I got my filter IC's from Farnell. Their website says they have 787 in stock @ £8.11 + VAT each (£9.73 inc). Go over £20 with an online order and you get free. UPS, next working day, delivery. Hope you have good eyesight they are flippin' tiny and not big enough for the "run a soldering along the pins" method. Fortunately they seem pretty robust, I missed soldering one complete edge of one of mine and it survived being powered.
That 20 kHz will almost certainly be Anthorn on 19.6. The LP filter is incredibly sharp set at around 16 kHz it'll pretty much remove even my huge 19.6 signal but at the expense of rise time and all the information above the cut-off frequency.
Spent the last couple of days re-engineering the aerials. Constructed another rotating mount, another single loop and a banana plug aerial patch panel. So I now have two vertical loops that can rotate independently. Ch1A has a loop with it's null aimed to get minimum signals from Anthorn/Skelton, meaning the lobes are more or less N/S. Ch1B has a loop set about 45 degrees clockwise from the first, so NW/SE. It still gets a fair amount of Anthorn/Skelton but less that being at 90 degrees. That's just how they landed, having drawn it out the second loop needs to go 135 deg clockwise to NE/SW. Ch1C has the horizontal loop.
Letting it run for a while like this to see how it performs. Alll HP filters in, only one LP filter set: 19 kHz in Ch1B.
PS. 4.5% cash back from Farnell via Quidco as well.
That 20 kHz will almost certainly be Anthorn on 19.6. The LP filter is incredibly sharp set at around 16 kHz it'll pretty much remove even my huge 19.6 signal but at the expense of rise time and all the information above the cut-off frequency.
Spent the last couple of days re-engineering the aerials. Constructed another rotating mount, another single loop and a banana plug aerial patch panel. So I now have two vertical loops that can rotate independently. Ch1A has a loop with it's null aimed to get minimum signals from Anthorn/Skelton, meaning the lobes are more or less N/S. Ch1B has a loop set about 45 degrees clockwise from the first, so NW/SE. It still gets a fair amount of Anthorn/Skelton but less that being at 90 degrees. That's just how they landed, having drawn it out the second loop needs to go 135 deg clockwise to NE/SW. Ch1C has the horizontal loop.
Letting it run for a while like this to see how it performs. Alll HP filters in, only one LP filter set: 19 kHz in Ch1B.
PS. 4.5% cash back from Farnell via Quidco as well.