New to Meteor Detecting

[John101]

steppenwolf, et all

Greetings,

Here is what I must do when I run an external sound card device into SpectrunLab

Power up the PC

then plug the external device into a USB port

IF drivers are needed PC will let you know

Some PC/drivers require you to define the COM Port

If so, run FindComPort (a free 48k download)

Goto your Control Panel, then click Sounds and Audio Devices

then click Audio tab (I ignore the Hardware tab)

Sound Playback and Sound Recording tabs now give me the option to choose

USB Audio CODEC

I also select USB Audio CODEC under the Voice tab (because I dont know the difference Hi

Hi)

Now click the Volume tabs under both to make sure the port is not mute and notice more level adjustment

Next launch SpectrumLab, goto Options, then Audio I/O device

then Input/Pipe and Output/Pipe and select USB Audio CODEC.

I dont have a 'dongle YET so I used the SignaLink USB for this setup

Now it is only MONO so I have no I/Q (quadrature) signals but SignaLink paints SL's rtl_sdr_test waterfall a delight!

If my Quasi-SRD Telescope was not packed away until winter drives me indoors ld hook its I/Q to rtl_sdr for a test drive and better define level adjustment.

72, 73

John

N3AAZ

[steppenwolf]

Thank you for your further input John but sadly 'USB Audio CODEC' does not appear and neither does any other choice apart from 'microphone' - I guess the SDR/RTL device is simply not recognised by SL for some reason.

The search continues

[steppenwolf]

......and another update! I have a workaround in that I am using a virtual cable to route the output data stream from SDR# into the input of Spectrum Lab and I now see the data stream and hear it in Spectrum Lab!! Not sure that I approve of my method but it is a move forward!

[SteveNickolls]

Hi Everyone, I've been going through the wealth of data recorded over the past several days and came across this automatic screen shot (attached) of a long meteor trail (around 10 seconds duration) taken on morning of the 26th July by the Spectrum Labs software. From looking at other records part of the interest will be in considering what events up in the atmosphere led to the different recorded trails. The FUNcube Dongle Pro+ is using a frequency of 143 048 000 Hz, that's 2kHz below the Graves radar signal frequency to detect signals. Can anyone explain if that means a returned trail with a Doppler changed signal frequency above 2kHz equals a meteor that was moving towards my location from Graves?

Cheers,

Steve

[John101]

Steve and Steve

Congrations both

Steve on your capture, and Doppler study, some airplanes will paint the same picture acting as a reflector, most transmit on frequencies around 121 MHz / AM and Doppler and voice may be seen direct

Steve your workaround, now gives you access to S L's Watch List / Plotter and 'ligtyears beyond...HI HI

I am at a dead end here until I have applaction specific hardware

GL es GUD DX

72, 73

John

N3AAZ

[SteveNickolls]

Hi John, very sorry to hear you have come up against a 'brick wall'. I must admit that going the FUNcube dongle Pro+/spectrum Labs route, although more costly has proved so easy to set up and use. I'm afraid I would not have been able to resolve software problems had I come up against them. Do hope you can overcome the matter.

For anyone intending to utilise the Graves radar signal there is an excellent read available to download at www.britastro.org/radio/projects/Detection_of_meteors_by_RADAR.pdf and it has a wealth of links to other literature on the subject.

Cheers,

Steve

[SteveNickolls]

Hi, I spent yesterday going through the detection records for my first trial over the period 25th to 31st July. Using just the raw data I'll try to attach a graph of the detections which shows a daily pattern of peaks and troughs.

Cheers,

Steve

Meteor Detections Graph July 2014.xlsx

[Gasman]

Interesting Steve, seems to peak about every 25hrs give or take a couple , any ideas what that could be? What time of day are the peaks?

Cheers

Steve

[SteveNickolls]

Hi Steve, yeah sorry I can't do graphs in Excel to make things easier to see. The peak values are during the hours either 04.00 to 5.00 AM or 5.00 to 6.00AM. I could reduce the divisions to get detections every half hour. During the period of detecting 10 long trails over 10 seconds duration were recorded. I will try and post or attach some screen shots of these large events-the interesting part is (1) was it a meteor and if it was (2) how to explain the trails created as they are often quite different from each other.

Cheers,

Steve

[SteveNickolls]

Steve,

I have re-read about when meteors tend to peak and they do show an increase around dawn. As I understand it the earth is moving at around 30km/s in its orbit around the sun. The velocity of meteors varies but the average found in studies is around 16km/s. Sporadic meteors which shower the Earth all the time have no strong preferred direction of arrival, but the number of such meteors observed does vary through the day. On the dusk side and trailing edge of the planet only the meteoroids travelling faster than the Earth (able to catch up) and moving in the same direction will be detected. On the dawn side  or leading edge of the planet meteoroids travelling slower than the Earth will additionally be observed, peaking at dawn. Of course the detections could have come from anywhere East-South-West of Dijon so the time of detection in Nottingham will relate to dawn someplace well away from the reception site but the correlation of  peak detections around dawn holds. I'm happy that a first short trial has shown a fluctuating count of detections and shows a dawn peak. Obviously any shower would affect detection numbers above sporadic meteoroids. I'm going to start a longer period of observation and see what results come from it.

Cheers,

Steve

[wxsatuser]

When I did meteorscatter on 144MHz the best times for sporadic meteors was always from 0300 to 0600 local.

If you wanted a decent scheduled contact we always wanted a time in this period.

Of course it never meant you would get any decent meteors or complete a contact.

[SteveNickolls]

Yes thanks for that wxsatuser, early morning seems the time for most detections/hour. Holidays permitting I'm going to run a long session soon to see if other variations can be seen over time and whether any known shower shows itself by a higher number of detections. Very interesting stuff and it's keeping the grey matter working!

Cheers,

Steve

[wxsatuser]

Yes thanks for that wxsatuser, early morning seems the time for most detections/hour. Holidays permitting I'm going to run a long session soon to see if other variations can be seen over time and whether any known shower shows itself by a higher number of detections. Very interesting stuff and it's keeping the grey matter working!

Cheers,

Steve

For sure!

There is nothing like experimenting and getting results.

I might even give it a go myself, still have a 25 element log periodic on the mast, just need to recable it.

[SteveNickolls]

Hi wxsatuser,

Best of luck with the aerial and have fun detecting those meteoroids!

Cheers,

Steve

[John101]

Hi Steve,

Curiosity got the best of me…

To my knowledge, we (this side of the big pond) do not have a radar beacon such as Graves.  In search for a substitute over the horizon transmitter neat the 2 meter ham band, since my only decent vhf antenna is a 3 element Yagi, I discover commercial television video frequencies work a delight.

Receiver for now is the Yaesu 817, CW mode, via USB SignaLink to PC.  Not SDR yet, but needless to say a SDR dongle should arrive this QTH next couple days :>))

73

John

N3AAZ

FM19xa

[John101]

oops

Sorry about the double image :>((

[SteveNickolls]

Hi John,

Great to hear you can use tv video frequencies for detecting where you are, I think we are all digital tv in the UK now

Are you going for the Funcube dongle Pro+?

Thanks too for the screen shot.

Cheers,

Steve

[John101]

Hi Steve,

>>I think we are all digital tv in the UK now<<

…Not sure if my over the horizon TV transmitter is analog or digital, I’ll check and get back…

>>Are you going for the...<<

Since I now have a working meteor detector (FT817 / Argo es/or SpectrumLab [but not SDR])  I chose the ‘el-el cheepO!   NooElec SDR Mini USB RTL-SDR.  Some say toss the antenna that comes in the package but if it is as pictured (vertical (uhf - ¼ wave on 440) mag-mount then the threaded element can be modified with a ¼ or 5/8 wire/whip for an outstanding 2 meter ground plane antenna or 440 MHz ham band as is.  The mag-mount is too light for auto roof top highway speed but outstanding for stationary mountaintop DXpedition.  I am excited!

73

John

[Gasman]

Hi guys

Well got me a funcube dongle pro+ today, not tried my Sky@night aerial yet but wondering about a good wide band antenna for it. I`d also like to listen to occasional HF below 30Mhz as well as meteor monitoring and maybe the other ham bands too. I`ve seen the discone types but they cover 25Mhz to about 1500Mhz so am I likely to need two antenna for the ranges I`m looking at or is there an allrounder that could cover say 3Mhz to 2Ghz at all?.

cheers

Steve

[wxsatuser]

I use a Wonder Wand on my FT 817/Elecraft K2.

Not an outdoor antenna but can be used portable, tunes from 1.8>432Mhz

Not cheap around £130.......it has a huge whip that goes on the tuner or other bnc ants can be attached.

http://www.hamradio.co.uk/aerials-amateur-antennas-portable-antennas-wonder-portable-antennas/wonder-wand/wonder-wand-widebander-pd-2914.php

[Gasman]

Looks a good one but I wonder how it would fair with meteor scatter? I thought they had to be outside with unrestricted view SE as per the S@N instructions?

Cheers

Steve

[SteveNickolls]

Hi Gasman,

Congratulations on getting your FUNcube dongle pro+. Can't help re other aerials for picking up radio stations, I innocently expected if I wanted that I would need a commercial aerial fitted to the chimney stack. Once you start listening to the meteor pings you won't want other stations.   Good luck connecting up and aligning your home built aerial and we all await your future posts ("thinks" if we got enough people on-board detecting meteors we could share detection data/screenshots?).

Cheers,

Steve

[JRWASTRO]

.hi Steve,

This thread is so interesting I have been following it and wish we had such a clean source of RF to use as a meteor detecting radar as the Graves Radar.

About:

Can anyone explain if that means a returned trail with a Doppler changed signal frequency above 2kHz equals a meteor that was moving towards my location from Graves?

The RF doppler shift that you observe is due to the relative change in range between your antenna and the meteor.If the meteor was moving towards your antenna then there will be increasing RFD. If the meteor is moving away from you then the frequency will be dropping. If the meteor was moving on a circular path in relation to your antenna then no RF Doppler shift would be observed.

Jeremy.

[John101]

Greetings All,

Like a kid at the candy store here with my new dongle : > ))))

The only time an antenna and its transmission line match (pruned or cut or ‘tuned’ to a specific frequency) must be near perfect is for transmitting else the transmitter see a ’mismatch at the antenna feed point and a large percentage of power is reflected back down the transmission line for lost radiated energy that can damage the transmitter final amplifier.

My take on receiving antenna…for what its worth…been SWL-ing since 1955 and ham since 1957, retired 1997 electronic engineer.

All receiving antenna (unless tuned to a specific transmitting frequency) are an efficiency compromise.  IF not all antenna then the vast majority are referenced to the half wave dipole. The basic (single element) horizontal half wave dipole is ‘almost’ bi-directional with the radiation pattern broadside to its length (none off the ends) lQQking east, up through zenith, to west. In this case earth acts like a reflector and dipole height (above earth) makes an efficiency difference. The basic vertical dipole is omni directional with a 360-degree pattern about its axes, not lQQking (off the ends) at zenith. 

In my opinion a sloping (apx 45 degree) dipole broadside to the sunrise makes the best low cost, quick start, meteor scatter receiving antenna. The multi element Yagi (a dipole with more elements) is far more efficient gain wise with a more narrow bandwidth but almost impossible to setup with out an antenna analyzer.

Your dipole must be cut to Graves 143.05 MHz …

Your cut length mileage will vary (most efficient bandwidth in this case is between 485 to 502 mm) depending on height, transmission line type and length, near objects (roof, trees etc). IF using an antenna analyzer cut each element long then ‘prune in small increments for best SWR at 143.05

In free space and with an SWR of less than 2:1 >each<  element is

145 MHz, 19.25 in, 485 mm

143.05 MHz, 19.5 in, 495 mm

140 MHZ, 19.75 in, 502 mm

re image, in this case (a basic dipole) ignore the horizontal set of elements, they are not connected, they are second dipole used for cross polarization (apx 3dB gain) for better satellite comms. This antenna-set started life as TV ‘rabbit ears, two different telescoping sets.

Addressing a general coverage SWL antenna, the ‘long wire’ and the longer and higher the better has always worked best for me on MF, HF and low-VHF bands.  I can address a matching BALUN (between antenna and transmission line, for transmitting, with less than 2:1 SWR) if interested. Using this type dongle with a ‘giant broad band long wire energy catcher’ a band pass filters and/or attenuator may be required to protect dongles front end.  … BUT… I would defiantly install a set of back-to-back diodes at the dongle input port for protection! 

73 John

[Gasman]

Hi guys

So thinking I could just get an adaptor for the aerial coax plug to Sma fitting on the FCD mmmmm, not so easy apparently so I now need either to crimp an Sma plug or a Sma to BNC adaptor and then fit a BNC plug on the coax!. I guess there must be a good reason for Howard who designed the FCD to use Sma plugs!

Steve

PS thanks for the antenna info John!