Date   

Re: Lidl levels

pjm <pauljmarsh@...>
 

I think I will have to bit the bullet and pay top dollar. I
have found several Digital Spirit Levels on eBay at various (higher)
prices.
Hi Clive,

Also 330159990331 is worth a look - 25£ including P&P.

Measuring Range ±180°
Resolution 0.1°
Accuracy 0.1°
Response Time <1.0 second
Operating Temp. 0-45°C
Power Lithium 3V (CR2032)
Battery Life 2000 hours
Weight 120g
Size 51 x 51 x 33mm
Auto Shut Off 5 minutes
Sealing IP54

not bad at all for the price...

regards,

Paul M0EYT.


Re: Lidl levels

Clive Jenner <clivejenner@...>
 

As usual I am late on parade with this, so the Lidl's I have checked had no stock. I think I will have to bit the bullet and pay top dollar. I have found several Digital Spirit Levels on eBay at various (higher) prices. Here is one example item number 280145137881.
Good luck and 73 Clive G0PPO


Radcom 10GHz Quickstart Project and other Updates

Murray Niman <mjniman@...>
 

The article on how to quickly get started on 10GHz DX by UKuG in the
August-2007 edition of Radcom has been kindly made available for free
download on the UKuG website - http://www.microwavers.org/

If you havent looked recently, other updates include

a) Crawley Roundtable programme
b) 75GHz QSO video
c) The next Microwave Beginners Workshop at RSGB HQ!
d) Updated tables of Microwave Firsts

regards

Murray G6JYB


Re: stripline tuning discs?

Chris Bartram <yahoo@...>
 

Paul

As for actually tuning the stripline from the Imfets, I guess the idea
locations are right at the output of the device to the track, or at
the track positions where the bias DC lines are connected. This
particular PA has a pair of fets in parallel - is there anything I
need to watch out for when tuning these, like the phasing of the
outputs etc? Or can I tune for maximum RF out and be happy with that?
The location of the 'snowflakes' can, in principle, be anywhere on the output
line, and while you are playing they will need to be able to move over a half
(guided) wavelength along the line.

I suggest you revisit 'impedance matching with stub tuners' in the Microwave
Handbook before you start playing...

Tuning a PA empirically is always a bit fraught!

You _will_ need to go around a loop. With modern devices, the impedances are
likely to be reasonably similar from device to device, particularly within
the design bandwidth. Are you using IMFETs which actually cover the band? If
you are, you are unlikely to get more than a remarkably few tenths of a dB
extra output by snowflaking for matching, and you should concentrate on
getting the phase relationship right.

Were I building a two (or more) amplifier PA at 10GHz, I'd build two separate
amplifiers, and use external hybrids with an SMA phase adjuster in one of the
input legs to get the phase right.

If your amplifier uses IMFETs operating outside of their design band, then I'd
optimise each amplifier individually for best performance wrt matching, power
output and gain, while trying to keep the matching topology similar in each
case. Only when you are happy with that should you try to combine them.

If you do that, you'll save yourself much confused twiddling, and probably the
cost of several damaged devices!!

I know about these things, and I have a remarkable collection of undersized
tee-shirts to prove it! I've been there both in a work context, and in my own
station where I use reasonably 'serious' four-amplifier PAs on both 144 and
432 (and sometime, when I get time, will have QRO on 1296 by the same route).

Vy 73

Chris
GW4DGU


Re: stripline tuning discs?

pjm <pauljmarsh@...>
 

Copper tape is probably the best option if you can get it,
especially the self-adhesive stuff, but it might not be cheap!

Hi Grant, all,

I have a roll of adhesive copper tape which I have tried to use in the
past. The only down side is when you are tuning the lines, you have to
use the tape with sticky side up, or it makes it hard to move around
to peak the signal. The idea of 2 thou shim might be a good one
providing I can cut it without it curling up, this is one of the
problems I've had with the stuff before.

As for actually tuning the stripline from the Imfets, I guess the idea
locations are right at the output of the device to the track, or at
the track positions where the bias DC lines are connected. This
particular PA has a pair of fets in parallel - is there anything I
need to watch out for when tuning these, like the phasing of the
outputs etc? Or can I tune for maximum RF out and be happy with that?

regards,

Paul M0EYT.


Re: stripline tuning discs?

Chris Bartram <yahoo@...>
 

I'll second Grant's suggestion. 19mm copper tape is quite easily available
from Farnell eg. 120-8995 and not super-expensive at about £4 in short 3.66m
lengths.

It's an essential part of the RF/microwave circuit designers toolkit!

Incidentally, I don't want to be accused of unwarranted pedantry, but
_stripline_ is a transmission-line medium consisting of a conductor contained
between two groundplanes. That is fundamentally different from the
_microstripline_ (conductor above a single groundplane) medium which most
amateurs are familiar with.

One of the great attractions of stripline is that (unlike microstrip) it has a
set of design equations which can be derived unambiguously from first
principles. Although good microstrip design equations have existed for a
couple of decades, it took nearly 25years of effort by some very clever
people to get to that state...  

Although some people might (wrongly!) consider stripline something from the
1950s and '60s, the availability of low-cost multilayer PCB manufacturing and
low-loss substrate materials with processing profiles similar to that of
standard FR4 is making the use of stripline structures very attractive to
professionals once again.

Vy 73

Chris
GW4DGU


Re: stripline tuning discs?

Grant Hodgson <grant@...>
 

Paul

The technique used to tune circuits on microstrip is referred to as 'snow-flaking', and the pieces of metal don't need to be circular - they can be any shape - square, triangular, rectangular, or even snow-flake shaped...

The easiest things to use are very thin pieces of brass or copper - the thinner the better - 0.002" is good. Thin brass sheet is available from good hobby shops and can be cut with tin snips or even scissors/wire cutters - but these will soon go blunt. Or you could buy it from the sheet metal suppliers that supply the hobby market via the internet.

Copper tape is probably the best option if you can get it, especially the self-adhesive stuff, but it might not be cheap! If you only want a small amount then you can probably scrounge some - I'll have a look to see if I've got any. 1" square will make an awful lot of snowflakes.

The 'snowflakes' can be glued, although soldering is preferred.

regards

Grant

pjm wrote:

Morning all,
Has anyone seen stripline in commercial equipment that is tuned with
small metal discs, about 3mm or 4mm diameter? If so, where does one
get these? I need to tune up a PA for some EME tests, and want small
flat pieces of metal, and these must be cheap I'm sure. I guess the
answer would be to find somewhere that makes mesh out of brass, and go
and collect the punch outs...
regards,


stripline tuning discs?

pjm <pauljmarsh@...>
 

Morning all,

Has anyone seen stripline in commercial equipment that is tuned with
small metal discs, about 3mm or 4mm diameter? If so, where does one
get these? I need to tune up a PA for some EME tests, and want small
flat pieces of metal, and these must be cheap I'm sure. I guess the
answer would be to find somewhere that makes mesh out of brass, and go
and collect the punch outs...

regards,

Paul M0EYT.


Re: reverse beacons..agn

SAM JEWELL
 

A cross-band linear translator?

I see a similar argument about what is a repeater is raging in the USA, where it has implications for whether D Stars 'repeaters' are really just digital FM repeaters (or not...) and therefore have to abide by repeater planning rules.
Ho Hum.

Anyway, off to say some Hail Mary's, or summat, especially if it's a cardinal sin.



Alan Melia wrote:

Hi Sam, I am afraid you committed a cardinal sin in your message !! That was
not a "repeater" that Crawley set up on 136khz (that term has inflamatory
attractions for some) the device was a "remotely sited receiver with radio
downlinking". :-))

I see little point on worrying about the PC I ran SnagIt and ARGO on a
200MHz PII (under Win95 ) which can be picked up from the tip (er Recycling
Centre) these days. The unit ran happily cool on a 150watt PSU (I didnt have
a smaller one to try) With this operation it is probably not a disaster if
it crashes occasionally on power outages, and has to be manually reset ...a
non updated screen on the web site indicates it is down, so we dont have
everyone ripping their equipment apart. The problem with a Linux machine is
that much of this software is written for Windows and whist most will run
happily under WINE it is another layer of complexity......but I believe it
does all work.

Of course if you invoke SDR or SoftRock you require a soundcard and a more
powerful, thirsty machine. It should not be necessary to supply a wide
bandwidth so they are nice but not really necessary. At the maximum one SSB
channel is all that is required. I am sure that modern microwavers can put a
CW signal somewhere inside that even at 24GHz...... like the beacon
network....... start simple.

Depending upon the band and the bandwidth used stability is nice but not
essential. A low-level local stable source bled into the RX is a cheaper way
than GPS locking, though a system with that would be much more useful. At LF
we have the sidebands of Loran-C about every 2Hz to act as a frequency
calibrator.

http://www.qsl.net/on7yd/136khz.htm click "Software" and see "Argo Upload"
http://www.techsmith.com/order for "SnagIt" a very versatile program with
many other uses
http://www.weaksignals.com/ for Alberto's site which I am sure you know.
ARGO is the recommended "easy operating" screen waterfall Spectran is more
finicky about the soundcards

Cheers de Alan G3NYK



reverse beacons..agn

Alan Melia
 

Hi Sam, I am afraid you committed a cardinal sin in your message !! That was
not a "repeater" that Crawley set up on 136khz (that term has inflamatory
attractions for some) the device was a "remotely sited receiver with radio
downlinking". :-))

I see little point on worrying about the PC I ran SnagIt and ARGO on a
200MHz PII (under Win95 ) which can be picked up from the tip (er Recycling
Centre) these days. The unit ran happily cool on a 150watt PSU (I didnt have
a smaller one to try) With this operation it is probably not a disaster if
it crashes occasionally on power outages, and has to be manually reset ...a
non updated screen on the web site indicates it is down, so we dont have
everyone ripping their equipment apart. The problem with a Linux machine is
that much of this software is written for Windows and whist most will run
happily under WINE it is another layer of complexity......but I believe it
does all work.

Of course if you invoke SDR or SoftRock you require a soundcard and a more
powerful, thirsty machine. It should not be necessary to supply a wide
bandwidth so they are nice but not really necessary. At the maximum one SSB
channel is all that is required. I am sure that modern microwavers can put a
CW signal somewhere inside that even at 24GHz...... like the beacon
network....... start simple.

Depending upon the band and the bandwidth used stability is nice but not
essential. A low-level local stable source bled into the RX is a cheaper way
than GPS locking, though a system with that would be much more useful. At LF
we have the sidebands of Loran-C about every 2Hz to act as a frequency
calibrator.

http://www.qsl.net/on7yd/136khz.htm click "Software" and see "Argo Upload"
http://www.techsmith.com/order for "SnagIt" a very versatile program with
many other uses
http://www.weaksignals.com/ for Alberto's site which I am sure you know.
ARGO is the recommended "easy operating" screen waterfall Spectran is more
finicky about the soundcards


Cheers de Alan G3NYK


DFCW-I Soundcard Generating Software

Andy Talbot <andy.g4jnt@...>
 


Inverse Beacons

Chris Bartram <yahoo@...>
 

Quite a lot of the work currently being done by members of the uWSDR group
would be applicable to putting inverse beacons on the air.

<uwsdr.berlios.de>

In particular, the software, written by Jonathan, G4KLX, is already being used
with Softrocks (both receive and transceive versions). It is currently
available for windoze, MacOSX, and Linux platforms. I've already suggested to
the uWSDR development group that it might be possible to add software modules
to allow its use as an inverse beacon.

The hardware is also developing, but the project is suffering from the few of
us involved in both hardware and firmware development all having fairly
demanding jobs, and relatively little time to devote to the project. We would
still welcome offers of help with development from anyone with the relevant
skills. In particular we need more people with experience of RF/Microwave
and baseband circuit design. PCB and documentation people would also be
welcome.

uWSDR is releasing all of the intellectual property we're generating under
Open Source licences, hopefully for the greater good of the Amater Radio
Community.

Incidentally, my interest in the inverse beacon concept comes from one of my
other amateur radio interests - extreme range DXing on 144MHz. It seems
likely that inverse beacons will be used widely in the 'beaconisation' (OK, I
know it's a horrible word!) of the Atlantic basin, an area which is rapidly
becoming the new North Sea for VHF'ers.

Vy 73

Chris
GW4DGU


Re: Reverse beacons

Lehane Kellett G8KMH
 

Mike,
Why not a Win PC? I'm sure I can find one, though if it is doing SDR
from a Softrock I may need to beef it up and, even better, my office
is only up the road in Abingdon.

Lehane


--- In ukmicrowaves@yahoogroups.com, Mike Willis <m.j.willis@...> wrote:

Indeed - it is not as if it is difficult any more to get the network
setup. I wanted to install one at RAL back in around 2000, the
problem -
which was insurmountable to me, was finding a software package to
capture the data and put it on a web page. Nowadays this is reasonably
easy to do, so why am I not doing it? Mainly because I personally don't
know how to do it without tying up a Windows PC 24/7. what we need is
someone to come up with a mini-linux distribution disk to do it that
simply runs on inexpensive, low power hardware, an obsolete notebook
for
example. Ideally with something like a softrock as the front end.

Mike

SAM JEWELL wrote:

Folks,
It's not that long ago. I recall the conversations with Lehane and
other UKuG Committee members discussing reverse beacons in 1999/2000.
I think it was not long after Crawley's 137kHz repeater came up on
2m.
We thought then that a similar system might be suitable for 10GHz
rainscatter remote monitoring. But, the problems of network access
and doppler spread signals looked insurmountable. Broadband was not
widespread and the network was then probably going to be based on GSM.

Not only, but SDR radios like the SDR1000, Flexradio 5000, Softrock
and SDR-IQ were not available, so the monitoring of specific
frequencies would have been a problem as little frequency locking was
in use.

The project was quietly left to die.

The situation has changed dramatically since and the use of an SDR
based remote monitor and relatively easy broadband access now make it
look very promising. Like Andy's DFCW idea, maybe the time has come?!

73 de Sam, G4DDK


Re: Reverse beacons

mw1fgq <owen.home@...>
 

Mainly because I personally don't
know how to do it without tying up a Windows PC 24/7. what we need is
someone to come up with a mini-linux distribution disk to do it that
simply runs on inexpensive, low power hardware,
Maybe something like this would be suitable:-
http://www.excito.com
Regards
John
MW1FGQ


Re: Reverse beacons

John Randall <m0els@...>
 

Hallo SAM, I have a laptop running win98 that I can donate..its a 286 I think...so nothing fancy
 
 
73
John

SAM JEWELL wrote:
Sounds like a good first step.

Sam



Mike Willis ac.uk> wrote:
Indeed - it is not as if it is difficult any more to get the network
setup. I wanted to install one at RAL back in around 2000, the problem -
which was insurmountable to me, was finding a software package to
capture the data and put it on a web page. Nowadays this is reasonably
easy to do, so why am I not doing it? Mainly because I personally don't
know how to do it without tying up a Windows PC 24/7. what we need is
someone to come up with a mini-linux distribution disk to do it that
simply runs on inexpensive, low power hardware, an obsolete notebook for
example. Ideally with something like a softrock as the front end.

Mike

SAM JEWELL wrote:
>
> Folks,
> It's not that long ago. I recall the conversations with Lehane and
> other UKuG Committee members discussing reverse beacons in 1999/2000.
> I think it was not long after Crawley's 137kHz repeater came up on 2m.
> We thought then that a similar system might be suitable for 10GHz
> rainscatter remote monitoring. But, the problems of network access
> and doppler spread signals looked insurmountable. Broadband was not
> widespread and the network was then probably going to be based on GSM.
>
> Not only, but SDR radios like the SDR1000, Flexradio 5000, Softrock
> and SDR-IQ were not available, so the monitoring of specific
> frequencies would have been a problem as little frequency locking was
> in use.
>
> The project was quietly left to die.
>
> The situation has changed dramatically since and the use of an SDR
> based remote monitor and relatively easy broadband access now make it
> look very promising. Like Andy's DFCW idea, maybe the time has come?!
>
> 73 de Sam, G4DDK
>
>




For ideas on reducing your carbon footprint visit Yahoo! For Good this month.


Re: Reverse beacons

SAM JEWELL
 

Sounds like a good first step.

Sam



Mike Willis wrote:

Indeed - it is not as if it is difficult any more to get the network
setup. I wanted to install one at RAL back in around 2000, the problem -
which was insurmountable to me, was finding a software package to
capture the data and put it on a web page. Nowadays this is reasonably
easy to do, so why am I not doing it? Mainly because I personally don't
know how to do it without tying up a Windows PC 24/7. what we need is
someone to come up with a mini-linux distribution disk to do it that
simply runs on inexpensive, low power hardware, an obsolete notebook for
example. Ideally with something like a softrock as the front end.

Mike

SAM JEWELL wrote:
>
> Folks,
> It's not that long ago. I recall the conversations with Lehane and
> other UKuG Committee members discussing reverse beacons in 1999/2000.
> I think it was not long after Crawley's 137kHz repeater came up on 2m.
> We thought then that a similar system might be suitable for 10GHz
> rainscatter remote monitoring. But, the problems of network access
> and doppler spread signals looked insurmountable. Broadband was not
> widespread and the network was then probably going to be based on GSM.
>
> Not only, but SDR radios like the SDR1000, Flexradio 5000, Softrock
> and SDR-IQ were not available, so the monitoring of specific
> frequencies would have been a problem as little frequency locking was
> in use.
>
> The project was quietly left to die.
>
> The situation has changed dramatically since and the use of an SDR
> based remote monitor and relatively easy broadband access now make it
> look very promising. Like Andy's DFCW idea, maybe the time has come?!
>
> 73 de Sam, G4DDK
>
>



Re: Reverse beacons

Mike Willis <m.j.willis@...>
 

Indeed - it is not as if it is difficult any more to get the network setup. I wanted to install one at RAL back in around 2000, the problem - which was insurmountable to me, was finding a software package to capture the data and put it on a web page. Nowadays this is reasonably easy to do, so why am I not doing it? Mainly because I personally don't know how to do it without tying up a Windows PC 24/7. what we need is someone to come up with a mini-linux distribution disk to do it that simply runs on inexpensive, low power hardware, an obsolete notebook for example. Ideally with something like a softrock as the front end.

Mike

SAM JEWELL wrote:


Folks,
It's not that long ago. I recall the conversations with Lehane and other UKuG Committee members discussing reverse beacons in 1999/2000. I think it was not long after Crawley's 137kHz repeater came up on 2m. We thought then that a similar system might be suitable for 10GHz rainscatter remote monitoring. But, the problems of network access and doppler spread signals looked insurmountable. Broadband was not widespread and the network was then probably going to be based on GSM.

Not only, but SDR radios like the SDR1000, Flexradio 5000, Softrock and SDR-IQ were not available, so the monitoring of specific frequencies would have been a problem as little frequency locking was in use.

The project was quietly left to die.

The situation has changed dramatically since and the use of an SDR based remote monitor and relatively easy broadband access now make it look very promising. Like Andy's DFCW idea, maybe the time has come?!

73 de Sam, G4DDK


Re: Reverse beacons

SAM JEWELL
 

Folks,
It's not that long ago.  I recall the conversations with Lehane and other UKuG Committee members discussing reverse beacons in 1999/2000. I think it was not long after Crawley's 137kHz repeater came up on 2m. We thought then that a similar system might be suitable for 10GHz rainscatter  remote monitoring. But, the problems of network access and doppler spread signals looked insurmountable. Broadband was not widespread and the network was then probably going to be based on GSM.

Not only, but SDR radios like the SDR1000, Flexradio 5000, Softrock and SDR-IQ were not available, so the monitoring of specific frequencies would have been a problem as little frequency locking was in use.

The project was quietly left to die.

The situation has changed dramatically since and the use of an SDR based remote monitor and relatively easy broadband access now make it look very promising. Like Andy's DFCW idea, maybe the time has come?

73 de Sam, G4DDK


Reverse beacons

Alan Melia
 

Hi all, yes I am surprised that this aspect has not taken off in the
microwave area. Everyone is too busy building and trying to keep up I guess.
There are several of these setups world wide on 136khz and the original idea
came from a microwaver !! They tend to be refered to generically on LF as
"Grabbers" from the "screen grab" context.

There are several ways of achieving the goal and it is all possible with
freeware. I have even run one on 136kHz using a dial-up line and a 120
seconds update. It does work but broadband access is more sensible.

Rik Strobbe http://www.qsl.net/on7yd has written a program that will "grab"
a waterfall screen, such as ARGO and upload it to a web site. ( There is
also a very good tutorial on slow cw modes and operating techniqes ). The
program will also automatical refresh a download if you are watching for
your signal. A commercial very versatile program which is shareware is
SnagIt which works extremely well and has lots of other facilities to
capture parts of a screen to disc as well.

LF sites are operation most nights in Germany, France, Holland, Portugal,
Hungary, Croatia, USA, Singapore (and until recently Shanghai !!) and UK.
There are most certainly a stimulus to activity on very difficult long
paths, and something for listeners to check even closer to. DX listening
stations like 9V1LF will often check a European site to see who is active.

Beware it does raise the spectre of being able to check an Internet site
close to the sender and read the data easily !! :-)) You can only get
round this by providing your own clearly readable capture screen !! ...or
sticking the reverse repeaters away from the centre of qso
activity....probably required anyway.

Yes let's see some up and running !!

Cheers de Alan G3NYK


Re: DFCW for weak signals - thoughts on structure

Lehane Kellett G8KMH
 

Some time back I proposed a similar reverse beacon concept. Then GPRS
wasn't available so the concept could now be updated on the control side.

http://www.g0czd.clara.net/ukug/issue3.pdf (pg 8)

Lehane


--- In ukmicrowaves@yahoogroups.com, David Wrigley <zen130696@...> wrote:

Hi Chris,

Yes interesting - I've thought a bit about that - if we have an omni
receiver using a slotted WG antenna there is a loss there which brings
the advantage down. If we want to keep up the gain at the Rx end we
would need an internet operated steerable receiver antenna -not
impossible -or perhaps more easily a fixed sector horn. It would be
nice
to be able to see my signal appear on a distant receiver - and perhaps
display signal strength like a display from the DSP-10.

The DMC unit I have is not quite to 24GHz - it is set to the max of
23.74GHz and then I add 308.5MHz to get it on the right freq. So far
it's keeping within 1 or 2KHz.for a few degrees temp change, but I
haven't checked it over the likely temp range - so it will probably
move
quite a bit more.. The indoor DDS unit generating the 308MHz to the
mixer has a couple of push buttons on it to shift the freq up or
down in
330 Hz steps. This has been added as an interim solution to a future
drift. In the longer term I have another (MK3) beacon being built
which
will replace the DMC unit with a GPS locked Hi Q cavity oscillator at
4.7GHz feeding a multiplier to 23GHz. Hopefully this will cut out the
need to continually watch the freq. The signal from it looks and sounds
impressively clean.

With regard to the perfect pitch - I never was as good as my dad - he
played professionally for a while - whereas I gave up the violin at an
early age.

73 David G6GXK






Chris Bartram wrote:

Hello David
...............

Incidentally, I'm becoming much more interested in the idea of
'inverse
beacons': essentially a remote receiver outputting its receive audio
to the
internet. It would probably be easier to licence than a conventional
beacon,
if indeed it needs a licence in the UK, and could take advantage of
the ERP
of fixed stations transmitting to it being much greater than any
conventional
beacon.

Vy 73

Chris
GW4DGU