> On 20/4/19 12:21 am, Joerg wrote:
>> On 2019-04-18 15:33, Clifford Heath wrote:
>>> On 19/4/19 2:25 am, Joerg wrote:
>>>> Also, many of the older gizmos now come in USB pods. My spectrum
>>>> analyzer plus tracking generator which can double as a network
>>>> analyzer are the size of three cigarette packs each. Plus they go to
>>>> 4400GHz
>>> Well now, that *is* impressive :)
>>
>>
>> It's from Signalhound, essentially a glorified SDR with a stepped
>> pre-mixer up front. Does have it's downside such as software-only
>> image rejection which will not work for pulsed signals. They now have
>> a 12GHz version.
>
> But not 4.4THz :)
>
> On 2019-04-18 15:33, Clifford Heath wrote:
>> On 19/4/19 2:25 am, Joerg wrote:
>>> Also, many of the older gizmos now come in USB pods. My spectrum
>>> analyzer plus tracking generator which can double as a network
>>> analyzer are the size of three cigarette packs each. Plus they go to
>>> 4400GHz
>> Well now, that *is* impressive :)
>
>
> It's from Signalhound, essentially a glorified SDR with a stepped
> pre-mixer up front. Does have it's downside such as software-only image
> rejection which will not work for pulsed signals. They now have a 12GHz
> version.
But not 4.4THz :)
Reply by Cursitor Doom●April 19, 20192019-04-19
On Fri, 19 Apr 2019 07:28:11 -0700, Joerg wrote:
> We had several of those at my last employer. I'd always bolt those down.
> It it ever falls onto someone during an earthquake or some mishap it can
> kill.
3/4 of a ton and somewhat top-heavy? Yeah, I'd say so.
--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.
Reply by Cursitor Doom●April 19, 20192019-04-19
On Thu, 18 Apr 2019 11:27:24 -0700, John Larkin wrote:
Ah, the good ol' Bridgeport. Got one here, too. Not quite the same as
yours, though. I mean, it's essentially a J-head mill like yours, but
there are many different bits on yours compared to mine control-wise.
Most glaring disparity is the motor on the top of yours. Looks about 1/3
the size of the one on mine. But you run on a funny voltage over there
AIUI. Mine also has the coolant tank in the base casting with a wire
gauze filter exactly on the front left hand side as you look at it.
They're great. Mebe not as great as the Cincinnati equivalent, but OTOH,
mebe better in certain other ways. It's difficult to source correct
lubricants for this machine on the 'wrong side of the Atlantic' from you.
Oh well. That's life.
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.
Reply by Phil Hobbs●April 19, 20192019-04-19
On 4/19/19 10:28 AM, Joerg wrote:
> On 2019-04-18 11:27, John Larkin wrote:
>> On Thu, 18 Apr 2019 09:27:24 -0700, Joerg <news@analogconsultants.com>
>> wrote:
>>
>>> On 2019-04-17 08:33, John Larkin wrote:
>>>> On Wed, 17 Apr 2019 07:54:17 -0700, Joerg <news@analogconsultants.com>
>>>> wrote:
>>>>
>>>>> On 2019-04-13 09:35, John Larkin wrote:
>>>>>> On Sat, 13 Apr 2019 09:01:38 -0700 (PDT), sroberts6328@gmail.com
>>>>>> wrote:
>>>>>>
>>>>>>> Jeorg is the one looking for board, I have enough Duroid for a
>>>>>>> life time of experiments.
>>>>>>>
>>>>>>> Steve
>>>>>>
>>>>>> I used to use duroid for prototypes, before I got good at Dremeling
>>>>>> FR4. You can score the duroid with an x-acto knife and then peel up
>>>>>> strips of copper. But adhesion is poor, so pads tend to lift.
>>>>>>
>>>>>
>>>>> If you do this milling out of FR-4 a lot one of the Carbide 3D routers
>>>>> could be really useful:
>>>>>
>>>>> https://carbide3d.com/shapeoko/
>>>>>
>>>>> It would allow you to mill down very close to the top copper and
>>>>> maintain a consistently low remaining-layer thickness.
>>>>
>>>> We have two milling machines, a big old Bridgeport and a fancy n/c
>>>> Tormach. We can optionally chuck a high-speed router in either one, so
>>>> we could shave out FR4 from below. Chucking a small regular end mill
>>>> would probably be good enough. We can do that for you but it will cost
>>>> you beer.
>>>>
>>>
>>> I could bring some homebrew as well.
>>
>> That might be acceptable if it's not hoppy. I don't like hoppy.
>>
>
> My Belgians are not hoppy at all but require to put the car keys aside.
>
>>>
>>>
>>>> PCB houses have told me that they don't mind routing from below. I
>>>> wanted to reduce the capacitance and capacitive tempco of some big
>>>> layer 1 pads. FR4 pcb capacitance has a ghastly tempco, like +900
>>>> PPM/K.
>>>>
>>>> My guys refurbed the ancient Bridgeport and the last step was to paint
>>>> it. I wanted to make it purple, but they insisted on old boring grey.
>>>>
>>>
>>> Well, at least make it Giant's orange. With logo.
>>
>> The Giant(s) Milling Machine.
>>
>> We had to move it from the old building into the basement here. I was
>> surprised that it only weighs about 1800 lbs.
>>
>> https://www.dropbox.com/s/7kf8v6j2hzaghyk/DSC00334.JPG?dl=0
>>
>
> We had several of those at my last employer. I'd always bolt those down.
> It it ever falls onto someone during an earthquake or some mishap it can
> kill.
Or even if you leave the box wrench on the head nut when you turn it on.
A Bridgeport walking across the floor is no joke--it happened in our
model shop at IBM one time.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
Reply by Joerg●April 19, 20192019-04-19
On 2019-04-18 11:27, John Larkin wrote:
> On Thu, 18 Apr 2019 09:27:24 -0700, Joerg <news@analogconsultants.com>
> wrote:
>
>> On 2019-04-17 08:33, John Larkin wrote:
>>> On Wed, 17 Apr 2019 07:54:17 -0700, Joerg <news@analogconsultants.com>
>>> wrote:
>>>
>>>> On 2019-04-13 09:35, John Larkin wrote:
>>>>> On Sat, 13 Apr 2019 09:01:38 -0700 (PDT), sroberts6328@gmail.com
>>>>> wrote:
>>>>>
>>>>>> Jeorg is the one looking for board, I have enough Duroid for a life time of experiments.
>>>>>>
>>>>>> Steve
>>>>>
>>>>> I used to use duroid for prototypes, before I got good at Dremeling
>>>>> FR4. You can score the duroid with an x-acto knife and then peel up
>>>>> strips of copper. But adhesion is poor, so pads tend to lift.
>>>>>
>>>>
>>>> If you do this milling out of FR-4 a lot one of the Carbide 3D routers
>>>> could be really useful:
>>>>
>>>> https://carbide3d.com/shapeoko/
>>>>
>>>> It would allow you to mill down very close to the top copper and
>>>> maintain a consistently low remaining-layer thickness.
>>>
>>> We have two milling machines, a big old Bridgeport and a fancy n/c
>>> Tormach. We can optionally chuck a high-speed router in either one, so
>>> we could shave out FR4 from below. Chucking a small regular end mill
>>> would probably be good enough. We can do that for you but it will cost
>>> you beer.
>>>
>>
>> I could bring some homebrew as well.
>
> That might be acceptable if it's not hoppy. I don't like hoppy.
>
My Belgians are not hoppy at all but require to put the car keys aside.
>>
>>
>>> PCB houses have told me that they don't mind routing from below. I
>>> wanted to reduce the capacitance and capacitive tempco of some big
>>> layer 1 pads. FR4 pcb capacitance has a ghastly tempco, like +900
>>> PPM/K.
>>>
>>> My guys refurbed the ancient Bridgeport and the last step was to paint
>>> it. I wanted to make it purple, but they insisted on old boring grey.
>>>
>>
>> Well, at least make it Giant's orange. With logo.
>
> The Giant(s) Milling Machine.
>
> We had to move it from the old building into the basement here. I was
> surprised that it only weighs about 1800 lbs.
>
> https://www.dropbox.com/s/7kf8v6j2hzaghyk/DSC00334.JPG?dl=0
>
We had several of those at my last employer. I'd always bolt those down.
It it ever falls onto someone during an earthquake or some mishap it can
kill.
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by Joerg●April 19, 20192019-04-19
On 2019-04-18 17:22, DecadentLinuxUserNumeroUno@decadence.org wrote:
> Joerg <news@analogconsultants.com> wrote in
> news:ghrhk4FsmlvU1@mid.individual.net:
>
>> On 2019-04-17 08:20, John Larkin wrote:
>>> On Wed, 17 Apr 2019 07:47:15 -0700, Joerg
>>> <news@analogconsultants.com> wrote:
>>>
>>>> On 2019-04-08 19:42, bill.sloman@ieee.org wrote:
>>
>> [...]
>>
>>
>>>>> Not strictly accurate. Joerg just wanted to know if he could
>>>>> get away with FR4 because it is absolutely the cheapest and
>>>>> easiest option.
>>>>>
>>>>> A more expensive laminate might well be the cheapest option -
>>>>> looking at the problem as a whole - but Joerg doesn't like
>>>>> spending any more than he absolutely has to.
>>>>>
>>>>
>>>> I remember the days when people said that under no circumstances
>>>> could phenolic be used for UHF and higher. I still have examples
>>>> to the contrary in the garage. In a similar way I have used low
>>>> cost DC cables for pulse-echo at several GHz and it works well.
>>>> Lossy, yes, but it's only the echoes we were after.
>>>>
>>>> What is key in most such cases isn't to achieve close to ideal
>>>> RF performance but one that is merely good enough in terms of
>>>> margins.
>>>
>>> I'm using FR4 at 40 ps edges. Just keep the traces short.
>>>
>>
>> The fastest I have used FR-4 for so far was at 100psec and there
>> it worked well. Nothing was longer than an inch though. No milling
>> was involved.
>>
>> It got interesting when trying to measure resolution, dispersion
>> and all that. Not having a 20GHz sampling scope required McGyver
>> style methods such as flattened paperclips on thin transmission
>> line. Paperclips have almost as many uses as duct tape.
>>
>>
>>> FR4 would be terrible to use for a high-Q planar filter, and
>>> maybe for a narrowband antenna.
>>>
>>
>> The application would be wideband, several GHz BW, and traces less
>> than 1". Losses are ok, dispersion not so much.
>>
> Quoted:
>
> Some circuit materials, such as FR-4 and pure PTFE, can undergo
> large variations in Dk with changes in temperature and they lack the
> consistency needed for maintaining constant impedance at millimeter-
> wave frequencies.
>
> Yet another reason FR4 is probably a bad choice.
>
With the under-milling that John explained it won't be so bad because
then teh dielectric consists mostly of air. Still not ideal but in this
case "good enough" is gong to be the ticket if it becomes a project.
I have done 100psec pulse-echo on FR-4 without under-milling and it
works great. What's an order of magnitude more? :-)
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by Joerg●April 19, 20192019-04-19
On 2019-04-18 15:33, Clifford Heath wrote:
> On 19/4/19 2:25 am, Joerg wrote:
>> Also, many of the older gizmos now come in USB pods. My spectrum
>> analyzer plus tracking generator which can double as a network
>> analyzer are the size of three cigarette packs each. Plus they go to
>> 4400GHz
> Well now, that *is* impressive :)
It's from Signalhound, essentially a glorified SDR with a stepped
pre-mixer up front. Does have it's downside such as software-only image
rejection which will not work for pulsed signals. They now have a 12GHz
version.
--
Regards, Joerg
http://www.analogconsultants.com/
Reply by ●April 19, 20192019-04-19
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote in
news:1LKdncy8Z61vvyTBnZ2dnUU7-WednZ2d@supernews.com:
> On 4/18/19 6:33 PM, Clifford Heath wrote:
>> On 19/4/19 2:25 am, Joerg wrote:
>>> Also, many of the older gizmos now come in USB pods. My spectrum
>>> analyzer plus tracking generator which can double as a network
>>> analyzer are the size of three cigarette packs each. Plus they
>>> go to 4400GHz
>> Well now, that *is* impressive :)
>
> Nah, that's 68 um wavelength. My tunnel junction stuff worked at
> 40 times that frequency. ;)
>
> Cheers
>
> Phil Hobbs
>
There is some 10 bit 51GHz ADC out there.
My boss's daughter is a PhD down at Purdue, and she is developing
a MEMS clock for it... She gets a Q of 50,000 (=very low noise)
using a mere 0.8V @ 120uA in a size of 200nm x 200nm.
That's some clock!
Reply by Phil Hobbs●April 18, 20192019-04-18
On 4/18/19 6:33 PM, Clifford Heath wrote:
> On 19/4/19 2:25 am, Joerg wrote:
>> Also, many of the older gizmos now come in USB pods. My spectrum
>> analyzer plus tracking generator which can double as a network
>> analyzer are the size of three cigarette packs each. Plus they go to
>> 4400GHz
> Well now, that *is* impressive :)
Nah, that's 68 um wavelength. My tunnel junction stuff worked at 40
times that frequency. ;)
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com