Date   

Re: Since I was a bit bored ...

G0FCU
 

Thanks for posting this Robin, very interesting.


On Tue, 16 Feb 2021, 13:59 Robin Szemeti - G1YFG, <robin@...> wrote:
So, not much going on over the weekend, work seems a little quiet, I thought you might like a bit of an update on what I've been up to with my SMD pick and place machine.

I usually use it for stuff I do at work, and we have a chap who has the offline programming software who comes in and sets up the programs for us, which is fine for paying production runs, but I have long wanted to be able to program it myself for ad-hoc projects and prototypes. I can enter all the parts manually, but that is no fun, and I really wanted to be able to go direct from a PCB in Eagle to a completed board popping out of the machine.

With lockdown showing no signs of ending, and we have another 2 of these machines in the USA for production, I dragged the one back home from my unit to my shed, where I could waste many hours on it. When it's just at the bottom of the garden it seems an easier task than driving into town to the unit.

image.png

The official offline programming software costs a fortune, so i couldn't really justify it for projects but I did find some free software[1]  that will parse an Eagle PCB file and write a production file for the machine, but sadly, only for a slightly different version of machine firmware.  After a bit of asking around, I managed to get a later version of the machine firmware. 

For added fun, the firmware I managed to get was DOS files ... and it is stored on the machine in some EPROMS.  I managed to read out the contents of the EPROMS, combine them together into one file and mount it as a DOS FAT12 file system, then replace the files with the new ones, split it up into 3 eproms worth and re-write the eproms. Its years since I wrote an eprom and finding a computer with a working parallel port was quite a big hurdle!

Unfortunately, after all that effort, even this new version of firmware did not work with the "free" programming tool, so, I wrote my own.  Reverse engineering the binary file format was a bit of a task, lots of trial and error. After many, many hours of work, I had a pretty good "map" of the binary file format, althoug I never quite managed to get to the bottom of some of the internal checksums, so the first time it loads it moans about checksum error, but once re-saved to disc it is fine.

The first version succesfully read an Eagle file and spat out a Juki PCB machine file ... assigning all components to feeders and you just tell the machine to ignore the ones you don't have

It ran the bulk components on the Ionica 9cm transverter boards without issue:


That got a bunch of the "reel fed" components done, but there was still a significant number of "odds and sods" to sort out and I really did not fancy doing them by hand.:

image.png

Small runs and prototypes often need just a few weird one off components, not something you would want to buy a whole reel of .. and with 70 or 80 different components on a design, even if you buy part reels, there is a £3.50 re-reeling charge from Farnell for each one, it soon adds up!

What the machine can do, as well as picking from reels and stick feeders is pick parts from a tray, with a grid of components ... I had the idea if I could arrange strips of cut-tape components on a flat surface, the machine could treat it like a matrix tray (in strips of 20x1 components, 2mm or 4mm pitch) ... lay each strip down next to each other and tell it that it has 40 "trays", each one column wide and 20 components long.

I modified the board parser software to pull the data out of the board file and put it into a database,  then produced a simple web interface to go through the database and let me decide if the component is going to be "reel fed", "tray" or "hand placement" ...

So in the web interface, I have a list of boards:

image.png


And for each board, I have a list of components, with their position, rotation, package data:
image.png
And finally, I have a list of feeders, with how many components of each type are needed.

image.png


To make the construction of the "trays" idiot proof, I print out a sheet of A4 on the laser printer that has the components laid out in cut strip, with the value and package shown, along with the quantity required.  I'm going to stick these down to A4 pieces of MDF, use sticky spray to mount the component strips and then mount the pre-prepared slab in the machine, removing the plastic top tape when its all set up.

image.png




The production file is all set up with the machine position offsets, so in theory I just load the bulk components on the reels, the oddballs onto the "sticky A4 sheet", use the camera and cross-hairs to confirm the base pick positions and off it should go!  Providing I don't jiggle the tray and bounce the components out anyway ...

I'll stick the software on GitHub[2], just in case it is ever useful to anyone apart from me, which I very much doubt.



--
Best regards,

Robin Szemeti
G1YFG


--
Robin Szemeti - G1YFG


Re: Since I was a bit bored ...

Maarten PA0MHE
 

Very nice job !!! congratulations.


Since I was a bit bored ...

Robin Szemeti - G1YFG
 

So, not much going on over the weekend, work seems a little quiet, I thought you might like a bit of an update on what I've been up to with my SMD pick and place machine.

I usually use it for stuff I do at work, and we have a chap who has the offline programming software who comes in and sets up the programs for us, which is fine for paying production runs, but I have long wanted to be able to program it myself for ad-hoc projects and prototypes. I can enter all the parts manually, but that is no fun, and I really wanted to be able to go direct from a PCB in Eagle to a completed board popping out of the machine.

With lockdown showing no signs of ending, and we have another 2 of these machines in the USA for production, I dragged the one back home from my unit to my shed, where I could waste many hours on it. When it's just at the bottom of the garden it seems an easier task than driving into town to the unit.

image.png

The official offline programming software costs a fortune, so i couldn't really justify it for projects but I did find some free software[1]  that will parse an Eagle PCB file and write a production file for the machine, but sadly, only for a slightly different version of machine firmware.  After a bit of asking around, I managed to get a later version of the machine firmware. 

For added fun, the firmware I managed to get was DOS files ... and it is stored on the machine in some EPROMS.  I managed to read out the contents of the EPROMS, combine them together into one file and mount it as a DOS FAT12 file system, then replace the files with the new ones, split it up into 3 eproms worth and re-write the eproms. Its years since I wrote an eprom and finding a computer with a working parallel port was quite a big hurdle!

Unfortunately, after all that effort, even this new version of firmware did not work with the "free" programming tool, so, I wrote my own.  Reverse engineering the binary file format was a bit of a task, lots of trial and error. After many, many hours of work, I had a pretty good "map" of the binary file format, althoug I never quite managed to get to the bottom of some of the internal checksums, so the first time it loads it moans about checksum error, but once re-saved to disc it is fine.

The first version succesfully read an Eagle file and spat out a Juki PCB machine file ... assigning all components to feeders and you just tell the machine to ignore the ones you don't have

It ran the bulk components on the Ionica 9cm transverter boards without issue:


That got a bunch of the "reel fed" components done, but there was still a significant number of "odds and sods" to sort out and I really did not fancy doing them by hand.:

image.png

Small runs and prototypes often need just a few weird one off components, not something you would want to buy a whole reel of .. and with 70 or 80 different components on a design, even if you buy part reels, there is a £3.50 re-reeling charge from Farnell for each one, it soon adds up!

What the machine can do, as well as picking from reels and stick feeders is pick parts from a tray, with a grid of components ... I had the idea if I could arrange strips of cut-tape components on a flat surface, the machine could treat it like a matrix tray (in strips of 20x1 components, 2mm or 4mm pitch) ... lay each strip down next to each other and tell it that it has 40 "trays", each one column wide and 20 components long.

I modified the board parser software to pull the data out of the board file and put it into a database,  then produced a simple web interface to go through the database and let me decide if the component is going to be "reel fed", "tray" or "hand placement" ...

So in the web interface, I have a list of boards:

image.png


And for each board, I have a list of components, with their position, rotation, package data:
image.png
And finally, I have a list of feeders, with how many components of each type are needed.

image.png


To make the construction of the "trays" idiot proof, I print out a sheet of A4 on the laser printer that has the components laid out in cut strip, with the value and package shown, along with the quantity required.  I'm going to stick these down to A4 pieces of MDF, use sticky spray to mount the component strips and then mount the pre-prepared slab in the machine, removing the plastic top tape when its all set up.

image.png




The production file is all set up with the machine position offsets, so in theory I just load the bulk components on the reels, the oddballs onto the "sticky A4 sheet", use the camera and cross-hairs to confirm the base pick positions and off it should go!  Providing I don't jiggle the tray and bounce the components out anyway ...

I'll stick the software on GitHub[2], just in case it is ever useful to anyone apart from me, which I very much doubt.



--
Best regards,

Robin Szemeti
G1YFG


--
Robin Szemeti - G1YFG


Re: Airscout

neil whiting
 

Anything in the log file? 
That's a very good question Neil.

I found the log file and indeed the error in mine is associated with the radarbox24 feed.
I removed that one from my selected feeds and no longer get the same error.
There were a couple of:
System.Net.WebException: The underlying connection was closed: The connection was closed unexpectedly
but the planes are showing again despite these messages.

I don't know how to set that ADSB Exchange feed path in the options.

Thanks/73
Neil G4BRK


High VSWR on 432 MHz

g4zod@btinternet.com
 

Good morning all.

Thank you all for your helpful feed back.

It is interesting that I can still hear the Beacon PI7CIS with my mast down. (and I am in Greater London) This seems to indicate that the Coax is still connected to the Antenna.

The last time I dropped the Scam Mast to change the seals and worked on the various Yagis, I found when we heaved the mast up, the VSWR had gone up up on the 70CMs Yagi .

What is interesting is that the VSWR goes up and down slightly depending on which meter I use to test it. ( But I can understand why I get these variation) (I did use a Bird Meter with a 800 MHz slug and it gave me a VSWR reading of about 3-1.)

It seems that my new radio senses a higher VSWR then all my other stand alone meters.

Until HMG and Boris ease the the restrictions sufficiently to get a "Working Party" around to my house I will stick to my 70Cms Colinear.

Thank you for the advice about the possible use of a suitable ATU. I think I will shelve the idea.

The good news is the my 2 Metre 5 element MET and 23 CMs 14 over 14 Tonna which have been on my mast for 28 Years are still working perfectly, so I can still get some contacts.

Julian G4ZOD



Re: 432MHz ATU?

Mike Willis
 

ATU is a waste of time. Sounds like the coax connection is broken at the top. Enjoy 23cms and up until you can get it fixed.
--
Mike G0MJW


Re: Airscout

Neil Smith G4DBN
 

Anything in the log file?  I'm using the ADSB Exchange feed with the internal API key and query URL string

https://public-api.adsbexchange.com/VirtualRadar/AircraftList.json?fNBnd=%MAXLAT%&fSBnd=%MINLAT%&fWBnd=%MINLON%&fEBnd=%MAXLON%&fAltL=%MINALTFT%&fAltU=%MAXALTFT%

and it seems to be working normally at the moment.

Neil G4DBN

On 16/02/2021 09:13, John Lemay wrote:
For the past week or so, Airscout has not been working well, and I see error
messages like "the remote server returned an error; (500) internal server
error".

I've disabled the Planefinder.net feed, which has improved things somewhat,
but it's not a cure.

Are others seeing error messages, and what can be done ?

Thanks,

John G4ZTR


Re: Airscout

Dave
 

Hello John,
The top half of my Airscout has never worked and I only realised recently how it might look. So I would be pleased to have it function as it should , though it is not essential to using the program. I await other posts with interest.
73
Dave G4GLT.

On 16 Feb 2021, at 10:01, neil whiting <neil@ignika.com> wrote:

Hi John,

I've had this too - first noticed it last week.
I tried messing with the feeds too but like you I don't think it is fixed.

73, Neil G4BRK





Re: Airscout

neil whiting
 

Hi John,

I've had this too - first noticed it last week.
I tried messing with the feeds too but like you I don't think it is fixed.

73, Neil G4BRK


Airscout

John Lemay
 

For the past week or so, Airscout has not been working well, and I see error
messages like "the remote server returned an error; (500) internal server
error".

I've disabled the Planefinder.net feed, which has improved things somewhat,
but it's not a cure.

Are others seeing error messages, and what can be done ?

Thanks,

John G4ZTR


--
This email has been checked for viruses by AVG.
https://www.avg.com


Re: 432MHz ATU?

Robin Szemeti - G1YFG
 

I would have to agree with others,  with a 3dB return loss (6:1 VSWR) the chances are the aerial is no longer  connected and you just have feeder left.   1.5dB up,  1.5dB on the way back down and there you are.

You may do better to erect a temporary aerial, even a small 9ele beam on a bit of pole might be a significant improvement.



On Mon, 15 Feb 2021 at 23:44, Gordon REASON via groups.io <gordonj.reason=virgin.net@groups.io> wrote:

Your club members are coming to do some work ...Thats ofk .

But do'nt gather for drinks and sarnies .


On 15 February 2021 at 23:03 "g4zod@... via groups.io" <g4zod=btinternet.com@groups.io> wrote:

I have a long term problem with my 17 element MET Yagi. The VSWR is rather high at about 6-1 and I cannot risk blowing my new radio!

I have no way of taking down my pump up mast to adjust the matching on the antenna. The current restrictions mean I cannot get my fellow club members around to help me drop the mast.

As this means my activities on 432MHz have to be put on hold for possibly many more months I need to find an interim solution. In the mist and cobwebs of mind I recall an ATU for UHF frequencies. I did a quick search and nothing came up.

Can any group member confirm if an ATU for 432 MHz is practical and if so any reference to one?

Many thanks

Julian G4ZOD


 


 


--
Robin Szemeti - G1YFG


Re: 432MHz ATU?

Gordon REASON <gordonj.reason@...>
 

Your club members are coming to do some work ...Thats ofk .

But do'nt gather for drinks and sarnies .


On 15 February 2021 at 23:03 "g4zod@... via groups.io" <g4zod@...> wrote:

I have a long term problem with my 17 element MET Yagi. The VSWR is rather high at about 6-1 and I cannot risk blowing my new radio!

I have no way of taking down my pump up mast to adjust the matching on the antenna. The current restrictions mean I cannot get my fellow club members around to help me drop the mast.

As this means my activities on 432MHz have to be put on hold for possibly many more months I need to find an interim solution. In the mist and cobwebs of mind I recall an ATU for UHF frequencies. I did a quick search and nothing came up.

Can any group member confirm if an ATU for 432 MHz is practical and if so any reference to one?

Many thanks

Julian G4ZOD


 


 


Re: 432MHz ATU?

Neil Smith G4DBN
 

If you can get hold of a VNA and see what the impedance looks like, you could make a two-stub tuner from coax. 6:1 sounds like the coax outer has corroded away or something, was the match ever OK, or has it always been off? Does it change across  the band? If so, what is the curve like?


A NanoVNA would illuminate the problem. Loads of examples of two-stub tuners out on the internet.

6:1 sounds like something disastrous though.


Neil G4DBN


On 15/02/2021 23:12, ian hope (2E0IJH) wrote:
 
Ian
M5IJH
 
 
Sent: Monday, February 15, 2021 at 11:03 PM
From: "g4zod@... via groups.io" <g4zod@...>
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 432MHz ATU?

I have a long term problem with my 17 element MET Yagi. The VSWR is rather high at about 6-1 and I cannot risk blowing my new radio!

I have no way of taking down my pump up mast to adjust the matching on the antenna. The current restrictions mean I cannot get my fellow club members around to help me drop the mast.

As this means my activities on 432MHz have to be put on hold for possibly many more months I need to find an interim solution. In the mist and cobwebs of mind I recall an ATU for UHF frequencies. I did a quick search and nothing came up.

Can any group member confirm if an ATU for 432 MHz is practical and if so any reference to one?

Many thanks

Julian G4ZOD

_._,_._,_


Re: 432MHz ATU?

Mark GM4ISM
 

Julian

A 6:1 VSWR is about 3dB Return Loss. Think of it of this way, if your feeder has 1.5dB  loss (not unreasonable)

and you had no antenna at all, just an open cct, you would get 3dB Return Loss (feeder loss x 2)  I suspect that whatever is left of the connection to the yagi will not radiate that well... 

Whist matching that is theoretically possible, the  'good' match would likely  be very narrowband and  changing frequency may  make the mismatch worse, risking damage  anyway.

 If the mismatch changes in any way  the matching cct will make it worse,  risking damage.

 If you must use this  a 6dB power attenuator rated at the full TX power would add 12dB to the  return loss,  The rig will probably survive 15dB return loss 1.4:1 VSWR  That sort of attenuator is not common

You will hear and work even less but the rig would be reasonably safe

 Best option is to pop a dipole on a long fishing pole and use that as an antenna. It will probably work better than what is left of your MET

I do not recommend trying to use the MET antenna until it is fixed.

Mark GM4ISM



On 15/02/2021 23:03, g4zod@... via groups.io wrote:

I have a long term problem with my 17 element MET Yagi. The VSWR is rather high at about 6-1 and I cannot risk blowing my new radio!

I have no way of taking down my pump up mast to adjust the matching on the antenna. The current restrictions mean I cannot get my fellow club members around to help me drop the mast.

As this means my activities on 432MHz have to be put on hold for possibly many more months I need to find an interim solution. In the mist and cobwebs of mind I recall an ATU for UHF frequencies. I did a quick search and nothing came up.

Can any group member confirm if an ATU for 432 MHz is practical and if so any reference to one?

Many thanks

Julian G4ZOD


Virus-free. www.avg.com


Re: 432MHz ATU?

ian hope (2E0IJH)
 

Yes MFJ make one, MFJ-924, but looks hard to get, https://www.hamradio.co.uk/accessories-aerial-tuning-units-mfj-aerial-tuning-units/mfj/mfj-924-antenna-tuner-w-wattmeter-pd-44.php
 
Ian
M5IJH

 
 
Sent: Monday, February 15, 2021 at 11:03 PM
From: "g4zod@... via groups.io" <g4zod@...>
To: UKMicrowaves@groups.io
Subject: [UKMicrowaves] 432MHz ATU?

I have a long term problem with my 17 element MET Yagi. The VSWR is rather high at about 6-1 and I cannot risk blowing my new radio!

I have no way of taking down my pump up mast to adjust the matching on the antenna. The current restrictions mean I cannot get my fellow club members around to help me drop the mast.

As this means my activities on 432MHz have to be put on hold for possibly many more months I need to find an interim solution. In the mist and cobwebs of mind I recall an ATU for UHF frequencies. I did a quick search and nothing came up.

Can any group member confirm if an ATU for 432 MHz is practical and if so any reference to one?

Many thanks

Julian G4ZOD


432MHz ATU?

g4zod@btinternet.com
 

I have a long term problem with my 17 element MET Yagi. The VSWR is rather high at about 6-1 and I cannot risk blowing my new radio!

I have no way of taking down my pump up mast to adjust the matching on the antenna. The current restrictions mean I cannot get my fellow club members around to help me drop the mast.

As this means my activities on 432MHz have to be put on hold for possibly many more months I need to find an interim solution. In the mist and cobwebs of mind I recall an ATU for UHF frequencies. I did a quick search and nothing came up.

Can any group member confirm if an ATU for 432 MHz is practical and if so any reference to one?

Many thanks

Julian G4ZOD


Re: Programming Nort SLO registers

Daniel DL3IAE
 

Hi Noel,
I have just sent you an emails with some info.
Hope it helps.

73
Daniel


Re: Matching LDMOS device

Greg - ZL3IX
 

I'm not a PA specialist, but have designed one or two in the distant past. I believe that you need to use the impedance characteristics under drive at a typical power level, and these are not usually the same as would be the case under small signal conditions, ie when measured with a VNA. Making impedance measurements under drive is not a simple matter, and you may do well to take the manufacturer's data, here https://www.nxp.com/docs/en/data-sheet/MRF184.pdf.  Admittedly it only goes to 1 GHz, so you would need to attempt extrapolation up to 1.3 GHz. Even at 1 GHz the plot looks like around 1 ohm for Zin, which is way different from the 13 ohms you measured on your VNA.


Re: Programming Nort SLO registers

Noel G8GTZ
 

Hi Daniel,

Yes, I have done the hardware mods on one of my 2 units - Frequencies are 2916MHz for one unit for 432 IF and 3060 for the 2nd unit for 10,368 IF.

73
Noel - G8GTZ


Re: Matching LDMOS device

geoffrey pike
 

Hi Clive,
You dont say what the original device was in this case. The VNA reading is what not the old device as its broken? anyway the if its the old device its too high and the sign is probably wrong.
Anyway what to do, i recently did something at 2.4 GHz with a LDMOS device on a blank canvas Rogers 4003 i think
 I used an old DOS program called Puff from CalTech (there must be a modern equivalent)
So you obviously need to have some impedance info from the the data sheet and the substrate Er.
The process i use is to take the the complex input impedance and initially match it to the geometric mean of the source impedance and device impedance, in this case about 6 ohms, then match this to 50 ohms. So both the input and output are transformed in 2 stages and not directly from 0.7 ohms to 50 ohms or 1.6 ohms to 50 ohms.
The Puff program will give you the length of the low Z transmission line (try around 10 to 12 Ohms to give reasonable line dimensions) that you need to take the input or output to this level and real. Then transform to 50 ohms with another line.
All very vague but it will do it. Puff will take the complete s-parameter file and then you can try it over the F range you are interested in, at this point S12 will raise its head and the values you got for the input and output match need to be fine tuned with either flakes or strips previously etched onto the pcb. As S12 is 0.007 you may see only a small effect.
Puff runs under Windows XP but i haven't yet managed to get it to run under Windows 10.


Inline image


Inline image
These 2 quick look examles use a single low Z line to do the transformation and not 2 as mentioned previously, i used the data for 1GHz at 1,3GHz. Worth a try ! ( the output line was shortened to allow a trimmer to finish the transformation)
cheers
Geoff
GI0GDP

On Sunday, 14 February 2021, 21:49:42 GMT, Clive, G3GJA <clive@...> wrote:


Can someone explain how to approach matching an LDMOS PA transistor. I’m repairing a 23cm PA that used a PCB cut from a power amplifier designed around a device internally matched for use around 1485MHz. The PCB had been snowflaked on the output line and a trimmer added to the input matching to get the amp to work at 23cm.

 

The original device was overdriven resulting in the gate insulation breaking down. The replacement, an MRF184, is not ideal but should still be usable.

 

I can look at the input with my miniVNA and extract the input impedance at 23cm; it’s 13.3 -j42.4. Is this valid? Is there an easy way to use an online Smith Chart simulator to work out what I need to do to get the input to look like 50R?

 

I presume that the reading is not much help as it is what is presented to the input socket and not the device itself. The problem isn’t helped by not knowing exactly what frequency the amplifier was originally designed for, so I’ve no idea what the existing matching is doing.

 

Where do I start?

 

TIA

 

Clive G3GJA



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