardline Connector

Robin Szemeti - G1YFG
 

I seem to have acquired a small power amplifier that I intend to use on 70cm ... but it has a 7/8" hardline output for the RF.

I was thinking that 7/16 DIN was probably the connector of choice, but before I get the lathe fired up ... I don't suppose anyone has a suitable 7/8! to *something* adaptor? Or even bright ideas on an easy way to connect it to LDF4-50?

--
Best regards,

Robin Szemeti

Redpoint Consulting Limited

E: robin@...
T: +44 (0) 1299 405028
M: +44 (0) 7971 883371

CONFIDENTIALITY NOTICE
The information contained in this e-mail is intended only for the
confidential use of the above named recipient. If you are not the
intended recipient or person responsible for delivering it to the
intended recipient, you have received this communication in error
and must not distribute or copy it.
Please accept the sender's apologies, notify the sender immediately
by return e-mail and delete this communication.

Thank you.


Re: Low ESR Capacitors

Michael Scott
 

Thanks Neill, I assume you have to e-mail him for a price. Roughly how much are they?
 
Mike
 

From: Neil Smith G4DBN
Sent: Saturday, June 27, 2020 5:00 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Low ESR Capacitors
 

I use a Hutale LCR meter from Dr Le Hung. Must put it into a box.  Comes with kelvin clips.  Does all sorts as well as LCR.

Neil G4DBN

http://lcr.is-best.net/en/LCR_eng.pdf

 

 

On 27/06/2020 16:40, Michael Scott via groups.io wrote:
Following the recent discussion on low ESR capacitors ( 7L18 ), what is a reliable method of measurement of ESR? Peak do a meter for around £100, but there are several cheaper multimeters which claim to be able to measure ESR.
 
Has anyone any advice/experience of these devices.
 
I am asking because the subject has come up recently when I have been asked for capacitors from the Chipbank for Sam’s Iceni and other transverters. Many of the capacitors I have in stock were given to me in plastic pots with no information other than the capacitance value. Sam specifies COG/NPO for most of his designs, and in some cases I have reels where the spec or code is given and I can track back to a datasheet, but for the loose ones it is pot luck what you get!
 
73,
 
Mike G3LYP
 


Re: But it's the wrong satellite, Grommit.

Robin Szemeti - G1YFG
 

I'm not sufficiently up to speed on the differences between a "space qualified" Rb standard and a "normal" one, but they are much smaller and simpler than they used to be.  I once had to repair the HP Rubidium reference that the studios in B'ham were locked to.  It was a fearsome beast, a full depth 3U unit, with plenty of fun stuff to play with, the rubidium lamp, the RF excited plasma cell, the uWave 6.x GHz source ...  

These days, the whole thing comes in a 2" square block ... and weighs 100 grammes.  


On Sat, 27 Jun 2020 at 18:21, Andy G4JNT <andy.g4jnt@...> wrote:
Because the LEO constellation is some 70 strong,  and there's a huge cost and reliability issue with space-borne  Cs standards.



On Sat, 27 Jun 2020 at 18:08, Chris M0WEF <chris.m0wef@...> wrote:
Why would it be infeasible to put atomic clocks on LEO satellites?

Chris.


Re: But it's the wrong satellite, Grommit.

Andy G4JNT
 

Because the LEO constellation is some 70 strong,  and there's a huge cost and reliability issue with space-borne  Cs standards.



On Sat, 27 Jun 2020 at 18:08, Chris M0WEF <chris.m0wef@...> wrote:
Why would it be infeasible to put atomic clocks on LEO satellites?

Chris.


Re: But it's the wrong satellite, Grommit.

Andy
 

On 27/06/2020 17:51, Andy G4JNT wrote:
https://www.theguardian.com/science/2020/jun/26/satellite-experts-oneweb-investment-uk-galileo-brexit
I can't imagine that a range of decision makers can be that foolish or forced by government pressures.    Anyone know the real story? (and, more to the point, are allowed to revel properly)
The FT (hidden behind a paywall) went on saying the idea was not to build another GPS system.

The FT quote is

"Moreover, the US was pushing its partner in the Five Eyes intelligence-sharing alliance to avoid replicating the GPS system, said three people with knowledge of the situation. “The Americans do not think a British Galileo would be sufficiently different to GPS,” said one. “They understand the vulnerabilities of GPS. They want something technologically different.”

"US officials had been drawn to the idea that important navigation technology could be “hidden in plain sight” on up to 80 of OneWeb’s planned 648 satellites, making them harder to compromise, according to two people who held discussions with both US defence officials and the UK government.

"In early March, Stuart Martin, chief executive of the Satellite Applications Catapult, told the Financial Times that while it would be challenging to develop this “cutting-edge” technology on satellites at low orbit, the UK had the expertise and it would be highly exportable.

"“This would offer something genuinely different that enhances GPS,” he said. “It is another way to achieve a global system at lower cost and it makes more economic sense.”"



LOCSTAR was cancelled part-way through because, we know now, but didn't then,  people had looked to the future and seen GPS coming along .
There's nothing inherently wrong in principle with a location system based on LEO satellites.  TRANSIT did it in teh 1960s using V/UHF - but not to anyhting like such accuracy.  100s of metres ISTR
GPS was known about in the mid 80s to the right people.

I had a mate at university in 1983 who did his final year project on TRANSIT. Then he did a PhD. on satellite navigation and used to receive 9track tapes from the US which had the kind of data you should receive for the replacement for TRANSIT. One he got his PhD. he was snapped up by a US company (Hughes or TRW ISTR) and worked on GPS technology till a lucky stock options gamble paid off and he retired in his 40s.


Andy
(The other one)


Bits for sale

Reg Woolley
 
Edited


Hi all I have just been to a friends garden shed in Peterborough.  He has large amounts of cable and other bits for sale. From SMA cables up to ldf 5 50 and much in between.  Even some dummy loads and other stuff. Attached is just a small example of what he has. 

For more info e mail r.halliday@...

Reg G8VHI


Sent from my Samsung Galaxy S10e - Powered by Three


Re: Low ESR Capacitors - Part 2

Chris Bartram G4DGU
 

However, he says after being tempted away from the computer ... Making ESR measurements of RF capacitors is a different matter. Probably the best way is to use a calibrated network analyser, I guess that one of the £50 Chinese jobbies would be able to do the job, but whatever you use, it does require _good_ cal. standards to make realistic measurements. Sadly, you don't get those thrown-in with most affordable net.ans.

In practice most 1206, 0805 and 0402 SMD capacitors below 100pF can probably be assumed to be COG/NPO, and probably low loss, but there will always be exceptions ...

73

Chris G4DGU


Re: But it's the wrong satellite, Grommit.

Chris M0WEF
 

Why would it be infeasible to put atomic clocks on LEO satellites?

Chris.


Re: But it's the wrong satellite, Grommit.

Robin Szemeti - G1YFG
 

From what I read, the system would not be a true stand alone PTN system, but would piggyback on the GPS system as an enhancement, delivering stronger signals into deep attenuation areas such as inside buildings ... and this is what encouraged the US military to give it the thumbs-up, as they would still ultimately be in control.


On Sat, 27 Jun 2020 at 17:51, Andy G4JNT <andy.g4jnt@...> wrote:

I can't imagine that a range of decision makers can be that foolish or forced by government pressures.    Anyone know the real story? (and, more to the point, are allowed to revel properly)

Back in 1990, long before GPS, I worked on a satellite location system based on two way transponders carrying spread spectrum signals for ranging.   The    LOCSTAR project.  I don't recall the full constellation, but think is was two sats in Geostationary and worked with a-priori information on approximate (eg country, location beforehand.   Probably just aimed at just part of the World like Eu.     The US had a not-dissimilar system, GEOSTAR in the pipeline.  NOt sure whether it went ahead fully.

LOCSTAR was cancelled part-way through because, we know now, but didn't then,  people had looked to the future and seen GPS coming along .

There's nothing inherently wrong in principle with a location system based on LEO satellites.  TRANSIT did it in teh 1960s using V/UHF - but not to anyhting like such accuracy.  100s of metres ISTR

If used in the same way as GNSS, they'd all have to carry highly accurate clocks Cs or Rb  which is totally infeasible (? nowadays ?).   But it's not unreasonable to use them as transponders carrying a ranging PN sequence transmitted from the ground.   Then the same correlation techniques can be carried out by users as with satellite generated PN codes.  Of course, satellite ephemeris will have to be known to cm accuracy if it's to match the performance of GNSS.   But given this, and a transponder payload with good phase stability for the PN code it's feasible I'd have thought.

The  ground station requirements are a bit frightening though.

As for mass produced low cost receivers.  IF the frequency band is around the same as GNSS, ie L-Band, I can see all those GNSS chip set manufacturers just yawning and building in compatibility.   After all, they upgraded from GPS to GLONASS,  Beidou, Galileo and I think there's another they work with now as well all in one tiny module costing a few quid.    It's all just IP/Firmare/juggling with numbers.


Re: Low ESR Capacitors

Chris Bartram G4DGU
 

FWIW, I use a 'Multifunction Transistor Tester Diodes LCR - TC1 Full Color Graphics Display' bought off Epay for about a tenner. Probably not accurate by lab standards, but a quick shotgun test using a 4.7uF polyester capacitor and a series resistor gave realistic results. It's certainly been good enough to detect a couple of high-ESR aluminium electrolytics in my spec.an.

73

Chris

G4DGU



But it's the wrong satellite, Grommit.

Andy G4JNT
 


I can't imagine that a range of decision makers can be that foolish or forced by government pressures.    Anyone know the real story? (and, more to the point, are allowed to revel properly)

Back in 1990, long before GPS, I worked on a satellite location system based on two way transponders carrying spread spectrum signals for ranging.   The    LOCSTAR project.  I don't recall the full constellation, but think is was two sats in Geostationary and worked with a-priori information on approximate (eg country, location beforehand.   Probably just aimed at just part of the World like Eu.     The US had a not-dissimilar system, GEOSTAR in the pipeline.  NOt sure whether it went ahead fully.

LOCSTAR was cancelled part-way through because, we know now, but didn't then,  people had looked to the future and seen GPS coming along .

There's nothing inherently wrong in principle with a location system based on LEO satellites.  TRANSIT did it in teh 1960s using V/UHF - but not to anyhting like such accuracy.  100s of metres ISTR

If used in the same way as GNSS, they'd all have to carry highly accurate clocks Cs or Rb  which is totally infeasible (? nowadays ?).   But it's not unreasonable to use them as transponders carrying a ranging PN sequence transmitted from the ground.   Then the same correlation techniques can be carried out by users as with satellite generated PN codes.  Of course, satellite ephemeris will have to be known to cm accuracy if it's to match the performance of GNSS.   But given this, and a transponder payload with good phase stability for the PN code it's feasible I'd have thought.

The  ground station requirements are a bit frightening though.

As for mass produced low cost receivers.  IF the frequency band is around the same as GNSS, ie L-Band, I can see all those GNSS chip set manufacturers just yawning and building in compatibility.   After all, they upgraded from GPS to GLONASS,  Beidou, Galileo and I think there's another they work with now as well all in one tiny module costing a few quid.    It's all just IP/Firmare/juggling with numbers.


Re: Low ESR Capacitors

Gordon REASON <gordonj.reason@...>
 

I made one up , from a simple circuit , taken fron google .........

Analogue panel meter ........ works fine .........

get's used about every five years or so , if I can find it !

On 27 June 2020 at 16:40 "Michael Scott via groups.io" <g3lyp@...> wrote:

Following the recent discussion on low ESR capacitors ( 7L18 ), what is a reliable method of measurement of ESR? Peak do a meter for around £100, but there are several cheaper multimeters which claim to be able to measure ESR.
 
Has anyone any advice/experience of these devices.
 
I am asking because the subject has come up recently when I have been asked for capacitors from the Chipbank for Sam’s Iceni and other transverters. Many of the capacitors I have in stock were given to me in plastic pots with no information other than the capacitance value. Sam specifies COG/NPO for most of his designs, and in some cases I have reels where the spec or code is given and I can track back to a datasheet, but for the loose ones it is pot luck what you get!
 
73,
 
Mike G3LYP
 
From: Paul G8KFW
Sent: Saturday, June 27, 2020 2:54 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?
 

Hi

 

This is a subject that has been talked about a lot over the last 2 plus years on the HP Groups

 

and in general unless it is a switch mode power supply the replacement with a good quality ( not a copy ) non tantalum is considered a good replacement

But Low ESR capacitors  are quit often required for switch mode power used on certain HP equipment   but they are a lot more expensive

 

Regards Paul

 


From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of Paul Randall G3NJV
Sent: 27 June 2020 09:24
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?

 

Ditto for three Racal 1792 receivers I acquired. Dozens of tantalum caps faulty. I'd say,  if you find more than one or two faulty,  bite the bullet and replace the lot. 

Question,  what's the opinion on what type to use for the replacements?

Paul

 

-------- Original message --------

From: Paul G8KFW <paul@...>

Date: 26/06/2020 23:57 (GMT+00:00)

To: UKMicrowaves@groups.io

Subject: Re: [UKMicrowaves] 7L18?

 

Hi Ben

 

The last 7L18 I worked on required replacement of a large number of  Tantalum capacitors

 

Suggest you get an ESR meter and look at all the caps first don’t unsolder them just do the testing in CCT  and record the results

Then replace the suspect ones

 

Regards Paul B

 


From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of militaryoperator via groups.io
Sent: 26 June 2020 22:35
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 7L18?

 

Does anyone have experience of working on the 7L18 spectrum analyser in the 7603 mainframe?

 

Only mine has a problem.

 

Ben

--------------------------------------

Curator, Owner and Display coordinator

Military Wireless Museum

Kidderminster , UK .

 

This message was meant for the recipient

Any likeness to persons living or dead is odd

---------------------------------------

 

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.


--
Paul Bicknell G8KFW   South Coast UK

No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.


--
Paul Bicknell G8KFW   South Coast UK


 


 


F1JGP 10GHz PA

Adrian G4UVZ
 

Built from an original F1JGP PCB fitted with a genuine FLM1011-8F Fet 
12 volt single supply and output monitor etc see attached details...delivering 5 -6 watts when last used about a year ago ...would probably benefit from snowflaking!
Please PM me with offers if interested..


Re: Low ESR Capacitors

Michael Scott
 

Sorry Ben, we have been chastised for going off topic without changing the subject line!!
 
Mike.
 

From: militaryoperator via groups.io
Sent: Saturday, June 27, 2020 4:44 PM
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Low ESR Capacitors
 
 
Following the recent discussion on low ESR capacitors ( 7L18 ),
Thanks for changing the subject line Mike. 
 
Every time a 7L18 popped up I was hoping for a solution, hi.
 
Ben

 
 
-----Original Message-----
From: Michael Scott via groups.io <g3lyp@...>
To: UKMicrowaves@groups.io
Sent: Sat, 27 Jun 2020 16:40
Subject: [UKMicrowaves] Low ESR Capacitors

Following the recent discussion on low ESR capacitors ( 7L18 ), what is a reliable method of measurement of ESR? Peak do a meter for around £100, but there are several cheaper multimeters which claim to be able to measure ESR.
 
Has anyone any advice/experience of these devices.
 
I am asking because the subject has come up recently when I have been asked for capacitors from the Chipbank for Sam’s Iceni and other transverters. Many of the capacitors I have in stock were given to me in plastic pots with no information other than the capacitance value. Sam specifies COG/NPO for most of his designs, and in some cases I have reels where the spec or code is given and I can track back to a datasheet, but for the loose ones it is pot luck what you get!
 
73,
 
Mike G3LYP
 
From: Paul G8KFW
Sent: Saturday, June 27, 2020 2:54 PM
Subject: Re: [UKMicrowaves] 7L18?
 
Hi
 
This is a subject that has been talked about a lot over the last 2 plus years on the HP Groups
 
and in general unless it is a switch mode power supply the replacement with a good quality ( not a copy ) non tantalum is considered a good replacement
But Low ESR capacitors  are quit often required for switch mode power used on certain HP equipment   but they are a lot more expensive
 
Regards Paul
 

From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of Paul Randall G3NJV
Sent: 27 June 2020 09:24
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?
 
Ditto for three Racal 1792 receivers I acquired. Dozens of tantalum caps faulty. I'd say,  if you find more than one or two faulty,  bite the bullet and replace the lot. 
Question,  what's the opinion on what type to use for the replacements?
Paul
 
-------- Original message --------
From: Paul G8KFW <paul@...>
Date: 26/06/2020 23:57 (GMT+00:00)
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?
 
Hi Ben
 
The last 7L18 I worked on required replacement of a large number of  Tantalum capacitors
 
Suggest you get an ESR meter and look at all the caps first don’t unsolder them just do the testing in CCT  and record the results
Then replace the suspect ones
 
Regards Paul B
 

From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of militaryoperator via groups.io
Sent: 26 June 2020 22:35
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 7L18?
 
Does anyone have experience of working on the 7L18 spectrum analyser in the 7603 mainframe?
 
Only mine has a problem.
 
Ben
--------------------------------------
Curator, Owner and Display coordinator
Military Wireless Museum
Kidderminster, UK.
 
This message was meant for the recipient
Any likeness to persons living or dead is odd
---------------------------------------
 
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.

--
Paul Bicknell G8KFW   South Coast UK
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.

--
Paul Bicknell G8KFW   South Coast UK


Re: Low ESR Capacitors

Neil Smith G4DBN
 

I use a Hutale LCR meter from Dr Le Hung. Must put it into a box.  Comes with kelvin clips.  Does all sorts as well as LCR.

Neil G4DBN

http://lcr.is-best.net/en/LCR_eng.pdf



On 27/06/2020 16:40, Michael Scott via groups.io wrote:
Following the recent discussion on low ESR capacitors ( 7L18 ), what is a reliable method of measurement of ESR? Peak do a meter for around £100, but there are several cheaper multimeters which claim to be able to measure ESR.
 
Has anyone any advice/experience of these devices.
 
I am asking because the subject has come up recently when I have been asked for capacitors from the Chipbank for Sam’s Iceni and other transverters. Many of the capacitors I have in stock were given to me in plastic pots with no information other than the capacitance value. Sam specifies COG/NPO for most of his designs, and in some cases I have reels where the spec or code is given and I can track back to a datasheet, but for the loose ones it is pot luck what you get!
 
73,
 
Mike G3LYP
 


Re: Low ESR Capacitors

militaryoperator
 


Following the recent discussion on low ESR capacitors ( 7L18 ),
Thanks for changing the subject line Mike. 

Every time a 7L18 popped up I was hoping for a solution, hi. 

Ben



-----Original Message-----
From: Michael Scott via groups.io <g3lyp@...>
To: UKMicrowaves@groups.io
Sent: Sat, 27 Jun 2020 16:40
Subject: [UKMicrowaves] Low ESR Capacitors

Following the recent discussion on low ESR capacitors ( 7L18 ), what is a reliable method of measurement of ESR? Peak do a meter for around £100, but there are several cheaper multimeters which claim to be able to measure ESR.
 
Has anyone any advice/experience of these devices.
 
I am asking because the subject has come up recently when I have been asked for capacitors from the Chipbank for Sam’s Iceni and other transverters. Many of the capacitors I have in stock were given to me in plastic pots with no information other than the capacitance value. Sam specifies COG/NPO for most of his designs, and in some cases I have reels where the spec or code is given and I can track back to a datasheet, but for the loose ones it is pot luck what you get!
 
73,
 
Mike G3LYP
 
From: Paul G8KFW
Sent: Saturday, June 27, 2020 2:54 PM
Subject: Re: [UKMicrowaves] 7L18?
 
Hi
 
This is a subject that has been talked about a lot over the last 2 plus years on the HP Groups
 
and in general unless it is a switch mode power supply the replacement with a good quality ( not a copy ) non tantalum is considered a good replacement
But Low ESR capacitors  are quit often required for switch mode power used on certain HP equipment   but they are a lot more expensive
 
Regards Paul
 

From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of Paul Randall G3NJV
Sent: 27 June 2020 09:24
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?
 
Ditto for three Racal 1792 receivers I acquired. Dozens of tantalum caps faulty. I'd say,  if you find more than one or two faulty,  bite the bullet and replace the lot. 
Question,  what's the opinion on what type to use for the replacements?
Paul
 
-------- Original message --------
From: Paul G8KFW <paul@...>
Date: 26/06/2020 23:57 (GMT+00:00)
To: UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] 7L18?
 
Hi Ben
 
The last 7L18 I worked on required replacement of a large number of  Tantalum capacitors
 
Suggest you get an ESR meter and look at all the caps first don’t unsolder them just do the testing in CCT  and record the results
Then replace the suspect ones
 
Regards Paul B
 

From: UKMicrowaves@groups.io [mailto: UKMicrowaves@groups.io ] On Behalf Of militaryoperator via groups.io
Sent: 26 June 2020 22:35
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 7L18?
 
Does anyone have experience of working on the 7L18 spectrum analyser in the 7603 mainframe?
 
Only mine has a problem.
 
Ben
--------------------------------------
Curator, Owner and Display coordinator
Military Wireless Museum
Kidderminster, UK.
 
This message was meant for the recipient
Any likeness to persons living or dead is odd
---------------------------------------
 
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.

--
Paul Bicknell G8KFW   South Coast UK
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.8048 / Virus Database: 4793/15886 - Release Date: 08/14/18
Internal Virus Database is out of date.

--
Paul Bicknell G8KFW   South Coast UK

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