| Author |
Message |
    
Wrk3
Junior Member
Username: Wrk3
Post Number: 13
Registered: 4-2004
| | Posted on Thursday, April 29, 2004 - 6:46 pm: | 
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when looking 4 a good, low pass filter, what kind of specs should i look 4? |
Tech808
Moderator
Username: Tech808
Post Number: 2256
Registered: 8-2002
| | Posted on Thursday, April 29, 2004 - 8:04 pm: |
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Wrk3,
Look for one that will cover from 1.8 to 30 MHz
and handle at least 1KW of Power.
Copper should have the MTI ~ LM-TVX2 TVI FILTER's in Shortly.
Hope this help's.
Lon
Tech808 |
Tech237
Moderator
Username: Tech237
Post Number: 7
Registered: 4-2004
| | Posted on Friday, April 30, 2004 - 9:36 am: |
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Also look for a low insertion loss. This is measured in db and should be a low figure - around 0.1 is nice.
Anything you plug into your coax between your radio and the antenna will cause a loss of signal at the antenna on tx and at the radio on rx. Obviously you want to keep this as low as possible. I mention this as I have seen filters that worked great but showed a 1db or worse insertion loss. Admittedly they usually dont stay on the market for long.
The MTI Tech808 mentions is good, as is Vectronics, MFI and a couple of other lesser known brands.
I would also suggest that you do not buy a "cheap" one - it may be good, then it may not. |
Creator
Member
Username: Creator
Post Number: 77
Registered: 1-2004
| | Posted on Friday, April 30, 2004 - 10:54 am: |
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How does the Para-Dynamics PDC-1089 Rate? |
Tech808
Moderator
Username: Tech808
Post Number: 2260
Registered: 8-2002
| | Posted on Friday, April 30, 2004 - 1:03 pm: |
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Creator,
http://www.copperelectronics.com/cgi-bin/checkitout/checkitout.cgi?catalogSTORE:CKIE:prodV10-05780+
It is rated at 1000 Watts on 0-30MHz and 50 ohm
which is what you need to look for in one.
While I personally have not used or tried this brand I did check back thru the forum and found No negative comment's on it.
As Copper tries to carry the best in Equipment for it's Customer's I would give it a  up.
Lon
Tech808 |
Mdiver
Member
Username: Mdiver
Post Number: 82
Registered: 11-2003
| | Posted on Friday, April 30, 2004 - 9:01 pm: |
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When I run my amp the cordless phone has interferience, but the Sattlite tv does not??? Now my Neighbors that have also cordless phones And CABLE TV I block them out.
Amp is a Dave Made 2 Pill 400-peak
Ok the question is will This TVI filter help me??
If it doesn't can I convert my BASE dave made AMP to Moble???or Combo both 12 volt or AC.
Mdiver-252 |
Tech8541
Moderator
Username: Tech8541
Post Number: 175
Registered: 12-2003
| | Posted on Friday, April 30, 2004 - 10:57 pm: |
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if you search the forum, you will see where i did a test on one (hp8920's tracking gen). it tested almost as good as the higher dollar filters. i can't remember the figures, but i gave the insertion loss (the amount of power used by the filter) and the attenuation at 54mhz. anyway, like i said, it was almost as good as the higher dollar filters. i was sceptical myself at 1st due to the low price, and this is why i tested one. |
Tech237
Moderator
Username: Tech237
Post Number: 8
Registered: 4-2004
| | Posted on Saturday, May 01, 2004 - 9:31 am: |
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Mdiver,
While an TVI filter wouldnt hurt I dont think it would cure the problem either. Try a standard Phone RFI filter on the phones, either a commercial one or by winding any spare phone cord on a No 43 ferrite toroid (about 10-20 turns). Try doing the same for the power supply cable to.
K-Comm (Box 82 Randolph OH 44265. Ph 216 325-2110) make phone RFI filters and could probably put you in touch with a seller near you. |
Kirk
Intermediate Member
Username: Kirk
Post Number: 199
Registered: 6-2002
| | Posted on Monday, May 03, 2004 - 5:18 pm: |
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I agree with 237, but I think I'd wind my own. I've had some RF problems in the past on 20 meter HF and a Pioneer Subwoofer that had common-mode RFI. That cleaned it up rather nice....but that's a different problem. But go back to your radio. Is your limiter clipped and radio over-modulating? If so, nothing is gonna help you. You need to run as clean as possible. What are the cordless phones frequencies? Your Sat. is way up there in frequency, but some cordless phones were (and may still be) made around 45Mhz (I think). Most are 900Mhz or so, but maybe you have an older one? Or your antenna could be dumping RF into the box outside.....many different things. One thing is for sure, if you got rid of your amp, you could probably solve your problem....but I doubt you want to do that. CB Frequencies are troublesome to use any kind of power on. They tend to have spurs that land in other areas that consumer products use. Check http://www.palomar-engineers.com if you need a source for ferrite cores.--- |
Skunkweed
New member
Username: Skunkweed
Post Number: 8
Registered: 1-2004
| | Posted on Tuesday, May 04, 2004 - 2:35 am: |
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Buy Bencher YA-1 I`m using one of them. There is nothing better to buy. Mike |
Geekster
New member
Username: Geekster
Post Number: 3
Registered: 6-2004
| | Posted on Tuesday, June 15, 2004 - 12:32 pm: |
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On the Para Dynamics 1089...
I would say not the best out there. I can say this now as an unbiased comment LOL.
I used to work for Para Dynamics from 1993-1996 as a tech. PDC had a much better one which was built for PDC by Vectronics back in the day.
I use the Vectronics LPF's I have about 4 of em.
Good Luck. |
Ca346
Advanced Member
Username: Ca346
Post Number: 826
Registered: 8-2003
| | Posted on Tuesday, June 15, 2004 - 7:28 pm: |
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I use both the Vectronics (1500Watts) and the Para Dynamics (1000Watts). Appears to be a big difference in metal casings. Vectronics is much thicker metal. Much more solid. But guess what? No discernable difference in performance. BIG difference in price. Paid alot less for the COPPER unit. |
Geekster
New member
Username: Geekster
Post Number: 5
Registered: 6-2004
| | Posted on Tuesday, June 15, 2004 - 9:31 pm: |
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The Vectronics were made of aluminum. The PDC 1089 was a simple LC circuit where as the Vectronics used the 9 pole Chebyshev filter. The attenuation was much better on the spectrum analyzer after tuning them.
The PDC was never hand tuned so...? I guess it all depends on your ground, any mods to the radio and antenna height.
I may give the Copper unit a looking at.
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Bob_p
Intermediate Member
Username: Bob_p
Post Number: 194
Registered: 7-2004
| | Posted on Tuesday, August 17, 2004 - 8:59 pm: |
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Do you think the PDC 1089 would work with a Copper tuned RCI 2970DX with an I-Max 2K antenna? No other mod's or power. Just the radio as it came from Copper. |
Tech808
Moderator
Username: Tech808
Post Number: 3324
Registered: 8-2002
| | Posted on Tuesday, August 17, 2004 - 9:26 pm: |
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Bob p,
Yes it will.
http://www.copperelectronics.com/cgi-bin/checkitout/checkitout.cgi?catalogSTORE:CKIE:prodV10-05780+
FEATURES:
Helps eliminate TV interference.
Rated at 1000 Watts when used at 0-30 MHz
Includes two SO-239 jacks for PL-259 connectors.
Impedance 50 Ohm.
Size 5" x 4" x 2".
Lon
Tech808
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Bob_p
Intermediate Member
Username: Bob_p
Post Number: 195
Registered: 7-2004
| | Posted on Tuesday, August 17, 2004 - 10:59 pm: |
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Thanks Lon I had a PDC 1089 and when I was cleaning out the radio room it was tossed by accident. I wan't sure if it was helping but since I joined the board have learned that I should have grounded it.
So thanks again your knowledge is much appreciated
Bob |
Tech808
Moderator
Username: Tech808
Post Number: 3327
Registered: 8-2002
| | Posted on Tuesday, August 17, 2004 - 11:09 pm: |
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You are very welcome!
Always glad to help when & where I can.
Lon
Tech808 |
Ca346
Advanced Member
Username: Ca346
Post Number: 964
Registered: 8-2003
| | Posted on Wednesday, August 18, 2004 - 4:39 pm: |
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This posting thread reminded me I also had to ground my PDC1089 that I use on my HR2510 and a Galaxy350 thru an IMAX2000 in the shop/garage. This time of year (Hot!) it sits out there collecting dust. I have never had a neighbor omplain when I operate that system. Great little low pass filter. |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 202
Registered: 7-2004
| | Posted on Wednesday, August 18, 2004 - 6:40 pm: |
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Ca346 thanks I had one inline with my Cobra 148 GTL and Palomar 250. But when I took that setup outta line and replaced it with the RCI 2970DX
I put it in a junk box. I just thought I would get around to putting it back inline when or if someone said something. But when I was thinning out the junk box, I didn't notice it and out it went.
I had never grounded that filter and now after reading what people have said here. I will ground the new one as best I can.
I have a B&W 425 that rasises my SWR from 1.1.1 to over 1.5.1 and I just hate to see the SWR that high. Though I've heard the B&W filters are really great filters. That much of a change just doesn't seem right, and I'm not even sure it works. |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 257
Registered: 7-2004
| | Posted on Wednesday, August 25, 2004 - 10:11 pm: |
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Ca346 how did you ground it? Did you drill a hole or just use very thin wire to ground it with? Just wondering because the screws a really small and I don't think they would hold a #14 wire very well.
Thanks
Bob |
Ca346
Advanced Member
Username: Ca346
Post Number: 976
Registered: 8-2003
| | Posted on Thursday, August 26, 2004 - 10:44 am: |
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Attached a open flat spade type wire connector to one of the case screws. Used the original screw. #12 wire directly to a seperate ground rod. Solved my SWR problem. |
Bob_p
Intermediate Member
Username: Bob_p
Post Number: 258
Registered: 7-2004
| | Posted on Thursday, August 26, 2004 - 2:08 pm: |
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Ca346 thank you very much. I should have thought about the flat spade wire connector.
Thanks again
Bob |
