VHFcontesting
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Re: [VHFcontesting] Portable 50 MHz beam antennas

To: David Olean <K1WHS@metrocast.net>
Subject: Re: [VHFcontesting] Portable 50 MHz beam antennas
From: Mark Spencer <mark@alignedsolutions.com>
Date: Fri, 16 Feb 2018 10:35:13 -0800
List-post: <mailto:vhfcontesting@contesting.com>
Yes.   That does make sense..   Depending on where I am setting up and how 
ambitious I am I typically run my 50 MHz beam at approx 24 to 32 feet above 
ground level while roving / operating portable.   I'd like to go higher (often 
to help clear near by trees) but 32 feet seems to be the practical limit for me 
and often I don't go that high.

I'm also starting to think that using a free standing tripod (usually with 
guys) away from the truck (vs my trailer hitch mount, or a tripod in the truck 
bead) works a bit better but don't really have any actual data to support that 
belief.   I usually position the truck behind the beams.   Most of my 
operations involve beaming in one  direction (from BC into the PNW) so I don't 
need to move the beams much.  At 50 MHz I'm not overly worried about feed line 
losses.

I'd be curious to hear more thoughts from others.

73

Mark S
VE7AFZ

mark@alignedsolutions.com
604 762 4099

> On Feb 16, 2018, at 9:53 AM, David Olean <K1WHS@metrocast.net> wrote:
> 
> More data....
> 
> We ran a similar test using a rover station 4 element 50 MHz yagi at 12-14 ft 
> vs a halo at 35 ft. This was a real test and not a quick exchange during a 
> contest. The path was about 280 miles long and the halo was a definite winner 
> over the low yagi for the rover station.  A home station was on the other end 
> of the path.  The rover was W2GE/r with N2CEI and WB2ONA at the Packrat 
> contest location in the Poconos in FN21. I was operating the home station in 
> FN43 in Maine. Height above ground makes all the difference on 50 MHz.
> 
> Dave K1WHS
> 
> 
>> On 2/16/2018 5:07 PM, Bill Olson 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 wi
 th
>>  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 su
 dde
>>  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.
>>> For me, compact is nothing longer than 40 inches.
>>> (I'm actually thinking SOTA more than VHF contesting but I sometimes 
>>> combine the two.)
>>> 
>>> 73, Bob K0NR
>>> 
>>>> On 15-Feb-18 7:57 AM, Zack Widup wrote:
>>>> I got a design from VE3BFM for a four-element 6m beam on a 13 foot boom.
>>>> It's a great performer. Since I operate portable 95% of the time, I built a
>>>> version I could quickly assemble and disassemble at a portable site. The
>>>> boom and each element is in two pieces. I never formally wrote up an
>>>> article about how to build it, but I did talk about it at the VHF forum at
>>>> Dayton a couple years ago. Maybe I should write it up.
>>>> 
>>>> I have similar portable Yagis for 144 through 432 MHz. I can assemble and
>>>> disassemble them pretty quickly. My 144 MHz Yagi has six elements
>>>> wide-spaced on a 12 foot boom. I believe the gain predicted by Yagi
>>>> Optimizer is about 12 dBd. I haven't measured it yet.
>>>> 
>>>> 73, Zack W9SZ
>>>> 
>>>> 
>>>>> On Thu, Feb 15, 2018 at 8:23 AM, jon jones <n0jk@hotmail.com> wrote:
>>>>> 
>>>>> Mark:
>>>>> 
>>>>> 
>>>>> Another idea is to build your own portable 6 meter beam. I have found a 2
>>>>> element yagi is easy to build, break down and re-assemble quickly. A 2
>>>>> element yagi offers about 3 - 4 dB gain over a dipole. It is easier to put
>>>>> up and take down than a 3 el.
>>>>> 
>>>>> 
>>>>> I use one for my VHF contest and portable operations. A picture of it is
>>>>> in the NCJ March/April 2016 pp. 32. It works... have WAC with it on 6 with
>>>>> 100 W from KS on ssb/cw.
>>>>> 
>>>>> 
>>>>> A plan for one is here:  http://www.qsl.net/k7yo/6m2Yagi.htm
>> [http://www.qsl.net/k7yo/6m2yagi.jpg]<http://www.qsl.net/k7yo/6m2Yagi.htm>
>> 
>> 6 meter 2 element yagi - QSL.net<http://www.qsl.net/k7yo/6m2Yagi.htm>
>> www.qsl.net
>> 6 meter, 2 element yagi. A simple, compact and effective antenna for 50 Mhz. 
>> This antenna was built in about an hour after using K6STI's AO simulation ...
>> 
>> 
>> 
>>>>> 
>>>>> 
>>>>>  - Jon N0JK
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> ________________________________
>>>>> 
>>>>> Hi:
>>>>> 
>>>>> I finally took delivery of a suitable LiPo battery to facilitate "back
>>>>> pack portable" operation at the 50 to 100 watt level.   If any of my
>>>>> Canadian colleagues are interested I can provide the contact details for a
>>>>> Canadian distributor.
>>>>> 
>>>>> At this point I'm planning on simply taking my 50 MHz three element beam
>>>>> apart and re assembling it on site.   In my view the beam I have isn't
>>>>> really intended for that type of use and I'm curious if anyone knows of 
>>>>> any
>>>>> suppliers for small 50 MHz beams that break down and re assemble quickly
>>>>> and easily.   Google searching on my part didn't turn up anything that is
>>>>> currently in production.
>>>>> 
>>>>> I'm hoping to shift my focus a bit this year and actually reach the true
>>>>> summit of at least one local mountain (vs simply driving most of the way 
>>>>> up
>>>>> via logging roads.)  Having this ability would also have been useful
>>>>> earlier this year when I had to abort my CO81 visit during the sept
>>>>> contest.   In hindsight I suspect I could have activated the grid for a 
>>>>> few
>>>>> hours on foot.
>>>>> 
>>>>> 73
>>>>> 
>>>>> Mark S
>>>>> 
>>>>> Aligned Solutions Co.
>>>>> mark@alignedsolutions.com
>>>>> 604 762 4099
>>>>> 
>>>>> ------------------------------
>>>>> 
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>>> --
>>> 
>>> --
>>> Bob Witte K0NR
>>> bob@k0nr.com
>>> 
>>> _______________________________________________
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>> aspects of contesting on frequencies of 50 MHz and above. We hope to 
>> generate discussions of any ...
>> 
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>> aspects of contesting on frequencies of 50 MHz and above. We hope to 
>> generate discussions of any ...
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