| Author |
Message |
    
Sinker
Intermediate Member
Username: Sinker
Post Number: 120
Registered: 8-2005
| | Posted on Saturday, October 01, 2005 - 4:58 pm: | 
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Got a question for you. Seems I have run into a temporary issue as my Boomer AMP is soon to be replaced with a KLV.
However, I have a meter set between the amp and the antenna and the radio also has a swr meter on it.
With the amp OFF I get 1.1:1 to 1.2:1 readings through out the band. Things go up with the amp on though but only on the meter between the amp and the antenna the one on the radio does show some increase but nothing as drastic as the other.
On low power I get 1.2:1 to 1.4:1 between the amp and antenna
On med power I get 1.3:1 to 1.5:1 between the amp and antenna
On high power I get straight into the 3.1 range needle all in the red.
The swr reading on the radio though never goes higher than 1.3:1
Is this normal for the swr readings to be different at the radio and between the amp & antenna ???
Any ideas what would cause this problem???
Tim
CEF-634 |
Tech291
Moderator
Username: Tech291
Post Number: 247
Registered: 11-2004
| | Posted on Saturday, October 01, 2005 - 8:00 pm: |
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Sinker,
Are you recalibrating your swr bridge each time you are changing power level?
tech291
cef#291
kc8zpj
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Sinker
Intermediate Member
Username: Sinker
Post Number: 121
Registered: 8-2005
| | Posted on Saturday, October 01, 2005 - 8:42 pm: |
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Yes I am for every channel I check and for every power level as well.
The meter between the amp & the antenna is a Workman 5000 I just got from Copper but not sure how accurate it is as I have heard people say some meters are not.
At the radio I am just using the SWR meter on the radio itself (TR-696F-SSB Base), but have also heard people say they are less than accurate as well.
I do have a digital meter I could throw on and check things with. May try that in the AM before the CEF NET.
Antenna is now 41 feet from ground to feed point. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1581
Registered: 7-2004
| | Posted on Sunday, October 02, 2005 - 9:49 pm: |
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when SWRs with NO AMP INLINE are real low & staying the same with it inline but off & only climbing minimally with amp in lo & med, but skyrocketing on hi, it is not an indication of an antenna/swr problem, but reflect problem. try a few different lengths of jumper cable, radio to amp & amp to meter, see what changes you get that way(the coax length is NOT changing the SWRs, but affecting the reflect on high power, & how much power is getting pushed back). ground loop/poor ground also could cause high reflect on hi power, but not lower power levels. some installs work perfect the 1st time, & there are those that make me grab for whatever hair i have left |
Sinker
Intermediate Member
Username: Sinker
Post Number: 126
Registered: 8-2005
| | Posted on Sunday, October 02, 2005 - 10:43 pm: |
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Hey Patzerozero THANKS. I think I will just let this one go till the KLV comes in as that is what will be hooked up permanently. Then I can mess with all the jumpers etc. if there is a problem.
Tim
CEF-634 |
Kid_vicious
Advanced Member
Username: Kid_vicious
Post Number: 722
Registered: 9-2004
| | Posted on Monday, October 03, 2005 - 12:30 am: |
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hey tim, when you get that amp back from copper, make sure that you give the tubes a good "burn in"
period.
by that i mean, hook up all the coax, the power and everything else, then turn the amp on for the first time and leave it on standby (only the first switch on) for about 8-10 hours.
yep, leave it on for that long before you ever flip the second switch.
your tubes will thank you for this by lasting longer.
opinions? disagreements?
matt |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1591
Registered: 7-2004
| | Posted on Monday, October 03, 2005 - 10:22 am: |
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is 8-10 hours enough? not sure what the klv instructions say about that, but for that matter i think i get more out of the straight italian language instructions then i do out of the english translation-if that's what you can call it ! |
Sinker
Intermediate Member
Username: Sinker
Post Number: 128
Registered: 8-2005
| | Posted on Monday, October 03, 2005 - 11:56 am: |
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Got bored, checked all my grounds, changed out coax cables and still the same issue - Oh Well - Only one more week.
8 to 10 hours - I had NO IDEA but will do - thanks for the heads up and will read the book thoroughly - I can't read Italian though so will have to work with the English Translation....
Tim
CEF-634 |
Chad
Intermediate Member
Username: Chad
Post Number: 475
Registered: 11-2004
| | Posted on Monday, October 03, 2005 - 12:18 pm: |
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All you are doing diring that type of "Burn in" is running the heaters. I don't think it is needed. I burn in guitar amps but run plate voltage and signal into a dummy load to get the tube to the sound it will have after several hours of play, this keeps people from coming back claiming it sounds different. For RF I don't see it necessary other than some tuning settings may change after a few hours of use... I say run the new toy from the get-go!
Chad |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1592
Registered: 7-2004
| | Posted on Monday, October 03, 2005 - 5:49 pm: |
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last time i changed tubes in my 101E, rf parts instructions for burn in were some ridiculously long time like 100 hours or something like that...actually i think it was the fl2100b amp, not the radio, but it was a LONG time. |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1648
Registered: 7-2004
| | Posted on Monday, October 10, 2005 - 4:06 pm: |
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just checked-YES, the 100 hour burn in time was recommended for the tubes in my fl2100b.
if you go to rf parts 2005 catalog page 91, 'tube applications and suggestions', it says 'in an amateur radio amplifier, tubes will often require 50-200 hours of 'key-down' transmit time to remove the residual gas and condition the filament for full emission. it is well advised to allow tubes to operate in stand-by mode(filaments on, no transmit) for 10 hours before tuneup.
the article taking up about 2/3 of the page has some quickie info regarding radios & amps for those with little experience with tubes. |
Chad
Intermediate Member
Username: Chad
Post Number: 481
Registered: 11-2004
| | Posted on Monday, October 10, 2005 - 9:15 pm: |
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Right... KEY DOWN, Plates are high and electrons are flowing with load. As for standby burn in, if The tube is a directly heated cathode (filament IS cathode) I can see a point but so many today (most) are indirectly heated, I don't understand the advantage of stand-by burn in. My thoughts are let the ENTIRE tube guts get to operating temp WITHOUT plate voltage, apply juice, bias up, and let-er-rip, Heat it up further to normal operating temp, re-check and readjust bias if necessary and don't sweat it.
Chad |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1651
Registered: 7-2004
| | Posted on Tuesday, October 11, 2005 - 7:48 pm: |
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but, they do add the 10 hours in standby... |
