Home |
Search |
Today's Posts |
#1
![]() |
|||
|
|||
![]() I'll be moving my rig to a second floor OP here soon, I've always been at/below ground level with a short run to a ground rod. I'm only running a trap dipole nowdays and I don't want to get into the mess of a counterpoise. Can I/will I get an acceptable ground by running a ground strap to a ground rod? I imagine that a lot of folks are doing this - is there any advice regarding getting it grounded from this height? tnx - Mark/n0lf |
#2
![]() |
|||
|
|||
![]()
Mark,
Sounds like a 'balanced' antenna to me, why a ground other than for electrical purposes (not RF)? - 'Doc |
#3
![]() |
|||
|
|||
![]() I needed to hear it from somebody else, that's all. I'm not quite balanced in the feed, as I'm using coax out to the dipole feedpoint, but probably close enough. tnx - Mark On Sun, 27 Nov 2005 17:27:04 GMT, 'Doc wrote: Mark, Sounds like a 'balanced' antenna to me, why a ground other than for electrical purposes (not RF)? - 'Doc |
#4
![]() |
|||
|
|||
![]()
Mark Sheffield wrote:
I'm not quite balanced in the feed, as I'm using coax out to the dipole feedpoint, but probably close enough. A W2DU choke would probably eliminate the need for an RF ground and also be good engineering practice. -- 73, Cecil http://www.qsl.net/w5dxp |
#5
![]() |
|||
|
|||
![]()
I have a 2nd floor shack too, and the antenna is a ground mounted vertical
(Butternut HF6V). I use a W2DU choke to connect my coax feedline to the vertical and a 2nd W2DU choke between my Orion and Drake L-4B. Finally, I found that the only way to prevent feedback on SSB was to NOT connect my system to the #8 ground wire that runs out the window sill and down to a ground rod. "Cecil Moore" wrote in message . com... Mark Sheffield wrote: I'm not quite balanced in the feed, as I'm using coax out to the dipole feedpoint, but probably close enough. A W2DU choke would probably eliminate the need for an RF ground and also be good engineering practice. -- 73, Cecil http://www.qsl.net/w5dxp |
#6
![]() |
|||
|
|||
![]()
John, N9JG wrote:
Finally, I found that the only way to prevent feedback on SSB was to NOT connect my system to the #8 ground wire that runs out the window sill and down to a ground rod. Yep, everyone should realize that a ground wire is N*1/4 wavelength at certain frequencies, and at those frequencies, is an RF transformer that locates the standing-wave voltage maximum points at the transmitter. (ouch!) That's what artificial grounds do - change that *electrical* length to N*1/2 wavelength. For anyone insisting on an RF ground for an upper floor, an artificial ground is probably the way to go. I, myself, prefer balanced antennas and feedlines. -- 73, Cecil http://www.qsl.net/w5dxp |
#7
![]() |
|||
|
|||
![]() Cecil Moore wrote: Yep, everyone should realize that a ground wire is N*1/4 wavelength at certain frequencies, and at those frequencies, is an RF transformer that locates the standing-wave voltage maximum points at the transmitter. (ouch!) That's what artificial grounds do - change that *electrical* length to N*1/2 wavelength. For anyone insisting on an RF ground for an upper floor, an artificial ground is probably the way to go. I, myself, prefer balanced antennas and feedlines. -- 73, Cecil http://www.qsl.net/w5dxp Cecil, Don't you mean that when a ground wire is N*1/4 wavelength at a particular frequency it locates the voltage mininum (current maximum) at the transmitter, and the voltage maximum well away from the transmitter. Artifical grounds use a series LC circuit to try and tune your ground wire to look like 1/4 wave. If they change the *electrical* length to 1/2 wave then you would have a voltage maximum at the transmitter (ouch!). Gary N4AST |
#8
![]() |
|||
|
|||
![]()
Cecil Moore wrote:
John, N9JG wrote: Finally, I found that the only way to prevent feedback on SSB was to NOT connect my system to the #8 ground wire that runs out the window sill and down to a ground rod. Yep, everyone should realize that a ground wire is N*1/4 wavelength at certain frequencies, and at those frequencies, is an RF transformer that locates the standing-wave voltage maximum points at the transmitter. (ouch!) That's what artificial grounds do - change that *electrical* length to N*1/2 wavelength. For anyone insisting on an RF ground for an upper floor, an artificial ground is probably the way to go. I, myself, prefer balanced antennas and feedlines. -- 73, Cecil http://www.qsl.net/w5dxp Why not run two ground wires in parallel -- one twice as long as the other? When one is Hi-Z the other will be Lo-Z and vice versa. Irv VE6BP -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/index.html Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
#10
![]() |
|||
|
|||
![]()
Irv Finkleman wrote:
Why not run two ground wires in parallel -- one twice as long as the other? When one is Hi-Z the other will be Lo-Z and vice versa. That will help on some frequencies but it is akin to trying to erect a 1/2WL fan dipole for all frequencies - can't be done. Sooner or later, you will run into a frequency where length #1 is N*1/4WL and length #2 is (N+1)1/4WL. "It's not nice to fool Mother Nature." -- 73, Cecil http://www.qsl.net/w5dxp |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
FCC SHUTS DOWN the 'Boy Broadcaster" from ME | Scanner | |||
K1MAN The crap has hit the fan. | Policy | |||
a great read | CB | |||
FS: Palomar 225 | CB | |||
I also need Diy plans for a 300 watt linear | CB |