(meteorobs) Question - radio meteor

[Paul Goelz]

At 10:10 AM 5/5/2014, you wrote:

>Well, up here in Halifax,NS,Canada 44N 63W there is not many 
>analogue stations now, I still use 83.24 MHz and hear a few meteors, 
>rest of frequencies 67.24,55.24 I hear nothing at all. I have no 
>idea what others are hearing at 61 MHz! tried but nothing.

For the record, I am still getting some residual carrier and lots of 
airplanes and meteors here in the Detroit area on 55.259 USB 
(produces a roughly 1KHz tone).  There is a second station displaced 
about 25 Hz down from the strong station that is too weak for 
residual carrier or airplanes but it does produce weak meteor 
pings.  I had a bit of a scare a couple weeks ago, though.  I glanced 
into the library (where I keep the sprectrogram running 24/7) and the 
stronger of the two stations had vanished!  I thought they had 
finally gone dark.  But it was temporary... it returned about 30 
minutes later.  WHEW!

>Anyway, just a curosity question. I listen in CW mode but a few 
>times messing around I listened on AM mode and heard odd meteor 
>pings just like a tuning fork. Why can I hear theses on AM ? Is this 
>the same AM as our radio use?     wish we could use AM!     I am 
>just at a loss now to find some frequency to try.

If you are hearing pings in AM mode..... and they are real, you 
should hear them in USB or CW mode also if you are tuned to the right 
frequency.  The key is where you are tuned and how wide your bandpass 
is.  In AM mode, your receiver probably hears plus/minus 10KHz from 
where it is tuned.  In USB or LSB mode, it hears maybe 3KHz up or 
down (depending on the mode) plus to hear a tone, the receiver needs 
to be tuned up or down from the actual carrier frequency by an amount 
equal to the tone.  In CW, it might be restricted to an even narrower 
bandwidth, with the same requirement of being tuned away from the 
carrier frequency by the desired tone pitch.  OR..... some receivers 
will offset the receive frequency by the desired tone frequency in CW mode.

The key to all this is accurate frequency calibration so you are SURE 
you are listening on the correct frequency.  I know I've asked 
before, but how absolutely sure are you that your receiver is 
receiving where it says it is?

You can also try another approach..... if you have a decent antenna, 
you can do surprisingly well with a TV tuner dongle and HDSDR 
software.  HDSDR is a complete receiver in software.  Add the TV 
tuner dongle as the front end, and you are on the air.  The nice 
thing about HDSDR is that in addition to all common software defined 
receiver functions, it also includes a spectrogram display.  But what 
it adds that your discrete receiver lacks is an RF spectrum display 
so you can see stuff that is not exactly where you are tuned.  Total 
investment (not counting antenna) is under $20 if you can believe 
that.  I have used both the dongle and HDSDR alongside my Kenwood 
TS480 and on the same antenna, they are VERY close in 
performance.  There is a learning curve, but you would be surprised 
how well the setup works.  I can tune between about 25MHz and 
2GHz.  For 20 bux!

Paul


Paul Goelz
Rochester Hills, MI
pgoelz at comcast.net
www.pgoelz.com