01:18:10	Brian Clark:	Hey Dave—Have you thought about the absolute calibration of the calibration sources themselves? That is, I assume the plan will need to have e.g. an absolute measurement of the pulser output power. And you probably need to characterize the beam pattern, cross-pol, etc of the transmitting antenna?
01:28:30	Frank Schroeder:	Speaking about passive sources: Do you see Galactic noise down in the ice at low frequencies? If at high frequencies there is only thermal noise and at low frequencies thermal + Galactic,, the Galactic part may be useful for calibration.
01:28:56	daveZ Besson:	brian: yes, absolutely. We did an anechoic chamber measurement (same chamber that Jordan derived the data from the paper that he just referred to) for the SPUNK Spice Core antenna.
01:29:26	daveZ Besson:	although we definitely should have done that in finer bins in angle.
01:30:37	Anna Nelles:	@Frank: The LPDAs see the Galaxy. But only the upward facing ones. Also, the ARA testbed saw it, but I am not sure whether the deep antennas see it.
01:31:12	Frank Schroeder:	Just brainstorming: if you have an azimuthally symmetric antenna, there should be no time-dependence of the Galactic noise over the day. So you could test how isotropic your antenna pattern is in reality if you search for variations of the Galactic noise part.
01:31:21	Cosmin Deaconu:	@Frank:  I didn't have time to talk about that obviously, but the high pass on our current downhole antennas is probably too high, so I don't think we expect a sizeable signal 200 m down, although if you averaged enough you could probably see it. The sun is a more interesting natural source at ~200 MHz frequencies, although that's only up for half the year!
01:32:26	Frank Schroeder:	Ok. You can average over several years though to look for variations in Galactic noise.
01:32:51	daveZ Besson:	to add to cosmin's response - yes, we have tracked the sidereal variation of signal strength in the testbed, A1, A2 and A3 surface antennas, which are the 'standard' fat dipoles. 
01:33:42	daveZ Besson:	As cosmin said, the in-ice antenna response to the galaxy is much harder to sort out (as well as the solar signal), in part because the source is moving and getting the interferometry right is touch in-ice....
01:33:48	daveZ Besson:	'tough'
01:36:39	Brian Clark:	@Dave,okay, thanks.
01:37:10	Frank Schroeder:	You would just need a periodic readout of individual antenna traces, no need for interferometry. If the source (Galactic Center) circles around at constant zenith angle, as it does at the Pole, the point would be not to expect a variation for rotational symmetric antennas (in contrast to LPDAs).
01:41:27	daveZ Besson:	@frank-yes, we already take such traces at 1 pps in ARA. Since the in-ice antennas are (as you point out) azimuthally symmetric, you won't see a sidereal variation...
01:41:45	daveZ Besson:	so I'm not sure what the signature would be if you don't see the source interferometrically?
01:42:58	Cosmin Deaconu:	I think the expected size of the effect downhole is likely too small to learn much without coherently summing waveforms.  The problem is that as you go deep, all above-surface signals get mapped to  steep angles at which your antenna is not very sensitive, so the already small added noise temperature gets even smaller, but since we already take the required data, it's certainly worth looking into!
01:44:20	Frank Schroeder:	There may be a number of things you can check:  1) Is there really no variation, or is there some non-uniform coupling to / propagation in the firn? 2) Is the attenuation of the Galactic noise with increasing depth of the antennas as expected? 3) Is the absolute height of the Galactic noise the same at all antennas at the same depth.
02:01:45	Krijn krijn.de.vries@vub.be:	I think this would actually be very interesting to see for a single track.
02:19:27	Cosmin Deaconu:	it's not hard to model that, but it will excite frequencies up to the discretization scale, which will not be well modeled (and you also have to worry about aliasing effects from the alignment of the grid with the track direction at that scale).
02:22:31	Krijn krijn.de.vries@vub.be:	Thanks for explaining. That gives a whole set of other features indeed.