Last days of the 172s on the electrified GOBLIN
 

On Thu, 25 Jan 2018 14:36:54 -0600
wrote:
In article
-september
..org, (Recliner) wrote:
By your logic, TfL should have ordered more of the proven, in-service
313s, not the dangerously new-fangled 378s, when increasing the LO fleet.

In fact, with modern manufacturing, especially where electronics are
involved, technology can move on to the point where obsolete design
manufacture is no longer affordable because the machinery is no longer
available.

This happened in the late 1990s with the radios used for RETB signalling.
Railtrack wanted more of an obsolete design of the radios which used a form
of electronics which was no longer makeable, more or less at any price. This

That sounds highly unlikely. You can still buy chips designed in the 70s
if you so desi

https://www.digikey.co.uk/catalog/en...roup/z80/15507

so the chances of whatever microcontroller the radios used being unavailable
is pretty slim. Plus the analogue radio components and op-amps will always be
available until someone invents usable optotronics. More than likely the cost
of redesigning the board for SMDs was more than railtrack was prepared to pay.

Last days of the 172s on the electrified GOBLIN
 

In message , at 09:47:43 on Fri, 26 Jan
2018, remarked:

You can still buy

a subset of

chips designed in the 70s if you so desi

Hence stories about NASA having to scour eBay for some parts need for
maintaining legacy equipment.
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

In article , () wrote:

On Thu, 25 Jan 2018 14:36:54 -0600
wrote:
In article
-s
eptember.org, (Recliner) wrote:
By your logic, TfL should have ordered more of the proven, in-service
313s, not the dangerously new-fangled 378s, when increasing the LO
fleet.

In fact, with modern manufacturing, especially where electronics are
involved, technology can move on to the point where obsolete design
manufacture is no longer affordable because the machinery is no longer
available.

This happened in the late 1990s with the radios used for RETB signalling.
Railtrack wanted more of an obsolete design of the radios which used a
form of electronics which was no longer makeable, more or less at any
price.

That sounds highly unlikely. You can still buy chips designed in the
70s if you so desi

https://www.digikey.co.uk/catalog/en...roup/z80/15507

But you can't create the circuit boards and assemble them at affordable
costs. Repairing existing boards is another matter. There is an established
cottage industry that kept similar radios in use on the NRN until it was
switched off.

so the chances of whatever microcontroller the radios used being
unavailable is pretty slim. Plus the analogue radio components and op-amps
will always be available until someone invents usable optotronics. More
than likely the cost of redesigning the board for SMDs was more than
railtrack was prepared to pay.

So you know more than a multi-national radio manufacturing company? It's a
true story, as told to me by our salesman to Railtrack at the time.

The problem was the cost and time taken to get new technology-based radios
type approved for use in the small quantities needed for the areas of RETB
signalling.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

On Fri, 26 Jan 2018 12:02:51 +0000
Roland Perry wrote:
In message , at 09:47:43 on Fri, 26 Jan
2018, remarked:

You can still buy

a subset of

chips designed in the 70s if you so desi

Hence stories about NASA having to scour eBay for some parts need for
maintaining legacy equipment.

NASA tends not to use off the shelf parts.

Last days of the 172s on the electrified GOBLIN
 

On Fri, 26 Jan 2018 06:32:11 -0600
wrote:
In article , () wrote:
That sounds highly unlikely. You can still buy chips designed in the
70s if you so desi

https://www.digikey.co.uk/catalog/en...roup/z80/15507

But you can't create the circuit boards and assemble them at affordable
costs.

Which is what I said.

so the chances of whatever microcontroller the radios used being
unavailable is pretty slim. Plus the analogue radio components and op-amps
will always be available until someone invents usable optotronics. More
than likely the cost of redesigning the board for SMDs was more than
railtrack was prepared to pay.

So you know more than a multi-national radio manufacturing company? It's a
true story, as told to me by our salesman to Railtrack at the time.

Told to you by a salesman? Oh well, it MUST be true then.

Last days of the 172s on the electrified GOBLIN
 

In message , at 14:22:42 on Fri, 26 Jan
2018, remarked:

You can still buy

a subset of

chips designed in the 70s if you so desi

Hence stories about NASA having to scour eBay for some parts need for
maintaining legacy equipment.

NASA tends not to use off the shelf parts.

The ones in question are, otherwise they'd not be on eBay [as a result
of someone breaking up some old equipment and selling whatever they can
dis-assemble as spares].

Often they are things as boring as specific versions of a generic
processor or memory chip, which come in thousands of different variants.
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

On Fri, 26 Jan 2018 14:46:42 +0000
Roland Perry wrote:
In message , at 14:22:42 on Fri, 26 Jan
2018, remarked:

You can still buy

a subset of

chips designed in the 70s if you so desi

Hence stories about NASA having to scour eBay for some parts need for
maintaining legacy equipment.

NASA tends not to use off the shelf parts.

The ones in question are, otherwise they'd not be on eBay [as a result
of someone breaking up some old equipment and selling whatever they can
dis-assemble as spares].

Often they are things as boring as specific versions of a generic
processor or memory chip, which come in thousands of different variants.

Be that as it may, I doubt a GPRS radio used such obscure parts that they
were unavailable a decade later.

Last days of the 172s on the electrified GOBLIN
 

In message , at 15:34:23 on Fri, 26 Jan
2018, remarked:
You can still buy

a subset of

chips designed in the 70s if you so desi

Hence stories about NASA having to scour eBay for some parts need for
maintaining legacy equipment.

NASA tends not to use off the shelf parts.

The ones in question are, otherwise they'd not be on eBay [as a result
of someone breaking up some old equipment and selling whatever they can
dis-assemble as spares].

Often they are things as boring as specific versions of a generic
processor or memory chip, which come in thousands of different variants.

Be that as it may, I doubt a GPRS radio used such obscure parts that they
were unavailable a decade later.

Everyone familiar with the specific project has told you otherwise.
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

In article , (Roland Perry)
wrote:

In message , at 15:34:23 on Fri, 26 Jan
2018, remarked:
You can still buy

a subset of

chips designed in the 70s if you so desi

Hence stories about NASA having to scour eBay for some parts need for
maintaining legacy equipment.

NASA tends not to use off the shelf parts.

The ones in question are, otherwise they'd not be on eBay [as a result
of someone breaking up some old equipment and selling whatever they can
dis-assemble as spares].

Often they are things as boring as specific versions of a generic
processor or memory chip, which come in thousands of different
variants.

Be that as it may, I doubt a GPRS radio used such obscure parts that they
were unavailable a decade later.

Everyone familiar with the specific project has told you otherwise.

The RETB radios weren't GPRS for a start.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

In article , () wrote:

On Fri, 26 Jan 2018 06:32:11 -0600
wrote:
In article , () wrote:
That sounds highly unlikely. You can still buy chips designed in the
70s if you so desi

https://www.digikey.co.uk/catalog/en...roup/z80/15507

But you can't create the circuit boards and assemble them at affordable
costs.

Which is what I said.

so the chances of whatever microcontroller the radios used being
unavailable is pretty slim. Plus the analogue radio components and
op-amps will always be available until someone invents usable
optotronics. More than likely the cost of redesigning the board for
SMDs was more than railtrack was prepared to pay.

So you know more than a multi-national radio manufacturing company? It's
a true story, as told to me by our salesman to Railtrack at the time.

Told to you by a salesman? Oh well, it MUST be true then.

He was an engineer who maintained the company's relationship with the
railway. We made all the NRN radios in the 1980s and 1990s (at least all
those I've seen in cabs on depot visits in recent years). I worked there for
over 25 years so knew a lot about how the kit was manufactured.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

On Fri, 26 Jan 2018 17:32:28 -0600
wrote:
In article , () wrote:

On Fri, 26 Jan 2018 06:32:11 -0600
wrote:
In article , () wrote:
That sounds highly unlikely. You can still buy chips designed in the
70s if you so desi

https://www.digikey.co.uk/catalog/en...roup/z80/15507

But you can't create the circuit boards and assemble them at affordable
costs.

Which is what I said.

so the chances of whatever microcontroller the radios used being
unavailable is pretty slim. Plus the analogue radio components and
op-amps will always be available until someone invents usable
optotronics. More than likely the cost of redesigning the board for
SMDs was more than railtrack was prepared to pay.

So you know more than a multi-national radio manufacturing company? It's
a true story, as told to me by our salesman to Railtrack at the time.

Told to you by a salesman? Oh well, it MUST be true then.

He was an engineer who maintained the company's relationship with the
railway. We made all the NRN radios in the 1980s and 1990s (at least all
those I've seen in cabs on depot visits in recent years). I worked there for
over 25 years so knew a lot about how the kit was manufactured.

You'll know then which components were impossible to source. Feel free to fill
us in on which ones they were.

Last days of the 172s on the electrified GOBLIN
 

In article , () wrote:

On Fri, 26 Jan 2018 17:32:28 -0600
wrote:
In article , () wrote:

On Fri, 26 Jan 2018 06:32:11 -0600
wrote:
In article , ()
wrote:
That sounds highly unlikely. You can still buy chips designed in the
70s if you so desi

https://www.digikey.co.uk/catalog/en...roup/z80/15507

But you can't create the circuit boards and assemble them at
affordable costs.
Which is what I said.

so the chances of whatever microcontroller the radios used being
unavailable is pretty slim. Plus the analogue radio components and
op-amps will always be available until someone invents usable
optotronics. More than likely the cost of redesigning the board for
SMDs was more than railtrack was prepared to pay.

So you know more than a multi-national radio manufacturing company?
It's a true story, as told to me by our salesman to Railtrack at the
time.

Told to you by a salesman? Oh well, it MUST be true then.

He was an engineer who maintained the company's relationship with the
railway. We made all the NRN radios in the 1980s and 1990s (at least all
those I've seen in cabs on depot visits in recent years). I worked there
for over 25 years so knew a lot about how the kit was manufactured.

You'll know then which components were impossible to source. Feel free to
fill us in on which ones they were.

As I've said more than once it wasn't a components problem. It's that the
boards were unmanufacturable at any affordable price. They needed
redesigning for modern components and assembly methods which meant starting
the approval process all over again from scratch.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

In message , at 05:58:57
on Mon, 29 Jan 2018, remarked:

You'll know then which components were impossible to source. Feel free to
fill us in on which ones they were.

As I've said more than once it wasn't a components problem. It's that the
boards were unmanufacturable at any affordable price. They needed
redesigning for modern components

I think Spud wants to know why they couldn't use the old boards with the
*old* components.
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

In article , (Roland Perry)
wrote:

In message , at
05:58:57 on Mon, 29 Jan 2018, remarked:

You'll know then which components were impossible to source. Feel free
to fill us in on which ones they were.

As I've said more than once it wasn't a components problem. It's that the
boards were unmanufacturable at any affordable price. They needed
redesigning for modern components

I think Spud wants to know why they couldn't use the old boards with
the *old* components.

What old boards? They would have to be made and assembled from scratch, an
unaffordable prospect for the additional radios Railtrack wanted.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

In message , at 12:25:30
on Mon, 29 Jan 2018, remarked:

You'll know then which components were impossible to source. Feel free
to fill us in on which ones they were.

As I've said more than once it wasn't a components problem. It's that the
boards were unmanufacturable at any affordable price. They needed
redesigning for modern components

I think Spud wants to know why they couldn't use the old boards with
the *old* components.

What old boards? They would have to be made and assembled from scratch, an
unaffordable prospect for the additional radios Railtrack wanted.

So we may be getting closer - the problem was a lack of boards, not a
lack of components to put on them?
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

In article , (Roland Perry)
wrote:

In message , at
12:25:30 on Mon, 29 Jan 2018, remarked:

You'll know then which components were impossible to source. Feel
free to fill us in on which ones they were.

As I've said more than once it wasn't a components problem. It's that
the boards were unmanufacturable at any affordable price. They needed
redesigning for modern components

I think Spud wants to know why they couldn't use the old boards with
the *old* components.

What old boards? They would have to be made and assembled from scratch,
an unaffordable prospect for the additional radios Railtrack wanted.

So we may be getting closer - the problem was a lack of boards, not a
lack of components to put on them?

Unmanufacturable covers a range of situations.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

On 30/01/2018 00:03, wrote:
In article , (Roland Perry)
wrote:

In message , at
12:25:30 on Mon, 29 Jan 2018, remarked:

You'll know then which components were impossible to source. Feel
free to fill us in on which ones they were.

As I've said more than once it wasn't a components problem. It's that
the boards were unmanufacturable at any affordable price. They needed
redesigning for modern components

I think Spud wants to know why they couldn't use the old boards with
the *old* components.

What old boards? They would have to be made and assembled from scratch,
an unaffordable prospect for the additional radios Railtrack wanted.

So we may be getting closer - the problem was a lack of boards, not a
lack of components to put on them?

Unmanufacturable covers a range of situations.

Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so, or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built again.

Last days of the 172s on the electrified GOBLIN
 

In message , at 09:08:18 on Tue, 30 Jan
2018, Someone Somewhere remarked:
You'll know then which components were impossible to source. Feel
free to fill us in on which ones they were.

As I've said more than once it wasn't a components problem. It's that
the boards were unmanufacturable at any affordable price. They needed
redesigning for modern components

I think Spud wants to know why they couldn't use the old boards with
the *old* components.

What old boards? They would have to be made and assembled from scratch,
an unaffordable prospect for the additional radios Railtrack wanted.

So we may be getting closer - the problem was a lack of boards, not a
lack of components to put on them?
Unmanufacturable covers a range of situations.

Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so, or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built again.

There are whole generations of custom-chips which aren't manufacturable
any more. Either the company which made them originally has gone out of
business/disappeared within another that's not longer in the foundry
business, or the tools and machinery required to produce a new batch
have long since been consigned to the dustbin of history.

A handful of generic chips may still be available, so you could perhaps
get a brand-new Z80 equivalent/clone processor chip to build a replica
Amstrad CPC464, but good luck getting Ferranti or SGS to make you a
fresh one of the ULAs.
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

On 30/01/2018 10:06, Roland Perry wrote:
In message , at 09:08:18 on Tue, 30 Jan
2018, Someone Somewhere remarked:


Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so,Â* or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built again.

There are whole generations of custom-chips which aren't manufacturable
any more. Either the company which made them originally has gone out of
business/disappeared within another that's not longer in the foundry
business, or the tools and machinery required to produce a new batch
have long since been consigned to the dustbin of history.

A handful of generic chips may still be available, so you could perhaps
get a brand-new Z80 equivalent/clone processor chip to build a replica
Amstrad CPC464, but good luck getting Ferranti or SGS to make you a
fresh one of the ULAs.

You could still recreate them with enough time and money - they aren't
made of unobtanium - so it's economics. Now to rebuild the Ferranti fab
may be a ludicrous amount of money, but it's theoretically possible.

Or of course you could use FPGAs to do the same thing these days.

Last days of the 172s on the electrified GOBLIN
 

Someone Somewhere wrote:
On 30/01/2018 10:06, Roland Perry wrote:
In message , at 09:08:18 on Tue, 30 Jan
2018, Someone Somewhere remarked:


Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so,Â* or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built again.

There are whole generations of custom-chips which aren't manufacturable
any more. Either the company which made them originally has gone out of
business/disappeared within another that's not longer in the foundry
business, or the tools and machinery required to produce a new batch
have long since been consigned to the dustbin of history.

A handful of generic chips may still be available, so you could perhaps
get a brand-new Z80 equivalent/clone processor chip to build a replica
Amstrad CPC464, but good luck getting Ferranti or SGS to make you a
fresh one of the ULAs.

You could still recreate them with enough time and money - they aren't
made of unobtanium - so it's economics. Now to rebuild the Ferranti fab
may be a ludicrous amount of money, but it's theoretically possible.

Or of course you could use FPGAs to do the same thing these days.


Would it be feasible to simply emulate all the old electronics and computer
components in software, running on a standard modern commodity CPU? The
modern CPU would be so much faster that it might deliver enough performance
to be able to precisely emulate the timing as well as the behaviour of the
old stuff.

Last days of the 172s on the electrified GOBLIN
 

On 30/01/2018 11:39, Recliner wrote:
Someone Somewhere wrote:
On 30/01/2018 10:06, Roland Perry wrote:
In message , at 09:08:18 on Tue, 30 Jan
2018, Someone Somewhere remarked:


Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so,Â* or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built again.

There are whole generations of custom-chips which aren't manufacturable
any more. Either the company which made them originally has gone out of
business/disappeared within another that's not longer in the foundry
business, or the tools and machinery required to produce a new batch
have long since been consigned to the dustbin of history.

A handful of generic chips may still be available, so you could perhaps
get a brand-new Z80 equivalent/clone processor chip to build a replica
Amstrad CPC464, but good luck getting Ferranti or SGS to make you a
fresh one of the ULAs.

You could still recreate them with enough time and money - they aren't
made of unobtanium - so it's economics. Now to rebuild the Ferranti fab
may be a ludicrous amount of money, but it's theoretically possible.

Or of course you could use FPGAs to do the same thing these days.


Would it be feasible to simply emulate all the old electronics and computer
components in software, running on a standard modern commodity CPU? The
modern CPU would be so much faster that it might deliver enough performance
to be able to precisely emulate the timing as well as the behaviour of the
old stuff.


Presumably there are issues getting it to talk to all the other bits and
the outside world (ie enought I/O pins and level converters etc) but I'm
sure that could be resolved.

What might be harder is proving it is equivalent - particularly for
organisations with a high and detailed safety requirement. You keep
your certification if the thing is exactly the same, but if it changes
you need it to be re-certified which may actually be impossible if the
relevant certification organisation no longer exists or offers that
certification.

Last days of the 172s on the electrified GOBLIN
 

In message , at 11:19:55 on Tue, 30 Jan
2018, Someone Somewhere remarked:

Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so,* or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built again.
There are whole generations of custom-chips which aren't
manufacturable any more. Either the company which made them
originally has gone out of business/disappeared within another that's
not longer in the foundry business, or the tools and machinery
required to produce a new batch have long since been consigned to the
dustbin of history.
A handful of generic chips may still be available, so you could
perhaps get a brand-new Z80 equivalent/clone processor chip to build
a replica Amstrad CPC464, but good luck getting Ferranti or SGS to
make you a fresh one of the ULAs.

You could still recreate them with enough time and money - they aren't
made of unobtanium - so it's economics. Now to rebuild the Ferranti
fab may be a ludicrous amount of money, but it's theoretically possible.

I thought we were discussing things which *were* [claimed to be]
economically feasible. Like restarting Electrostar production.

Or of course you could use FPGAs to do the same thing these days.

If you can reverse engineer the circuitry inside the ULA.

Can you make a radio transceiver out of FPGA's?
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

In message
-sept
ember.org, at 11:39:49 on Tue, 30 Jan 2018, Recliner
remarked:
Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so,* or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built again.

There are whole generations of custom-chips which aren't manufacturable
any more. Either the company which made them originally has gone out of
business/disappeared within another that's not longer in the foundry
business, or the tools and machinery required to produce a new batch
have long since been consigned to the dustbin of history.

A handful of generic chips may still be available, so you could perhaps
get a brand-new Z80 equivalent/clone processor chip to build a replica
Amstrad CPC464, but good luck getting Ferranti or SGS to make you a
fresh one of the ULAs.

You could still recreate them with enough time and money - they aren't
made of unobtanium - so it's economics. Now to rebuild the Ferranti fab
may be a ludicrous amount of money, but it's theoretically possible.

Or of course you could use FPGAs to do the same thing these days.

Would it be feasible to simply emulate all the old electronics and computer
components in software, running on a standard modern commodity CPU? The
modern CPU would be so much faster that it might deliver enough performance
to be able to precisely emulate the timing as well as the behaviour of the
old stuff.

How plausible is a software emulation of an NRN radio, and how would one
get it approved for use?
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

On 30/01/2018 12:41, Roland Perry wrote:

Can you make a radio transceiver out of FPGA's?

Probably not, but you can get SDRs which presumably you can make a radio
tranceiver out of.

However as I said, and as I see you said, getting type approval for such
a thing may be the unobtanium in this sauce.

Last days of the 172s on the electrified GOBLIN
 

Someone Somewhere wrote:
On 30/01/2018 12:41, Roland Perry wrote:

Can you make a radio transceiver out of FPGA's?

Probably not, but you can get SDRs which presumably you can make a radio
tranceiver out of.

And you can make an SDR out of an FPGA. For instance:
http://kiwisdr.com/

You do need a little bit of help with the frontend - ie an analogue
amplifier and ADC. Once you have I/Q samples you can do the rest in
soft-logic (or software). A lot of mobile base stations operate this way.

(You could, in principle, try and do a one-bit ADC using a bare FPGA pin
with an antenna. The gain is such that it won't receive anything but a very
strong signal, which is more likely to be local noise than anything else)

However as I said, and as I see you said, getting type approval for such
a thing may be the unobtanium in this sauce.

Indeed.

Theo

Last days of the 172s on the electrified GOBLIN
 

In article , (Roland Perry)
wrote:

In message
-
september.org, at 11:39:49 on Tue, 30 Jan 2018, Recliner
remarked:
Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so,* or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built
again.

There are whole generations of custom-chips which aren't
manufacturable any more. Either the company which made them originally
has gone out of business/disappeared within another that's not longer
in the foundry business, or the tools and machinery required to
produce a new batch have long since been consigned to the dustbin of
history.

A handful of generic chips may still be available, so you could
perhaps get a brand-new Z80 equivalent/clone processor chip to build
a replica Amstrad CPC464, but good luck getting Ferranti or SGS to
make you a fresh one of the ULAs.

You could still recreate them with enough time and money - they aren't
made of unobtanium - so it's economics. Now to rebuild the Ferranti
fab may be a ludicrous amount of money, but it's theoretically
possible.

Or of course you could use FPGAs to do the same thing these days.

Would it be feasible to simply emulate all the old electronics and
computer components in software, running on a standard modern commodity
CPU? The modern CPU would be so much faster that it might deliver enough
performance to be able to precisely emulate the timing as well as the
behaviour of the old stuff.

How plausible is a software emulation of an NRN radio, and how would
one get it approved for use?

NRN radios weren't the problem. First of all, the later technology FM1000
type was type approved and in widespread use and they were standard enough
for a cottage industry to spring up keeping them going until NRNJ was
switched off recently. The problem was with the more specialised RETB radios
which were never made in such numbers and only used on a few lines, mainly
in the Highlands. Making a scratch-built CPC464 isn't a problem because it
doesn't have to be certified as in conformance to safety standards. RETB
radios are vital railway signalling components with a very strict approvals
regime.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

In article , (Someone
Somewhere) wrote:

On 30/01/2018 12:41, Roland Perry wrote:

Can you make a radio transceiver out of FPGA's?

Probably not, but you can get SDRs which presumably you can make a
radio tranceiver out of.

However as I said, and as I see you said, getting type approval for
such a thing may be the unobtanium in this sauce.

Even if you get a working radio that way you wouldn't have one type approved
to use on the railway. As far as type approval was concerned it would be a
new radio which would require to go through the approval process from
scratch.

If you were going to do that, you might as well use the modern design radio
which would also need type approval but if approved would allow more new
radios readily to be manufactured. In 1998, the type approval process was
too onerous and also unaffordable for the small additional RETB requirement.

--
Colin Rosenstiel

Last days of the 172s on the electrified GOBLIN
 

In message , at 14:55:47
on Tue, 30 Jan 2018, remarked:
Nothing that was manufactered is unmanufacturable - it may not be
reasonably economic to do so,* or in certain cases legislation may
prevent it (lead etc) but if it was built once, it could be built
again.

There are whole generations of custom-chips which aren't
manufacturable any more. Either the company which made them originally
has gone out of business/disappeared within another that's not longer
in the foundry business, or the tools and machinery required to
produce a new batch have long since been consigned to the dustbin of
history.

A handful of generic chips may still be available, so you could
perhaps get a brand-new Z80 equivalent/clone processor chip to build
a replica Amstrad CPC464, but good luck getting Ferranti or SGS to
make you a fresh one of the ULAs.

You could still recreate them with enough time and money - they aren't
made of unobtanium - so it's economics. Now to rebuild the Ferranti
fab may be a ludicrous amount of money, but it's theoretically
possible.

Or of course you could use FPGAs to do the same thing these days.

Would it be feasible to simply emulate all the old electronics and
computer components in software, running on a standard modern commodity
CPU? The modern CPU would be so much faster that it might deliver enough
performance to be able to precisely emulate the timing as well as the
behaviour of the old stuff.

How plausible is a software emulation of an NRN radio, and how would
one get it approved for use?

NRN radios

Typo, I meant RETB

weren't the problem. First of all, the later technology FM1000
type was type approved and in widespread use and they were standard enough
for a cottage industry to spring up keeping them going until NRNJ was
switched off recently. The problem was with the more specialised RETB radios
which were never made in such numbers and only used on a few lines, mainly
in the Highlands. Making a scratch-built CPC464 isn't a problem because it
doesn't have to be certified as in conformance to safety standards.

It *is* a problem, because the custom chip can't be made any more.

RETB radios are vital railway signalling components with a very strict
approvals regime.

Which both of us have mentioned earlier in the thread.
--
Roland Perry

Last days of the 172s on the electrified GOBLIN
 

On 30/01/2018 20:55, wrote:
In article , (Someone
Somewhere) wrote:

On 30/01/2018 12:41, Roland Perry wrote:

Can you make a radio transceiver out of FPGA's?

Probably not, but you can get SDRs which presumably you can make a
radio tranceiver out of.

However as I said, and as I see you said, getting type approval for
such a thing may be the unobtanium in this sauce.

Even if you get a working radio that way you wouldn't have one type approved
to use on the railway. As far as type approval was concerned it would be a
new radio which would require to go through the approval process from
scratch.

If you were going to do that, you might as well use the modern design radio
which would also need type approval but if approved would allow more new
radios readily to be manufactured. In 1998, the type approval process was
too onerous and also unaffordable for the small additional RETB requirement.


Which is what I said and what Roland said....