[AK-VHF] [Moon-Net] 2m Array Down

Wed Nov 4 19:47:16 EST 2020

Update:

The tower is guyed to prevent further falling.

As many of you know, I put up a 6m-eme array in December 2018 and it 
is ready for use after replacing the azimuth rotator in Sept.
http://www.kl7uw.com/6m.htm

I also mounted two 11-element yagis made from a KLM 22c satellite 
x-yagi by drilling a second boom.  They are mounted above the 6m 
yagis in Vpol.  Array gain is about 15.2 dBd (17.35 dBI)  which is 
approx. 4-dB less than my XP20 array (21.3 dBi)
http://www.kl7uw.com/6M_eme_dualyagi.jpg

I tested SWR about an hour ago and have 1.2 at 144.000-144.300 so 
should make my 1500w amp happy.  The preamp/TR box needs to be moved 
from the old broken array to the 6m tower.  They will not be 
installed as close to the antennas as before, so I calculate 0.66 dB 
line loss so my NF will be about 0.75 dB.  I will have 1.25 dB line 
loss so my 1385w PA will result in 1038w at the feeds.   This is 83w 
more than I had at the 4x array.

So  working toward getting this backup system QRV before the ARRL EME 
WE (Nov.24-25).  I will run wsjt-x in single pol.  Still need to test 
the antenna system at QRO.

Elecraft shipped my serial interface (KIO3A) back to me today so 
should have K3 back in service by next Monday.  I have the KX3 set up 
for computer control so it is usable for 2m eme as an alternate. Both 
do 6m as well.

73, Ed - KL7UW

At 10:48 AM 11/2/2020, Edward R Cole via Moon-net wrote:
>Bottom section of tower is bent so all must be taken down. Upper 
>four sections of tower look OK and most antennas OK (two lower one's 
>hit the ground bending elements and broke end of one antenna (will 
>need new boom to rebuild). Hazer Lift crashed and may be too damaged 
>to reuse (cost $600 22 years ago). Winch may also be damaged ($150). 
>Antenna H-frame and new rotator look OK. Going to attach guys from 
>tower top to prevent total tower failure which would destroy it all 
>($3,000+). Nothing can be done until next summer. Will ask my tower 
>guys whether their boom truck can cross my lawn (may take boards for 
>it to run onto or putting in a driveway to handle a 5-ton truck).
>
>If concrete base is bent then a new base will be needed, as 
>well.  Will think it over the winter.  I may opt to put up 30-foot 
>of tower without Hazer with only preamps and TR relay on 
>tower.  That would entail running cables to ground level where all 
>amps would live.  Maintenance would entail using a man-lift but that 
>is much cheaper than the boom truck.
>
>I will explore using my two KLM yagis for 2m-eme in meantime.
>
>73, Ed - KL7UW
>http://www.kl7uw.com/2m-eme_down_1.jpg.
>http://www.kl7uw.com/2m-eme_down_2.jpg
>
>At 09:35 AM 11/2/2020, Edward R Cole wrote:
>>I may have a backup to the 2m-eme array (maybe).  I installed two 
>>11-element KLM yagis in Vpol above my 6m eme yagis.  So all move 
>>with az-el.  The KLM yagis are rated for 2 kW PEP.  I would have to 
>>retrofit one of my 2m-eme preamps and TR relay to run eme on those 
>>antenna.  KLM claimed 13 dBd gain (I wonder).
>>
>>I have 50-foot of LDF4-50A 1/2-inch line to the tower base and 
>>33-foot of LMR-600 up the tower.  Two-way splitter is made of RG-11 
>>with LMR-400 phasing lines.  Driven elements are folded dipoles 
>>with coax baluns.
>>
>>Assessing the situation later.
>>
>>73, Ed - KL7UW
>>
>>At 08:49 AM 11/2/2020, Edward R Cole via Moon-net wrote:
>>>We've had very strong winds yesterday and today.  I discovered my 
>>>2m array came down last night.  My wife heard a big noise about 
>>>9pm and thought something hit the house.
>>>
>>>The array was mounted on a Hazer lift and it appears it dropped 
>>>which indicates the brake failed and maybe the hauling cable 
>>>broke, as well.  The array stopped before hitting the ground so 
>>>antennas look OK, but the 50-foot Rohn-25 tower is bent near the 
>>>base.  All the guys went slack but this is normal when the array 
>>>is lowered.  I realized that the top guys to the tower were not 
>>>attached (which is normal for operating eme).  Had they been 
>>>attached to the guys the tower might have survived.
>>>
>>>Still strong winds so have not gone out to inspect, closely.  I 
>>>suspecting one of the Hazer guy attachment gave way to cause the tower damage.
>>>
>>>At this late in the season, probably unlikely to get tower down 
>>>for repair (if possible).  It will take a boom truck to pick it 
>>>off (not safe to climb).  Ground has been rain soaked for the last 
>>>month or tow so will not likely support a boom truck.
>>>
>>>6m eme array looks fine.  4.9m dish was removed last month and is 
>>>on the ground with weights on the edge.  Pictures later.
>>>
>>>73, Ed - KL7UW
>>>   http://www.kl7uw.com
>>>Dubus-NA Business mail:
>>>   dubususa at gmail.com
>>>_______________________________________________
>>>Moon-Net posting and subscription instructions are at 
>>>http://www.nlsa.com/nets/moon-net-help.html
>>
>>73, Ed - KL7UW
>>   http://www.kl7uw.com
>>Dubus-NA Business mail:
>>   dubususa at gmail.com
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>
>73, Ed - KL7UW
>   http://www.kl7uw.com
>Dubus-NA Business mail:
>   dubususa at gmail.com
>_______________________________________________
>Moon-Net posting and subscription instructions are at 
>http://www.nlsa.com/nets/moon-net-help.html

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   dubususa at gmail.com 