New to Meteor Detecting

[Al.Grant]

Hi

Hi Al

Which actions are you using or have you modified your own and are those actions capable of saving only screen shots of hits please?

cheers

Steve

Hi Steve,

I'm using a script that only captures images for the larger meteors but it still counts the smaller ones for the RMOB data file.

All I've really done is some very minor tweaks to make it suit my setup.

I'll be away now until either Sunday evening or Monday morning when I can get more details on the full script and what to tweak.

Until then have a look here:  http://stargazerslounge.com/topic/220150-new-to-meteor-detecting/?p=2420099 (Page 5, post #84 of this thread).

This was the first version of the script that put limits on what to actually capture.

Make sure you have a /meteorlog directory (you may already have one if you are running the original Dawes script).

Towards the bottom of the script (line 40) you'll find  if( (M_BIG>3) ) then timer1.restart(15)  the >3 figure is the duration of the smallest detection that you want to trigger a screenshot.  I started off with >3 then moved up until I was happy.  I think it's on about >8 or 10 at the moment.  All smaller meteors get counted, just not captured.

If you use this script you will also need to check your THRESHOLD limits and the LOW/HIGH figures at the top of the script to suit your system

if( (initialising) ) then THRESHOLD=17:LOW=1500:HIGH=2500   I think you'll find the LOW/HIGH should be OK but Threshold may need raising a little.

This version of the script does NOT apply limits to the audio capture, so be very careful about leaving .wav capture enabled!  (those files soon get massive)

I can get you the version that adds audio limits after the weekend.  With that one you can leave audio capture enabled and it will only record to the level you've set.   So at the moment I can leave both on and when I check each morning I have a screen capture and matching audio file for the larger meteors

Al

[Gasman]

Great stuff, thanks that Al much appreciated,

Steve

[Al.Grant]

No worries.  Actually just had another script sent to me by Phil.

Not had a chance to run it yet but should be able to give it a try tomorrow and then it should allow me to put some new stuff on my webpage.

Al

[SteveNickolls]

Hi,

I started looking at the distribution of 'pings' by duration today that my system has been getting as I felt  it would be good to have an approximate value of how many saved screenshots could be potentially reduced (and hard drive space) by setting some minimum capture value on the conditional action script s you mention above Al. As expected the shorter duration trails account for a vast majority of detections. Detections with a duration of 1 made up 37.6% of the total, with duration 2 adding 32.6%, duration 3 a further 15.9%, duration 4 another 2.4% with  duration 5 adding 3.0% (cumulatively 91.5%). Using a minimum duration of 20 would reduce screenshots by 98.1%. Using a value of 30 would reduce screenshots by 99%.

Al, I have also been working on trying to increase the number of detections. I've done this through trial and error tweeking of the modified Simon Dawes conditional action script (specifically the secondary test values rather than just removing them) while using a threshold value of 18. In the past couple of days I am now seeing my detection levels more in line both with yours and the Lincoln ones on the RMOB site. My QC of sitting at the pc looking and listening to the detections show that almost all detections I would expect to be detected are being recorded by SL so I'm pretty happy if this state of affairs continues. Fingers crossed and we should have a greater consistency both in meteor numbers detected and in the hourly pattern of detections. It's looking as if aerial polarisation isn't the issue after all which in itself is interesting.

Cheers,

Steve

[John101]

Greetings, complements and good wishes as your thread continues to put into words such awareness,

With respect to antenna polarization and efficiency at 2 meter radio frequencies…

Defined to be that of its electric field in the direction where the field strength is maximum. If a basic half-wave wire dipole is mounted horizontal over the earth the electric field is strongest parallel to both the earth and broadside the wire and if the dipole is mounted vertical the electric field is vertical polarized.  If a dipole is mounted in free space its polarization is indeterminate. So one can only imagine the polarization of a radio signal reflected back to earth from the ionized tail of a meteor.

On earth, dipole antenna mounted in the same polarization are most efficient. Crossed polarized dipoles on earth (a-far-field, one horizontal the other vertical) result in about a 3 dB (half power) signal loss.

How can we make our antenna system more sensitive to signals from space?

Multi element antenna such as the Yagi offer signal amplification from 3 dB (double that of a basic dipole) to 10 dB (an order of magnitude) 10 times that of a basic dipole or crossed polarized dipoles (mounted at right angles to each other) with quarter-wave phasing line.  Crossed dipoles mounted in the same plane with a flat metal reflector (about 4 feet square at Graves radio frequency) called the Turnstile Reflector. It is simple, effective, makes a nice easy homebrew attic antenna for amateur and weather satellite as well as 2 meter meteor scatter without the need for test equipment, ‘google for images and calculator.

73

John

N3AAZ

[SteveNickolls]

Thanks John for this. If I ever get the loft cleared this may be an option :-)

Cheers,

Steve

[jarraman]

hi.

interesting group,have just built my own meteor detecting equipment on the strength of the posts in here.i went the cheapo dongle route with HDSDR  and the ariel to s@n instructions.

i think i am detecting meteors,but there is not that much information out there to decipher what is going on in the software.i have set it to the GRAVES frequency and i am getting some blips in the waterfall,so i suppose i should note the times they appear and see if anyone else is seeing the same thing.

ken.

[allcart]

Is there a link to this S@N article or is it subscription only. I am thinking of setting up a radio monitoring system myself.

[The Admiral]

Is there a link to this S@N article or is it subscription only. I am thinking of setting up a radio monitoring system myself.

Hi allcart, I thought I'd seen a copy posted on this forum, and I've found it! It's post #20 here

There's a lot of stuff on this forum, but this thread started by Steve Nickols is a good diving off point. Being fairly well south of the UK you should be able to get good signals. I use a FunCube dongle and my antenna is in the loft, certainly not ideal and I'd like to get it outside, but which presents problems. My background noise levels tend to be a bit on the high side (compared to Steve's), but I capture a good many meteors.

Good luck

Ian

Ian

[The Admiral]

hi.

interesting group,have just built my own meteor detecting equipment on the strength of the posts in here.i went the cheapo dongle route with HDSDR  and the ariel to s@n instructions.

i think i am detecting meteors,but there is not that much information out there to decipher what is going on in the software.i have set it to the GRAVES frequency and i am getting some blips in the waterfall,so i suppose i should note the times they appear and see if anyone else is seeing the same thing.

ken.

Welcome Ken to SGL and to this forum. I'm not familiar with HDSDR; I started off with SDR Console, and followed that up with Spectrum Lab. The latter takes a bit of getting used to, and if you are wanting to record your events and take screen shots of the traces (so that you don't have to sit in front of the screen all the time!), you'll need to run a short script within it. Anyway, for the moment it would be interesting if you could post a screen shot of one of your detections and we should be able to say if it is a meteor or not. It is normal practice not to tune exactly to the Graves' 143.050MHz, but to 1 or 2kHz away (i.e. 143.048MHz), so that you get an output signal of 1 or 2kHz. That way you avoid any low frequency attenuation in the system, and in any event, you want a signal, not 0Hz! Traces generally last fractions of a second, but during the meteor showers you often get traces lasting many seconds.

There's plenty of info in this thread, but look at other relevant threads as well. It's not difficult as long as you've a clear idea what you are doing, but it's not so easy to work out from the trace what is exactly going on!

Ian

[allcart]

Hi allcart, I thought I'd seen a copy posted on this forum, and I've found it! It's post #20 here

There's a lot of stuff on this forum, but this thread started by Steve Nickols is a good diving off point. Being fairly well south of the UK you should be able to get good signals. I use a FunCube dongle and my antenna is in the loft, certainly not ideal and I'd like to get it outside, but which presents problems. My background noise levels tend to be a bit on the high side (compared to Steve's), but I capture a good many meteors.

Good luck

Ian

Ian

Thanks for the links.

Like yourself, I may have to install the antenna in the loft as I don't have a south east view unless I go up onto the ridge of my roof (no chimney either). I already have a 4 camera video meteor detection system on the roof just above gutter height so anything I mount up there will obscure the cameras. I have thought that maybe a turnstile reflector design could work as it would lay flat in the loft space, but have not researched enough to know yet.

lots to think about.

[The Admiral]

A quick off the cuff reply. I believe a turnstile antenna is uniform in polar response, and is most sensitive towards the higher angles, useful for satellite reception. For meteor detection you want to detect reflections from meteors over southern France. In other words, very close to the SE horizon. So a directional antenna like a Yagi or one of its derivatives is what you need. I started a thread on this a while back: http://stargazerslounge.com/topic/233057-how-well-can-we-detect-meteors-using-the-graves-transmitter/

[allcart]

Interesting !!

 So are you saying that I and everyone else will only be detecting meteors over the south of France and not over the UK.

I had hoped that I would be able to detect the radio signal from the same meteors that I capture on video. My fov will only cover the channel as far as callais.

[The Admiral]

If you are using the Graves transmissions, then yes Allan, but you are not alone in expecting to be able to detect what we see above us. Years ago I gather folk used the tv transmissions, so you'd get a much more local detection, but apparently that doesn't work with the digital transmissions. Some people use a weaker transmission from the BRAMS transmitter in Belgium, so reflections will be much more local. The downside is that it operates at 50MHz, so an efficient antenna will be a lot bigger. I've not tried it, but one day perhaps. Have a look at this note by Dr David Morgan: http://www.britastro.org/radio/projects/BRAMS_Meteor_Radar.pdf

I'm a little surprised that you think you can only see as far as Calais. I live in Oxfordshire, which is further away from the Channel than yourself, and with an antenna in the loft I can pick up signals no problem. Steve Nickols (and others) live in the North of the UK, and with an outside antenna he picks up more than I do!

Ah! On second reading, do you mean that your video system only covers as far as Calais?

Ian

[jarraman]

hi ian.

as i am still learning how to use HDSDR,i have no screen shot of what i thought was a meteorite.i am still not sure about my antenna.i have built the sky @night one and have attached it to 3m wooden pole on top of my shed,pointing south east,,but,,,my house is in the way,so i have pointed the arial just above the roof line,which i think is about 40 to 50 degrees,is that to high?.

also trying to understand the HDSDR screen ,is there any help on what to learn about the frequency,s,,enough for now,plenty of questions to ask,lol.

ken.

[The Admiral]

Hi Ken

Well, your antenna should be OK, but I'm not sure what effect the house will have as the signals that you need to detect will be from close to the horizon. The azimuthal directional sensitivity (i.e. in the vertical plane) of the antenna is largely dictated by the presence of the ground, so canting the antenna upwards won't make a lot of difference to what you you'll see. The big question to my mind is how much is likely to creep over the top of the house. Apart from sheer difficulty of erecting an external antenna in my house, that is why I put my antenna in the loft. I gain a much better 'line of sight' view to the horizon, but with the detrimental effects of the roof and its structure, and interference. Far from ideal, but it works reasonably well, though clearly not as well as a good high external antenna, say strapped to the chimney.

As to HDSDR I can't help, never used it. Sorry. You will need to be able to tune your dongle to 143.048MHz, and have a 'waterfall' display of your signal  centred on an audio signal of 2kHz.

Ian

[allcart]

Hi Ian, yes I meant the cameras only see across to Northern France.

That was a useful link and an interesting read. I will have to read it again to digest it, but on first reading it does seem that a 50MHz antenna will be too big for my uses. I don't think it would even fit in my loft.

But still, its all food for thought.

[jarraman]

well.

bit the bullit,,bought funcube and downloaded spectrum lab,bit of a pain to make it fit to the coaxel,think there are about 3 parts to it,no doubt there is an easier solution,lol.

need to figure out s.l. now.will let you know how i get on.

ken.

[The Admiral]

I'm not sure how you are trying to fit the coax Ken but I use an SMA to N-type adapter, though you could equally use an SMA to PL259-type adapter. They consist of short lengths of coax with the appropriate plugs/sockets at either end, and make life easy as the N-type or PL259-type plugs/sockets are best suited to normal size coax and are easier to assemble. You can get them at Westlakes for example  http://www.whwestlake.co.uk/  (You need to click on the price list to find them!).

Spectrum Lab has a bit of a steep learning curve I found, but once mastered does the job.

Ian

[jarraman]

hi ian,

sorted the coax out,went to maplins and they sorted me out.had S.L. working waterfall showing,but no sound,done a sound test through the generator,gor the signal in the water fall,but no sound.then S.L. decided to freeze,so went through all the configs again.still no sound,froze again.checked component tag,every thing showing green.

i wonder if its windows ten,got another computer with windows  7 on,will try that.im not giving up ,lol.

ken.

[The Admiral]

Glad you've got yourself sorted with the antenna connection. You may find this a silly question, but have you also downloaded the FCD+ Frequency Control program from the FCD site, and set it to the correct frequency? Or does the latest version of SL work directly with the FCD Pro+  and enable you to set it from within SL itself? My version (2.82.b05) doesn't have that option.

Assuming that you are well aware of that requirement, from what I recall, dealing with the sound issue can be a vexing one, and I'm sure Windows 10 will only make it more so! I have to say it has worked OK for me with Win 7, but I believe it is very much dependent on system set-up and the hardware. Have a read of SL's user manual; it is very detailed, and certain particulars can often be indicated by a single word! Have a look at the SL configuration dialogue http://www.qsl.net/dl4yhf/speclab/settings.htm#audio_settings

Let us know how you get on!

Ian

[allcart]

I've now got my FCD and the antenna has been ordered. Will download software and read some articles ready for when I set up.

[The Admiral]

I've now got my FCD and the antenna has been ordered. Will download software and read some articles ready for when I set up.

Good news Allan. Join the select 'gang'! Which antenna are you going for?

Ian

[allcart]

Hi ian, I opted for the 144MHz 3el LFA design from Innovantennas, in the end.

[jarraman]

hi ian.

sorted sound out.did you have to do anything in the scripts,or did you leave it as it come?,,questions ,questions,lol.