Re: Ground noise on 23cm?

Neil Smith G4DBN

I've used one of John's filters for ages. Through loss is tiny, something around 0.15dB increase in NF when I put it in front of a DDK preamp on my HP8970B compared with an SMA barrel connector.

I am 51km LOS from Emley Moor and there are no cellphone masts within 2km, but the problem was severe. I had about 15 noise spikes in many directions before I added the interdigital filter. It has SMA connectors.

Neil G4DBN

On 17/09/2020 10:05, Anthony Coldman via wrote:

Morning all


I would agree with others that a filter in front of a preamp is an almost must now, I have built ones for 23cm and 13cm using the information on this site and the difference is night and day, If you prefer to buy you can also have a look at PE1RKI site he produces nice filters as well.




Anthony G7LRQ

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