low pass filter

[295 antenna]

With today's electronic is a low pass filter necessary ? i installed one but as i was reading some info online i came across a discussion regarding low pass filters and that they are not needed anymore or maybe just on older equipment ?
Charles (Chuck)

[MDYoungblood]

I still use one, I have a radio that would knock out my DSL router, the radio doesn't interfere with anything else, using the low pass filter stopped that from happening. I tried other things first, the snap beads, a coaxial choke, etc.

3's

Greg

[Deleted User 14541]

It never hurts. I don't use them for my mobile but on the base I have one after the radio and after my 2 pill driver. A good tube amp doesn't so much need one but a filter is a good idea for a transistor amplifier. A few have a built in low pass filter but most don't.

You never know what kind of crap appliances the neighbors down the street have so I make every effort I can to stay clean.

[Mtn Lynx]

haven't gotten any complaints yet, but after reading about low pass filters I guess I'm going to install one just to keep the peace

[Deleted User 14541]

Guys that don't like them will say they have lower wattage with the filter installed. If your signal is clean to begin with you may not see any change in output.

[295 antenna]

Thanks guys .I installed on because like what was said earlier you dont know what the neighbors are using and i was also worried about my computer and modem .I was knocking out my external hard drive but not now

[KP68]

I have one in line after my drivers and before my final tube amp. I'm still getting settled in at my new station location but when I do get all settled in, I'll also have one installed after the final. No complaints from any neighbors and I do not cause any disruptions/interference with my household electronics and I want to keep it that way. Most important is how you run your station to begin with. Keep it clean and mean.

[Mtn Lynx]

Is the Paradynamics 1089 rated at 1000 watts any good? I read about it, as long as it is grounded I guess it's not a bad low pass filter.

[jessejamesdallas]

Had a problem pop-up couple weeks ago with my daughters headphones...When running my little tube amp she could hear me a little. So got out my trusty old MFJ low pass filter and hooked it up, and no change at all. Then tried my RL Drake low pass filter, and still no change.

Got a ferrite choke and snapped it on the headphone cord, and no more problem...

I don't put allot of stock in those low pass filters. specially running a Amp.

[Deleted User 14541]

You should be fine with the paradynamics brand. They have been around. My rule of thumb is use a filter rated for twice the power I'll put through it. No worries about running a ground wire to it. Use a double male pl259 and put it on the back of the transmitter. If you have to use coax keep it very short. Inches. You can find some higher end Drake or bencher filters and rf limited used to make a 3kw filter. I have a couple of the rf limited filters. Not saying they will work any better than the paradynamics.

The headphone issue probably wasn't because of harmonics. Your tube amp should be pretty clean because of the pi network you tune it with. The exception is those amps that have 6 or 8 final tubes in parallel. More tubes = lower plate impedance and the closer it becomes to 50 ohms the less effective your tank circuit is as a filter.

If the amp is overdriven, mistuned or the radio is super trucker tuned the IMD goes through the roof and a low pass filter will not help with that. If you buy a used filter it never hurts to open it up and test the caps. The last owner may have burned it up and you'll never know. It just won't filter.

[Blue Ox2]

GOOD info. I'll be adding some ferrite cores around my wife's stuff and I have a low pass filter I'll put in line with the amp when that project is better suited.

[Cutlass327]

So does the filter go after the radio before everything else or after everything before the antenna lead?

[295 antenna]

It should go after the radio or amplifier. Make sure of the watt rating