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Bill
Posted on Wednesday, January 23, 2002 - 3:13 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I am in the process of setting up a new base and I could use a little help.
As a base I will use a late 1980's Cobra 142 GTL and a Galaxy DX99V. The 99 will be run by a Tripp Lite PR-40 Power supply.
The Antenna will be a Imax 2000 about 20ft off the ground at the base.
Does anyone have any experience with X-Force around 500 to 700 watts out with this set up?
Also does anyone know if these amps. have variable power setttings or positions? Also do they have Pre-Amps?
I will welcome any helpful comments.

Thanks for the time
Bill
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Warlock
Posted on Wednesday, January 23, 2002 - 9:17 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The 412 is an awesome base amp. Very clean, has preamp, ssb delay, and standby. These are on/off only amps. The output is controlled by your input. I don't recommend running the carrier (out of the amp) higher than 350w. With your 142 driving it, you should get easy 700w. I recommend grounding your antenna with double shielded coax, connecting the solid center to the antenna bracket and ground rod. The double shielding helps stop bleed. With your antenna so low, it will limit your local talking distance, but you will be a skip talking machine.
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Bill
Posted on Thursday, January 24, 2002 - 12:25 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Warlock:
Thanks for the quick reply. I like the idea of grounding the antenna with the double shielded coax.
Thanks again for the information.

Bill
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RCI2990
Posted on Thursday, February 21, 2002 - 3:46 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Now ive questioned this before. wont grounding the coax to the center "hot" of the coax cause the SWR to go higher than a kite???
If that is a way to prevent RFI then ill try it but i want to be sure it will work.. Dont feel like having my RCI 2990 or my ranger AR 3500 blow up!!!!!!
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RCI2990
Posted on Thursday, February 21, 2002 - 3:48 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

BTW i do use double sheilded coax but mine has the stranded center. I do bleed over two TV here in the house though even if my antennas are grounded and my switchbox is grounded as well..
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Warlock
Posted on Thursday, February 21, 2002 - 9:37 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The shielded coax as ground is seperate from your radio coax. It's like using an entirely new piece of coax with the center conductor being the connection from your antenna ground to ground rod, and shielded by the braid around it.
Do not connect ground to the center conductor of your radio coax.
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Marconi
Posted on Friday, February 22, 2002 - 5:16 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Haven't thought about doing this, so I have a few questions.

So you leave the shield for this coaxial ground line open at each end of the ground line, using only the center conductor to physically make the grounding connections. If this is correct, then what is your thinking regarding the purpose of the shield in this case?

Wouldn't a similar wire (plain), whether shielded or not, do the same thing?

Is your contention here, that this ground serves primarily as an RF ground or for protection in case of lightning, or both?

Thanks,

Marconi
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Warlock
Posted on Friday, February 22, 2002 - 8:45 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The idea is not to have your ground wire radiate RF.
I have a friend that lives in an old subdivision. He runs a 2 tube Z box, and was killing his neighbors. Someone told him to try the shielded coax as ground, he did, he doesn't bother his neighbors anymore.\
Will it work for everyone? I don't know, it did for him and I would think it worth a try.
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RCI2990
Posted on Sunday, February 24, 2002 - 2:06 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I dont want to run the risk of sounding like an ignorant low IQ Cber but i............ dont get it entirely....
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Warlock
Posted on Sunday, February 24, 2002 - 10:33 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Ok, the double shielded coax you might use for your radio. The center conducts the power, the shield provides the ground to shield the power from getting out.
Using the same principle, when your base antenna radiates, it can also radiate off of your ground wire, making the ground wire become part of the antenna. By using double shielded coax as your ground wire, connecting only the center conductor to the antenna ground and to ground rod leaving the shield connected to nothing but acting as a protective barrier so that the antenna won't radiate off of that wire.
Hope this made sense.
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Biged
Posted on Monday, February 25, 2002 - 9:06 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Warlock,
That war a great explanation.I have read this on many posts and never understood it.Now I see the light.Makes sense!!Thanks...Eddie
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Jerzee G
Posted on Saturday, March 02, 2002 - 1:41 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Hey RCI2990,

I used to run my 2990 and XFORCE HD60012 and it was awesome. 1200+ watts!
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Etchasketch
Posted on Saturday, March 02, 2002 - 1:27 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Don't forget to ground the shielding of your coax at your grounding rod .
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RCI2990
Posted on Sunday, March 03, 2002 - 4:16 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Jerzee G.
What kind of watts did you swing into that HD60012? My 2990 has been modified to key up and swing big watts(no im not gonnna say how much becaused then this post will go on and on and on and on about meters and swing and ect,ect,ect and i dont wanna hear it!) so im just curious thats all!!! :-)
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Kraig
Posted on Thursday, March 07, 2002 - 6:13 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I adjust the RF on the Transmitter (Saturn Galaxy Turbo) to get 700 watts dead key out of the X force 6 pill High drive amp. On voice peaks I get around 1600+ Watts swing. I'm using a digital watt / SWR meter VFD series (http://www.rfapps.com/vfd.htm) made by RFD applications.
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Taz
Posted on Thursday, March 07, 2002 - 7:42 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

what does that meter cost?
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RCI2990
Posted on Thursday, March 07, 2002 - 7:50 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Ok. Those meters look cool! I like the SWR alarm feature..
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Kraig
Posted on Friday, March 08, 2002 - 3:55 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

The meter is pricey. $249 + $20 for SWR relay. I consider it worth the price. I have had it unkey the amp and radio on high SWR when my Moonraker lost a 10 cent nut on the horizontal gamma match. The investment in this meter saved me a Galaxy Saturn Turbo and X force 60012 HD!
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Taz
Posted on Friday, March 08, 2002 - 4:45 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

nice!
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RCI2990
Posted on Friday, March 08, 2002 - 7:09 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Very very cool! If i had the extra $$$ id consider one of those!! Very nice feature.. Ive had my moonraker lose a verticle driven element and a stinger once but i saw it and didnt key up. Therefore i saved myself a galaxy 2527 and a D&A phantom. lol
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skeptical
Posted on Sunday, April 21, 2002 - 5:23 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

yadda yadda yadda, if ya want some real advice just ask marconi the name says it all. he can educate you in the art of radiating rf
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Taz
Posted on Monday, April 22, 2002 - 12:07 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

lol,

it seems you are skeptacle on that statement


j/k

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