Thanks for sharing your story Steve. Scary stuff. So glad you came out of this accident without a serious injury.
Looking forward to hearing you on 160 this winter with the new driven element. Tree N6TR On Mon, Sep 2, 2024 at 7:55 AM VE6WZ_Steve <[email protected]> wrote: > Hello fellow DXers...... > > VE6WZ will be QRT from the HF bands above 160m. > > On Tuesday Aug 27, I suffered a main lift cable failure on my crank up > tower that destroyed all of my Yagi's and the US tower. > At the time of the failure, I was beside the tower (doing work) in my man > lift while the tower was going up. > The tower was almost at full height (at 100') when the main lift cable > broke. > About 500 pounds of Yagis came crashing down almost instantly from 100'. > I was in the manlift, and my reaction was to "go down" into the man basket > when I heard the crash. This is what saved me. The man basket cage was > somewhat damaged and bent. > I am totally ok, with not a scratch, but the cage of the man basket > protected me. > There was debris, bolts, brackets, tubing, pieces of the booms flying > everywhere, but somehow, the man lift was not knocked down. After the > collapse, one of the 80m Yagi elements was laying on the man basket, but I > was able to push it off, and lower the man lift to get out. > The tower, my 80m-40m Yagis are completely destroyed. Unrepairable. The > high band Optibeam is probably repairable. > https://drive.google.com/file/d/1WPDpMbGaS1r8qgjWlj4AFyS8Gog5uSnY/view?usp=sharing > < > https://drive.google.com/file/d/1WPDpMbGaS1r8qgjWlj4AFyS8Gog5uSnY/view?usp=sharing > > > > Why did this happen? > It was my mistake. > I am building a 4 element, 160m, 6 direction triangular parasitic array > and needed to modify the shunt feed for the US tower crankup. The crankup > is the driver for the parasitic elements. > The existing shunt feed for the tower needed to me modified into a > symmetrical skirt surrounding the tower to maintain balanced coupling to > the parasitics. > I clamped brackets to the outside of each section to support the > shunt-wire standoffs. > These clamps were working well for the last 3 months, but after a high > wind, some of the shunt wires moved and caused the support arms to bend > inward. > This bending shifted one (or more) of the brackets to bend INWARD into the > inner moving sections, then toward the main lift cable and basically sliced > the main lift cable. > The point is, this failure was not something that would have happened > normally, but was only because of my poor engineering/ modifications. I > guess that’s why they are called accidents? > > I have owned the US tower crankup for 26 years, (beginning at my city QTH) > and have been fastidious about maintenance of the cables, sheaves and > motorized raising fixture, and have had trouble free use of it. > I will miss it. > My homebrew 80m-40m 2 el Yagis have been in service for 22 years and I > have had great enjoyment using them. > On 40m I have worked DXCC Honour roll with 336 confirmed, and have 293 > DXCC confirmed on 80m. > I really wanted to make it to 300 DXCC on 80m, but maybe that will > encourage me to build an 80m vertical array? > > I have decided not to replace the tower. I want to simplify my remote > station, and looking back over the last few years, I have been almost > exclusively active on 160m anyway. > It has been pretty rare to hear ve6wz above 40m, let alone on 80m for the > last few years. > I plan to remove (and sell for scrap) the 2,000 lb US tower, and replace > it with another 90' irrigation tubing vertical to complete my 4 element > triangular 160m TX array. > > Here is a some detail about the 160m array: > > The driver "was" the shunt fed tower, but that (next year) will be > replaced with a 90' irrigation tubing vertical. > There are 3 parasitic elements surrounding the driver (75' toploaded > irrigation verts) spaced at 60'. > At any time, 3 elements are active, one parasitic tuned as a director, the > other as a reflector. > The array is a variant of the classic K3LR, K9CT, VE3EJ 3 element inline > array, but in my case, the 3 elements are spatially "offset". > For example, the north parasitic tuned as a director pushes forward gain > north, but the SW parasitic pushes the pattern NE. > The really crazy thing, is that modelling shows the forward gain and F/B > to be down only .4 dB from the inline design, PLUS, I get 6 directions! > To my knowledge no one has ever built an array like this. > > Before the tower collapse, I actually had completed the array and was just > finalizing the expanded radial system for the north element. (another > 8,000' of copper wire) > I had done some field testing with my signal source and RX testing in the > field while TXing. The field test where identical to my model. > The array shows 3.5-4dB forward gain (compared to a single vertical) and > about 20 dB F/B. > My plan was to make a YouTube video (and a .pdf paper) describing the > array, modelling, installation and field testing, but that will now be > delayed until next year. > > Since the tower failure, I have already modified the north parasitic, so > it is now tuned and fed as a driver, and using the SW and SE parasitics as > refelctors I at least have gain to EU and JA. > So VE6WZ I will still be QRV on 160m this winter season. > My 9 band RBN CW skimmer is offline until I reinstall a new antenna since > that skimmer antenna was on the tower. > Both of my 160m RBN skimmers are still running. > > That’s a long story, but I wanted to share this with the topband community > since the VE6WZ remote station will be taking a slightly different > direction. > > Steve, Ve6wz. > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
