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Enviable height and should really perform up there.

In my own experience mounting an IMAX2000 on a large iron/steel farmers gate (G-clamping the IMAX plate direct to the gate) I could never seem to get the SWR lower than 2:1 either, I have tried all sorts of choke types ferite and coaxial to no avail. I suspect if that was on an 18 feet pole the SWR would drop down no problems. All antennas I have used seem to like to be in as close as open space as possible, other than a mounting pole. You would think that a crane would be an awesome ground plane/counterpoise but sometimes a lot of metal under an antenna with no decent length of pole can cause high SWR in my own experiences.

(I suspect it can also affect the take of angle of some antennas, dipole types react especially badly including the Gain Master.. SWR is ok on the GM but you get high TOA's for DX and thus few contacts)

It seems to be very much exact setup specific, you can get lucky and get a good SWR and performance or a bad SWR and not so good performance. ( I know a guy who puts it on his ladders on the top of a van and it works fine for him) Other than this it seems impossible to predict what is and is not going to work when it comes to attaching an IMAX to a large metal structure. Results vary wildly and myself I only get an IMAX working when it is on 15 feet of pole and only with no chokes of any kind. That is where I get a SWR of 1.4:1 which is ok.

Of course an 18 feet pole and an IMAX on top, on top of a crane could become quite a safety issue for man handling so be careful.

I suspect that metal close the the lower portion of an IMAX does not work well. I also suspect you may find the antenna becomes slightly directional in the direction where most metal from the cranes horizontal elements exist. All guess work from my experiences here in the UK but hope you get the SWR down and have some fun contacts.

<blockquote data-quote="RadioDaze2.0" data-source="post: 549681" data-attributes="member: 45866">Enviable height and should really perform up there.In my own experience mounting an IMAX2000 on a large iron/steel farmers gate (G-clamping the IMAX plate direct to the gate) I could never seem to get the SWR lower than 2:1 either, I have tried all sorts of choke types ferite and coaxial to no avail. I suspect if that was on an 18 feet pole the SWR would drop down no problems. All antennas I have used seem to like to be in as close as open space as possible, other than a mounting pole. You would think that a crane would be an awesome ground plane/counterpoise but sometimes a lot of metal under an antenna with no decent length of pole can cause high SWR in my own experiences.(I suspect it can also affect the take of angle of some antennas, dipole types react especially badly including the Gain Master.. SWR is ok on the GM but you get high TOA&#039;s for DX and thus few contacts)It seems to be very much exact setup specific, you can get lucky and get a good SWR and performance or a bad SWR and not so good performance. ( I know a guy who puts it on his ladders on the top of a van and it works fine for him) Other than this it seems impossible to predict what is and is not going to work when it comes to attaching an IMAX to a large metal structure. Results vary wildly and myself I only get an IMAX working when it is on 15 feet of pole and only with no chokes of any kind. That is where I get a SWR of 1.4:1 which is ok.Of course an 18 feet pole and an IMAX on top, on top of a crane could become quite a safety issue for man handling so be careful.I suspect that metal close the the lower portion of an IMAX does not work well. I also suspect you may find the antenna becomes slightly directional in the direction where most metal from the cranes horizontal elements exist. All guess work from my experiences here in the UK but hope you get the SWR down and have some fun contacts.</blockquote>

[QUOTE="RadioDaze2.0, post: 549681, member: 45866"] Enviable height and should really perform up there. In my own experience mounting an IMAX2000 on a large iron/steel farmers gate (G-clamping the IMAX plate direct to the gate) I could never seem to get the SWR lower than 2:1 either, I have tried all sorts of choke types ferite and coaxial to no avail. I suspect if that was on an 18 feet pole the SWR would drop down no problems. All antennas I have used seem to like to be in as close as open space as possible, other than a mounting pole. You would think that a crane would be an awesome ground plane/counterpoise but sometimes a lot of metal under an antenna with no decent length of pole can cause high SWR in my own experiences. (I suspect it can also affect the take of angle of some antennas, dipole types react especially badly including the Gain Master.. SWR is ok on the GM but you get high TOA's for DX and thus few contacts) It seems to be very much exact setup specific, you can get lucky and get a good SWR and performance or a bad SWR and not so good performance. ( I know a guy who puts it on his ladders on the top of a van and it works fine for him) Other than this it seems impossible to predict what is and is not going to work when it comes to attaching an IMAX to a large metal structure. Results vary wildly and myself I only get an IMAX working when it is on 15 feet of pole and only with no chokes of any kind. That is where I get a SWR of 1.4:1 which is ok. Of course an 18 feet pole and an IMAX on top, on top of a crane could become quite a safety issue for man handling so be careful. I suspect that metal close the the lower portion of an IMAX does not work well. I also suspect you may find the antenna becomes slightly directional in the direction where most metal from the cranes horizontal elements exist. All guess work from my experiences here in the UK but hope you get the SWR down and have some fun contacts. [/QUOTE]

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