| Author |
Message |
    
Cbblackbeard
Member
Username: Cbblackbeard
Post Number: 61
Registered: 12-2003
| | Posted on Tuesday, May 25, 2004 - 11:40 pm: | 
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I had virtually flat SWR when I just had my Antron 99 hooked directly to my radio. After hooking up my amp and a low pass filter, my SWR is through the roof. What can cause this? What should I do? |
Cuddlebear
Intermediate Member
Username: Cuddlebear
Post Number: 168
Registered: 3-2002
| | Posted on Wednesday, May 26, 2004 - 2:33 pm: |
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cbblackbeard,
You know, I've seen this many times and there are a few people out there that have had this problem. I have talked to a few techs out there that say that some amps are just not SWR friendly. The Blackcat 300 for one. I have never heard of a fix however for this problem except for one guy who said the only way he got it down was a antenna matcher. But someone out here might know more. |
Tech548
Moderator
Username: Tech548
Post Number: 76
Registered: 5-2004
| | Posted on Wednesday, May 26, 2004 - 6:26 pm: |
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Cbblackbeard
What is your SWR without the filter in line? If the SWR remains the same, then we know the problem is NOT the filter.
Jeff. |
Honkytonkman593
Intermediate Member
Username: Honkytonkman593
Post Number: 150
Registered: 12-2001
| | Posted on Wednesday, May 26, 2004 - 6:50 pm: |
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try a external ground to the amp preferably to a outside the house ground. if it fails raise yes raise the power from radio into linear slowly until the swr lowers abit...or try less. good luck |
Dx431
Advanced Member
Username: Dx431
Post Number: 863
Registered: 2-2002
| | Posted on Wednesday, May 26, 2004 - 7:19 pm: |
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Process of allimination...... |
Tech808
Moderator
Username: Tech808
Post Number: 2488
Registered: 8-2002
| | Posted on Wednesday, May 26, 2004 - 7:42 pm: |
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Just a thought here,
Is your Low Pass Filter hooked up Before the Amplifier as below,
ie: RADIO - LOW PASS FILTER - AMPLIFIER - ANTENNA? |
Allagator
Intermediate Member
Username: Allagator
Post Number: 291
Registered: 9-2002
| | Posted on Wednesday, May 26, 2004 - 8:00 pm: |
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I heard this thing one time about base radios that said ground helps a bunch !!!!! LOLL i had to do it !!!
I run a Lincoln and a blackcat 300 with a 102 whip and i have everything grounded (yes its a mobile and its still grounded ) and with the amp on i have no tvi !!!
NOTE dont go to auction and try to contact soneone on the CEF net it sounds like there in town and your yelling at them to come to the front desk at walmart but louder !! LOL
As for the LOW pass i dont use them cause i havent had the problem with that yet !!!
hope it helps !!!! If not come to my town and ill yell for you the next time they have a auction over here !!!!! LOL
Allagator |
Cbblackbeard
Member
Username: Cbblackbeard
Post Number: 62
Registered: 12-2003
| | Posted on Wednesday, May 26, 2004 - 9:59 pm: |
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Okay, here is my set up:
Radio - Jb76 - Low Pass Filter - Antron 99.
With the radio by itself into the Antron 99, I have almost flat SWR. When I hook up the JB76, my SWR raises. When I hook up the low pass filter, my SWR raises ALOT.
A friend of mine here said I should try longer jumpers from the radio to the amp, and from the amp to the filter. Would this help? |
Dindin
Intermediate Member
Username: Dindin
Post Number: 128
Registered: 2-2004
| | Posted on Wednesday, May 26, 2004 - 10:11 pm: |
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Cbblackbeard,where inline is your swr meter?are you reading swr of the antenna,the amp or the filter?i have seen a lot of mobil amps that had poorly designed tuning networks resulting in high swr,feedback and /or low output.that is why an antenna tuner or matchbox can help.HME is the only manufacturer I can recall that put an adjustable pi network on there solid state mobile amps.same thing as the tune and load on a tube amp. |
Hoskinmage
Junior Member
Username: Hoskinmage
Post Number: 26
Registered: 3-2002
| | Posted on Saturday, May 29, 2004 - 7:04 am: |
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you know i thought that i was the only one that this has happen to. i run a vr9000 and i run a black cat 300 with a dosey meter.with my radio only its 1.5 and when i hook up my cat it jumps to 2.0. i run at trunk mt. with a 5 ft. francis.i usely get a kee up of 200-225 and it mods. around 175. i have tryed almost every thing i could think of.is a francis a good ant.i used to run a pc76xl and a texas star 350 and francis and never had any problem.does a vr9000 known for standing wave(i had a pc76xl in the same set up,only thing differnt was the radio)or the black cat known also. my key up was set to 4 watt key up.
i hope this helps.
crybaby in e.ky |
Tech808
Moderator
Username: Tech808
Post Number: 2518
Registered: 8-2002
| | Posted on Saturday, May 29, 2004 - 8:29 am: |
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VR 9000 known for standing Wave?
HMMMMMMMMMMMMMMM,
Let's see now ordered one From Copper for Renegade CEF 296 hooked to a Palomar 775 and set it up with Standing wave 1.1 to 1.7 across the band. (using RG213 coax)
Also ordered one from Copper for CornCob CEF 166, Set it up, Works great with a an old palomar 250 1,1 to 1.6 across the band. (Wilson 1000 Trunk Lip Mount Antenna on his truck)
Also ordered one from Copper for Monk CEF296 Works great with a Old Texas Star 300-400 not sure. Again no high swr's. (Wilson 1000 Mag Mount)
Also ordered one from Copper for Beerman CEF322 and set it up and he runs it with a KLV-300 1.1 to 1.5 across tha band. (Mirror Mount on his 2000 Pete, with Astatic 3K Single)
We run our's with a KLV-300 and has 1.1 to 1.4 across the band. (Wilson 1000 Mag Mount)
Also orderd one for Mavrick with no amp has a 1.1 to 1.3 across the band. (Wilson 1000 Mag Mount).
I set all of them up with a 2 1/2 to 3 watt dead key with the RF Power Knob turned to the 7 o clock position.
If you have a LOW SWR with ONLY the Radio hooked up then it is not the Radio causing HIGH SWR Readings.
With High SWR's look/check at Coax, Jumper's, Grounding (Radio & Amp), Antenna, Mounting Location (Again make sure mounting location and antenna are grounded well.
High SWR's can be a nitemare to find the problem but when you do it is generally something very easy to fix.
Just my thought's.
Lon
Tech808
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Cbblackbeard
Member
Username: Cbblackbeard
Post Number: 63
Registered: 12-2003
| | Posted on Saturday, May 29, 2004 - 5:01 pm: |
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Thanks 808,
Like Dindin said, I also experienced lower output with the amp inline. I am going by the meter on my TR 696F-SSB. Should I try longer jumpers, or an antenna tuner? How should I be grounding my antenna, radio, amp? |
Allagator
Intermediate Member
Username: Allagator
Post Number: 296
Registered: 9-2002
| | Posted on Saturday, May 29, 2004 - 5:26 pm: |
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CB try to take the filter out and see if that helps !! if not take the blackcat out and check it if nothing helps try new jumpers !!!! its always the little things that gets ya sometimes !!!
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Hoskinmage
Junior Member
Username: Hoskinmage
Post Number: 28
Registered: 3-2002
| | Posted on Tuesday, June 01, 2004 - 7:44 am: |
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you dont have to respond to me like that. all i wanted was to know if my radio or box could have standing wav.i had tried to hook my past radio upn and i get 1.1 to1.4. also i didnt apreceiate the coment about these past radios. i have bought good radios(more than one)and i ahve good luck with them. you can be sure that i will not post agin.
john |
Tech808
Moderator
Username: Tech808
Post Number: 2545
Registered: 8-2002
| | Posted on Tuesday, June 01, 2004 - 8:58 am: |
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Cbblackbeard,
First I would suggest useing an External SWR/Watt Meter to check the meter in your radio to make sure it match's.
Try different length's of Jumper's say 3' and 6' and see if this help's.
On the Grounding:
Antenna or antenna mast pipe or tower should be grounded to a Copper or Copper clad ground rod 8' or 10'.
I have all of my Radio's, Antenna Tuner, Amps, and Meter's, Rotor Control, Power Supplies grounded to a separate ground rod less than 10' form all of the equipment.
It also is Possible the you may have a bad or loose SO-239 Connector on your TVI Filter or Amp.
You can check this with a Volt/Ohm Meter or check to make sure the Center of the SO-239 has not been pushed in on the filter or amp and is making good contact.
Hope this help's.
Lon
Tech808 |
Cbblackbeard
Member
Username: Cbblackbeard
Post Number: 64
Registered: 12-2003
| | Posted on Tuesday, June 01, 2004 - 6:46 pm: |
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808
Grounding my antenna in the manner that you described might be a little difficult. My antenna is on the roof of a ten story apartment building, and the manager doesn't even know it's up there.
As for an external SWR meter, I hooked up my Dosy PM 1000 and got the same readings.
I also checked all the connections and they all seem to be fine.
I think I might start with longer jumpers. I am using 3' sections of RG213 between my radio - amp - and filter. I'm going to try 6' sections. |
Dindin
Intermediate Member
Username: Dindin
Post Number: 143
Registered: 2-2004
| | Posted on Wednesday, June 02, 2004 - 5:28 pm: |
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Blackbeard,on a tall building you do still have usable ground options.in older buildings castiron was used for vent stacks.metal flashing around the perimeter of the building or maybe plumbing running to rooftop cooling towers.another thought is do a search on the web for counterpoise ground for other ideas. |
Cbblackbeard
Member
Username: Cbblackbeard
Post Number: 65
Registered: 12-2003
| | Posted on Wednesday, June 02, 2004 - 7:30 pm: |
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Thanks Dindin.
Now that you mention it, there ARE vent stacks and things like that up there. |
