- #1
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hi gang,
got a friend who lifes relatively close to a 1407kHz (multi kW) AM broadcast transmitter
he has a ~ 50metre run of 75 Ohm coax between a security camera and the recording/viewing equip. The 1407 kHz is getting into the system and causing the usual herringbone pattern on the displayed video
I have suggested trying some clamp on ferrite chokes on the outside of the coax to see if that minimises the RF signal. Still awaiting for a response on that test.
Secondly am looking at an inline notch filter (trap) a parallelled L/C combination and having a variable C so as to have some tuning ability of the notch freq.
firstly, there's lots of filter calculators online, none of them I have seen so far take the feedline or load impedance into account. how critical is that ?
In his case of course its a 75 Ohm system.
And Yes I know that at a last resort he may have to do a 2.4gig radio link for the camera. Tho a few components and connectors for a filter would be cheaper to implement ;)
Dave
got a friend who lifes relatively close to a 1407kHz (multi kW) AM broadcast transmitter
he has a ~ 50metre run of 75 Ohm coax between a security camera and the recording/viewing equip. The 1407 kHz is getting into the system and causing the usual herringbone pattern on the displayed video
I have suggested trying some clamp on ferrite chokes on the outside of the coax to see if that minimises the RF signal. Still awaiting for a response on that test.
Secondly am looking at an inline notch filter (trap) a parallelled L/C combination and having a variable C so as to have some tuning ability of the notch freq.
firstly, there's lots of filter calculators online, none of them I have seen so far take the feedline or load impedance into account. how critical is that ?
In his case of course its a 75 Ohm system.
And Yes I know that at a last resort he may have to do a 2.4gig radio link for the camera. Tho a few components and connectors for a filter would be cheaper to implement ;)
Dave