Date   

Re: GPS RX Type TU35-D140-041

Richard <richard@...>
 

On Sat, 26 Nov 2011 10:11:46 +0000
Andy Talbot <andy.g4jnt@gmail.com> wrote:

11.2896MHz NO it wasn't a junk box crystal ! ! ! ! ! ! ! ! ! ! !
That frequency was very carefully selected after much thought and
deliberation and painstaking back of envelope calculations and much burning
of midnight oil

(Well, to be fair I just glanced though the Farnell catalogue looking for a
cheap crystal not too far from 10MHz that divided nidcely by 44100, but the
principle holds )

The underlying sampling rate in WSJT is that of old soundcards and CDs,
ie. 44100Hz.
256 * 44100 = 11.2896MHz

The latest generation of WSJT / WSPR generating software I've written for
PICs is more versatile. The latest versions can free run and can be used
with a variety of crystal frequencies - so long as the freqs meet certain
divider criteria. Of course, free running operation is not suitable for
beacon use, but for short term runs - several hours to a day or two - its
OK. There are also traditional GPS times ones too.

At the moment code exists only to drive the PIC based DDS for optical
subcarrier and baseband IQ conversion, but if/when time and need arises,
its only a case of adding the appropriate subroutines for driving DDS
chips.
See http://www.g4jnt.com/OpticalComms/LF_DDS_Beacon_Source.pdf and
http://www.g4jnt.com/OpticalComms/LF_DDS_Beacon.zip

Andy
www.g4jnt.com

I don't know why Andy you didn't use the 10 MHz reference signal to clock the PIC, and that way the
clock which you depend on for accuracy of tones is locked back to the 10 MHz reference.
Just needs a bit of buffering. Thats what I did to avoid having two 10 MHz sources and intermod products
between the two.



--
Best wishes / 73
Richard Bown

e-mail: richard@g8jvm.com or richard.bown@blueyonder.co.uk

nil carborundum a illegitemis
##################################################################################
Ham Call G8JVM . OS Debian Wheezy/Sid amd64 on a Dual core AMD Athlon 5200, 4 GB RAM
Maidenhead QRA: IO82SP38, LAT. 52 39.720' N LONG. 2 28.171 W ( degs mins )
QRV HF + VHF Microwave 23 cms:140W,13 cms:100W,6 cms:10W & 3 cms:5W
##################################################################################


Re: GPS RX Type TU35-D140-041

Andy G4JNT
 

11.2896MHz   NO it wasn't a junk box crystal ! ! ! ! ! ! ! ! ! ! !
That frequency was very carefully selected after much thought and deliberation and painstaking back of envelope calculations and much burning of midnight oil
 
(Well, to be fair I just glanced though the Farnell catalogue looking for a cheap crystal not too far from 10MHz that divided nidcely by 44100, but the principle holds )
 
The underlying sampling rate in WSJT is that of old soundcards and CDs, ie. 44100Hz.   
 256 * 44100 = 11.2896MHz
 
The latest generation of WSJT / WSPR generating software I've written for PICs  is more versatile. The latest versions can free run and can be used with a variety of crystal frequencies - so long as the freqs meet certain divider criteria.  Of course, free running operation is not suitable for beacon use, but for short term runs - several hours to a day or two - its OK.  There are also traditional GPS times ones too.
 
At the moment code exists only to drive the PIC based DDS for optical subcarrier and baseband IQ conversion, but if/when time and need arises, its only a case of adding the appropriate subroutines for driving DDS chips.   
 
Andy


 

On 25 November 2011 22:32, Joe McElvenney <ximac@...> wrote:
 

Hi,

The same principle applies but I had programmed my first divider PIC a
couple of years before. I had seen a listing some time previous to
that for a divide-by-ten which gave me the idea for a by-1,000. I even
brought it up in "Time-Nuts" but they were ahead of me. As for the
rest of the GPSDO, I used a type-II phase-detector with a current pump
output and a Motorola VC-TCXO.

I've also just re-programmed an RDDS (call sign, etc.) for a local
24GHz beacon which, of course, uses your software. BTW, is the new
clock frequency (11-and a bit megs) something special or just the
result of a junk-box search.

Cheers - Joe G3LLV



Re: GPS RX Type TU35-D140-041

Joe McElvenney <ximac@...>
 

Hi,

The same principle applies but I had programmed my first divider PIC a
couple of years before. I had seen a listing some time previous to
that for a divide-by-ten which gave me the idea for a by-1,000. I even
brought it up in "Time-Nuts" but they were ahead of me. As for the
rest of the GPSDO, I used a type-II phase-detector with a current pump
output and a Motorola VC-TCXO.

I've also just re-programmed an RDDS (call sign, etc.) for a local
24GHz beacon which, of course, uses your software. BTW, is the new
clock frequency (11-and a bit megs) something special or just the
result of a junk-box search.


Cheers - Joe G3LLV


Re: GPS RX Type TU35-D140-041

Andy G4JNT
 

On 25 November 2011 21:55, Joe McElvenney <ximac@...> wrote:
 

Hi,

If you mean the common Jupiter-T (TU30-D140), I am owed one after just
completing a GPSDO for a local beacon and so you can have that.

Somewhere I have the correct 20-way field connector but the simplest
way is to solder a ribbon cable directly onto the pins and to use a
tie-wrap around the board to secure it. I actually broke apart a
turned-pin DIL socket and used its individual sockets pushed over the
ends instead.

BTW, if you need the software for a 12F629 PIC to do the
divide-by-thousand trick, instead of using three 74HCT390 chips, I can
help there or can even send you a programmed chip. Apart from the
simplicity it makes a synchronous counter - much better than a series
of ripple-throughs.

Cheers - Joe G3LLV



Re: GPS RX Type TU35-D140-041

Joe McElvenney <ximac@...>
 

Hi,

If you mean the common Jupiter-T (TU30-D140), I am owed one after just
completing a GPSDO for a local beacon and so you can have that.

Somewhere I have the correct 20-way field connector but the simplest
way is to solder a ribbon cable directly onto the pins and to use a
tie-wrap around the board to secure it. I actually broke apart a
turned-pin DIL socket and used its individual sockets pushed over the
ends instead.

BTW, if you need the software for a 12F629 PIC to do the
divide-by-thousand trick, instead of using three 74HCT390 chips, I can
help there or can even send you a programmed chip. Apart from the
simplicity it makes a synchronous counter - much better than a series
of ripple-throughs.


Cheers - Joe G3LLV


Re: GPS RX Type TU35-D140-041

Ed <ed.murphy31@...>
 

--- In ukmicrowaves@yahoogroups.com, Andy Talbot <andy.g4jnt@...> wrote:

Does that one give a reliable NMEA output ?
Trouble is Andy that I have a system that is already built. I need a part that is a direct replacement otherwise I shall have to make an entirely new system . new box, psu etc ,etc. My present GPS part has just decided to fail. There must be lots of these lying about just rusting away. I need just ONE.
Come on guys, look in your junk box.

Thanks Ed GM3SBC


Coz I've been thinking about the JT4 (and JT65 and WSPR) generation. There
is no need to actually read the time - the PPS alone is probably good
enough. You just synchronise it to the right x2:00 point and it'll run
from there...

A nice 1 PPS based GPSDO would be a good idea too - the ZAZ is already
excellent design and I have two of them, but does rely on having a good
OCXO to start with. An intermediate spec one based on a good TCXO and
giving a similar short term stability to the low cost Jupiter 10kHz design
seems to be needed. They're made commercially so it certainly possible.

We're all placing too much reliance on that Jupiter concept - and its a
single point failure if the source dries up.

Andy
www.g4jnt.com



On 25 November 2011 14:38, Ed <ed.murphy31@...> wrote:

**


Hello All,

Has anyone got a spare TU35-D140-041 GPS Rx for sale ?

1PPS and 10Khz o/p.

Its going to a good cause, a 10 Ghz JT4 Beacon.

Cheers Ed GM3SBC



Re: Soundcard based Noise Figure Alignment aid

Ian White
 

Andy Talbot wrote:
If you've read December's RadCom (Design Notes) you'll have seen my
outline for a soundcard replacement for the G4COM box and request for
someone to write some code to do it.

Even before opening my copy of the magazine (having been away in
Birmingham for the RSGB EGM) Peter G3PLX had written some suitable
software and emailed it to me for testing.    Got back home, built up
a suitable driver, tested, and after a bit of tweaking it all works
FB.

Wrote it up,  and this plus the software can be found at
http://www.g4jnt.com/NoiseMeter.zip

The new design cantake in audio up to 22kHz, so by using both
sidebands from a direct downconverter you have 44kHz of noise
bandwidth to smooth out the reading better than an SSB filter
bandwidth allows.    Also, with a 16 bit soundcard means it can work
over 80dB or so of dynamic range
A very similar design with comprehensive software was published by Dave
Roberts G8KBB in Radcom January 2007. Details of the downconverter and
software are downloadable from
<http://g8kbb.roberts-family-home.co.uk/html/downloads.html> along with
some very detailed assessments of errors and performance.

Dave's software allows both manual control and automatic switching of
the noise source (and if needed, the DUT as well) through either a COM,
LPT or USB port. The automatic switching cycle includes a settling time
to allow the noise source and DUT to stabilise before the measurement
begins, and a delay after the end of each measuring period before the
system changes state. When the settling time is set correctly, this
should also take care of timing uncertainties in the PC ports.

If a 28V switched supply is provided for the noise head, that interface
needs to conform to industry standards: the instrument provides a
switched voltage source and the current regulator is in the noise head.
(I'm not sure what happens when two series-connected current sources are
switched on and off, but it probably isn't good.)

G(M)4PMK's RATS design in Radcom July-August 1995 includes a suitable
hardware interface, an LM317LZ voltage regulator with a MOSFET switch.



--

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek


Re: Activity List for UKuG 1.3/2.3/3.4GHz Contest 27 November

g4bao
 

I shall be on 3.4GHz only from the warmth of my shack.JO02cg

15 Watts to 45cm dish, 8m agl sub 0.7dB system noise figure  

Looking forward to working you brave souls out portables in rare squares!

I hope condx will be better than Tuesday night!

Talkback on 144.175  or ON4KST

73
John
.
 


On 25 November 2011 19:20, John <gm8oti@...> wrote:


Hi all,

Still not finally decided as the forecast is changing all the time. However at present it looks promising so I am a "probable" to go out.

If out, GM8OTI/P will be active probably in IO86 somewhere near JF.

1.3GHz 4W 15-ele

2.3GHz 4W 12-ele (!) (newish to the band, still to build a better one!)

No ON4KST available, I could set up 2m talkback but no-one uses it ;-)

I will call CQ and do a lot of listening for those beaming north.

Times: probably from about 11:00 for a couple of hours or so, it depends how cold it is and how few contacts there are!

73
John GM8OTI





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Re: Activity List for UKuG 1.3/2.3/3.4GHz Contest 27 November

John <gm8oti@...>
 

Hi all,

Still not finally decided as the forecast is changing all the time. However at present it looks promising so I am a "probable" to go out.

If out, GM8OTI/P will be active probably in IO86 somewhere near JF.

1.3GHz 4W 15-ele

2.3GHz 4W 12-ele (!) (newish to the band, still to build a better one!)

No ON4KST available, I could set up 2m talkback but no-one uses it ;-)

I will call CQ and do a lot of listening for those beaming north.

Times: probably from about 11:00 for a couple of hours or so, it depends how cold it is and how few contacts there are!

73
John GM8OTI


Re: GPS RX Type TU35-D140-041

Andy G4JNT
 

Does that one give a reliable NMEA output ?
 
Coz I've been thinking about the JT4 (and JT65 and WSPR) generation.  There is no need to actually read the time - the PPS alone is probably good enough.   You just synchronise it to the right x2:00 point and it'll run from there...
 
A nice 1 PPS based GPSDO would be a good idea too - the ZAZ is already excellent design and I have two of them, but does rely on having a good OCXO to start with.   An intermediate spec one  based on a good TCXO and giving a similar short term stability to the low cost Jupiter 10kHz design seems to be needed.  They're made commercially so it certainly possible.
 
We're all placing too much reliance on that Jupiter concept - and its a single point failure if the source dries up.
 
Andy


 

On 25 November 2011 14:38, Ed <ed.murphy31@...> wrote:
 

Hello All,

Has anyone got a spare TU35-D140-041 GPS Rx for sale ?

1PPS and 10Khz o/p.

Its going to a good cause, a 10 Ghz JT4 Beacon.

Cheers Ed GM3SBC



Re: Soundcard based Noise Figure Alignment aid

Brian Flynn GM8BJF
 

I thought that was a really neat idea. I just happen to have an HP 346B noise head and no meter. I must try it out when I get some time.

73s
Brian, GM8BJF.

--- In ukmicrowaves@yahoogroups.com, <mike.willis@...> wrote:

This is all very well but it still needs a receiver. How about using something like the Funcube Dongle and use the bias output as a switch for the noise source? This could then be used to optimise pre-amps for all bands up to 23cms. It needs software and very little hardware.

Mike

--
Scanned by iCritical.


Re: Activity List for UKuG 1.3/2.3/3.4GHz Contest 27 November

Keith GW3TKH
 

Weather dependent activity for Sunday:

Call:            GW3TKH/P
Locator:        IO81LS
Bands:        23, 13 & 9cm
Talkback:    144.175Mhz.
Times:         From start until batteries fail.

73 Keith
GW3TKH


From: G3XDY
To: ukmicrowaves@...
Sent: Saturday, 19 November 2011, 13:23
Subject: [ukmicrowaves] Activity List for UKuG 1.3/2.3/3.4GHz Contest 27 November

The final UK Microwave Group contest of 2011 takes place on Sunday the 27th
November, on 1.3, 2.3 and 3.4GHz.

As usual I will circulate an activity list beforehand, so please let me know
your operating plans.

I will be active as follows:

Call:                G3XDY
Locator:        JO02OB
Bands:            1.3GHz  400W  4x23ele
                        2.3GHz    100W  0.8m dish
                        3.4GHz      20W 0.6m dish
Talkback:    Direct CQ on 23cms, ON4KST.
Times:        From 10:00 for an hour or so.


73

John G3XDY



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GPS RX Type TU35-D140-041

Ed <ed.murphy31@...>
 

Hello All,

Has anyone got a spare TU35-D140-041 GPS Rx for sale ?

1PPS and 10Khz o/p.


Its going to a good cause, a 10 Ghz JT4 Beacon.


Cheers Ed GM3SBC


Re: Soundcard based Noise Figure Alignment aid

mike.willis@...
 

This is all very well but it still needs a receiver. How about using something like the Funcube Dongle and use the bias output as a switch for the noise source? This could then be used to optimise pre-amps for all bands up to 23cms. It needs software and very little hardware.

 

Mike


--
Scanned by iCritical.



Soundcard based Noise Figure Alignment aid

Andy G4JNT
 

If you've read December's RadCom (Design Notes) you'll have seen my
outline for a soundcard replacement for the G4COM box and request for
someone to write some code to do it.

Even before opening my copy of the magazine (having been away in
Birmingham for the RSGB EGM) Peter G3PLX had written some suitable
software and emailed it to me for testing.    Got back home, built up
a suitable driver, tested, and after a bit of tweaking it all works
FB.

Wrote it up,  and this plus the software can be found at
http://www.g4jnt.com/NoiseMeter.zip

The new design cantake in audio up to 22kHz, so by using both
sidebands from a direct downconverter you have 44kHz of noise
bandwidth to smooth out the reading better than an SSB filter
bandwidth allows.    Also, with a 16 bit soundcard means it can work
over 80dB or so of dynamic range

Enjoy

Andy
www.g4jnt.com


Test only

Andy G4JNT
 

??


UKuG Contest

Martin A Hall <gorrell77@...>
 

It's looking increasingly unlikely that I'll be on for the contest on Sunday.  Severe gales gusting to 80 mph are forecast over the next few days, so I won't be raising the tower, or even turning the beam, let alone getting the masthead preamplifier back in place.  I shall just be keeping my fingers crossed that none of the antennas take off in the direction of Lerwick!
 
Hope the weather is kinder where you are!
 
73,
Martin
GM8IEM - IO78HF
 
 


November SHF UKAC - 13cm Report

Ray James <gm4cxm@...>
 

Tuesday nights SHF UKAC was blessed with good activity but flat conditions on 13cm.
Local contacts therefore become a very important commodity and it was excellent seven stations within GM were available on this band.
Alan GM0USI/P activated IO76 and John GM8OTI/P (IO85) also braved the November weather elements.
Robert GM4GUF (IO85) came on from home as did Andy GM7GDE (IO75) with an indoor flat panel fixed on the GB3CSB beacon location.
Unfortunately I had no success with Jim GM3UAG (IO87) and despite attempting to contact Jon GM4JTJ (IO86) early in the contest and for 30 minutes at the end, nothing.
The first 40 minutes produced seven contacts including all the GMs workable plus an aircraft reflection contact with Kjeld OZ1FF (782Km to JO45) and two into IO91 with Mike G0MJW catching one aircraft reflection and Neil G4BRK starting when Mike finished but having to wait until a second aircraft came into our mid-point zone in order to complete all required exchanges.
The next hour produced three tropo contacts with good readable signals from Tony G4CBW (IO83) and Ian G8IFT at G8OHM (IO92) but Bob G8DTF (IO83) and I struggled for a long time before confirmation could take place.
All in all a very satisfactory contest despite flat conditions and a challenge to the end but having to work hard for contacts is par for the course.  
My QSO map can be viewed at http://maps.google.com/maps?q=http://www.rsgbcc.org/vhf/kml_files/2011/y6OxCr0UKMjBiKs4x1hyK1Fqpziz3Kf

73 Ray GM4CXM IO75TW
60w 67el



Re: 10GHz whitebox for sale

Peter Day <microwaves@...>
 

On 22/11/2011 22:32, G3RIR wrote:
Peter,

Is that White box transverter system capable of being driven from 12V supply
for portable operation?

Neil, G3RIR

I don't think so... you need to ask Dave directly. However you could buy a cheap 12VDC to 230V AC inverter and do it that way. I use one for my laptop and it works well. A 150 watt version is available at Maplin I believe. They are 95% efficient so a large leisure battery would last all day. the other way is to use a 230V AC petrol generator for the whole portable station :-)

I had a similar white box years ago but had to make a 12DC PSU for it with the various voltages needed... eg +12VDC, -5V DC and +5V DC

73

Peter


Re: clean voltage sources

Richard <richard@...>
 

On Wed, 23 Nov 2011 17:36:31 -0000
"simon" <simon@g8atb.co.uk> wrote:

CPC - Farnell Supply the 723 (DIL) for £.58. Not to bad

Simon


Much better RS comps 661-6698 £0.738 ea Pk of 5
Texas Instruments
UA723CDG4

--
Best wishes / 73
Richard Bown

e-mail: richard@g8jvm.com or richard.bown@blueyonder.co.uk

nil carborundum a illegitemis
##################################################################################
Ham Call G8JVM . OS Debian Wheezy/Sid amd64 on a Dual core AMD Athlon 5200, 4 GB RAM
Maidenhead QRA: IO82SP38, LAT. 52 39.720' N LONG. 2 28.171 W ( degs mins )
QRV HF + VHF Microwave 23 cms:140W,13 cms:100W,6 cms:10W & 3 cms:5W
##################################################################################