Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

A FEW QUESTIONS ABOUT LOW PASS FILTERS

Stellasstillarat

Stellasstillarat

Active Member
Aug 14, 2014
488
59
38
59
Is there only reason to use a low pass filter ? Interferance ?

Or can it benefit your station. If so what other benefits besides stopping rfi?

Drake seems to be the choice of many.

Has anyone ever used the rf industries df 3000,, MFJ 704 or Nye.

If I do need one id like to know what your using and how long you've had the same one without issues. And of cause how's it perform?
Only requirements is 1000 RMS.
 

Basically a low pass filter suppresses harmonics generated by your signal ie 27Mhz second harmonic is 54 Mhz and that was right in the analog TV band. Heres the catch, If you are blowing 1000+ and the amp is dirty a low pass filter just makes your transmission line a little longer. I got a guy across town that runs a 1x4 pill. I can sit 5 channels either way and hear him. Thats why we have filters on our radios as well. Sure they help but remember to ground the filter too. Not just are TV's affected but anything that can resonate at either the fundamental or one of the harmonics. Back in the day I ran into someone almost two blocks away telling me they heard me on the phone. He was very cool about it and I realized just how dirty my amp was running. Take a little time and read up on the subject, it's interesting.
 
I use one of the RF Limited DF3000's and it works well. While it's not a bencher or Drake made one, it still works like intended and can be plugged in either way. Just add it inline with your current setup. If running an amp as well I would recommmed getting 2 of them. One for after the radio and one for after the amp. JMO and experience with the RF Limited df3000. Keep away from the MFJ one, read the reviews of it and you'll see all the issues people have had with them new out of the box. Again JMO.
 
  • Like
Reactions: cwk
I use a Barker & Williamson FL1500/10. Handles 1500 watts easily, cut-off freq. of 34 MHz with max. attenuation at 52 MHz. MINIMUM attenuation is 72 dB. Negligible insertion loss.
 
  • Like
Reactions: cwk
I've definitely been reading. I've found that before concidrting purchasing any thing I might want to add to my station research is required. Then I ask you guy's for advice. I need to figure out how to ground my station and antenna as I've never had one, a ground that is. On either my station or antenna. I think I'm going to add a post about proper grounding. This I feel is going to be a tough oen concidering the room my stations set up in. There's so much I need to learn if I want to run a proper setup, or as close to proper as I csn get it. I've a feeling this one's gonna be a real bicth!
222DBFL said:
I use one of the RF Limited DF3000's and it works well. While it's not a bencher or Drake made one, it still works like intended and can be plugged in either way. Just add it inline with your current setup. If running an amp as well I would recommmed getting 2 of them. One for after the radio and one for after the amp. JMO and experience with the RF Limited df3000. Keep away from the MFJ one, read the reviews of it and you'll see all the issues people have had with them new out of the box. Again JMO.
Click to expand...
 
Good stuff here. I know I shouldn't be saying this therefore I will. Sometimes it's nice to kick out the lpf and "Entertain" certain pain in the ass neighbors at 3:00am by just rolling down the power a bit and playing Frank Sinatra.' In The Wee Small Hours' comes to mind but like I said I shouldn't be saying this.

I hear it sounds pretty good yet weird coming from the blender.
 
  • Like
Reactions: 222DBFL
I'm glad you brought that up. My intrest in a low pass filter only came to me because of my change from the a99 to the I max. I did post in an earlier posting that In six months of operating with my a99 at 12' in the air not a single complaint from nabour's about rfi. For some reason I have it in my head that the I max is going to change that. I think I'd better get a grounding system setup. And I've no idea where to begin. So I will be doing some research on that and put the low pass filter on the burner for now. What good is a low pass filter if my station isn't grounded.I definitely got ahead of myself.
cwk said:
Good stuff here. I know I shouldn't be saying this therefore I will. Sometimes it's nice to kick out the lpf and "Entertain" certain pain in the ass neighbors at 3:00am by just rolling down the power a bit and playing Frank Sinatra.' In The Wee Small Hours' comes to mind but like I said I shouldn't be saying this.

I hear it sounds pretty good yet weird coming from the blender.
Click to expand...
 
Stellasstillarat said:
I need to figure out how to ground my station and antenna as I've never had one, a ground that is. On either my station or antenna. I think I'm going to add a post about proper grounding. This I feel is going to be a tough oen concidering the room my stations set up in. There's so much I need to learn if I want to run a proper setup, or as close to proper as I csn get it. I've a feeling this one's gonna be a real bicth!
Click to expand...

The following link talks about wind turbine towers but is equally applicable to radio towers. Lots of reading and links included.

Lightning Protection
 
  • Like
Reactions: cwk and 222DBFL
One thing worth mentioning that no one has. Put the filter after the radio but before the amp. It will cut out a lot of the junk before it gets amplified. As the saying goes, junk in = junk out. Also by doing this, the power level is much lower therefore a lot less stress on components in filter.
 
  • Like
Reactions: 222DBFL
Same thing I recommended Crusher. One after radio and one after amp. 3rd post. But yes, clean in equals clean out. Been hearing this one a lot lately!!
 
  • Like
Reactions: Crusher
yup you said it, my bad. Usually if you can knock it out at the source. Much easier on rest of system. Even better would be a band pass filter. With modulation cranked and a lot of guys using the export radios that have been leaked and tweaked so the output of radio does double what final is rated for. Your gonna have harmonics all over the place.
 
  • Like
Reactions: 222DBFL and wavrider
I know you know what you're talking about and you are probably the one that mentioned the low pass filters to me a long time ago. At any rate, good info!!
 
I have used the Bencher YA-1 low pass filters for years now. Like your antenna and coax, why skimp? Although... I read on here that a staff member burned one up :whistle::whistle:

They can still be found on DX Engineering's site as I've read Bencher Inc. sold out to them:

http://www.dxengineering.com/parts/bnr-ya-1
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back