Halo Stacking Question
KC7...@aol.com
Hello all,
Does anyone have any suggestions on how I should stack 3 different halo type antennas at my home? I have a 6m, 2m and 70cm that I want to put on one pole that’s 15 feet tall (ground to top). I'm looking for both what order to stack them and the separation distance between them. What problems, if any, would I have if I add a 2m/70cm j-pole to the top of the stack? And what would be a good resource for getting more information?
My feeling is the 6m, 2m, 70cm for the order, but I'm not sure on spacing distance and that the j-pole would have none to minor interaction. I know this is not going to get me any great distance for contacts, but we all start small.
73's
Scott
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Daly, Greg
Scott:
I have a stack of 3 M2 “HO loops” on a common mast. The 6 meter loop is at the bottom of the stack, the 2 meter loop is 36 inches up, and the 70 cm antenna is another 24 inches up. Except for a single stupid oversight, the stack performs as expected. Omnidirectional antennas are very handy for chatting with the neighbors, even better if you line on a hill.
I discovered that operating my 2 meter transmitter at 200 watts, would destroy the front end RF preamp FET in my 6 meter transverter….. oops! Fortunately Elecraft uses an Agilent (now Avago) E-PHEMT in the RF preamp section of all of their transverters, they aren’t hard to find in small quantities, and SOT-343 packages are just big enough to replace without resorting to exotic soldering methods…… In any case, the 6 meter loop is close enough to 3 times the size of the 2 meter loop, that the 2 meter loop couples A LOT of energy into it if they are close together. The same problem may occur with the 432 MHz antenna coupling a lot of energy into the 144 MHz, I wasn’t brave enough to try it on purpose. By the way, with the loops 36 inches apart, I observed only a little more than 20 dB isolation between the 2 meter loop and the 6 meter loop….. the gate of the little tiny GaAs FET didn’t think a watt and a half of RF was funny at all.
If you are using a single transceiver and a switch to select antennas, this would not be a problem. In my station, I have to make sure I don’t leave any of the transverters switched to the loops when I shut down the station.
If the J- Pole is vertically polarized, mounting it conveniently close above the horizontal loops shouldn’t be a problem……. I think…… some experimentation may be called for ;-)
73, have fun with your loops, I like mine a lot.
Greg Daly WB7RSG
Kevin Imel
Scott:
I have a stack of 3 M2 "HO loops" on a common mast. The 6 meter loop is at the bottom of the stack, the 2 meter loop is 36 inches up, and the 70 cm antenna is another 24 inches up. Except for a single stupid oversight, the stack performs as expected. Omnidirectional antennas are very handy for chatting with the neighbors, even better if you line on a hill.
I discovered that operating my 2 meter transmitter at 200 watts, would destroy the front end RF preamp FET in my 6 meter transverter..... oops! Fortunately Elecraft uses an Agilent (now Avago) E-PHEMT in the RF preamp section of all of their transverters, they aren't hard to find in small quantities, and SOT-343 packages are just big enough to replace without resorting to exotic soldering methods...... In any case, the 6 meter loop is close enough to 3 times the size of the 2 meter loop, that the 2 meter loop couples A LOT of energy into it if they are close together. The same problem may occur with the 432 MHz antenna coupling a lot of energy into the 144 MHz, I wasn't brave enough to try it on purpose. By the way, with the loops 36 inches apart, I observed only a little more than 20 dB isolation between the 2 meter loop and the 6 meter loop..... the gate of the little tiny GaAs FET didn't think a watt and a half of RF was funny at all.
If you are using a single transceiver and a switch to select antennas, this would not be a problem. In my station, I have to make sure I don't leave any of the transverters switched to the loops when I shut down the station.
If the J- Pole is vertically polarized, mounting it conveniently close above the horizontal loops shouldn't be a problem....... I think...... some experimentation may be called for ;-)
mikeberg...@comcast.net
From: "Kevin Imel" <kevin...@gmail.com>
I was concerned about interaction with the mast from the 70 cm loop so I inserted a length of wooden dowel (painted) in the top of the mast and mounted the 70 cm loop to that.
I have run it in multiple different staacking configurations with best results, when used on a mobile, with 6M as high as possible due to interaction between the loop and car. With your mast height this shouldn't be an issue however.Good luck!
On 8/31/07, Daly, Greg <gd...@tqs.com> wrote:
Scott:
I have a stack of 3 M2 "HO loops" on a common mast. The 6 meter loop is at the bottom of the stack, the 2 meter loop is 36 inches up, and the 70 cm antenna is another 24 inches up. Except for a single stupid oversight, the stack performs as expected. Omnidirectional antennas are very handy for chatting with the neighbors, even better if you line on a hill.
I discovered that operating my 2 meter transmitter at 200 watts, would destroy the front end RF preamp FET in my 6 meter transverter..... oops! Fortunately Elecraft uses an Agilent (now Avago) E-PHEMT in the RF preamp section of all of their transverters, they aren't hard to find in small quantities, and SOT-343 packages are just big enough to replace without resorting to exotic soldering methods...... In any case, the 6 meter loop is close enough to 3 times the size of the 2 meter loop, that the 2 meter loop couples A LOT of energy into it if they are close together. The same problem may occur with the 432 MHz antenna coupling a lot of energy into the 144 MHz, I wasn't brave enough to try it on purpose. By the way, with the loops 36 inches apart, I observed only a little more than 20 dB isolation between the 2 meter loop and the 6 meter loop..... the gate o f the little tiny GaAs FET didn't think a watt and a half of RF was funny at all.