Moved subject to new thread for sixer I have not been here long but have learned a sh#% load of stuff from you guys (and girls, still wishing Kage) I just finished my first project a low pass filter ,and I post it here for your criticizm. I started with a Coilcraft P7LP-157L with a cutoff of 150mhz. 2 female bnc connecters a small heat sink and some very ugly soldering, sorry no pics of the solder( this was my first electronics project)
I was reading another post on here about using a police scanner to find 2nd 3rd 4th harmonics well I did just that, my scanner could not go low enough for 2nd or 3rd but did pick up 4th at 385.2mhz and 5th at 481.5mhz but after installing my new filter the scanner would not lock on to anything, so I think I have a winner.
These Coilcraft filters are way easier than building a circuit from scratch and I got them to send me two for FREE!. Now on to my vhf field strength meter. Sixer
I came across coilcraft searching for low pass filters then I saw the free trial products, I wish I would have ordered more stuff 'cause it appears to be a one time only deal. So if you use the free trial, order lots.. Sixer
One of my next projects happens to be the same thing. My plan is to make a 7 pole filter or at least a 5 pole.
My transmitter runs clean enough as is right now, but could always use filtering improvement from the initial amplifier tank tuning. Last time I checked I do have a 2nd order harmonic that is weak enough that I didn't worry at the time. Lucky for me it's on a frequency that isn't used by anything.
I use a 10 watt tube amplifier instead of a transistor amp so the natural matching output section does a good job at removing most harmonics as is.
You're on the right track though. One of the most important things is filtering that signal. First thing that usually gets pirates caught is interfering with other communications.
Should probably split this thread into a new one for you.. hmm
Would be really neat to build a whole transmitter into a clear plexiglass box. Sure would make for eye candy when showing it off to friends. I just used the floppy disk box because that was what was laying around and I needed something quick. Sometimes cool ideas come from thinking fast.
center pin on the bnc connector input to pin#1, outer shield of bnc to ground, same on the output, center pin of bnc to pin#9 outer to ground. Thats all I can say about that, double check and try again??? mine worked great first time out. DiD you get this as part of their free trial? sixer.. CYNR 96.3Fm Playing good music for BAD people
Hey Sixer. The only difference is I used so-239 in and out and used 52 ohm coax for in out. Yes i did follow your GREAT advise and was shipped 2 lpf smd pc modules for free.. Im ashammed to say that i am an etech working on consumer electronics since 1981 . I really appreceate your help .Man i was so disappointed my lpf didnt work. Of course so was my wife ( my xmitter kills tv) as i use an outside antenna for our tv signal source.If you want you can phone me at 540-895-9465 and i can give you all details on my set-up.TIA Sixer . Craig
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