Copper Talk » Ask The Tech » General Technical Questions » Low Pass Filter efficacy « Previous Next »

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

Stacy_adams
Junior Member
Username: Stacy_adams

Post Number: 16
Registered: 12-2009
Posted on Friday, May 07, 2010 - 2:44 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I recently acquired a Bencher YA-1 to prevent TVI for a few folks in my neighborhood when running amplification. It does the job nicely. However, I noticed that a 100 watt dead key measured without the filter equals 88 watts measured with the filter in line. (I am using a LP-100A for these measurements). We swept the filter with a frequency generator and measured the response on a scope. We noticed it was a bit more narrow at 10 meters than at 80/40/20. Is this is characteristic of these filters? I recognize that there is some loss in the coils/caps which is stated as .2db but is this the real-world loss to be expected?

If anyone has experience with these filters I'd be appreciative of any feedback.
Top of pagePrevious messageNext messageBottom of page Link to this message

Stacy_adams
Junior Member
Username: Stacy_adams

Post Number: 17
Registered: 12-2009
Posted on Monday, May 10, 2010 - 10:50 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I received a reply to my email to Bencher. They advised that the filter is tunable and must have been tuned toward the 80/40/20 range with a rolloff and therefore less watts in the 10/11 meter band.
Top of pagePrevious messageNext messageBottom of page Link to this message

Dale
Senior Member
Username: Dale

Post Number: 1588
Registered: 12-2002
Posted on Tuesday, May 11, 2010 - 6:00 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

im thinking about buying one .just alot of money
i dont reeally have at the moment.wonder how ya
tune them .id want mine tuned for 10/11 meters
dale/a.k.a.hotrod
cef426
cvc#64
Top of pagePrevious messageNext messageBottom of page Link to this message

Stacy_adams
Junior Member
Username: Stacy_adams

Post Number: 19
Registered: 12-2009
Posted on Tuesday, May 11, 2010 - 10:59 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

There are 3 screws on the bottom of the case. They are set at the factory to rolloff above 30mhz. Mine was used and somebody messed with it. I retuned it by taking it apart and adjusting them until the watts in equalled watts out. That means the rolloff is above 28mhz or 10 meters. Fine by me...
Top of pagePrevious messageNext messageBottom of page Link to this message

Tech833
Intermediate Member
Username: Tech833

Post Number: 179
Registered: 12-2001
Posted on Wednesday, May 12, 2010 - 1:22 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

In order to tune that filter properly, you need a spectrum analyzer with tracking generator. But, your method might get it 'close enough' for what you need.

I do have the proper equipment to tune that, and would be happy to tune it for you if you pay postage both ways.

Your radio 'Mythbuster' since 1998
Top of pagePrevious messageNext messageBottom of page Link to this message

Charliebrown
Member
Username: Charliebrown

Post Number: 88
Registered: 10-2002
Posted on Tuesday, August 17, 2010 - 10:50 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

TECH 833, Is the p03-00003 df3000 3kw low pass filter that copper sells tuned best for 11 meters or is it like the bencher low pass filter? How well will this filter perform for 11 meters? This filter copper sells is the lowest price filter I have ever seen for the amount of power it can handle. What can you tell me about this filter?. I hope to get my order out to copper on some more equipment next week and I might include this item depending on the facts you give me. I thank you for your help as always. Your freind CB
Top of pagePrevious messageNext messageBottom of page Link to this message

Charliebrown
Member
Username: Charliebrown

Post Number: 91
Registered: 10-2002
Posted on Monday, August 23, 2010 - 6:38 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Does anyone know just how well this low pass filter works that copper sell and if it is tuned for 11 meter or is it like the bencher low pass filter and needs tuned to work better?
Top of pagePrevious messageNext messageBottom of page Link to this message

Tech833
Moderator
Username: Tech833

Post Number: 1849
Registered: 8-2002
Posted on Tuesday, August 24, 2010 - 12:53 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hi there, CB.

The full review is here- http://www.copperelectronics.com/cgi-bin/discus4/board-auth.cgi?lm=1265669558&file=/7750/112600.html

That chart in the review is not something reprinted from their literature. I actually swept that using a tracking generator and spectrum analyzer and plotted the response for that chart. What you see is what you get. A darned good filter that does not require tuning.
Your radio 'Mythbuster' since 1998
Top of pagePrevious messageNext messageBottom of page Link to this message

Charliebrown
Member
Username: Charliebrown

Post Number: 92
Registered: 10-2002
Posted on Tuesday, August 24, 2010 - 7:52 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Sorry 833 I had not seen the review. I will be adding this to my order. The review did answer another question I had been wondering about and that was if a cb would cause tvi on the new digital tv set. Good to see that it does not. Thanks a lot again for the facts and info TECH 833.
Top of pagePrevious messageNext messageBottom of page Link to this message

Tech833
Moderator
Username: Tech833

Post Number: 1850
Registered: 8-2002
Posted on Wednesday, August 25, 2010 - 1:06 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I never said it wouldn't interfere with a new DTV, but it is certainly much less likely.

The worst thing we have to worry about now is those darned cheap amplified speakers.
Your radio 'Mythbuster' since 1998
Top of pagePrevious messageNext messageBottom of page Link to this message

Charliebrown
Member
Username: Charliebrown

Post Number: 93
Registered: 10-2002
Posted on Saturday, August 28, 2010 - 7:46 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

TECH 833, I received my low pass filter and when I connected it I noticed that I had no receive. So I tested my swr and it was out of site. I then disconnected the filter and connected the ohm meter to each side of the center pin on the filter and I had nothing showing on the filter? I only ran 4 watts through the filter when I checked the swr so I know I did nothing to it. All my jumpers checked good and when I connected the radio back the way it was before I connected the filter and everything was fine. I think I got a bad filter. What do you think?
Top of pagePrevious messageNext messageBottom of page Link to this message

Tech833
Moderator
Username: Tech833

Post Number: 1857
Registered: 8-2002
Posted on Saturday, August 28, 2010 - 12:05 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I think you're right.
Your radio 'Mythbuster' since 1998
Top of pagePrevious messageNext messageBottom of page Link to this message

Charliebrown
Member
Username: Charliebrown

Post Number: 94
Registered: 10-2002
Posted on Saturday, August 28, 2010 - 4:26 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Thanks TECH 833 for your fast response. I have informed Copper of the problem.

Add Your Message Here
Post:
Username: Posting Information:
This is a private posting area. Only registered users and moderators may post messages here.
Password:
Options: Enable HTML code in message
Automatically activate URLs in message
Action: