UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Amateur and Military Radio

Notices

Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

Closed Thread
 
Thread Tools
Old 22nd Jul 2019, 2:40 pm   #1
newlite4
Octode
 
newlite4's Avatar
 
Join Date: Nov 2003
Location: Bath, Somerset, UK.
Posts: 1,804
Default Eddystone 750 digital readout

I am sure that there are those of us with the Eddystone broken dial cord problem, a useable set is used as a last resort because of this. The cord is difficult to replace involving a large strip-down and a tricky cord re-fit. Just wondered if anyone has attempted to couple a frequency meter to the tuned circuit to act as a back-up until a cord replacement is carried out, maybe even becoming a permanent add-on.
Neil
__________________
preserving the recent past, for the distant future.
newlite4 is offline  
Old 26th Jul 2019, 12:41 pm   #2
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 750 digital readout

Hi Neil,

Good luck with that re-stringing- I get your drift there, when overhauling my 750, I was struck by just how fine the bronze (?) wire was, they must have had robot spiders spinning it in Alvechurch!

Taking a "sniff" from a classical simple valve HFO like this takes a little care and thought- enquiries on the 'net will throw up innumerable gurus who will glibly say, "just stick a J-FET source-follower buffer on the LO grid". That's not good enough, maybe it would serve on emitter/source/cathode of a Colpitts/Hartley-type VFO but the stability of the type of oscillator here is very, very critical indeed on both stray capacitance and impedance characteristics of anything connected to it. At the top end of the highest HF band, i.e. around 30MHz with sets like this, even moving a finger around the oscillator components can produce a shift of tens of kHz! Even if this is trimmed out when connecting a buffer, the tiny change in characteristics of any connected device with voltage and temperature can ruin the good oscillator stability of a previously dependable radio. I found a thread on just this subject on Antique Radio Forums regarding an SP-600 that was badly compromised by what seemed to be a "light-touch" oscillator sniffer some time back, but I've been unable to re-find it.

As well as minimal deleterious loading, there's the question of reverse-isolating from what is likely to be a noisy digital device. Simple valve oscillators can have a very clean output and it would be a shame to stir wide-band noise into the mixer from an external device. Cathode/emitter/source followers are poor from this point, boot-strapped buffers are pretty much ruled out and anything using feedback may require care. In the end, I decided that a lightly coupled small pentode with a low anode load would be the best initial approach. (Small implying both low power and low circuit capacitance). I used a DF60 pentode- these were available very cheaply and plentifully a few years ago but this may have changed, my heart sank when I once saw a charleton describing them as "substitute for EF86".... It has a 1.25V (not 1.4V) 50mA filament and is about the size and shape of one of those "Cola bottle" jelly sweets that have been rotting kids' teeth for a few generations now, with a screening coat of paint connected to a filament pin. I fitted it over the gang capacitor oscillator section secured by pushing through a grommet in an oval hole in the piece of angle steel I used, the 0.5pF input capacitor going straight down to the oscillator gang tab by the EF91 LO. I was going to add a two-transistor buffer to low-impedance coax powered by the second coax within a 4-pin S-VHS lead going to the frequency counter (lovely VFD module from China Inc.) but the circuit as illustrated worked fine with a short screened lead from the 750, feeding about 60mV RMS of buffered LO to the counter. Switching the DF60 filament on and off resulted in a pitch-change in 10m SSB reception, implying a few tens of Hz shift but I thought, that's pretty good and now subject to the curse of diminishing returns.... I "stole" about 1mA HT supply from the first mixer's screen grid feed of approximately 70V- this is pretty much negligible, if anything pentode action via the added buffer's screen grid will tend to stabilise the mixer screen-grid supply.

Unfortunately, I didn't take any photos as it was a quickie proof-of-concept that I knocked up a few years ago and then dismantled, the 750 having good enough resolution for HF broadcast usage. I was going to make up a DC filament feed from the 750's 3.15-0-3.15VAC heater supply but prototyping used a single NiMH "D" cell that lasted many hours between charges!

Hope this at least provides a pointer,

Colin
Attached Thumbnails
Click image for larger version

Name:	DF60 Osc buffer.jpg
Views:	207
Size:	73.6 KB
ID:	187368  
turretslug is offline  
Old 26th Jul 2019, 1:07 pm   #3
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 750 digital readout

Forgot to add- the output coupling capacitor is 100pF, a low value was deliberately used to minimise the amount of transient energy that could be coupled into one of these rather nice little counters. Most seem to have a couple of back-to-back SMD Si diodes across the input, but discretion is the better part of valour. The minimum 1st LO frequency of the 750 is 2MHz, 100pF seemed about right impedance-wise. I'll get round to adding that low-impedance succceeding buffer one day! The 0.5pF cylindrical capacitor with long silver-plated leads was from Birkett's stall at a rally long ago, he had bags of about 30 for a quid and I couldn't resist- finding bags of 0.5pF caps seemed like finding bags of phlogiston lol. I'm sure a cm or so of twisted wire would have done fine but this was a physicaly rigid component for this inter-reaching "free-space" situation.

https://www.radiomuseum.org/tubes/tube_5678.html
turretslug is offline  
Old 26th Jul 2019, 1:25 pm   #4
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
Default Re: Eddystone 750 digital readout

Quote:
Originally Posted by turretslug View Post
Taking a "sniff" from a classical simple valve HFO like this takes a little care and thought- enquiries on the 'net will throw up innumerable gurus who will glibly say, "just stick a J-FET source-follower buffer on the LO grid". That's not good enough, maybe it would serve on emitter/source/cathode of a Colpitts/Hartley-type VFO but the stability of the type of oscillator here is very, very critical indeed on both stray capacitance and impedance characteristics of anything connected to it. At the top end of the highest HF band, i.e. around 30MHz with sets like this, even moving a finger around the oscillator components can produce a shift of tens of kHz!
Colin
That's an interesting perspective on things and will be added to my file on adding DFC's to receivers! My on-going "multi-year" rebuild of my HRO eventually plans include the addition of a DFC, and as you say, the fet buffer is fairly ubiquitous, but may well be a sub-optimum solution!

B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.
Bazz4CQJ is offline  
Old 26th Jul 2019, 2:34 pm   #5
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
Default Re: Eddystone 750 digital readout

A sniff around ebay and Google seems to indicate that DF60's are now in shortish supply; not quite unobtainium but not far off.

Someone on the forum was talking recently about the wire-ended Nuvistors (originally of Soviet origin) which seem to be easy to get hold of. I wonder if that might be an alternative possibility in this role, but I recall the RCA 6.3V Nuvistors running quite hot.

Possibly a forum member has a box full of DF60 tucked under their bed?

B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.
Bazz4CQJ is offline  
Old 26th Jul 2019, 2:39 pm   #6
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
Default Re: Eddystone 750 digital readout

Quote:
Originally Posted by Bazz4CQJ View Post
That's an interesting perspective on things and will be added to my file on adding DFC's to receivers! My on-going "multi-year" rebuild of my HRO eventually plans include the addition of a DFC, and as you say, the fet buffer is fairly ubiquitous, but may well be a sub-optimum solution!

B
Given that the HRO's local-osc is quite powerful (when operating on 14MHz it leaked enough third harmonic to cause TVI !) I wouldn't worry too much about the need for much coupling between the LO circuitry and any buffer-stage.

Modern DFCs are surprisingly sensitive - the one I used to have would readily detect the LO of my little AR1000 scanner if I just rested the scanner against the DFC's input-connector.
G6Tanuki is offline  
Old 26th Jul 2019, 2:48 pm   #7
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
Default Re: Eddystone 750 digital readout

Quote:
Originally Posted by G6Tanuki View Post

Given that the HRO's local-osc is quite powerful (when operating on 14MHz it leaked enough third harmonic to cause TVI !) I wouldn't worry too much about the need for much coupling between the LO circuitry and any buffer-stage.
Yes, the HRO did have aspirations to be a transceiver, as my parents frequently told me as they tried to watch Band 2 TV while I was tuning 4-6MHz for my 2m converter .

The American equivalent to the DF60 is the 5678; that may be easier to find.

B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.
Bazz4CQJ is offline  
Old 26th Jul 2019, 4:18 pm   #8
Argus25
No Longer a Member
 
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Eddystone 750 digital readout

Quote:
Originally Posted by newlite4 View Post
Just wondered if anyone has attempted to couple a frequency meter to the tuned circuit to act as a back-up until a cord replacement is carried out, maybe even becoming a permanent add-on.
Neil
There are plenty of frequency counters available with offset options for the IF frequency. I have added frequency counters to most of my coms radios, Eddystone EC-10 and other radios like the ZC1.

Transistor radios require a different approach, those usually need a buffer amplifier if you want to ensure there is zero detectable pull on the the radio's L/O when the counter is attached, for those I even went as far as optical isolation which was better than any multi-stage transistor or fet buffer.(the acid test is to short out the signal at the output connector and see if there is a detectable effect on the L/O frequency)

However, there is a trick that you can use to extract the L/O signal from a valve set, where you do not require to add an active device or buffer amplifier.

It produces only a tiny near fixed offset in the L/O frequency which is easily tweaked out if needed. It simply involves using a very low value coupling capacitor and the capacitance of coaxial cable to form a capacitive divider. As the signal amplitude then is low, the counter may require a broadband amp at it input (I use monolithic amp IC's for that usually). The method applied to extracting the L/O out of a ZC1 radio is described on page 70 of this article:

http://worldphaco.com/uploads/ZC1_MK...R_SUPPLIES.pdf

In this case the signal was sent out a pre-existing connector on the front panel to avoid drilling any new holes.
Argus25 is offline  
Old 26th Jul 2019, 5:38 pm   #9
newlite4
Octode
 
newlite4's Avatar
 
Join Date: Nov 2003
Location: Bath, Somerset, UK.
Posts: 1,804
Default Re: Eddystone 750 digital readout

Thank you everyone for your input on this, it would appear a rather complex matter. Colin, I had not considered the effect of loading causing significant local oscillator drift although I expected some effects, very impressed with your reply. It might be worth trying to hang a sensitive modern digital frequency counter near the vicinity of the local oscillator, as long as I can get a rough idea as to where I am on the scale then that would be sufficient.
Thanks again everyone for your help, some positive ideas there.
Neil
__________________
preserving the recent past, for the distant future.
newlite4 is offline  
Old 26th Jul 2019, 10:51 pm   #10
Argus25
No Longer a Member
 
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Eddystone 750 digital readout

Quote:
Originally Posted by newlite4 View Post
It might be worth trying to hang a sensitive modern digital frequency counter near the vicinity of the local oscillator
Neil

Just another tip here, if you are planning to put the digital counter assembly inside the radio, due to the digital switching in it, it may produce RFI. So a small shielded enclosure helps around the 5 faces at least (if one face has the LED's) soldered up out of thin brass plate is ok and RF bypassed power supply wires too and a coax input feed helps to avoid any interference.
Argus25 is offline  
Old 27th Jul 2019, 12:26 pm   #11
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 750 digital readout

I ended up putting stainless steel mosquito mesh (this has better transmission ratio than standard metal gauze) across the display, as both VFD and LED versions of the Chinese PIC counters are rather hashy because of the display driving. The LCD ones might be better but I haven't tried these, I've never liked the "budget" look of LCD stuff and many can be a bit flaky long-term. No doubt a well-equipped RF lab could prove that pucker copper screening mesh performs better than stainless steel, but the latter is ubiquitous and cheap, and it's only a small area slot in a metal box. It also has an appealing tech look to it!
turretslug is offline  
Old 27th Jul 2019, 12:54 pm   #12
g4aaw pete
Heptode
 
g4aaw pete's Avatar
 
Join Date: Jan 2008
Location: Birchington Kent, UK.
Posts: 595
Default Re: Eddystone 750 digital readout

I've added a cheapo counter, (the type typically costing >£10), to two receivers.

B40 - loose coupling to local oscillator - drove counter easily.

CR100 - had to use much tighter coupling to local oscillator to get enough drive.

Both these receivers use a separate valve for local oscillator.
Attached Thumbnails
Click image for larger version

Name:	DSC_0345 900.jpg
Views:	133
Size:	51.8 KB
ID:	187415  
__________________
Regards
Pete
g4aaw pete is offline  
Old 27th Jul 2019, 12:59 pm   #13
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
Default Re: Eddystone 750 digital readout

I wonder how you plan to physically arrange the DFC Neil? In my HRO project, I'm creating what I refer to as a "set-top box" which is a chassis the same width as the HRO, and which sits on top of it, and will house the DFC and additional features such as a product detector. You can see it in this thread https://www.vintage-radio.net/forum/...d.php?t=141180.

I copied the idea from a guy who did the same thing with an RA17, and it's an interesting way of adding various updates to a vintage receiver without making significant mods to the receiver itself.

B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.
Bazz4CQJ is offline  
Old 27th Jul 2019, 2:26 pm   #14
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 750 digital readout

I like that idea- after all, B40, RA17 and R390A all got external SSB demodulaters and the RA17 famously also various other 19" gizmos including LF converters and HF preselecters. I've got a smart steel box here earmarked as muti-function meter, DFM etc "podule", possibly even clock and shielded-off AMU, for the 750 here involving the IO accessory socket on the rear panel. I could never quite help wincing at those once very expensive and rather nice ex-professional sets that had had the front panel gouged up to fit a sixpenny Far Eastern plastic "S-meter"! Much more couth to have an externally-boxed add-on that saves too much internal alteration to what is now becoming classic stuff.
turretslug is offline  
Old 27th Jul 2019, 8:11 pm   #15
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
Default Re: Eddystone 750 digital readout

As regards RFI from an in-receiver digital frequency display, I never had any issues regarding this when I used an Ambit "DFM7" kit [which used the nice little LCD FC177, which conveniently allows you to add diodes in various places to select the necessary frequency-offset].

LCD counters need only a few Microamps of power - meaning they're not switching/multiplexing significant current and so are intrinsically a lot quieter than old-style LED counters using TTL dividers etc.

One thing to watch though - quite a few frequency-counters have a long 'settle-time' meaning their display tends to be slow to catch-up when you change frequency. This can be really annoying - even back in the 1960s they got-round this by driving the Nixie-tube frequency-displays on professional receivers not by counting the actual VFO frequency but by using binary data from the encoder-switches that also fed the loop divider-chain.
G6Tanuki is offline  
Old 27th Jul 2019, 8:41 pm   #16
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 750 digital readout

Quote:
Originally Posted by g4aaw pete View Post
I've added a cheapo counter, (the type typically costing >£10), to two receivers.

B40 - loose coupling to local oscillator - drove counter easily.

CR100 - had to use much tighter coupling to local oscillator to get enough drive.

Both these receivers use a separate valve for local oscillator.
I first tried making an LO sniffer with a CR100, ISTR it consisted of a 2N3189 source follower feeding a BCY70 with a low collector load and a fair amount of current, the FET being fed by a couple of turns of insulated wire around a grid connection. This showed me just how critical even slight extra capacitance was to both calibration and stability, and also getting a good frequency response from a buffer. CR100 afficionados will recall that the wide tuning ratio means that very small trimmer capacitance changes makes a big change to HF-end calibration, the top 3 ranges being set by selected low-pF fixed capacitors as built.

Shifting this technique to the spookily-stable AR88 from the happy-to-wander CR100 showed even more starkly that a stable radio can be degraded by what is cheek-to-cheek with the original LO implementation. I'll plead guilty to a degree of perfectionism, but I always feel that add-ons should be a genuine enhancement!

That CR100 looks as though it is tuned to The Buzzer
turretslug is offline  
Old 27th Jul 2019, 9:23 pm   #17
Bazz4CQJ
Dekatron
 
Bazz4CQJ's Avatar
 
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
Default Re: Eddystone 750 digital readout

Here's a circuit diagram of an arrangement for adding a DFC to an HRO described on this Forum some years ago by the late Bob Green. It may have been that the DFC modules which were around at that time were less sensitive than the current ones, but this is an interesting implementation, putting the amplifier inside the receiver, but avoiding direct connection with the LO and using the same cable for the RF and DC.

B
Attached Files
File Type: pdf Bob Greens HRO DFC.doc.pdf (76.8 KB, 83 views)
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.
Bazz4CQJ is offline  
Old 27th Jul 2019, 9:34 pm   #18
g4aaw pete
Heptode
 
g4aaw pete's Avatar
 
Join Date: Jan 2008
Location: Birchington Kent, UK.
Posts: 595
Default Re: Eddystone 750 digital readout

Quote:
Originally Posted by turretslug View Post
Quote:
Originally Posted by g4aaw pete View Post
I've added a cheapo counter, (the type typically costing >£10), to two receivers.

B40 - loose coupling to local oscillator - drove counter easily.

CR100 - had to use much tighter coupling to local oscillator to get enough drive.

Both these receivers use a separate valve for local oscillator.
I first tried making an LO sniffer with a CR100, ISTR it consisted of a 2N3189 source follower feeding a BCY70 with a low collector load and a fair amount of current, the FET being fed by a couple of turns of insulated wire around a grid connection. This showed me just how critical even slight extra capacitance was to both calibration and stability, and also getting a good frequency response from a buffer. CR100 afficionados will recall that the wide tuning ratio means that very small trimmer capacitance changes makes a big change to HF-end calibration, the top 3 ranges being set by selected low-pF fixed capacitors as built.

Shifting this technique to the spookily-stable AR88 from the happy-to-wander CR100 showed even more starkly that a stable radio can be degraded by what is cheek-to-cheek with the original LO implementation. I'll plead guilty to a degree of perfectionism, but I always feel that add-ons should be a genuine enhancement!

That CR100 looks as though it is tuned to The Buzzer
I'm afraid my technique had a lot less finesse.
Attached Thumbnails
Click image for larger version

Name:	sniff point.jpg
Views:	89
Size:	115.3 KB
ID:	187450  
__________________
Regards
Pete
g4aaw pete is offline  
Old 27th Jul 2019, 11:20 pm   #19
Argus25
No Longer a Member
 
Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
Posts: 2,679
Default Re: Eddystone 750 digital readout

Back in the late 1990's I investigated the problem of how to extract the L/O from radios without disturbance to the frequency when the external counter may or may not be connected.

The results were surprising, you would think for example with a 5 stage fet input buffer, that would do nicely, or perhaps mutual coupling as loose as two coils one inch apart. (its the mutual part that gives the game away, its a two way street)

The problem is, no matter how much isolation you think your buffer amp is providing, if you load its output (shorting it is the acid test) the changes in impedance are reflected back to the input. Its exactly the same with with any form of capacitive or inductive coupling too.

In the end to only way to get what I called perfect isolation was optical, I made the device in the photo to couple the L/O out of one of my EC-10's.

However, I did note the other way to do this with valve radios; with a result easily as good as a buffer amp (better in some cases), is by using a small (1pF) coupling capacitance and a shunt to ground a much larger capacitance (either that of some coax or a fixed capacitor).

That way at the operating frequencies even if the shunt capacitance is loaded, or shorted or whatever, it makes little difference to the fixed frequency offset of the small capacitor. This method avoids having to add buffer circuitry inside your valve radio. However, since it significantly reduces the signal amplitude, it requires that the sensitivity of the counter be increased to a few mV, I simply added a broadband monolithic amplifier inside my counter.

I think this idea was just simply overlooked and most designers felt the way to get good isolation was to use a small coupling capacitance into a high impedance buffer amplifier.
Attached Thumbnails
Click image for larger version

Name:	buff1.jpg
Views:	109
Size:	67.4 KB
ID:	187453   Click image for larger version

Name:	BUFF2.jpg
Views:	93
Size:	58.7 KB
ID:	187454   Click image for larger version

Name:	BUFF3.jpg
Views:	97
Size:	77.8 KB
ID:	187455  

Last edited by Argus25; 27th Jul 2019 at 11:36 pm.
Argus25 is offline  
Old 28th Jul 2019, 10:28 am   #20
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 750 digital readout

I do like your idea of optical isolation Hugo, I agree with the philosophy that an add-on buffer shouldn't degrade oscillator stability or affect calibration, and the opto- route would certainly be a good barrier to digital hash getting into the mixer and degrading reciprocal mixing and other drawbacks. That was my motivation for using a screen-grid valve with its very good anode-to-control grid isolation rather than semiconductor buffers with their relative reverse transparency. Possibly a FET/FET or FET/BJT cascode would improve on a single transistor initial buffer but I'm sceptical that it would be as effective as a pentode.

The other problem in my mind was excess additional heat- it's rare to find an oscillator box that isn't cramped, and/or hemmed in externally- "our radio is bigger than the competition" rarely appears as a USP! Even a B7g-size buffer is difficult to squeeze in, and even late-era subminiatures seem to be difficult to find with indirectly-heated cathodes needing less than a "hot watt" of typically 6.3V 0.15A. I believe that Nuvistors have something like a 70mA heater but these little valves get quite fiercely hot, which would make them difficult to place in a cramped and temperature-critical situation. Not to mention the fact that they are getting rarer and more expensive, and the holders even more so. The DF60/5678 struck me as an excellent candidate for this usage- there is a developed version with a different designation that takes 20mA at 1.25V filament power rather than 50mA, but it seems rather rarer and lacks the metallic screening coat.

I also like your point re. the simplicity and effectiveness of your valve oscillator pick-off approach- my thinking was that having an active device added within the set gives extra isolation consistency with sets that have a relatively highly-resolving scale up at 30MHz whether or not a DFM feed cable is connected. Again, aiming for something near to perfection!

Colin
turretslug is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 8:29 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.