Hi Bill. Good point re the height issue. Yes I am planning on taking an
approx 20 mast with me during my back packing trips. I've found while roving
from my truck that getting the 50 MHz beam at least a wave length over ground
helps quite a bit.
I took a look at one of my roving masts and figure it is just barely viable for
back pack outings. (I'm aiming for a total load of 50 pounds including radio,
battery, mast and antenna.) I hope I'm still up to hauling a 50 pound pack
around (: My first planned outing is going to be a fairly easy walk up a de
activated logging road that I don't want to drive my truck up.
73
Mark S
VE7AFZ
Aligned Solutions Co.
mark@alignedsolutions.com
604 762 4099
> On Feb 16, 2018, at 9:07 AM, Bill Olson <callbill@hotmail.com> wrote:
>
> Hi all, This might be a good time to bring up "height above average terrain"
> for a 6 meter beam. I'll digress here a little then will get back to the
> point. I used to rove with the lower 6 bands. Antennas were all mounted on a
> rotor fixed to roof racks on my truck. There were ~ 8 ft yagis and loop Yagis
> on 2 thru 1296 BUT on 6 meters I had an old 4 element Yagi on a 12 foot boom.
> This got mounted right above the rotor so was maybe 7 feet off the ground.
> (Yeah the ~9-10ft long 6M elements hung over the sides of the vehicle a
> little - never was a problem with law enforcement hi). Everything worked
> great except 6M. It had reasonable SWR and I knew the Yagi worked because I
> had used it on the tower.. but signals were weak except when the band opened
> for e-skip.. Well that should have tipped me off right there but It wasn't
> until I had a talk with Pete, K9PW, who used to operate with the AA9D
> multi-multi VHF contest station in central Illinois. They had done some
> experiments wit
h
> their rovers and found that just a HALO antenna at 25 feet WAY out performed
> a multi-element Yagi at 10 feet.. Well duh, of course the Yagi's pattern in
> the vertical plane got more and more elevated off the horizon the closer it
> got to the ground and at 10 feet there was practically no response on the
> horizon. I haven't done any of the math BUT just experimenting with it, I
> arrived at about 20 feet for my rover 6M antenna. I built a 2 element beam on
> a four foot boom. This could easily ride on the roof racks with the elements
> pointing fore and aft. I put together a 20 foot mast and that got stowed up
> there too.. So, yeah, no operating 6m while in motion, but with a trailer
> hitch sort of mount for the mast, it really only took a couple minutes to get
> the 6M beam in place.. Armstrong rotated for me, but here in Maine pretty
> much everyone is in the same direction and with abroad pattern it was pretty
> much set it and forget it.. The results were quite amazing and all of a sudd
e
> n I worked stations on tropo at several hundred miles..
>
>
> To get back to the back-packer antennas, folding up the antenna and making it
> "packable" is one thing but then you need a 20 foot mast too and a way to
> keep it up in those high mountaintop winds!! The gain of the antenna is not
> doing you any good if it's peak is above the horizon and there is a null AT
> the horizon!
>
>
> just saying..
>
>
> bill, k1DY in Maine
>
>
> ________________________________
> From: VHFcontesting <vhfcontesting-bounces@contesting.com> on behalf of Mark
> Spencer <mark@alignedsolutions.com>
> Sent: Thursday, February 15, 2018 4:22 PM
> To: Bob K0NR - email list
> Cc: vhfcontesting@contesting.com
> Subject: Re: [VHFcontesting] Portable 50 MHz beam antennas
>
> Thanks All. I got some great on and off list responses.
>
> Yes I believe the 40" length limit is a reasonable one. (I have found
> carrying 48" mast sections via backpack to be a bit awkward for me.)
>
> 73
>
> Mark S
> VE7AFZ
>
> Aligned Solutions Co.
> mark@alignedsolutions.com
> 604 762 4099
>
>> On Feb 15, 2018, at 7:17 AM, Bob K0NR - email list <list@k0nr.com> wrote:
>>
>> Zack,
>>
>> I'd be interested in the 144 MHz yagi design for backpack portable operating.
>> Its got to be compact and easy to assemble, otherwise it tends to get left
>> at home.
>
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