Home |
Search |
Today's Posts |
|
#1
![]() |
|||
|
|||
![]()
Hi Guys,
Results of the build and test were that the 7Mhz HPF worked very well with the "6" grade cores, but the 20Mhz LPF was crap (it used #6 as well). It started to roll off at 20Mhz as expected, dropped smoothly to -10dB by the time it got to 40Mhz, then stayed at 10dB at all frequencies above 40Mhz. I suppose the core should be a grade #10 or #12 instead of #6? or perhaps just a normal air core? JEFF "Jeff" wrote in message ... Thanks for all the suggestions. Ive got some Amidon T68-6 toroids to wind up, and will test the completed filter on a spectrum analyser next week. JEFF "Jeff" wrote in message ... Hi, Im confused regarding the choice of iron powder toroid for a 7Mhz high pass filter. I need to use a small size (T68) toroid. For the freq range, some reference texts say T68-2 is the one, others say T68-6" grade. I see differing "best Q range" specs for the 6 grade.....2-30Mhz......10-50Mhz...etc. Have similar need for 20Mhz LPF, but assume "6" is really the choice there. Any suggestions as to the relative differences and reasons to choose between grades 2 and 6 for the HPF in T68 size? Thanks, JEFF |
#2
![]() |
|||
|
|||
![]() "Jeff" wrote in message ... Hi Guys, Results of the build and test were that the 7Mhz HPF worked very well with the "6" grade cores, but the 20Mhz LPF was crap (it used #6 as well). It started to roll off at 20Mhz as expected, dropped smoothly to -10dB by the time it got to 40Mhz, then stayed at 10dB at all frequencies above 40Mhz. I suppose the core should be a grade #10 or #12 instead of #6? or perhaps just a normal air core? JEFF Then you haven't built the filter that you designed. The choice of core material will not affect the blow-by. If you measured the inductors at a low frequency, I would be pretty certain that you have way too much inductance at 20-40 MHz. W4ZCB |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
OT- The Five Iron | CB | |||
PRO-95 good choice? | Scanner | |||
Iron powder vs. ferrite cores for low-power inductors | Homebrew | |||
Iron powder vs. ferrite cores for low-power inductors | Homebrew |