Date   

GPSDO Frequency Walkabout

Andy G4JNT
 

The frequency shifts noted on GB3SCX seemed to have righted themselves and no more have been detected over the last day or two,    GB3SCX is firmaly established back on 10368.9050068MHz  +/-  a couple of PPB normal GPSDO stability
 
Several others reported GPS locked frequencies wandering a bit, including one report of a quite abrupt step change at 0900 Tuesday morning.  So it does look as if something very odd was happening.   I've bene trying to get hold of an old collegue from work days who is seriously 'into' GPS to see if he can shed any light / give any inside information, but seems to be unavailalble - (as usual)
 
However, a recent suggestion is that a solar flare was to blame.   Which sounds plausible, after all, we are at a sunspot maximum..  
According to the BBC Horizon prog on the sun t'other night, we can all expect "problems" with electronic equipment and an active sun
 
Andy
G4JNT
 


Response to Ofcom Consultation

Michael Scott
 

Hi All
 
With only nine days to go to the closing date for the Ofcom consultation, I am concerned that there has been little advice on how to respond to the questions. I have followed the discussion on the RSGB website, but am still uncertain how to respond. Clearly saying we don't agree with any of the proposals will be unhelpful and will be disregarded. I was under the impression that following the meeting in Friedrichshafen, there was to be some advice on how to respond.
 
Does anyone have any information?
 
73, Mike 


Attenuators

Christopher Bartram <cbartram@...>
 

I'm about to buy some attenuators from Mini-Circuits for my own use.

If you haven't looked recently, go to Attenuators - Precision Attenuators on their website. MC are making good quality attenuators at sensible prices. A brand new 2W 18GHz device costs about 26 + VAT in the UK, while a 5W 18GHz attenuator is about 38 + VAT.

As MC seem to have have a minimum order policy in the UK, at least, I'd be happy to add other people's orders to my own.

This isn't a commercial offer! It will close at midnight bst on 9 July.

I will have to charge a 10% handling charge to cover my costs, and I will offer no guarantee. The attenuators I supply will come directly from Mini-Circuits, and will be in their original packaging. I will also have to make a p&p charge of 2.50 within the EU. If you want insurance that will be at cost. As I don't want to end up in a US gaol, I can only supply these to EU addresses, and to people who quote their callsign. Payment will have to be by Bank transfer at the time of order, only.

Email me direct <gw4dgu@chris-bartram.co.uk> if you are interested, and I'll send you an email quote.

Vy 73

Chris
GW4DGU


Ooops! - Finningley Microwave Round Table - 13/14 July

g4cch_1
 

Sorry - it looks like my attempt to cross post this to another reflector ended up back where it started...

--- In ukmicrowaves@yahoogroups.com, "Howard" <g4cch_1@...> wrote:

From UK Microwave Reflector
To anyone who might be interested...

Hi All

A gentle reminder if you haven't yet registered for the Finningley microwave round table this event will be held on the 13th 14th July please find registration details from the Clubs web site www.g0ghk.co.uk or from the uk microwave site www.microwavers.org

Please bring along your LNA's transverters filters antennas optical kit etc for testing in the labs..also the Antenna range will be run as usual by David G7CXK and Tom G4TWJ during the Sunday sessions only.

If you are staying for the Saturday evening meal could you please ensure your meal choice is emailed to Jan at the Reindeer inn by the 8th of July latest details and menu options in the Agenda.

Look forward to meeting you all over the weekend

73's

Kevin G3AAF


Re: Finningley Microwave round table 13th 14th July

David Wrigley <zen130696@...>
 

Hi Kevin,

two errors I can see:

1, The club website is
www.g0ghk.co.uk  - and not goghk!

2.  my callsign is G6GXK and not G7CXK!


I'm looking forward to the RT and meeting up with you all.
I'm bringing a 3.4 Alford slot antenna to check on the antenna test range against the one made by Mike Scott

Also I'm bringing to show those interested some bits I've been working on:
1. A compact and inexpensive Chinese sourced Rubidium freq std running off 12V with three 10MHz sine wave outputs
2. An Ionica based programmable 3.4GHz beacon
3. a 12mW 47GHz source.

Also I have some bits for the club to sell - many 10GHz waveguide parts.

all the best

David G6GXK





On 04/07/2013 20:10, kev wrote:
Hi All

A gentle reminder if you havent yet registered for the Finningley microwave round table this event will be held on the 13th 14th July please find registration details from the Clubs web site www.goghk.co.uk  or from the uk microwave site www.microwavers.org

Please bring along your LNA's transverters filters antennas optical kit etc for testing in the labs..also the Antenna range will be run as usual by David G7CXK and Tom G4TWJ during the Sunday sessions only.

If you are staying for the Saturday evening meal could you please ensure your meal choice is emailed to Jan at the Reindeer inn by the 8th of July latest details and menu options in the Agenda.

Look forward to meeting you all over the weekend

73's

Kevin G3AAF







No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.3345 / Virus Database: 3204/6463 - Release Date: 07/04/13



Finningley Microwave Round Table - 13/14 July

g4cch_1
 

From UK Microwave Reflector
To anyone who might be interested...

Hi All

A gentle reminder if you haven't yet registered for the Finningley microwave round table this event will be held on the 13th 14th July please find registration details from the Clubs web site www.g0ghk.co.uk or from the uk microwave site www.microwavers.org

Please bring along your LNA's transverters filters antennas optical kit etc for testing in the labs..also the Antenna range will be run as usual by David G7CXK and Tom G4TWJ during the Sunday sessions only.

If you are staying for the Saturday evening meal could you please ensure your meal choice is emailed to Jan at the Reindeer inn by the 8th of July latest details and menu options in the Agenda.

Look forward to meeting you all over the weekend

73's

Kevin G3AAF


Finningley Microwave round table 13th 14th July

kev <kevin@...>
 

Hi All

A gentle reminder if you havent yet registered for the Finningley microwave round table this event will be held on the 13th 14th July please find registration details from the Clubs web site www.goghk.co.uk  or from the uk microwave site www.microwavers.org

Please bring along your LNA's transverters filters antennas optical kit etc for testing in the labs..also the Antenna range will be run as usual by David G7CXK and Tom G4TWJ during the Sunday sessions only.

If you are staying for the Saturday evening meal could you please ensure your meal choice is emailed to Jan at the Reindeer inn by the 8th of July latest details and menu options in the Agenda.

Look forward to meeting you all over the weekend

73's

Kevin G3AAF








Re: elevation systems

Steve Bunting M0BPQ
 

Thanks for the comments received on and off list. There are some nice options to look at.

My system will be used infrequently and will be assembled FD style each time, so simplicity is most important to me. I don't plan to use a huge antenna, so accuracy is not a real issue. At the moment I am favouring simple manual control, but this could be an interesting project for my new raspberry pi in the future. I have a lot to learn to make that happen though!

Thanks again for your comments and perhaps I'll be on EME this autumn. He says boldly….

73
Steve
M0BPQ

--- In ukmicrowaves@yahoogroups.com, willis.mj@... wrote:

Steve,

A better solution is to use an accelerometer chip and a micro controller. An arduino nano and accelerometer (e.g. ADXL345) should be under £30 from ebay or sparkfun. It just needs a simple c program using the library that comes with the arduino is all you need to get that data back to your PC or to a meter or LED or LCD display.


http://www.coolcomponents.co.uk/catalog/triple-axis-accelerometer-breakout-adxl362-p-1145.html

or if you don't want to program, something really simple using the ADXL335 will give you a voltage for each axis. These are in packages that are more difficult to deal with but you can get one mounted on a board http://www.coolcomponents.co.uk/catalog/lilypad-accelerometer-adxl335-p-468.html for £15.


Accelerometers measure the direction of acceleration - the static acceleration due to gravity for example. Generally if you attach one to a dish it will be able give you the elevation angle. Accuracy is generally very good.

I am not sure why the Lidl units are still sought after with such nice simple chips available.

Mike

--- In ukmicrowaves@yahoogroups.com, "scjb86" <steve@> wrote:

Hi Folks,

I am building an elevation rotator using a linear actuator and need to find a way to feedback the elevation angle. I am looking to buy a digital inclinometer to do the job, so I wonder if anyone knows of a suitable level that I can hack at? There are lots of references to LIDL ones on the web, but they don't seem to be available anymore.

Or is there a more elegant way of doing things these days?

Thanks
Steve
M0BPQ


VHF NFD !

Brian Flynn GM8BJF
 

I will be on our usual site at IO74WV near Gatehouse this weekend for VHF NFD. No doubt I will get bored with VHF at times ;-) . I also plan to have the 10 GHz kit with me and would be up for the odd contact on that band. My mobile is 0796 966 8147

73s

Brian, GM8BJF.


Re: RE GB3SC# Frequency stability

Tony G4NBS
 

Maybe slightly OT but I was driving South from mid GM both Sat and Sun Afternoon/Evening and for a short period noticed my speed according to the GPS varying even though I was under cruise control on straight, clear roads at the time it happened. Can't say I'd ever noticed it do that before unless it lost signal under bridges, mountains etc which wasn't the case this time. Might be coincidence?
 
Regards
Tony NBS
 

-----Original Message-----
From: ukmicrowaves@... [mailto:ukmicrowaves@...]On Behalf Of Andy Talbot
Sent: 03 July 2013 11:08
To: ukmicrowaves@...
Subject: Re: RE [ukmicrowaves] GB3SC# Frequency stability

 

It happened early to mid evening by the look of things.   Was OK at 1300 UTC yesterday when I went out /P to check, but John was reporting it low in freq at 2000.  Ok again this morning.     The GPS constellation used to have periods when certain areas had poor coverage, and if that were coupled with poor antenna view or partial blockage, problems would occur.   Apparantly the period of the problem moves with sideral time, so it gets approximately four minutes later each day.
 
However, these days although the constallation has to be much the same as before, the GPS satellites Tx several dB more power and there are more of them in orbit, albeit duplicating each other, so should be less of a problem.
 
Andy


 
On 3 July 2013 10:54, DEHAYS Dominique <Dominique.DEHAYS@...> wrote:
 

Hi Andy ,

I'm interested to know at what time that signal loss occured . I've lost
my GPSlock signal as well , Hdop up to 13! I get this pb sometimes and I
don't know wether it is really an antenna problem or maybe some kind of
GPS jamming? All looks normal in the hardware so ???

73
Dom


No virus found in this message.
Checked by AVG - www.avg.com
Version: 2013.0.2904 / Virus Database: 3204/6458 - Release Date: 07/02/13


Re: RE GB3SC# Frequency stability

Andy G4JNT
 

It happened early to mid evening by the look of things.   Was OK at 1300 UTC yesterday when I went out /P to check, but John was reporting it low in freq at 2000.  Ok again this morning.     The GPS constellation used to have periods when certain areas had poor coverage, and if that were coupled with poor antenna view or partial blockage, problems would occur.   Apparantly the period of the problem moves with sideral time, so it gets approximately four minutes later each day.
 
However, these days although the constallation has to be much the same as before, the GPS satellites Tx several dB more power and there are more of them in orbit, albeit duplicating each other, so should be less of a problem.
 
Andy


 

On 3 July 2013 10:54, DEHAYS Dominique <Dominique.DEHAYS@...> wrote:
 

Hi Andy ,

I'm interested to know at what time that signal loss occured . I've lost
my GPSlock signal as well , Hdop up to 13! I get this pb sometimes and I
don't know wether it is really an antenna problem or maybe some kind of
GPS jamming? All looks normal in the hardware so ???

73
Dom



RE GB3SC# Frequency stability

F6DRO
 

Hi Andy ,

I'm interested to know at what time that signal loss occured . I've lost
my GPSlock signal as well , Hdop up to 13! I get this pb sometimes and I
don't know wether it is really an antenna problem or maybe some kind of
GPS jamming? All looks normal in the hardware so ???

73
Dom


GB3SC# Frequency stability

Andy G4JNT
 

Following yesterday's suspected loss of GPS frequency lock,   G0API has checked the freq and it seems to be locked again.  So it does indeed look like the GPS antenna may be being shielded by heavy foliage.   A gardening session needs to be scheduled...
 
Take a look at http://www.scrbg.org/lastsnap.jpg  which shows the view from the security camera up the mast.  The GPS antennas (there are two, one is for a timing Rx delivering NMEA only to GB3SCF) are visible on the near left of the cabin roof
 
'JNT
 


Re: elevation systems

Jules G0NZO
 

There is always the gook old fashioned analogue way...
A pot in a box, affixed to the back of the dish, with a bob weight on the shaft. Back to an indicator of some sort.
Used that for the elevation feedback for my LVB tracker for years.

Jules


Re: elevation systems

Mike Willis
 

I think you have it partially wrong and may be confusing gyros with accelerometers.

Yes you will need to set it to zero, I know of no system that does not need some setting, encoders and pendulums included. Its realtively easily done for a yagi or a prime feed dish with a spirit level.

The zero should not then drift. Even if it were to drift over the long term, e.g. if there is deflection in the mount, once you know where the park position is it ought to be easy to re-calibrate. The same is not true for MEMS gyros which will drift. By combining the two you can get azimuth and elevation but we were just discussing elevation.

The inclination only needs to measure 90 degrees, or 45 degrees either side of zero so with 2 or more axis you should be able to measure accurately enough for EME on 23cms. If not, just use two offset in angle, they are cheap enough. Tidal forces will have an effect, but I doubt you could measure it, the accuracy is only about 1 degree, but that's more than enough from 23cms unless you are lucky enough to have a very large array.

By the way, I was wrong about the price, the boards with just a voltage output are only £4. Not £30, that's the price for a development kits with embedded micro.

Mike

--- In ukmicrowaves@yahoogroups.com, "ferrymanr" <g4bbh@...> wrote:

Sorry for butting in but I thought the accelerometer method is not absolute, requiring setting 'zero' and gives elevation referenced to that 'zero'. This therefore requires that dish is acually at zero when set. I also understand that there is some drift so resetting would be required at regular intervals. Perhaps I have got this wrong?
Dick G4BBH

--- I


V-U-SHF Field Day 2013-07-06/07

oz1ff <oz1ff@...>
 

OZ1ALS JO44XX

We will be QRV on following bands:

50 MHz: 6 el./1 kW
70 MHz: 4 el./25 W
144 MHz: 8x4, 8x4 and 4x6 el./1 kW
432 MHz: 8x7el./1 kW
1296 MHz: 1,5m dish/150 W
2320 MHz: 1,5m dish/250 W
5760 MHz: 1,5m dish/7 W
10368 MHz: 65cm dish/5 W
24048 MHz: 65cm dish/2 W
47088 MHz: 48cm dish

We are monitoring the air traffic and hope to make a lot of AR contacts. Skeds can be arranged by email or DX-cluster/ON4KST during the contest. To avoid the long delays on the ON4KST chat during contests please use KST2Me. More on http://www.rudius.net/oz2m/software/kst2me/index.htm

Vy 73 es cu de OZ1FF/Kjeld
mailto:oz1ff@mail.dk


Re: elevation systems

Richard Ferryman
 

Sorry for butting in but I thought the accelerometer method is not absolute, requiring setting 'zero' and gives elevation referenced to that 'zero'. This therefore requires that dish is acually at zero when set. I also understand that there is some drift so resetting would be required at regular intervals. Perhaps I have got this wrong?
Dick G4BBH

--- In ukmicrowaves@yahoogroups.com, willis.mj@... wrote:

Steve,

A better solution is to use an accelerometer chip and a micro controller. An arduino nano and accelerometer (e.g. ADXL345) should be under £30 from ebay or sparkfun. It just needs a simple c program using the library that comes with the arduino is all you need to get that data back to your PC or to a meter or LED or LCD display.


http://www.coolcomponents.co.uk/catalog/triple-axis-accelerometer-breakout-adxl362-p-1145.html

or if you don't want to program, something really simple using the ADXL335 will give you a voltage for each axis. These are in packages that are more difficult to deal with but you can get one mounted on a board http://www.coolcomponents.co.uk/catalog/lilypad-accelerometer-adxl335-p-468.html for £15.


Accelerometers measure the direction of acceleration - the static acceleration due to gravity for example. Generally if you attach one to a dish it will be able give you the elevation angle. Accuracy is generally very good.

I am not sure why the Lidl units are still sought after with such nice simple chips available.

Mike

--- In ukmicrowaves@yahoogroups.com, "scjb86" <steve@> wrote:

Hi Folks,

I am building an elevation rotator using a linear actuator and need to find a way to feedback the elevation angle. I am looking to buy a digital inclinometer to do the job, so I wonder if anyone knows of a suitable level that I can hack at? There are lots of references to LIDL ones on the web, but they don't seem to be available anymore.

Or is there a more elegant way of doing things these days?

Thanks
Steve
M0BPQ


Re: elevation systems

Laurence Newell
 

In principle this seems like a good idea, but remember that the accelerometer measures a single component which varies with the angle. This will adversely affect the accuracy at higher angles. A bit of googling turned up this, which explains it nicely:

http://www.hobbytronics.co.uk/accelerometer-info

I'd be interested to hear how this idea evolves, I too have looked at inclinometers on eBay, but couldn't track down any useful interfacing details.

Laurence Newell

On 02/07/2013 20:22, willis.mj@... wrote:
 

Steve,

A better solution is to use an accelerometer chip and a micro controller. An arduino nano and accelerometer (e.g. ADXL345) should be under £30 from ebay or sparkfun. It just needs a simple c program using the library that comes with the arduino is all you need to get that data back to your PC or to a meter or LED or LCD display.

http://www.coolcomponents.co.uk/catalog/triple-axis-accelerometer-breakout-adxl362-p-1145.html

or if you don't want to program, something really simple using the ADXL335 will give you a voltage for each axis. These are in packages that are more difficult to deal with but you can get one mounted on a board http://www.coolcomponents.co.uk/catalog/lilypad-accelerometer-adxl335-p-468.html for £15.

Accelerometers measure the direction of acceleration - the static acceleration due to gravity for example. Generally if you attach one to a dish it will be able give you the elevation angle. Accuracy is generally very good.

I am not sure why the Lidl units are still sought after with such nice simple chips available.

Mike

--- In ukmicrowaves@..., "scjb86" wrote:
>
> Hi Folks,
>
> I am building an elevation rotator using a linear actuator and need to find a way to feedback the elevation angle. I am looking to buy a digital inclinometer to do the job, so I wonder if anyone knows of a suitable level that I can hack at? There are lots of references to LIDL ones on the web, but they don't seem to be available anymore.
>
> Or is there a more elegant way of doing things these days?
>
> Thanks
> Steve
> M0BPQ
>


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Re: elevation systems

Mike Willis
 

Steve,

A better solution is to use an accelerometer chip and a micro controller. An arduino nano and accelerometer (e.g. ADXL345) should be under £30 from ebay or sparkfun. It just needs a simple c program using the library that comes with the arduino is all you need to get that data back to your PC or to a meter or LED or LCD display.


http://www.coolcomponents.co.uk/catalog/triple-axis-accelerometer-breakout-adxl362-p-1145.html

or if you don't want to program, something really simple using the ADXL335 will give you a voltage for each axis. These are in packages that are more difficult to deal with but you can get one mounted on a board http://www.coolcomponents.co.uk/catalog/lilypad-accelerometer-adxl335-p-468.html for £15.


Accelerometers measure the direction of acceleration - the static acceleration due to gravity for example. Generally if you attach one to a dish it will be able give you the elevation angle. Accuracy is generally very good.

I am not sure why the Lidl units are still sought after with such nice simple chips available.

Mike

--- In ukmicrowaves@yahoogroups.com, "scjb86" <steve@...> wrote:

Hi Folks,

I am building an elevation rotator using a linear actuator and need to find a way to feedback the elevation angle. I am looking to buy a digital inclinometer to do the job, so I wonder if anyone knows of a suitable level that I can hack at? There are lots of references to LIDL ones on the web, but they don't seem to be available anymore.

Or is there a more elegant way of doing things these days?

Thanks
Steve
M0BPQ


Bell Hill Beacons Frequency - may be unlocked

Andy G4JNT
 

We have a slilght suspicion the Bell Hill beacons may be occasionally losing frequency lock.  It could be the trees have grown too far and are blocking the GPS signal. G8ACE reported a possible 200Hz error on GB3SCX this morning.  But when I went to a /P site in the afternoon to check, it was spot on frequency.
 
However, G0API is now seeing a frequency error of about 250Hz low and earlier it was blipping 300Hz or so, then recovering.   This corresponds to only 0.03ppm and as far as I recall is about what the Jupiter GPS receiver would go to if it lost signal for a while.
 
Can any other listeners who can hear any of the four lower frequency Bell Hill Beacons, GB3SCS/ C / F / X,   and can measure frequency accurately, take a listen and see if that error is present.
 
I can't remember now if any of the code generators look for the status of the GPS.   SCX certainly doesn't but if SCS isn't generating JT4G, or SCF isn't doing its JT65C that would be a real giveaway.  (SCC with DFCWi won't)   But they may not implement that - need to go back and examine the PIC code.
 
Andy
G4JNT