FM Filter for SDR dongles

spongella

spongella

Thread Starter
SatelliteGuys Pro
May 12, 2012
1,625
1,231
Central NJ
Bought one of these to reduce FM broadcast band interference that can occur when using a SDR dongle. It works pretty well.
 

Attachments

  • IMG_1478.JPG
    IMG_1478.JPG
    63.4 KB · Views: 111
jorgek

jorgek

SatelliteGuys Pro
Mar 11, 2013
1,219
226
Near Toronto
I recently bought this fiter. It works extremely well. The 75 foot long wire antenna picks up lots of signals and was over loading the SDR-RTL front end with mosltly AM band interference. With the filter, its like having a whole new radio. Short wave listening is clean and it appears the noise floor is also lower.
 

Attachments

  • SDR HPF filter.jpg
    SDR HPF filter.jpg
    45.1 KB · Views: 33
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
After the move 3 years ago, finally getting HF and shortwave back. Found everything but my par FM filter. Found the NOAA one, but this wekend went digging and found the Par FM trap. My MLA30 loop is hearing fine down to DC.
 
  • Like
Reactions: c-spand
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
Cspaned, I have a sodium light now, but have a manual loop mover, me. For optimum receive I need to point to the light. My noise floor jumps a ton. Maybe have the power company turn it off and line the driveway with solar LEDS.
 
  • Like
Reactions: c-spand
Titanium

Titanium

AI6US
Lifetime Supporter
May 23, 2013
7,375
8,508
Meadow Vista, Northern California
Brian, witch is worse a sodium light or a LED? I need one or another to find my house.
Have found RFI from both types. Had experienced significant noise from the sodium outdoor flood lights at my office. Maintenance replaced them with LED types and the noise floor was dramatically reduced on HF and startup hits disappeared.

Have also had problems with LED lamps, just found the bathroom LED globe lights spew RFI on 15m. Purchased LED globe replacements at Home Depot last week, but haven't tested them yet.

Most LED lamps incorporate a switching power supply and one must question if the FCC compliance statement on the product is backed-up with an actual compliance test.

Purchase the lights from a reputable vendor with a good return policy and give it a try. I now am now in the practice of firing up the radio and watching the waterfall while firing up a new appliances and devices. :(
 
C

c-spand

SatelliteGuys Pro
Feb 25, 2019
1,233
722
1
Never knew that about sodium bulbs. Just like that they last a long time.
 
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
The power company will change my driveway light to a LED, just wanted opinions first. I think or at least hope the LED will be quieter. Right now the sodium light raises the noise floor tremendously on HF.
 
  • Like
Reactions: c-spand
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
I use clip on ferrite chokes on my antenna leads and usb cables inside witch helps alot, but outsise the antennas are naked and within 25 feet of the sodium lamp.
 
  • Like
Reactions: c-spand
Titanium

Titanium

AI6US
Lifetime Supporter
May 23, 2013
7,375
8,508
Meadow Vista, Northern California
The power company will change my driveway light to a LED, just wanted opinions first. I think or at least hope the LED will be quieter. Right now the sodium light raises the noise floor tremendously on HF.
Our private street light was changed to LED last year. Wish it would have been to a lower wattage LED as it appears to be much brighter (to the point of what I consider light pollution), even though the estimated output lumen was equal to the removed fixture. I am thinking that it may be due to the LED being a broad spectrum and higher temperature lamp vs the spiked and lower Kelvin temp of the sodium. In my opinion, if they give you a choice, consider lower output and a warm 3-4K temperature fixture.
 
  • Like
Reactions: FTA4PA and Cham
Cham

Cham

VE4GLS
Pub Member / Supporter
Dec 19, 2008
2,444
1,006
Boonies
Yes unless it's an active job site, for ambient lighting 3500K should be the absolute max. Much easier on the eyes.

Light intensity depends on the fixture height, lens, coverage etc., so difficult to guess unless you try the fixture first.

I have a few 35-60 watt yard lights in the 4000K range that aren't too bad, the lenses are made to direct the light downward so there is little leakage to adjacent areas. When I bought them they had 4000K or 5500K. Glad I chose the lower temp ones, but could be lower yet. Will see how long they last. Much less power consumption than the sodium and mercury vapour units they replaced, and similar coverage.

So far these are quiet on the HF band, haven't noticed any new interference from them on the usual spots on the bands I frequent.
Some of those wall-wars are horrible though for RFI, only way to fix them is a sledge hammer!
 
  • Like
Reactions: Titanium
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
And must say, you are not the grammar police, but no one else brought it up, so maybe you are. Other people read it fine.
 
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
New rule for Sat Guy's all spelling must be correct even if it is done with auto correct, otherwise you are a dunce.
 
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
Waylew, try being a automotive tech for 40 years plus. You will find the arthritis and swollen fingers do happen. Sorry to offend you with my typing.
 
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
I will tell you all something. If you think having a tumor removed fro your brain stem, having no balance and continuing to work to is easy, some of you spell checkers might rethink
 
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
MNy god I am so tired of this society, people with real disabilities get bashed and ones with none get paid.
 
Comptech

Comptech

SatelliteGuys Pro
Jun 26, 2006
3,174
2,361
Travelers Rest SC
I am sorry to rant. But I give it my all. I can not climb a ladder. You see after having my vestibular nerves removed from my brainstem. i have to be careful, but can still install a cband dish, just have to be extra careful. And to Waylew my eyes are doing way more than yours. One is not checking spelling
 

Similar threads

spongella
Replies
2
Views
782
KE4EST
KE4EST
Titanium
Replies
7
Views
2K
spongella
spongella
spongella
Replies
1
Views
617
kittyhas1000legs
kittyhas1000legs
Scott Greczkowski
Replies
167
Views
31K
Titanium
Titanium

Users Who Are Viewing This Thread (Total: 0, Members: 0, Guests: 0)

Latest posts

Top