Date   

Re: UKMicrowave group Subscription - Cheque payments

Paul Selwood G3YDY
 

Some banks have arrangement for paying in cheques using scanned copies sent to them. May be worth investigating.

G3YDY

 

 

From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of John Worsnop
Sent: 05 June 2020 11:52
To: UKMicrowaves@groups.io; UKuG-Committee@groups.io
Subject: [UKMicrowaves] UKMicrowave group Subscription - Cheque payments

 

Due to the current situation I am unable to get to the bank to pay in cheques. So if you've sent me one recently, don't expect it to clear in the foreseeable future.

 

I will of course advise the membership secretary that the sub  has been paid if you do. 

 

You could really help by not paying your £6 (!!) by cheque,  and using our Paypal facility  (ukug@...) or contact me off reflector for UKuG bank details and doing a direct transfer (UK members only)

 

On reflection I'm of the view it's time, in the 21st Century, to stop accepting cheque payments altogether.

 

I plan to raise this with the committee in due course.

 

This currently is only my personal view as treasurer as I have to get in to my car, drive 5 miles in to Cambridge, park up, and walk for 20 minutes (from the only remaining free parking close to Cambridge Centre) to take them to the bank.

 

I'd appreciate member's feedback on this proposal

 

73

John G4BAO

UKuG Treasurer

 

  


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Re: UKMicrowave group Subscription - Cheque payments

John Fell
 

Wot , no bartering facility available !
Yes - move us all into the 21st Cent and only accept direct payment .

John
G0API

On Fri, 5 Jun 2020 at 11:52, John Worsnop <johnworsnop@...> wrote:
Due to the current situation I am unable to get to the bank to pay in cheques. So if you've sent me one recently, don't expect it to clear in the foreseeable future.

I will of course advise the membership secretary that the sub  has been paid if you do. 

You could really help by not paying your £6 (!!) by cheque,  and using our Paypal facility  (ukug@...) or contact me off reflector for UKuG bank details and doing a direct transfer (UK members only)

On reflection I'm of the view it's time, in the 21st Century, to stop accepting cheque payments altogether.

I plan to raise this with the committee in due course.

This currently is only my personal view as treasurer as I have to get in to my car, drive 5 miles in to Cambridge, park up, and walk for 20 minutes (from the only remaining free parking close to Cambridge Centre) to take them to the bank.

I'd appreciate member's feedback on this proposal

73
John G4BAO
UKuG Treasurer

  


UKMicrowave group Subscription - Cheque payments

John Worsnop
 

Due to the current situation I am unable to get to the bank to pay in cheques. So if you've sent me one recently, don't expect it to clear in the foreseeable future.

I will of course advise the membership secretary that the sub  has been paid if you do. 

You could really help by not paying your £6 (!!) by cheque,  and using our Paypal facility  (ukug@...) or contact me off reflector for UKuG bank details and doing a direct transfer (UK members only)

On reflection I'm of the view it's time, in the 21st Century, to stop accepting cheque payments altogether.

I plan to raise this with the committee in due course.

This currently is only my personal view as treasurer as I have to get in to my car, drive 5 miles in to Cambridge, park up, and walk for 20 minutes (from the only remaining free parking close to Cambridge Centre) to take them to the bank.

I'd appreciate member's feedback on this proposal

73
John G4BAO
UKuG Treasurer

  


Re: I want to document some RF techniques, help please

alwyn.seeds1
 

Dear All,

I’d be a little cautious about that filter chapter- diagram shows the E Field in a transmission line cavity to be parallel with the conductors!

Yes, you can capacitively load a 75 MHz transmission line cavity down to 50 MHz, but you will make a serious sacrifice in Q and achieving correct coupling will require a major re-design.

For 50 MHz, big helical resonators would be my choice.

Regards,

Alwyn G8DOH

_____________________________________________________

Alwyn Seeds, Director
SynOptika Ltd.,
114 Beaufort Street,
London,
SW3 6BU,
England.


SynOptika Ltd., Registered in England and Wales: No. 04606737
Registered Office: 114 Beaufort Street, London, SW3 6BU, United Kingdom.
_____________________________________________________


Re: Activity List for the UK Microwave Group Low Band Contest - Sunday June 7th

Phil Guttridge G3TCU
 

Hi John,

I'm staying at the home QTH again for this one and only expect to be QRV on 23cm.

Callsign: G3TCU
Locator: IO91QE
Bands: 1296MHz 250W 44 ele
             
Talkback: Direct CQ, ON4KST
Times: Various throughout, on KST when in the shack.


73, Phil G3TCU



On 31/05/2020 23:32, John Quarmby via groups.io wrote:
The fourth in the series of UKuG Low Band events takes place next Sunday 7th June, from  1000 to 1600 GMT (1000 - 1700 BST), on the 1296, 2300, 2320, and 3400MHz bands.

This contest is partially coincident with the IARU Region 1 coordinated Microwave Contest that takes place from 1400 GMT Saturday to 1400 GMT Sunday.

I will put together an activity list next Saturday, please post your operating plans in the usual format:

Callsign : G3XDY
Locator: JO02OB
Bands: 1296MHz 400W 4x 23el
             2300/2320MHz 200W 0.8m dish
              3400MHz 20W 0.8m dish
Talkback: Direct CQ on 1296MHz or via ON4KST
Times: Various throughout

73

John G3XDY




Re: Getting indication of rf

g4zod@btinternet.com
 

In our labs we had kilos of doped and undoped billets of silicon dioxide.
We used to slice them up on a diamond saw and do interesting things with them. ( I spent many hours lapping surfaces to micron finish and etching other surfaces with HF)
Most of them went as chemical waste in the end. ( But I did give some of them to other institutions).

Julian

Sent from BlueMail

On 4 Jun 2020, at 22:48, Andy G4JNT <andy.g4jnt@...> wrote:
But one purification cycle gives the raw materials for tens of thousands of chips.  May even be 100s of k devices - does anyone have figures?
So it's hardly a 'lot' of energy.

When the design already exists and the IP is made available, they're pretty easy to get made too.  Look at the story of the reincarnation of the old SL6270 VOGAD chip.

And this myth about static sensitivity.
OK, back in the dark ages of the 1970s, perhaps into the 1980s even, devices were susceptible and manufacturers weren't as careful as they should have been, but since then they've become orders of magnitude better.  It's not just  hearsay, I know someone who has worked in the highly specialised field of semiconductor static testing since that era and he has benn very closely involved with and  explained the progress made over the years with testing techniques and built in protection..  (He may even be a member of this Group now.  Paul, are you there ....?) 

It's really about time some of these myths of decades ago were forgotten and people looked at the real state of electronics today.   Trouble is, there are so few young electronics graduates in our Am. Rad. ranks now to tell the story ...

BTW, I connected a chunky 5V power supply the wrong way round to a PIC processor once.   It current limited at 3A and current must have passed for perhaps half a second, most of i- going through the device WHICH SURVIVED to carry on working.  What happened is that every I/O line and there were over 20 of them had reverse biassed diodes (for transient and over voltage protection) to ground and the supply rail. With the supply reversed all these diodes forward conducted, in parallel, and were able to able to sink that 3A  for the duration.  But longer and bond wires might have popped.  But the chip subsequently worked.

What's this got to do with the subject line of RF Indication - I dunno, but it's a good waffle anyway.  Back to the G+T



On Thu, 4 Jun 2020 at 22:11, John E. Beech < john@...> wrote:
Problem is that most silicon is locked up as silicon dioxide. Extracting it and purifying so that it can be made precisely impure enough to make it semi-conduct takes an enormous amount of energy and effort and exactly how robust are they? They don't like it up 'em Mr Mainwaring! Voltage spikes that is.

de John G8SEQ

>  -------Original Message-------
>  From: Andy G4JNT < andy.g4jnt@...>
>  To: UK Microwaves groups.io < UKMicrowaves@groups.io>
>  Subject: Re: [UKMicrowaves] Getting indication of rf
>  Sent: Jun 04 '20 14:42

>  Think of it in terms of cost and effort instead.

>  Transistors and anything inside an IC is only silicon - one of the
>  most abundant elements on Earth. ICs churned out by the quintillion
>  each day
>  Compare that with the cost, setting up, delicate mechanism, easy
>  damage of an analogue meter
>  Who'd ever choose the latter, again




Re: Getting indication of rf

Andy G4JNT
 

You can do a MUCH better job for high current reverse polarity protection using a P-Channel MOSFET used the wrong way round  See RadCom March 2016 Page 68 
or Page 149 of THE BOOK :-)   (Blatent plug https://www.rsgbshop.org/acatalog/Online_Catalogue_What_s_New_26.html )

No large currents having to blow fuses, or 700mV drops across high current diodes.    Just a few tens of mV across a FET in normal operation, and complete blockage to reverse polarity.



On Fri, 5 Jun 2020 at 10:21, John E. Beech <john@...> wrote:
Hi Andy,
            My comment was a bit tongue-in-cheek, but it has taken over seventy years of semiconductor development and expensive equipment to get to where we are now whereas a moving coil meter can be made or repaired by a competent watch/instrument maker with hand tools and a simple lathe. ( trouble is finding one these days!) You can also see when a MCM isn't working. I've managed to destroy no end of semiconductors in my time & a lot of them didn't look as though they were damaged. But as you say semis are so cheap to buy now you can incorporate as may as you like for protection. Incidentally the protection diode in my L 23 TVTR did its job of reverse voltage protection ie blew the fuse but failed itself in doing so as it went short circuit. So much for 100's amps peak non-repetitive current!

de John G8SEQ

>  -------Original Message-------
>  From: Paul Randall G3NJV <paulfrandall@...>
>  To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
>  Subject: Re: [UKMicrowaves] Getting indication of rf
>  Sent: Jun 04 '20 23:30

>  "What's this got to do with"
>  Maybe nothing, but .... keep the lines open so anyone can post without
>  fear.

>  -------------------------

>  FROM: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of
>  Andy G4JNT <andy.g4jnt@...>
>  SENT: 04 June 2020 22:47
>  TO: UK Microwaves groups.io <UKMicrowaves@groups.io>
>  SUBJECT: Re: [UKMicrowaves] Getting indication of rf

>  But one purification cycle gives the raw materials for tens of
>  thousands of chips. May even be 100s of k devices - does anyone have
>  figures?
>  So it's hardly a 'lot' of energy.

>  When the design already exists and the IP is made available, they're
>  pretty easy to get made too. Look at the story of the reincarnation of
>  the old SL6270 VOGAD chip.

>  And this myth about static sensitivity.
>  OK, back in the dark ages of the 1970s, perhaps into the 1980s even,
>  devices were susceptible and manufacturers weren't as careful as they
>  should have been, but since then they've become orders of magnitude
>  better. It's not just hearsay, I know someone who has worked in the
>  highly specialised field of semiconductor static testing since that
>  era and he has benn very closely involved with and explained the
>  progress made over the years with testing techniques and built in
>  protection.. (He may even be a member of this Group now. Paul, are you
>  there ....?)

>  It's really about time some of these myths of decades ago were
>  forgotten and people looked at the real state of electronics today.
>  Trouble is, there are so few young electronics graduates in our Am.
>  Rad. ranks now to tell the story ...

>  BTW, I connected a chunky 5V power supply the wrong way round to a PIC
>  processor once. It current limited at 3A and current must have passed
>  for perhaps half a second, most of i- going through the device WHICH
>  SURVIVED to carry on working. What happened is that every I/O line and
>  there were over 20 of them had reverse biassed diodes (for transient
>  and over voltage protection) to ground and the supply rail. With the
>  supply reversed all these diodes forward conducted, in parallel, and
>  were able to able to sink that 3A for the duration. But longer and
>  bond wires might have popped. But the chip subsequently worked.

>  What's this got to do with the subject line of RF Indication - I
>  dunno, but it's a good waffle anyway. Back to the G+T

>  Andy
www.g4jnt.com

>  On Thu, 4 Jun 2020 at 22:11, John E. Beech <john@...> wrote:

>  > Problem is that most silicon is locked up as silicon dioxide.
>  > Extracting it and purifying so that it can be made precisely impure
>  > enough to make it semi-conduct takes an enormous amount of energy
>  > and effort and exactly how robust are they? They don't like it up
>  > 'em Mr Mainwaring! Voltage spikes that is.
>  >
>  > de John G8SEQ
>  >
>  >> -------Original Message-------
>  >> From: Andy G4JNT <andy.g4jnt@...>
>  >> To: UK Microwaves groups.io <UKMicrowaves@groups.io>
>  >> Subject: Re: [UKMicrowaves] Getting indication of rf
>  >> Sent: Jun 04 '20 14:42
>  >>
>  >> Think of it in terms of cost and effort instead.
>  >>
>  >> Transistors and anything inside an IC is only silicon - one of
>  > the
>  >> most abundant elements on Earth. ICs churned out by the
>  > quintillion
>  >> each day
>  >> Compare that with the cost, setting up, delicate mechanism, easy
>  >> damage of an analogue meter
>  >> Who'd ever choose the latter, again






Re: semiconductor technology

militaryoperator
 


Hi Andy,
            My comment was a bit tongue-in-cheek, but it has taken over seventy years of semiconductor development and expensive equipment to get to where we are now whereas a moving coil meter can be made or repaired by a competent watch/instrument maker with hand tools and a simple lathe. ( trouble is finding one these days!) You can also see when a MCM isn't working. I've managed to destroy no end of semiconductors in my time & a lot of them didn't look as though they were damaged. But as you say semis are so cheap to buy now you can incorporate as may as you like for protection. Incidentally the protection diode in my L 23 TVTR did its job of reverse voltage protection ie blew the fuse but failed itself in doing so as it went short circuit. So much for 100's amps peak non-repetitive current!

de John G8SEQ

>  -------Original Message-------
>  From: Paul Randall G3NJV <paulfrandall@...>
>  To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
>  Subject: Re: [UKMicrowaves] Getting indication of rf
>  Sent: Jun 04 '20 23:30

>  "What's this got to do with"
>  Maybe nothing, but .... keep the lines open so anyone can post without
>  fear.

>  -------------------------

>  FROM: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of
>  Andy G4JNT <andy.g4jnt@...>
>  SENT: 04 June 2020 22:47
>  TO: UK Microwaves groups.io <UKMicrowaves@groups.io>
>  SUBJECT: Re: [UKMicrowaves] Getting indication of rf

>  But one purification cycle gives the raw materials for tens of
>  thousands of chips. May even be 100s of k devices - does anyone have
>  figures?
>  So it's hardly a 'lot' of energy.

>  When the design already exists and the IP is made available, they're
>  pretty easy to get made too. Look at the story of the reincarnation of
>  the old SL6270 VOGAD chip.

>  And this myth about static sensitivity.
>  OK, back in the dark ages of the 1970s, perhaps into the 1980s even,
>  devices were susceptible and manufacturers weren't as careful as they
>  should have been, but since then they've become orders of magnitude
>  better. It's not just hearsay, I know someone who has worked in the
>  highly specialised field of semiconductor static testing since that
>  era and he has benn very closely involved with and explained the
>  progress made over the years with testing techniques and built in
>  protection.. (He may even be a member of this Group now. Paul, are you
>  there ....?)

>  It's really about time some of these myths of decades ago were
>  forgotten and people looked at the real state of electronics today.
>  Trouble is, there are so few young electronics graduates in our Am.
>  Rad. ranks now to tell the story ...

>  BTW, I connected a chunky 5V power supply the wrong way round to a PIC
>  processor once. It current limited at 3A and current must have passed
>  for perhaps half a second, most of i- going through the device WHICH
>  SURVIVED to carry on working. What happened is that every I/O line and
>  there were over 20 of them had reverse biassed diodes (for transient
>  and over voltage protection) to ground and the supply rail. With the
>  supply reversed all these diodes forward conducted, in parallel, and
>  were able to able to sink that 3A for the duration. But longer and
>  bond wires might have popped. But the chip subsequently worked.

>  What's this got to do with the subject line of RF Indication - I
>  dunno, but it's a good waffle anyway. Back to the G+T

>  Andy
www.g4jnt.com

>  On Thu, 4 Jun 2020 at 22:11, John E. Beech <john@...> wrote:

>  > Problem is that most silicon is locked up as silicon dioxide.
>  > Extracting it and purifying so that it can be made precisely impure
>  > enough to make it semi-conduct takes an enormous amount of energy
>  > and effort and exactly how robust are they? They don't like it up
>  > 'em Mr Mainwaring! Voltage spikes that is.
>  >
>  > de John G8SEQ
>  >
>  >> -------Original Message-------
>  >> From: Andy G4JNT <andy.g4jnt@...>
>  >> To: UK Microwaves groups.io <UKMicrowaves@groups.io>
>  >> Subject: Re: [UKMicrowaves] Getting indication of rf
>  >> Sent: Jun 04 '20 14:42
>  >>
>  >> Think of it in terms of cost and effort instead.
>  >>
>  >> Transistors and anything inside an IC is only silicon - one of
>  > the
>  >> most abundant elements on Earth. ICs churned out by the
>  > quintillion
>  >> each day
>  >> Compare that with the cost, setting up, delicate mechanism, easy
>  >> damage of an analogue meter
>  >> Who'd ever choose the latter, again






Re: Getting indication of rf

John E. Beech
 

Hi Andy,
My comment was a bit tongue-in-cheek, but it has taken over seventy years of semiconductor development and expensive equipment to get to where we are now whereas a moving coil meter can be made or repaired by a competent watch/instrument maker with hand tools and a simple lathe. ( trouble is finding one these days!) You can also see when a MCM isn't working. I've managed to destroy no end of semiconductors in my time & a lot of them didn't look as though they were damaged. But as you say semis are so cheap to buy now you can incorporate as may as you like for protection. Incidentally the protection diode in my L 23 TVTR did its job of reverse voltage protection ie blew the fuse but failed itself in doing so as it went short circuit. So much for 100's amps peak non-repetitive current!

de John G8SEQ

-------Original Message-------
From: Paul Randall G3NJV <paulfrandall@hotmail.com>
To: UKMicrowaves@groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Getting indication of rf
Sent: Jun 04 '20 23:30

"What's this got to do with"
Maybe nothing, but .... keep the lines open so anyone can post without
fear.

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

FROM: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of
Andy G4JNT <andy.g4jnt@gmail.com>
SENT: 04 June 2020 22:47
TO: UK Microwaves groups.io <UKMicrowaves@groups.io>
SUBJECT: Re: [UKMicrowaves] Getting indication of rf

But one purification cycle gives the raw materials for tens of
thousands of chips. May even be 100s of k devices - does anyone have
figures?
So it's hardly a 'lot' of energy.

When the design already exists and the IP is made available, they're
pretty easy to get made too. Look at the story of the reincarnation of
the old SL6270 VOGAD chip.

And this myth about static sensitivity.
OK, back in the dark ages of the 1970s, perhaps into the 1980s even,
devices were susceptible and manufacturers weren't as careful as they
should have been, but since then they've become orders of magnitude
better. It's not just hearsay, I know someone who has worked in the
highly specialised field of semiconductor static testing since that
era and he has benn very closely involved with and explained the
progress made over the years with testing techniques and built in
protection.. (He may even be a member of this Group now. Paul, are you
there ....?)

It's really about time some of these myths of decades ago were
forgotten and people looked at the real state of electronics today.
Trouble is, there are so few young electronics graduates in our Am.
Rad. ranks now to tell the story ...

BTW, I connected a chunky 5V power supply the wrong way round to a PIC
processor once. It current limited at 3A and current must have passed
for perhaps half a second, most of i- going through the device WHICH
SURVIVED to carry on working. What happened is that every I/O line and
there were over 20 of them had reverse biassed diodes (for transient
and over voltage protection) to ground and the supply rail. With the
supply reversed all these diodes forward conducted, in parallel, and
were able to able to sink that 3A for the duration. But longer and
bond wires might have popped. But the chip subsequently worked.

What's this got to do with the subject line of RF Indication - I
dunno, but it's a good waffle anyway. Back to the G+T

Andy
www.g4jnt.com

On Thu, 4 Jun 2020 at 22:11, John E. Beech <john@g8seq.com> wrote:

> Problem is that most silicon is locked up as silicon dioxide.
> Extracting it and purifying so that it can be made precisely impure
> enough to make it semi-conduct takes an enormous amount of energy
> and effort and exactly how robust are they? They don't like it up
> 'em Mr Mainwaring! Voltage spikes that is.
>
> de John G8SEQ
>
>> -------Original Message-------
>> From: Andy G4JNT <andy.g4jnt@gmail.com>
>> To: UK Microwaves groups.io <UKMicrowaves@groups.io>
>> Subject: Re: [UKMicrowaves] Getting indication of rf
>> Sent: Jun 04 '20 14:42
>>
>> Think of it in terms of cost and effort instead.
>>
>> Transistors and anything inside an IC is only silicon - one of
> the
>> most abundant elements on Earth. ICs churned out by the
> quintillion
>> each day
>> Compare that with the cost, setting up, delicate mechanism, easy
>> damage of an analogue meter
>> Who'd ever choose the latter, again


10ghz test sig was: Getting indication of rf

militaryoperator
 

Thanks Robin. 

I'll let you know when I'm ready to test. 

Ben

-----Original Message-----
From: Robin Szemeti - G1YFG <robin@...>
To: UKMicrowaves@groups.io
Sent: Thu, 4 Jun 2020 17:45
Subject: Re: [UKMicrowaves] Getting indication of rf

Let me know if you want a signal on 3cm to test with, I have a 50mw personal beacon and a horn I can point your way and leave on for a day or two, on roughly 10,368.690  ... it has a keyer that sometimes even works ...



Re: Getting indication of rf EXACTLY......

militaryoperator
 


"What's this got to do with"
Maybe nothing, but .... keep the lines open so anyone can post without fear.

What's this got to do with the subject line of RF Indication - I dunno, but it's a good waffle anyway.  Back to the G+T



Folk do realise they can change the subject title don't they?................ 

that way those interested in the old thread can save all the time they use up opening an unrelated message, reading the first line and deleting it. 

Some of us don't have much time left to waste!   (guess who just had another click on the counter!)


Ben


Re: Getting indication of rf

Paul G4KZY
 

The reason why millions if not billions of transistors can fit in a modern IC is that the semiconductor industry has continuously managed to reduce the geometry of ICs to allow more and more devices to fit into an area of silicon.  With the advent of advanced CAD and advanced fabrication methodologies, modern ICs are more like PCBs of 20 or 30 years ago in terms of functionality, complexity and architecture.

The semiconductor industry has frequently broken through barriers where it was said to be impossible to reduce feature sizes due to some fundamental law of physics.  When I started in the industry (in the early 1980s) the talk was about feature sizes going sub-micron.  It was said that much smaller geometries would be impossible because of the wavelength of light causing problems with optical tooling.  We are now using ICs with two orders of magnitude smaller feature sizes.

There are essentially two things which cause semiconductor failure.  One is overvoltage causing damage to very thin oxide layers and the other is overheating.  If you statically charge up an IC to, say, 500V and then drop it on a metal surface you will get a current pulse going through the device of the order of 1A to 10A which lasts less than a ns.  The size of the pulse depends on the amount of stored charge, which in turn depends on the capacitance of the device to ground when it was charged.  A current pulse through an IC in the range of several amps causes quite a big voltage drop across junctions, which can easily puncture through the very thin oxide layers.

ESD is said to be one of the top three issues facing the modern semiconductor industry.

For overheating, as geometries decrease the amount of power required to melt the increasingly smaller areas of silicon becomes less and less.

The IC designers put quite a lot of effort towards designing protection circuits into their ICs to clamp the internal voltages and protect the devices from overvoltages of various types, including ESD.  If your IC fails, it is probable that a protection circuit is the location of the failure, by being overwhelmed (by too much current flowing over too long a time).

Bearing all this in mind, ICs are amazingly reliable these days.  If you get a power supply capable of delivering tens of watts and use it to overvoltage an IC then of course it will fail.  But it is very uncommon nowadays to have an IC fail when it has not been abused in some way.

I expect your 100uA moving coil meter would suffer a similar fate if you hit it with a few amps.

73 to all,

Paul G4KZY


Re: Getting indication of rf

Wilko
 

I once mistreated an UV-EPROM. You know, the ones with the quartz window to allow erasure. I saw a glowing bonding wire.. But believe it or not: it did survive this ordeal 😳😳 Copied its contents to a fresh EPROM to be safe, left the original one in-circuit. Never broke down.

Inpressive..

Wilko


Re: Activity List for the UK Microwave Group Low Band Contest - Sunday June 7th

Andy G4JNT
 

Callsign      G4JNT
Loc.           IO90IV58
Band         3400MHz 8W  15dBi Horn
Talkback    KST and phone 01489 787424


On 31/05/2020 23:32, John Quarmby via groups.io wrote:
> The fourth in the series of UKuG Low Band events takes place next
> Sunday 7th June, from  1000 to 1600 GMT (1000 - 1700 BST), on the
> 1296, 2300, 2320, and 3400MHz bands.
>
> This contest is partially coincident with the IARU Region 1
> coordinated Microwave Contest that takes place from 1400 GMT Saturday
> to 1400 GMT Sunday.
>
> I will put together an activity list next Saturday, please post your
> operating plans in the usual format:
>


Re: Activity List for the UK Microwave Group Low Band Contest - Sunday June 7th

Martyn G3UKV
 

Callsign : G3UKV
Locator: IO82RR
Bands: 1296MHz 80W, 35 ele
             2320MHz 55W 90cm dish
              3400MHz 15W 90cm dish
Talkback:  ON4KST & Direct
Times: Various. 9cm last hour or so.

73 Martyn G3UKV

On 31/05/2020 23:32, John Quarmby via groups.io wrote:
The fourth in the series of UKuG Low Band events takes place next Sunday 7th June, from  1000 to 1600 GMT (1000 - 1700 BST), on the 1296, 2300, 2320, and 3400MHz bands.

This contest is partially coincident with the IARU Region 1 coordinated Microwave Contest that takes place from 1400 GMT Saturday to 1400 GMT Sunday.

I will put together an activity list next Saturday, please post your operating plans in the usual format:

Callsign : G3XDY
Locator: JO02OB
Bands: 1296MHz 400W 4x 23el
             2300/2320MHz 200W 0.8m dish
              3400MHz 20W 0.8m dish
Talkback: Direct CQ on 1296MHz or via ON4KST
Times: Various throughout

73

John G3XDY

--
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Re: I want to document some RF techniques, help please

Robin Szemeti - G1YFG
 

Coupling loops are covered in Chapter 7 of the online book I linked you to.

On Fri, 5 Jun 2020 at 00:53, Alan Beard <beardal@...> wrote:
Actually Robin,

The cavities are not the problem. For my four RFS (Radio Frequency Systems or AEA) cavities, 
I tapped the end of the plunger, three holes, made a 100mm x 80mm cylinder and attached it
onto the plunger - done.

Back to the problem: Where do I find an article that has diagrams or pictures of ALL
coupling loop types or even capacitive coupling?

WE HAVE TO WRITE IT or there isn't one.

Alan VK2ZIW

On Fri, 5 Jun 2020 00:05:31 +0100, Robin Szemeti - G1YFG wrote
> What split are you trying to achieve with 4 cavities?   Also, getting a 75MHz cavity down to 6m (50MHz) is going to be a big challenge, I don't think they will tune that far. You may have to build a new set from scratch ... alloy outer tubes, copper resonator and a invar steel compensator are the way to go ...  unless they are helical filters, you want something a little over 1/4 wave long  that's going to be a fairly big cavity!
>
> Generally for the amateur splits (0.6m on 144, 1.6 on 432) you need 6 cavities ... you cannot get decent performance with 4 for the typical splits we use. 4 would probably manage a 600kc split on  50mhz .. depending on the quality of the cavities.  
>
> I'd go for 6 cavities .. the first as a bandpass ... 3 per side ... first one tuned as a bandpass, no top cap/inductor ... and then 2 notches.   Put a 2 port isolator between the TX and the first cavity,
>
> On Thu, 4 Jun 2020 at 23:23, Alan Beard <beardal@...> wrote:
>

> Thanks Robin,
>
>

> The w6nbc-duplexer-book/ch3 to 9.html pages are good general information 
> and the tuning YouTube video is good for tuning.
>
> However, when your small club wants a 6m repeater and you are presented
> with four 75MHz six inch cavities with one side entry port on each, how do you proceed?
>
> First, you'd like to find ALL coupling techniques possible.
> John W6NBC does not mention in two port cavities, capacitive coupling at the hot end.
> In his BpBr diagrams, an L or C between the ports is mentioned to swap
> the pass and notch. What about swapping the phase of one of the loops?
>
> How about the RxTx Vari-Notch, a parallel L and C between two connectors?
>
> I've provided a document in "Files" exploring as many as I know of the techniques,
> I want any incite here please?
> And here, a PICTURE speaks a THOUSAND words.
> (or a detailed diagram)
>
> Alan VK2ZIW
>  
>
>

> On Mon, 1 Jun 2020 10:16:33 +0100, Robin Szemeti - G1YFG wrote
> > Try this: http://www.repeater-builder.com/antenna/w6nbc-duplexer-book/ch3.html
> >
> > And a couple of good YouTube videos on the subject:
> >
> > https://www.youtube.com/watch?v=NKw6-x4gFJI
> >
> > https://www.youtube.com/watch?v=2Y1aMhCcxXY
> >
> > The problem may be that you are trying to achieve a narrower spacing than the notch is set up for, if you are trying to achieve a 1.6 MHz spacing from a setup deigned for a 5MHz spacing there may not be enough range on the trimmers to move the notch where you want it to be.   You will struggle to achieve 1.6MHz spacing on 2 cavities a side .. 3 is the minimum and 4 is better.
> >
>
> ---------------------------------------------------
> Alan Beard
>
> OpenWebMail 2.53
>
>
>
>


> --
>
>
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.


---------------------------------------------------
Alan Beard

OpenWebMail 2.53



--
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: I want to document some RF techniques, help please

Alan Beard
 

Actually Robin,

The cavities are not the problem. For my four RFS (Radio Frequency Systems or AEA) cavities, 
I tapped the end of the plunger, three holes, made a 100mm x 80mm cylinder and attached it
onto the plunger - done.

Back to the problem: Where do I find an article that has diagrams or pictures of ALL
coupling loop types or even capacitive coupling?

WE HAVE TO WRITE IT or there isn't one.

Alan VK2ZIW

On Fri, 5 Jun 2020 00:05:31 +0100, Robin Szemeti - G1YFG wrote
> What split are you trying to achieve with 4 cavities?   Also, getting a 75MHz cavity down to 6m (50MHz) is going to be a big challenge, I don't think they will tune that far. You may have to build a new set from scratch ... alloy outer tubes, copper resonator and a invar steel compensator are the way to go ...  unless they are helical filters, you want something a little over 1/4 wave long  that's going to be a fairly big cavity!
>
> Generally for the amateur splits (0.6m on 144, 1.6 on 432) you need 6 cavities ... you cannot get decent performance with 4 for the typical splits we use. 4 would probably manage a 600kc split on  50mhz .. depending on the quality of the cavities.  
>
> I'd go for 6 cavities .. the first as a bandpass ... 3 per side ... first one tuned as a bandpass, no top cap/inductor ... and then 2 notches.   Put a 2 port isolator between the TX and the first cavity,
>
> On Thu, 4 Jun 2020 at 23:23, Alan Beard <beardal@...> wrote:
>

> Thanks Robin,
>
>

> The w6nbc-duplexer-book/ch3 to 9.html pages are good general information 
> and the tuning YouTube video is good for tuning.
>
> However, when your small club wants a 6m repeater and you are presented
> with four 75MHz six inch cavities with one side entry port on each, how do you proceed?
>
> First, you'd like to find ALL coupling techniques possible.
> John W6NBC does not mention in two port cavities, capacitive coupling at the hot end.
> In his BpBr diagrams, an L or C between the ports is mentioned to swap
> the pass and notch. What about swapping the phase of one of the loops?
>
> How about the RxTx Vari-Notch, a parallel L and C between two connectors?
>
> I've provided a document in "Files" exploring as many as I know of the techniques,
> I want any incite here please?
> And here, a PICTURE speaks a THOUSAND words.
> (or a detailed diagram)
>
> Alan VK2ZIW
>  
>
>

> On Mon, 1 Jun 2020 10:16:33 +0100, Robin Szemeti - G1YFG wrote
> > Try this: http://www.repeater-builder.com/antenna/w6nbc-duplexer-book/ch3.html
> >
> > And a couple of good YouTube videos on the subject:
> >
> > https://www.youtube.com/watch?v=NKw6-x4gFJI
> >
> > https://www.youtube.com/watch?v=2Y1aMhCcxXY
> >
> > The problem may be that you are trying to achieve a narrower spacing than the notch is set up for, if you are trying to achieve a 1.6 MHz spacing from a setup deigned for a 5MHz spacing there may not be enough range on the trimmers to move the notch where you want it to be.   You will struggle to achieve 1.6MHz spacing on 2 cavities a side .. 3 is the minimum and 4 is better.
> >
>
> ---------------------------------------------------
> Alan Beard
>
> OpenWebMail 2.53
>
>
>
>


> --
>
>
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.


---------------------------------------------------
Alan Beard

OpenWebMail 2.53


Re: I want to document some RF techniques, help please

Robin Szemeti - G1YFG
 

What split are you trying to achieve with 4 cavities?   Also, getting a 75MHz cavity down to 6m (50MHz) is going to be a big challenge, I don't think they will tune that far. You may have to build a new set from scratch ... alloy outer tubes, copper resonator and a invar steel compensator are the way to go ...  unless they are helical filters, you want something a little over 1/4 wave long  that's going to be a fairly big cavity!

Generally for the amateur splits (0.6m on 144, 1.6 on 432) you need 6 cavities ... you cannot get decent performance with 4 for the typical splits we use. 4 would probably manage a 600kc split on  50mhz .. depending on the quality of the cavities.  

I'd go for 6 cavities .. the first as a bandpass ... 3 per side ... first one tuned as a bandpass, no top cap/inductor ... and then 2 notches.   Put a 2 port isolator between the TX and the first cavity,

On Thu, 4 Jun 2020 at 23:23, Alan Beard <beardal@...> wrote:
Thanks Robin,

The w6nbc-duplexer-book/ch3 to 9.html pages are good general information 
and the tuning YouTube video is good for tuning.

However, when your small club wants a 6m repeater and you are presented
with four 75MHz six inch cavities with one side entry port on each, how do you proceed?

First, you'd like to find ALL coupling techniques possible.
John W6NBC does not mention in two port cavities, capacitive coupling at the hot end.
In his BpBr diagrams, an L or C between the ports is mentioned to swap
the pass and notch. What about swapping the phase of one of the loops?

How about the RxTx Vari-Notch, a parallel L and C between two connectors?

I've provided a document in "Files" exploring as many as I know of the techniques,
I want any incite here please?
And here, a PICTURE speaks a THOUSAND words.
(or a detailed diagram)

Alan VK2ZIW
 

On Mon, 1 Jun 2020 10:16:33 +0100, Robin Szemeti - G1YFG wrote
> Try this: http://www.repeater-builder.com/antenna/w6nbc-duplexer-book/ch3.html
>
> And a couple of good YouTube videos on the subject:
>
> https://www.youtube.com/watch?v=NKw6-x4gFJI
>
> https://www.youtube.com/watch?v=2Y1aMhCcxXY
>
> The problem may be that you are trying to achieve a narrower spacing than the notch is set up for, if you are trying to achieve a 1.6 MHz spacing from a setup deigned for a 5MHz spacing there may not be enough range on the trimmers to move the notch where you want it to be.   You will struggle to achieve 1.6MHz spacing on 2 cavities a side .. 3 is the minimum and 4 is better.
>

---------------------------------------------------
Alan Beard

OpenWebMail 2.53



--
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: Getting indication of rf

Paul Randall G3NJV
 

"What's this got to do with"
Maybe nothing, but .... keep the lines open so anyone can post without fear.




From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> on behalf of Andy G4JNT <andy.g4jnt@...>
Sent: 04 June 2020 22:47
To: UK Microwaves groups.io <UKMicrowaves@groups.io>
Subject: Re: [UKMicrowaves] Getting indication of rf
 
But one purification cycle gives the raw materials for tens of thousands of chips.  May even be 100s of k devices - does anyone have figures?
So it's hardly a 'lot' of energy.

When the design already exists and the IP is made available, they're pretty easy to get made too.  Look at the story of the reincarnation of the old SL6270 VOGAD chip.

And this myth about static sensitivity.
OK, back in the dark ages of the 1970s, perhaps into the 1980s even, devices were susceptible and manufacturers weren't as careful as they should have been, but since then they've become orders of magnitude better.  It's not just  hearsay, I know someone who has worked in the highly specialised field of semiconductor static testing since that era and he has benn very closely involved with and  explained the progress made over the years with testing techniques and built in protection..  (He may even be a member of this Group now.  Paul, are you there ....?) 

It's really about time some of these myths of decades ago were forgotten and people looked at the real state of electronics today.   Trouble is, there are so few young electronics graduates in our Am. Rad. ranks now to tell the story ...

BTW, I connected a chunky 5V power supply the wrong way round to a PIC processor once.   It current limited at 3A and current must have passed for perhaps half a second, most of i- going through the device WHICH SURVIVED to carry on working.  What happened is that every I/O line and there were over 20 of them had reverse biassed diodes (for transient and over voltage protection) to ground and the supply rail. With the supply reversed all these diodes forward conducted, in parallel, and were able to able to sink that 3A  for the duration.  But longer and bond wires might have popped.  But the chip subsequently worked.

What's this got to do with the subject line of RF Indication - I dunno, but it's a good waffle anyway.  Back to the G+T



On Thu, 4 Jun 2020 at 22:11, John E. Beech <john@...> wrote:
Problem is that most silicon is locked up as silicon dioxide. Extracting it and purifying so that it can be made precisely impure enough to make it semi-conduct takes an enormous amount of energy and effort and exactly how robust are they? They don't like it up 'em Mr Mainwaring! Voltage spikes that is.

de John G8SEQ

>  -------Original Message-------
>  From: Andy G4JNT <andy.g4jnt@...>
>  To: UK Microwaves groups.io <UKMicrowaves@groups.io>
>  Subject: Re: [UKMicrowaves] Getting indication of rf
>  Sent: Jun 04 '20 14:42

>  Think of it in terms of cost and effort instead.

>  Transistors and anything inside an IC is only silicon - one of the
>  most abundant elements on Earth. ICs churned out by the quintillion
>  each day
>  Compare that with the cost, setting up, delicate mechanism, easy
>  damage of an analogue meter
>  Who'd ever choose the latter, again




Re: I want to document some RF techniques, help please

Alan Beard
 

Thanks Robin,

The w6nbc-duplexer-book/ch3 to 9.html pages are good general information 
and the tuning YouTube video is good for tuning.

However, when your small club wants a 6m repeater and you are presented
with four 75MHz six inch cavities with one side entry port on each, how do you proceed?

First, you'd like to find ALL coupling techniques possible.
John W6NBC does not mention in two port cavities, capacitive coupling at the hot end.
In his BpBr diagrams, an L or C between the ports is mentioned to swap
the pass and notch. What about swapping the phase of one of the loops?

How about the RxTx Vari-Notch, a parallel L and C between two connectors?

I've provided a document in "Files" exploring as many as I know of the techniques,
I want any incite here please?
And here, a PICTURE speaks a THOUSAND words.
(or a detailed diagram)

Alan VK2ZIW
 

On Mon, 1 Jun 2020 10:16:33 +0100, Robin Szemeti - G1YFG wrote
> Try this: http://www.repeater-builder.com/antenna/w6nbc-duplexer-book/ch3.html
>
> And a couple of good YouTube videos on the subject:
>
> https://www.youtube.com/watch?v=NKw6-x4gFJI
>
> https://www.youtube.com/watch?v=2Y1aMhCcxXY
>
> The problem may be that you are trying to achieve a narrower spacing than the notch is set up for, if you are trying to achieve a 1.6 MHz spacing from a setup deigned for a 5MHz spacing there may not be enough range on the trimmers to move the notch where you want it to be.   You will struggle to achieve 1.6MHz spacing on 2 cavities a side .. 3 is the minimum and 4 is better.
>

---------------------------------------------------
Alan Beard

OpenWebMail 2.53

7981 - 8000 of 64053