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Audiophile73
Intermediate Member
Username: Audiophile73
Post Number: 146
Registered: 5-2004
| | Posted on Friday, October 12, 2007 - 9:51 pm: | 
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Here it goes
-RCI 2950dx
-Texas star modulator driving xforce 400hd
-Wilson 1000 mounted on roof of extended cab full size truck
I have mini8 coax between radio and all amplifiers. The coax between final amp and antenna is whatever came with the wilson 1000 (looks like rg58). On CB band my SWR's are great (flat on ch1 and 1.2:1 on ch40). I just got my RCI and want to start talking on the other bands. Wilson rates the 1000 of working between 26 and 30 MHz. The only problem is my swr's are extremely high when not on cb bands. Does my antenna need to be grounded, if so how do I do this? Oh yeah I am measuring my SWR between the last amp and my antenna. I am using a DOSY and a Radio Schack meter and they both read the same. Any help would be good, thanks. |
Tech808
Moderator
Username: Tech808
Post Number: 14521
Registered: 8-2002
| | Posted on Saturday, October 13, 2007 - 6:55 am: |
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Audiophile73,
While the Wilson 1000 is designed to offer coverage from 26 MHz to 30 MHz you will need to adjust/cut the whip to cover the desired frequency/band you wish to use.
For FULL coverage from 26 MHz to 30 MHz you will need to use/add an antenna tuner/matcher.
For standard operation on a single band you will need to do the following and make sure that your antenna is grounded properly.
#1- Insert the antenna whip 1" into chrome antenna adjustment mast at the top of the coil.
#2- Using either the meter built into the radio or a good external SWR meter, calibrate on channel 20. Switch back to SWR and record the readings on three channels; 1, 20, & 40.
#3- If the lowest SWR reading occurs on channel 1, the antenna whip is to long and must be shortened. Loosen the mast set screws and lower the whip 1/4" into the mast. Tighten mast set screw and again read SWR. Repeat until lowest SWR is obtained. If the whip is fully lowered into mast and the SWR is still high, remove the whip from mast. Using a hacksaw, grinder, or bolt cutters, cut 1/4" from the bottom part of the whip. Re-insert the whip into the mast and test again for SWR. Repeat the above procedure until the SWR is below 1.5 of all channels.
#4- If the lowest SWR reading occurs on channel 40, the antenna whip is to short and must be raised. Loosen the mast set screws and raise the whip 1/4", re-tighten set screws and test SWR again. Repeat the above procedure until the SWR is below 1.5 of all channels.
#5- The whip is raised to the top, but the SWR is still lower on CH 40.
This generally occurs on vehicles with very small ground plains, such as the compact cars, cars with hatch-backs, etc. It indicates the need for a longer whip than the standard one supplied.
Lon ~ Tech808 ~ N9CEF
CEF#808 ~ CEF HAM#33 ~ CVC#002
Tech808@copperelectronics.com
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Dale
Senior Member
Username: Dale
Post Number: 1201
Registered: 12-2002
| | Posted on Saturday, October 13, 2007 - 11:15 am: |
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for below 26.9650 most likely raise whip
above 27.4050 most likely trim whip
this isnt aleays the case but usually how it works out.remember this if ya tune it good for say 10 meters then when uya go back to 11 meters
say ch.13 then your swrs maybe higher there now.
tune it for the band youll be using most.as this antenna WILL NOT cover both 10 and 11 meters with a 1.1 swr without a tuner
dale/a.k.a.hotrod
cef426
cvc#64
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Penrider
Intermediate Member
Username: Penrider
Post Number: 222
Registered: 1-2007
| | Posted on Saturday, October 13, 2007 - 12:20 pm: |
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same basic setup here minus the amp, the wilson will not tune both 10 and 11meters. In stock form it is Flat on 11meters, but well over 2:1 on 10 meters. Almost exactly vice-versa once trimmed for 10 meters. The wilson is an excellent antenna, but it is not broadbanded at all.
Sean
CEF867
Two tin cans and a string, it's still a contact...BTW, I need my can back when we're done!
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Audiophile73
Intermediate Member
Username: Audiophile73
Post Number: 147
Registered: 5-2004
| | Posted on Saturday, October 13, 2007 - 3:37 pm: |
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So if I get a matcher it will fix my problem, how much, who makes a good one. |
Dale
Senior Member
Username: Dale
Post Number: 1204
Registered: 12-2002
| | Posted on Saturday, October 13, 2007 - 8:40 pm: |
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do a search for mfj.they make some small ones just for mobiles.ya can tune it for 10 meters
but it will put 11 meters high,as penrider said
dale/a.k.a.hotrod
cef426
cvc#64
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Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3969
Registered: 7-2004
| | Posted on Saturday, October 13, 2007 - 10:06 pm: |
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the 'small ones just for mobiles' matcher is only going to be able to handle the power of the radio. to handle the 800+ watts of the x force, you're going to need a 'full legal limit' tuner. big bucks. best bet would be to change antenna to one that is broader-banded, then if you must use a mag mount, get one that will allow you to change coax & replace it with lmr240 or the best rg8x double shield you can find, if not a double-shielded version of regular 8. if it is decent quality mini-8 (rg8x) from radio to 400hd, you'll be OK with that, but i'd still consider an upgrade to BEST quality 8x/240.
i use a predator on a triple mag & have 1.1:1 on 27.025 & <1.7:1 on 28.360. i've never retuned to center SWR on those freqs. i don't use an amp on 10m, but with the heat dissapation available, it wouldn't be a problem if used cautiously. |
Hotwire
Senior Member
Username: Hotwire
Post Number: 2418
Registered: 1-2005
| | Posted on Monday, October 22, 2007 - 1:39 pm: |
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Possible that the RCI 2950 and Texas Star modulator together causing harmonics? Sure is a lot of radio for such a little driver amp. Just a thought.
KEEP IT REAL!
Kenny
cef491(27.115lsb)
2sf491(27.555usb)
Indiana
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