VHFcontesting
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Re: [VHFcontesting] Portable 50 MHz beam antennas

To: Bill Olson <callbill@hotmail.com>
Subject: Re: [VHFcontesting] Portable 50 MHz beam antennas
From: Mark Spencer <mark@alignedsolutions.com>
Date: Fri, 16 Feb 2018 09:30:37 -0800
List-post: <mailto:vhfcontesting@contesting.com>
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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