The 2011 SARA Regional Conference at TAO 
New to SARA -- Huge Interest in Pulsars
Joe Taylor, K1JT himself sent me to SARA. I am very interested in setting up for pulsar monitoring. I am a long-time ham, have about four acres (one in a nice, quiet area), and was wondering what other folks were using in terms of antennas, radios and the what the favorite frequencies are. I did find the Australian database of pulsars, but so far, that is as far as I have gotten.
Any help would be much appreciated.
tnx and 73
Robin / K4VU
Tags
Hi Robin,
Welcome to the SARAi forum. A pulsar-monitoring project is a fascinating undertaking, and you cannot do better than beginning with a recommendation from Joe Taylor, K1JT.
I'm not an expert on this (or any) topic but I'll offer a few approaches and we can discuss them more sometime, on or off-list. I'll point you to frequencies but what electronics to use depends on your approach, and is something for discussion. Signals are faint. People in general either want a big antenna, or they employ processing tricks.
You'll need to choose/build a receiver. Choosing a frequency will require a little research and there are many possibilities, starting with your available equipment. Choose a QRM-free spectral region -- one of the designated radio astronomy bands. The temptation will be to use a wide bandwidth to capture more energy, but remember that pulsar signals are dispersed (smeared across spectral space) by photon/electron interactions so that you'll need to de-disperse the signal for wide bandwidth if you intend to examine the pulse shape.
What antenna, and how to listen? First, you're an experienced ham with lots of planning and field experience, so you might build a big array and sensitive preamps, and identify a few known pulsars. The best starting point to identify candidates would be to download and play with Radio Eyes from radiosky.com, which is available as a free starter version and has a good pulsar data base. A big array is expensive in material and land, but it's a possibility. QRM will be a serious problem, as will antenna phasing. Few people would take this approach.
Second, and even with a smaller antenna, you can carefully time the capture of signals from known pulsars of known repetition rate and time-average the signals (digitizing several times across the expected pulse). The challenge here is one of timing the digitization of repeated 'windows' of signal, and recombining the windows to show the pulses. SARA member James van Prooyen is the best person to talk with about this approach and he has some words at http://www.radio-astronomy.org/?q=node/76 OK, OK, I know that this topic lists pulsars as transient phenomenon and I disagree.
Third, you can capture the signals in time but move to the frequency domain by doing an FFTi. You can start using Excel but will probably need to upgrade to Mathematica or another program that can deal with large data sets. Look for peaks corresponding to periods of pulsars that you would expect to find in the portion of sky that you are watching.
Fourth, you might apply the above FFT approach then select the nearby region of frequencies close to the pulsar frequency and discard all but this data. Then do an inverse transform and you'll recover the pulse shape.
Fifth, I've never found anyone using pulsars in SETIi search, but I have some ideas about how this might be done.
Hope this helps.
73,
David Fields
N4HBO
SARA board