[VHFcontesting] Portable 50 MHz beam antennas

Bob K0NR - email list list at k0nr.com
Fri Feb 16 18:41:44 EST 2018 

This is good stuff. Thanks for sharing.
73, Bob K0NR

On 16-Feb-18 10:53 AM, David Olean 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 with
>>   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 sudde
>>   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 at contesting.com> on behalf 
>> of Mark Spencer <mark at alignedsolutions.com>
>> Sent: Thursday, February 15, 2018 4:22 PM
>> To: Bob K0NR - email list
>> Cc: vhfcontesting at 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 at alignedsolutions.com
>> 604 762 4099
>>
>>> On Feb 15, 2018, at 7:17 AM, Bob K0NR - email list <list at 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 at 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 at alignedsolutions.com
>>>>> 604 762 4099
>>>>>
>>>>> ------------------------------
>>>>>
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>>> -- 
>>>
>>> -- 
>>> Bob Witte K0NR
>>> bob at 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 
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Bob Witte K0NR
bob at k0nr.com

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