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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 ! ! ! ! ! ! ! ! ! ! !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 ##################################################################################
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Re: GPS RX Type TU35-D140-041
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
On 25 November 2011 22:32, Joe McElvenney <ximac@...> wrote:
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Re: GPS RX Type TU35-D140-041
Joe McElvenney <ximac@...>
Hi,
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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
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Re: GPS RX Type TU35-D140-041
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On 25 November 2011 21:55, Joe McElvenney <ximac@...> wrote:
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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
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Re: GPS RX Type TU35-D140-041
Ed <ed.murphy31@...>
--- In ukmicrowaves@yahoogroups.com, Andy Talbot <andy.g4jnt@...> wrote:
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
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Re: Soundcard based Noise Figure Alignment aid
Andy Talbot wrote:
If you've read December's RadCom (Design Notes) you'll have seen myA 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
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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
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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:
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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
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Re: GPS RX Type TU35-D140-041
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:
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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.
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73s Brian, GM8BJF.
--- In ukmicrowaves@yahoogroups.com, <mike.willis@...> wrote:
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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 ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/ukmicrowaves/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/ukmicrowaves/join (Yahoo! ID required) <*> To change settings via email: ukmicrowaves-digest@... ukmicrowaves-fullfeatured@... <*> To unsubscribe from this group, send an email to: ukmicrowaves-unsubscribe@... <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
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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
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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 --
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Soundcard based Noise Figure Alignment aid
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
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Test only
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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
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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
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Re: 10GHz whitebox for sale
Peter Day <microwaves@...>
On 22/11/2011 22:32, G3RIR wrote:
Peter, 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
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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 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 ##################################################################################
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