| Author |
Message |
    
Sinker
Intermediate Member
Username: Sinker
Post Number: 197
Registered: 8-2005
| | Posted on Sunday, October 30, 2005 - 7:03 pm: | 
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Hey thanks to Starface my Maco V-5000 is sitting pretty atop its tower but now I have some SWR questions and perhaps issues:
OK the SWR readings running bearfoot are as follows:
- Channel 1 = 1.3:1
- Channel 20 = 1.1:1
- Channel 40 = 1.1:1
I like this and can live with it.
NOW - when I turn on the KLV nothing changes when it is in Stand By mode but once turned to Ready I get the following results:
SWR Reading Between Radio and Amp:
- Channel 1 = 1.5:1
- Channel 20 = 1.7:1
- Channel 40 = 1.9:1
These reading worry me and seem reversed from the readings above - I can't figure it out.
NOW the strange part is the reading between the Amp and the Antenna are as follows when also on:
- Channel 1 = 1.3:1
- Channel 20 = 1.3:1
- Channel 40 = 1.4:1
Could be better and may need to work on this.
So QUESTION 1: Why when the amp is on do the SWR Readings between the radio and amp go so high and why not in line with their barefoot readings (seems they reverse but higher)?
Question 2: What can I do to correct this problem?
Question 3: Am I going to hurt my equipment running it with these numbers?
BTW - Getting things dialed in, with 1.5 watts input on HI/HI2 I am getting just over 500 watts dead key and 750 watts swing on AM. I usually run it on LOW/HI1 and Dead Key about 300 and swing to between 450 and 500 watts on AM.
OH YEAH
Question 4: I have about 10' to 15' of extra coax laying on the ground. If I cut it to length and put on a new end will this change my SWR for the worse (I don't wanna do that - no way no how)...
Sorry if these question seems basic and dumb but I am still learning. Still have to clean up the installation a bit and then will get pics for all of you.
Tim
CEF-634
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Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1796
Registered: 7-2004
| | Posted on Sunday, October 30, 2005 - 8:47 pm: |
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1. assuming you are recalibrating 'cal' knob...impedance of amp may not be perfect, or of extra piece of coax; or 'reflect'. pretty close to normal, a bit lower would have been nice, but not bad. the reading between amp & antenna is more important. and those readings when 'ON' are GOOD!
2.try changing coax length or lengths between radio & amp, or radio/meter/amp & PHYSICALLY moving amp to avoid coiling coax if you need to go longer then what you are currently using. MANY times these problems arise when trying to use the SHORTEST piece of coax possible. rf is 'reflecting' back from short piece of coax. forget 1' or 18", try 6' for starters.
3. swr #'s, no. as for your BTW, swing #'s are much more in line with what i'd say the 4 EL509/EL519 tubes are likely to put out. FORGET the 1000 as implied by the name & FORGET 1400 as per brochure. as output nears 1kw, 'harmonics' & other demons begin to rear their ugly heads. i'd like to see a little less dead key, but since you have no variable watts on radio, keep an eye on heat. by design tubes get hot, but not owning a kl1000, i'm not sure HOW hot it really gets under normal operating.
4.leave it. if you didn't, & it's still possible, make a 1' coil of about 6 turns a couple feet underneath antenna & tape it to mast pipe. works a choke for rfi. sort of. otherwise, stretch out/reroute extra few feet & you'll be fine.
5.you have yet to ask a dumb question. several responses to your questions have reminded me of things i may need to do.
6. |
Starface
Intermediate Member
Username: Starface
Post Number: 269
Registered: 1-2005
| | Posted on Sunday, October 30, 2005 - 9:21 pm: |
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It was all in a days Fun and I hope a life time of friendship.
Till next time
Starface CEF#476
Southeast Net Control
Auburndale,FL
Dixie CEF#611
Southeast Net Control Asst
Auburndale,FL |
Kid_vicious
Advanced Member
Username: Kid_vicious
Post Number: 762
Registered: 9-2004
| | Posted on Monday, October 31, 2005 - 12:21 am: |
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sinker, congrats on getting the tower and maco in the air!
first off, dont worry! when we are discussing things on the forum, one thing we all have in common is the drive for perfection and the reality of never being able to get there.
no matter what you do, your SWR will never be a perfect 1 to 1. it only exists in theory.
the rule of thumb around here is, if it's 1.5 or less, and the actual antenna cant be adjusted for anything lower; then leave it, and sleep soundly at night.
now for the questions:
1. the output jack of your radio is 50 ohms. (i know you cant measure it on your VOM but dont worry, it is)
an amplifier that is intended to connect to your radio must have an input impedance of 50 ohms also. if the circuitry inside the amp ends up creating a 53 ohm load, then you will see a slight SWR between the radio and the amp.
this difference in impedances can be created by other means also. the improtant thing to remember here is that this is one of the only times when changing a jumper length will do some good.
in my setup, if i use a three foot jumper between the radio and amp, i see a 2.2 to 1 SWR.
if i use a 9 foot jumper, i see a 1.4 to one SWR.
i use the 9 foot jumper.
also, i dont like to run an external wattmeter/SWR meter in between the radio and the amp. too much excess signal loss for my tastes. i use the SWR meter in the radio to monitor mine.
make sure you are tuning the amp properly each time you change channels, because what you are doing is tuning the input of the amp to the channel you are on. if the amp is tuned for a different channel than the one that you are on, you will definitely see some reflected power back to the radio.
also, re-calibrate the SWR meter for each channel and each change in power output.
(i guess i kind of touched on question 2 here also)
3. you will not hurt your equipment. these numbers are fine to operate with.
the SWR numbers that you quote for the amp to the antenna with the amp on are GREAT!!!
do not mess with the antenna (of course you can if you feel you must!) 1.3 to 1 is a great SWR!
4. you will not change your SWR by cutting off some coax. if you do notice any slight change in the reading after cutting the coax, it is just the meter fooling you, the SWR is the same at the input of the antenna as it always was.
if i were you, i'd find a place to coil up that excess coax out of the way. im giong to bet that sometime in your radio future; you are going to need that extra length, and will be very mad at yourself for cutting it off back when you, "just cant possibly think of a reason why i would need it."
the only reason i would cut that LMR400 is if i needed it to make my new 9 foot jumper for my radio to amp connection.
have a good one,
matt |
Outkast
Member
Username: Outkast
Post Number: 51
Registered: 9-2005
| | Posted on Monday, October 31, 2005 - 12:42 am: |
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I have the exact opposite problem with my radio, although I dont really percive it as a problem, I have a 1.3-1 across the entire 11 Meter band with the linear off, and my meter shows an almost 1-1 match with the linear on. Either way as far as I can see nothing to worry about, everyone allways tells me to check the SWR with the AMP off anyways.
Outkast
CEF 650 |
Wildrat
Intermediate Member
Username: Wildrat
Post Number: 202
Registered: 12-2003
| | Posted on Monday, October 31, 2005 - 7:40 am: |
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Glad you got your antenna up Sinker/Remora!
Now if I can get my son around here to get mine up. We can use Star Face as a relay station when were not squawking at him.
Wildrat
CEF674 out of the swamps of Florida!
Well pool anyway, sometimes it looks like a swamp. Bring your swimming trunks when ya'll come over. |
Sinker
Intermediate Member
Username: Sinker
Post Number: 207
Registered: 8-2005
| | Posted on Wednesday, November 02, 2005 - 10:32 am: |
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Hey thanks to everyone for the advice.
Coiled excess cable at base of antenna with no ill effects.
Switched out jumpers and here is where my readings are now:
OK the SWR readings running bearfoot are as follows:
- Channel 1 = 1.0:1
- Channel 20 = 1.1:1
- Channel 40 = 1.2:1
I like this and can live with it.
NOW - when I turn on the KLV nothing changes when it is in Stand By mode but once turned to Ready I get the following results:
SWR Reading Between Radio and Amp:
- Channel 1 = 1.4:1
- Channel 20 = 1.3:1
- Channel 40 = 1.3:1
Think these are in the safe zone. For sure better than before.
The reading between the Amp and the Antenna are as follows when also on:
- Channel 1 = 1.1:1
- Channel 20 = 1.1:1
- Channel 40 = 1.1:1
Actually a little less than 1.1:1 but don't know how to show that.
Feeling much better about things now....
Tim
CEF-634 |
Crackshot
Junior Member
Username: Crackshot
Post Number: 45
Registered: 10-2005
| | Posted on Wednesday, November 02, 2005 - 12:05 pm: |
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So my SWR with my tube amp "on" and not in "standby" goes up on channel one to 2.1:1 and channel 40 1.4:1.
Ran it this way for 3 years and just tested all my tubes.
They are still at 112% and well in the green on my tester.
In "standby" with amp on, low SWR all across the band.
I think tube amps are not affected by high SWR that much.
I think what matters the most is the SWR from radio to amp and that should be at it's lowest as you can possibly get. |
Sinker
Intermediate Member
Username: Sinker
Post Number: 212
Registered: 8-2005
| | Posted on Thursday, November 03, 2005 - 8:39 am: |
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Thanks for the info Crackshot |
Kid_vicious
Advanced Member
Username: Kid_vicious
Post Number: 781
Registered: 9-2004
| | Posted on Thursday, November 03, 2005 - 11:31 pm: |
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sinker, your numbers are beautiful, nice job!
i seem to have an SWR of 1.5 to 1 between the radio and amp no matter what jumper length i use, and i can live with that just fine.
if anyone out there knows a thing or two about changing the input tuning of my KL300P though, i am very interested.
matt |
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