Interference problems

If you are experiencing problems due to interference (have a look at the shortest baseline on the SPD amplitude spectrum display), the following may help. Around 1420MHz you may experience `galactic' interference from 21cm line emission by local HI.

• Determine if there is a range of channels left that is ok. You may need to type x, followed by a, to get an Amplitude display with channel numbers along the bottom. If there is no interference free range of channels spanning about 50% of the band you may want to reconsider your frequency choice.
• In the CACOR window select a different channel range for CACAL calculations and display in vis with the command tvchans c1 c2 [c3 c4] in the command box in the CACOR GUI. (See section 8.4.2 on page  for more information.
• From now on VIS and CACAL will be using data based on the new channel range, so you can retry CACAL.