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#1
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Heathkit SA-2040: what's worst SWR it tune out.
Does anyone know what the worst SWR the Heathkit SA-2040 can tune out (to below 2:1 say).
Thanks, --- Rob |
#2
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Robert Myers wrote:
Does anyone know what the worst SWR the Heathkit SA-2040 can tune out (to below 2:1 say). Thanks, --- Rob Don't think it's that simple. Multiple impedances map into the same swr. But the limits of the tuner are based on impedances. That's why a tuner might match high SWR for some cable lengths but not others. SWR is just a scalar number that's easy to measure and very useful when you're just trying to get to 1:1 where it maps directly into properly terminated cable. mike -- Return address is VALID but some sites block emails with links. Delete this sig when replying. .. Wanted, PCMCIA SCSI Card for HP m820 CDRW. FS 500MHz Tek DSOscilloscope TDS540 Make Offer Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121 Wanted 12" LCD for Compaq Armada 7770MT. Bunch of stuff For Sale and Wanted at the link below. MAKE THE OBVIOUS CHANGES TO THE LINK htremovethistp://www.geocities.com/SiliconValley/Monitor/4710/ |
#3
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Rob, got a 2040 also, mine has 28 uh roller inductor
in the middle and it hanldes extreme loads! Dont know what your trying to tune, but have 2 loops here and its a breeze to work with! sometimes a single wire antenna poses a threat to the tuner. got a analyzer here and it seems to tell the truth more often than not! Key is a good ground, and is a must! steve.... gud luck. |
#4
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Hi Steve,
Thanks for the information. Good ground where, though? Around the antenna, like 'wires in the lawn.' Or, a good ground from your transmitter to ground, or good ground from your SA-2040 to ground (or both via separate braids to a common ground point --- like a cold water pipe. Not too sure. Can you elaborate? How did you create your good ground? How about if I soldered a 5 ft., 3/4 inch braid to the point where the cold water feed from the city enters the basement --- I can set up the whole station right in that location then (within that 5 feet I mean, because the basement is unfinished. How are you doing your grounding? Thanks for the help. --- Rob Steve wrote: Rob, got a 2040 also, mine has 28 uh roller inductor in the middle and it hanldes extreme loads! Dont know what your trying to tune, but have 2 loops here and its a breeze to work with! sometimes a single wire antenna poses a threat to the tuner. got a analyzer here and it seems to tell the truth more often than not! Key is a good ground, and is a must! steve.... gud luck. |
#5
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On Sun, 24 Apr 2005 11:10:53 -0400, Robert Myers
wrote: Hi Steve, Thanks for the information. Good ground where, though? Around the antenna, like 'wires in the lawn.' Or, a good ground from your transmitter to ground, or good ground from your SA-2040 to ground (or both via separate braids to a common ground point --- like a cold water pipe. Not too sure. Can you elaborate? How did you create your good ground? How about if I soldered a 5 ft., 3/4 inch braid to the point where the cold water feed from the city enters the basement --- I can set up the whole station right in that location then (within that 5 feet I mean, because the basement is unfinished. How are you doing your grounding? Thanks for the help. --- Rob You may or may not need an RF ground, depending on whether you are tuning a balanced or unbalanced antenna. I have 1/2" braid coming off the back of my mfj tuner to a short length of copper pipe (I have rock about 12" down), and then I have two 70-ft buried wires across the lawn. I'm still trying to decipher what constitutes a good or better tuner. I recently got an older Murch 2000 transmatch whose components, the two variable caps and the variable inductor, are about 50% bigger than those in my mfj-989c, but the Mighty Fine Junk tunes bands the Murch won't touch :-) Oh, well... bob k5qwg Steve wrote: Rob, got a 2040 also, mine has 28 uh roller inductor in the middle and it hanldes extreme loads! Dont know what your trying to tune, but have 2 loops here and its a breeze to work with! sometimes a single wire antenna poses a threat to the tuner. got a analyzer here and it seems to tell the truth more often than not! Key is a good ground, and is a must! steve.... gud luck. |
#6
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It most often depends on the electrical equivalent of the
antenna system. Sometimes only minor changes in the antenna system allow a tuner to do it's job. Your best bet is to configure the antenna with a higher radiation resistance than 50 ohms instead of lower. Try different grounds, different antenna lengths, different tuners. Often a different tuner configuration will allow a match. To expect a single tuner to handle infinite matching situations is ludicrous. Read up on the subject. The ARRL antenna manuals are rich in theory. Consider that there may be many undefined matching situations where infinite current or voltage may be placed in the tuner that would burn or arc. I have a 300w MFJ tuner (T net) that I bought used for $40 and an LDG kit tuner (Reversible L net). They work just fine when I design the antenna so that impossible matches are avoided. Although the LDG may tune a greater range, that also causes it to find a greater number of impossible matches. Jim, ac6tk "Bob Miller" wrote in message ... On Sun, 24 Apr 2005 11:10:53 -0400, Robert Myers wrote: Hi Steve, Thanks for the information. Good ground where, though? Around the antenna, like 'wires in the lawn.' Or, a good ground from your transmitter to ground, or good ground from your SA-2040 to ground (or both via separate braids to a common ground point --- like a cold water pipe. Not too sure. Can you elaborate? How did you create your good ground? How about if I soldered a 5 ft., 3/4 inch braid to the point where the cold water feed from the city enters the basement --- I can set up the whole station right in that location then (within that 5 feet I mean, because the basement is unfinished. How are you doing your grounding? Thanks for the help. --- Rob You may or may not need an RF ground, depending on whether you are tuning a balanced or unbalanced antenna. I have 1/2" braid coming off the back of my mfj tuner to a short length of copper pipe (I have rock about 12" down), and then I have two 70-ft buried wires across the lawn. I'm still trying to decipher what constitutes a good or better tuner. I recently got an older Murch 2000 transmatch whose components, the two variable caps and the variable inductor, are about 50% bigger than those in my mfj-989c, but the Mighty Fine Junk tunes bands the Murch won't touch :-) Oh, well... bob k5qwg Steve wrote: Rob, got a 2040 also, mine has 28 uh roller inductor in the middle and it hanldes extreme loads! Dont know what your trying to tune, but have 2 loops here and its a breeze to work with! sometimes a single wire antenna poses a threat to the tuner. got a analyzer here and it seems to tell the truth more often than not! Key is a good ground, and is a must! steve.... gud luck. |
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