Antenna Prepping for ARRL Field Day – the linked dipole

Started gathering my field day equipment together, and started to think of what kind of antenna I want to use this year. You see, the big advantage with field day for...

Started gathering my field day equipment together, and started to think of what kind of antenna I want to use this year. You see, the big advantage with field day for most folks is you’re usually able to get pretty creative with antennas, and definitely go up in size. The more wire in the air is always generally better IMO! I wanted to try something different this year, so initially a vertical popped up in my head – but after a bit more consideration, and searching various other hams experiences with verticals for field day, I’ve found that the amount of work required to deploy one, and lay a decent radial plane underneath would be too significant for just a 27 hour event. I also stumbled across K3AN’s post over on eHam regarding one hams question on whether or not a vertical would be a good idea for Field Day:

“I’d only go with a vertical for FD if my site had no means of supporting some kind of dipole/doublet/G5RV, even at just 35 feet. FD is a domestic “contest” so you want high-angle radiation on 80 and 40. A vertical is also going to be noisier than a horizontally polarized antenna, and with June usually having lots of thunderstorms throughout the U.S., why punish your ears with extra QRN?” (K3AN eHam post)

This made perfect sense.. .ugh… I had already started prepping the radial plate, and connecting radials with powerpole connectors for quick deployment.That’s ok. Shifting gears again…

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I used an OCF last year which has the advantage of not having to change the dipole links when changing bands, but it should only take me a matter of minutes with the drive on mast mount that I have planned. I could never get 80 meters below 3 to 1 on a 7 band OCF last go around (I think it was due to the height above ground, or interaction with the mast), but all the other bands were pretty much acceptable. Over on VK3ZPF’s blog, I found this idea & I built this box to set atop one of the sections on the spiderpole, though there’s no balun, effectively just splits the coax out:

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My plan is to do a DIY  linked dipole of sorts, simply just a linking the elements together using powerpoles as the links between bands & DX Engineering insulators to provide the stress relief between the links. Pruning & tuning a dipole is so much easier than trying to tune an OCF. I can usually have a simple dipole up, and in one or two snips, I can have it resonating exactly where I want!

I have a 40 foot spiderpole that I’m trying to employ as my mast, although fully deployed, there is quite a bit of bend at the top, but that also puts pressure on the mast joints so as not to make the mast collapse under it’s own weight. (I’ve had this problem with my Jackite in the past – but not yet with the spiderpole, it’s pretty new, and the joints are still fairly tight). So we’ll try to stick to the K.I.S.S. principle for field day, should allow for easier setup & breakdown.

Unfortunately I ran out of 18AWG wire, there was no way I was going to try and use regular ole’ big box 14awg on this, that stuff kinks like no other, and is very unruly to work with! So had to order some more. A video is forthcoming once i’ve had the chance to test everything out. I guess if a balun is needed, maybe I can squeeze a toroid in there somehow, but i’m hoping i’ll be ok with my 100w setup. I’ve actually never used a dipole without a balun. So this will be interesting to try, any kind of added weight, whether through a built balun, or an air wound coil would just add significant weight to the pole.

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The SOTAbeams band hopper uses RG-174 coax as well, the smallest coax that I have is RG-8X which i’ve used on the military mast, but i’m concerned it may be a bit heavy for the spiderpole… lots of stuff to test out before June 24 & 25 get here!

This is probably the one event our club (N5OAK) really looks forward to every year. Lots of planning and prep go into this event to make it a success, but mostly i’m just looking forward to kicking back with a beer under the Texas sky & playing ham radio with friends!

Edit… (here’s the video…):

73

k5acl

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ARRLContestingField DayHam RadioHF Antennas
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