Workman W-58 Help needed please!

[wavrider]

I have been following the thread.

If I am comprehending this correctly the best installation is to.

1. Isolate the antenna from the mast.

2. Install four 6' horizontal counterpoise radials at 90 degrees. Or the spider radials.

3. Ugly balun/ rf choke at the feed point.

In the near future the Imax 2000 will be removed from above the Mosley PRO67B and will be at the top of a 70' to 90' tower which will also have some wire antennas supported by the tower. So looking for best recommendations for the IMAX install.

 

[Needle Bender]

Makes me wonder why Bighair never marketed a BigMax20K with his massive & efficient high power matching network to offer a monster Imax-type for those who don't mind paying what they get for.

 

[Zman]

I wanted him to build me one of his antennas but that idea fell through. Hes really busy these days..

 

[Robb]

I have been following the thread.

If I am comprehending this correctly the best installation is to.

1. Isolate the antenna from the mast.

2. Install four 6' horizontal counterpoise radials at 90 degrees. Or the spider radials.

3. Ugly balun/ rf choke at the feed point.

In the near future the Imax 2000 will be removed from above the Mosley PRO67B and will be at the top of a 70' to 90' tower which will also have some wire antennas supported by the tower. So looking for best recommendations for the IMAX install.

I'd agree with all of that - except if there were four 104 inch radials instead of the stock 6 ft ones. The guys at eHam when reviewing this antenna used used full-length 1/4 wave length radials when isolating the antenna.

 

[wavrider]

I'd agree with all of that - except if there were four 104 inch radials instead of the stock 6 ft ones. The guys at eHam when reviewing this antenna used used full-length 1/4 wave length radials when isolating the antenna.

Robb I would also think the 1/4 wl would be the correct length but looking at Eddie's EZNEC graphs makes me re-think that.

I will wait for Eddie or Bob to post as to what length and how much angle if any for the counterpoise.

I only plan on putting that antenna on top of the tower one time so I want to get the best performance I can out of it.

Then again I could always put the spare hazer on that tower and just crank it up and down, the only down fall to that is I would be limited to three radials instead of four due to the hazer/tower.

 

[Marconi]

New idea for presenting these Imax results.

I worked with just one model here in order to prevent my accidental use of a different model with some different data entered. That is except for the data changes made for comparison.

I only changed the height, the angle for the radials, and the length of the radials between the stock 72" inches and a full 1/4 wave set at 102" inches, or 8.5' feet. It's probably true that 105"-107" might be better with the thin wire I used, but I've been using the middle of what Bob suggested earlier at 8'-9' feet for the radials, so I just maintained that use.

I did Cebikize the model before I started, so these results may be a bit different than some previous models presented.

Hope this hand written work is legible enough. Within reason I will make some reasonable additions in case I didn't think of some aspects to consider, or in the case of errors. I also didn't save any of these models, so if I have to redo one I'll have to tweak the model and the effort could produce a little different results.

The notation under currents for good, bad, medium, were made based on my personal judgments on how much current I noted in the Antenna View, and was done because I try to keep and eye on the currents. Sometimes bad currents on the mast really add to the overall gain, and maybe on rare occassions they don't, but in this case marked with an (*) I think the gains were improved due to the bad currents I noted.

I used 65' because of the work I did the other day for Needle Bender. I also made a group at 36' & 40' feet, common install heights.

Here is what Eznec5 says about a .625 radiator like an Imax. It is not matched, and is done using Eznec's Real Earth feature.

View attachment Imax radials height angle.pdf

Wavrider, I think you see the little advantage for 72" radials that I see. Maybe that's why Solarcon made their radials 72".

 

[Marconi]

I'd agree with all of that - except if there were four 104 inch radials instead of the stock 6 ft ones. The guys at eHam when reviewing this antenna used used full-length 1/4 wave length radials when isolating the antenna.

Robb, I don't know whether the length of radials will make a difference that anybody could tell just using their radio, but my models don't show 104" or 1/4 wave radials to be the best in all cases with the Imax, and maybe the same with the A99. I haven't done this checking on the A99 however.

Some believe 5/8 wave long radials will perform notably better on the Imax, and I think I've checked that out once maybe for Booty Monster, but I don't remember for sure what the results were. If I was to guess these longer radials might show a little better results if they are slanted down really low however, but we'll see. If these long radials were at some higher angel like 40* or higher toward horizontal, IMO they would likely dominate that vertical radiator and then who knows what pattern would result.

NB has asked me to model an Imax with 5/8 wave radials, but he didn't suggest the angle, so I'll use an idea that a ham here in Houston, use to tout big time on the air and on his Internet site. Sometime back he took all his stuff for CB down, but not before I saved it, but it doesn't copy or paste to the Internet well, because he's and architect and this stuff was done in blue print. I might try and post it anyway, because the text part reproduces pretty well and NB and Homer might like to see what he did.

He talked about it on the air some time back, so I looked his call up and I went to his location to check it out. I saw plenty of antenna, but his Imax looked just like a regular Imax with GPK, and the radials were not 22' feet long with a steep angle down, like he told everybody. He use to brag how much signal his design made locally and I had some words with him about his BS, and our contacts stopped fast. If I can find his Website address, I'll post it up and I'll try and post up his ten meter report on the Imax in different Exnec configurations too.

 

[jazzsinger]

BM, a small air gap will do what you ask here as long as its gap is protected from opening up too wide.

how does that work Eddie? most people ground to get rid of static, a dc ground is whats needed (just like when an antenna is dc grounded), a gap would prevent grouding, yeah it might work with high voltage lightning strikes, but chances are most peoples grounding wire would be so thin it would be like fusewire to lightning anyway. th groundwire could be coiled like an air choke, number of turns and diameter that offers best impedance at that particular frequency range would best be found using an antenna analyser on impedance setting, the same way Steve G3TXQ did it for coax,

 

[Marconi]

how does that work Eddie? most people ground to get rid of static, a dc ground is whats needed (just like when an antenna is dc grounded), a gap would prevent grouding, yeah it might work with high voltage lightning strikes, but chances are most peoples grounding wire would be so thin it would be like fusewire to lightning anyway. th groundwire could be coiled like an air choke, number of turns and diameter that offers best impedance at that particular frequency range would best be found using an antenna analyser on impedance setting, the same way Steve G3TXQ did it for coax,

I've got a picture around here of a ground mounted antenna with a ground rod with a heavy copper strip attached and it curves over very close to the base of the radiator at the other end, but not touching.

If I find it I will post it. I looked back at BM's post, and I may have misunderstood what he was trying to ask or say.

 

[jazzsinger]

I've got a picture around here of a ground mounted antenna with a ground rod with a heavy copper strip attached and it curves over very close to the base of the radiator at the other end, but not touching.

If I find it I will post it. I looked back at BM's post, and I may have misunderstood what he was trying to ask or say.

All electricity follows the path of least resistance, if theres a gap in the ground wire and lightning strikes it will choose the coax although if the voltage is high enough it may also jump the gap, but most of the current will still choose the coax.

static discharges are much lower voltage by their very nature and would find it very difficult to jump any gap however small.

 

[Marconi]

All electricity follows the path of least resistance, if theres a gap in the ground wire and lightning strikes it will choose the coax although if the voltage is high enough it may also jump the gap, but most of the current will still choose the coax.

static discharges are much lower voltage by their very nature and would find it very difficult to jump any gap however small.

I agree. I think the old picture of this idea was showing an old Ringo mounted close to the ground, with this setup for grounding was off to the side.

I think I rationalized that idea, saying to my self, maybe lightning would be looking for the path to Earth as the least resistance in that case. Even though coax is a low resistance pathway, that big old chunk of heavy solid copper might have looked more better.

I'm not to sure about the idea, but I think I might have even misread BM's question. I often have trouble figuring out when BM is speaking vs. others he may bring into his post. I think he uses " " marks a lot, but sometimes I just miss them.

 

[BOOTY MONSTER]

Quotation Marks, Basic Usage (Seton Hill University)

 

[Marconi]

Quotation Marks, Basic Usage (Seton Hill University)

"Thanks Booty, I needed that."

 

[jazzsinger]

"Thanks Booty, I needed that."

pmsl, Booty teaching anyone grammar is quality, i can dig that concept.{Cry_river}{Cry_river}

 

[BOOTY MONSTER]

i'm a part time idiot and a full time fat dude

but i'll try to make my future quotes stand out more for you eddie .