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Author Topic: Butternut HF9V versus Steppir BigIr for saltwater location  (Read 4865 times)
W4VKU
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Posts: 348




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« on: March 05, 2013, 06:07:22 AM »

Howdie folks,
 In preparation for 8Q7 operation, i am trying to figure out what to take along without breaking the bank.
 I have read that for 80-20m, the vertical will do well (opens and closes the band as compared to a horizontal antenna).   
 For 12/10m, i read that a horizontal antenna will do better at say 15-20ft near the beach.

 I have the HF9V on hand, but may have to shell out some doe for the Steppir.
 
 Pros of HF9V : Light weight, no band switching headaches
 Cons of HF9V: Tuning might be a headache even with an analyzer, esp standing in the water Smiley
                     Limited bandwidth on 80m. But not an issue, since will take 2 HF9V's instead of 1
                     for each of the 2 stations and tune for cw and ssb parts of the band.

 Pros of BigIr : Easy tuning
 Cons of BigIr: Price, need to carry the EHU and control cable, does not have 80m(extra $)

 Questions:
1) Just how much better will the BigIr be over the HF9V on 40-20m?
2) Can i just run say 2 radials cut for 80m, leave it in the salt water and
   adjust the tuning and expect a killer performance?
3) I have looked at the SVDA's.It appears that we need to carry multiples of
   these to cover all bands. Would prefer to switch bands from the shack
   rather. A bit more than a 100lb expedition, but cannot afford a container Smiley
4) For higher bands 12/10/6m, i have a 2ele steppir+40m trombone that i normally
   carry. I am thinking if a hexbeam would be better. The weight difference
   is about 10-15lbs. While the hex is lighter, the steppir has 180/bi-dir modes
   and also adds 30/40m coverage for short haul, that could be a skip for the vertical.
   To top it off, i have the steppir yagi(in VU), but need to buy the hexbeam which is about $400
   and is not too bad a price.



Any thoughts/suggestions?

73s
krish
w4vku
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KB4QAA
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Posts: 2409




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« Reply #1 on: March 05, 2013, 08:06:15 AM »

Ah, the magical salt water ground plane.  Solves all problems, cures all ills, direct EM pipeline to all DX entities, better than any other arrangement.....

Except a decent copper radial field!  harumph.  Noting that a copper wire is several thousand times more conductive (and effective) than salt water.

There are other benefits to being close to water (any water) relating to near field and far field effects.  You get these from being within a couple hundred feet of the water and direct grounding is not required.

-Use whichever antenna strikes your fancy.  Both require radials.  The IR antenna will be harder to clean and may suffer long term corrosion.

-Water has a fairly shallow skin effect.  So don't put any grounding plates or radials more than a few feet deep.  Putting specific radial lengths in water is pointless.

Probably the most effective installation would be to set up over land, and use one or two tuned, elevated radials for each band.

Enjoy your expedition!  bill
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KH6DC
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Posts: 645




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« Reply #2 on: March 05, 2013, 12:23:35 PM »

I live in Honolulu and we have salt air all the time.  I had a HF6V up for maybe 8 months before I replaced it with a BigIR.  Why?  Because of the BigIR's ability to tune wherever you go.  The HF6V is an excellent antenna but when I took it down, I noticed the entire antenna pitted and spots of aluminum corrosion or white rust everywhere.  I had the BigIR up for a year and a half and when I took it down I inspected the copper-berrylium tape and it was just tarnished, no corrosion.  Just something to think about.
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73 and Aloha,
de Delwyn, KH6DC
K3VAT
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Posts: 731




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« Reply #3 on: March 05, 2013, 08:57:10 PM »

Howdie folks,
 In preparation for 8Q7 operation, ...

Any thoughts/suggestions?

73s krish w4vku

Recommend you first read K2KW's and N6BT's accounts of Team Vertical - a record setting performance from Jamaica (and other QTHs) seaside location using verticals (and arrays of verticals).  Here's the links:  http://www.k2kw.com/6y2astory/story.html and http://www.n6bt.com/n6bt-C6-2010-1.htm.

IMHO, keep all antennas as simple as possible, thus I would nix the BigIR despite its positive attributes (mainly 'tune anywhere') as it isn't as trouble-free as the Butternut.  You may also check out N6BT's line of verticals.

KB4QAA: over the past decades, top DXpeditions that have had access to beach side locations clearly dominate over those that operate from inland locations, especially using verticals and arrays of verticals placed directly on the beach and the simplicity of their radial fields might amaze you.  Reference the two above links.

GL, 73, Rich, K3VAT
« Last Edit: March 05, 2013, 09:07:03 PM by K3VAT » Logged
AC4RD
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Posts: 1235




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« Reply #4 on: March 06, 2013, 04:11:17 AM »


 In preparation for 8Q7 operation   ...
Any thoughts/suggestions?

Krish, I don't know anything about the antennas, but I DO have a suggestion:  For your own peace of mind and wellbeing, you should set up a sked with the hams back in the Raleigh area.  Particularly those of us who don't have 8Q7 confirmed yet.  Wink    --ken
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W4VKU
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Posts: 348




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« Reply #5 on: March 06, 2013, 06:31:26 AM »

Ken et all,
 Pse drop me a line. We can sync up on Skype prior to the trip or pse join the 7163net dot com boys and you
 will definitely be able to work. The plan is to get a 2G/3G access for the laptops. Now that the expectations are
 for realtime logs, will need to see how to go about it as we run 2 stations.

 Just heard back that the water line at the resort is just 130ft from the room. I was worried about a 250ft run per the
 google map scale, but the shorter distance is good news. Might just haul the LMR400.

 Thanks all. Please keep the comments coming along. All good and helpful.

73s
krish
w4vku
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W5WSS
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Posts: 1745




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« Reply #6 on: March 06, 2013, 07:31:28 AM »

For best longevity relative to galvanic salt water corrosion I suppose the Stepir would be since it is encased within a tube.

For any Aluminum tube vertical

One could seal the nested tube joints after the tightening sequence is completed during the construction stage.
using an electrical tape designed for UV exposure.

One might ask why bother with tape since the UV will require more frequent maintenance intervals caused by the tape deteriorating?
I lived in south Florida right near the salt water and maintenance needs to be done, and the tape tripled the time between service and the joints were perfectly preserved. Shiny and same as brand new. The service intervals decreased to 4yrs for changing the tape and when done I noticed that the second layer of the tape was like brand new.

Installation of the electrical tape using very tight wraps where the tape is stretched and more than normal turns are used along with 2-3" overlap beyond the joint always proved best.

73


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W5WSS
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Posts: 1745




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« Reply #7 on: March 06, 2013, 07:33:57 AM »

 Huh oops answered a question not asked.

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W5WSS
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« Reply #8 on: March 06, 2013, 07:35:45 AM »

Going to the Coffee pot
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NQ3X
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Posts: 64




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« Reply #9 on: March 08, 2013, 04:15:40 AM »

Rich, K3VAT is spot on.  My ground plane is within 3' of the waterline and it BARKS. Smiley  Repeatedly in ARRL DX SSB, I had stations asking me if I wanted to change me "59 100" to "59 1k".  Note it's a ground plane, however, not just radials tossed into the sea; that really doesn't work as well for some reason probably detailed in the Team Vertical data. 

I'm about to install a 4BTV for testing purposes.  It'll be further away from the water (about a wavelength on 10M), but higher.  We'll see how it compares to the wire GP.

Cheers de Bob WP2XX
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W4VKU
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Posts: 348




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« Reply #10 on: March 08, 2013, 09:07:32 AM »

Thank you for the advice. I just pulled out the HF6V-X that was sitting in the garage(since last year). Need
to purchase a Delrin insulator tube and the ground mount aluminum stub pipe and i should be all set. Also
purchased a new 12/17m coil set to go with it and make it a HF8V-X.

I also have a HF9V in VU, but i see that the HF6V-X is only 3ft and packs realy well as compared to the
4ft HF9V. I wish i could purchase another used HF6V-X. The 2Ele steppir will be used for 12/10m.

We now have 8Q7KP as the assigned call with VU2PAI & I going active from Apr23-Apr 30. The rigs are
a K3 and TS480. The amps are an Acom 1000 and a Ten Tec hercules 2. Plans are for CW/SSB & Rtty.
Plans for 10-80m.

If you need 8Q7 for an ATNO, please drop us a note. We should have internet access and hope to watch
the cluster too.

Any other suggestions, please drop us a note.
73s
krish
w4vku
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AB3CX
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« Reply #11 on: March 10, 2013, 06:42:54 PM »

When/If your Steppir breaks down in the Maldives, you will be off the air.  Take the HF-9V
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KF7DS
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Posts: 191




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« Reply #12 on: March 10, 2013, 07:56:57 PM »

When/If your Steppir breaks down in the Maldives, you will be off the air.  Take the HF-9V

That is exactly why I passed on the SteppIr....too many parts that can go wrong. Got an HF6V which was easy to tune with an analyzer...little to mess up.

Don KF7DS
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W4VKU
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Posts: 348




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« Reply #13 on: March 11, 2013, 09:27:13 AM »

We needed to have the steppir controller on a UPS during the last expedition.
Prior to adding the UPS, the antenna was off calibration with each power shutdown.

For 8Q7, the island is powered by generators, so definitely a fixed vertical will help.
It takes a few hours to put together and tune each HF9V, but i agree that it is a one time deal.

73s
krish
w4vku
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K6AER
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« Reply #14 on: March 11, 2013, 01:13:34 PM »

I have had my big SteppIR up for 9 years.  Snow, ICE, UV, very large owls, two lightning strikes and a tornado have not damages the antenna at all. Contrary to popular belief the StepperIR antenna has very little parts. Stepper motor, real for the tape and a recoil spring and a single beryllium copper tape. The antenna is sealed against moisture. Four wires connect to the controller. Some radials and you're on the air.

With any MTBF (Mean Time Between Failure) the total number of critical parts is your determining factor in reliability. Every trap, coil, capacitor are parts which effect the reliability. The high the total critical parts count the lower the MTBF.  The other part of the equations is your ground resistance, capacitance coupling and nearby objects determine the tuning for each band.

What might have been perfect in North Carolina might be hundreds of ohms off in feed impedance on a beach somewhere.  The ability to tune an antenna remotely is a tremendous advantage when time is a factor.

Don't get caught in the salt water is a conductor trap.  RF might reflect off of salt water at a low angle but as a RF conductor it is very poor.  When the guys went to Antarctica (3Y0X) years ago (2006 I think) they took StepperIR’s. Can't think of conditions any harsher or more critical than that.

Given the Maldives  are half a world away, I would seriously consider and amplifier and a three element beam. You will have to control the pileup and 100 watts and a vertical will be hard at best.
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