Sunday, October 24, 2010

Penetrox & Smoked

If you have been following my blog, I have mentioned that I began experiencing some problems with high SWR after a RTTY contest last year. I looked at some supporting documentation available from Mosley that helped me narrow down the issue to 15 meters. Each trap consists of two coils, with the inner trap catching 10 meters (band is still flat across the board), the second coil traps 15 (SWR off the scale) and 20 as it turns out, is a summation of the element (about 4.0 to 1 SWR in the SSB portion). Keeping that in mind, I knew I had to drop my beam and start pulling traps off of my elements to see which was producing my problem. Alaska has been seeing some pretty warm weather here due to a SE wind pattern so I took advantage to drop my driven element off of the boom to dive into the traps. I accomplished this yesterday and today I pulled the element apart.

If you have never used Penetrox, I would highly suggest it. One of my long time friends and one of the hams that helped me get my start into this hobby  suggested Penetrox. I have been using it ever since. When placed on connecting parts, it helps prevent oxidation without effecting the electrical characteristics of your antenna. I have had my beam up for several years now and when I pulled a piece of the driven element out of the trap, I found it to be in the same shape as it had been when I put it together a few years ago (see photo above). I will not build an antenna without this stuff!

I proceeded to pull the traps off of the driven element and I found that the Penetrox did an outstanding job there as well. In the photo above, I just wiped off the excess (bottom trap in the photo) and it shines like the day I assembled this beam.  Now, keep in mind, I used this beam for several years when I lived in Ohio. It operated there, made the trip to Alaska, and has taken a beating with extreme weather we experience here. I'm happy to say, with continued preventative maintenance, this beam will probably outlast me.

As I tore into the one of the traps on the driven element, I could detect an odor that pretty much confirmed my suspicions. I also had a bit of difficulty getting the trap apart on one end. As I was finally able to muscle the inner workings of the trap from the housing, I found the following damage showing

what happened during the RTTY contest I had been operating. I happened to make my best score yet in a RTTY contest but success came at a cost.

 When I pulled both traps apart, I found only one had this extensive damage. I wonder what my chances are of having the problem in only one trap? I won't be able to tell until I either inspect each trap individually or repair this one and put it back on checking the SWR curve with my beam to see. The other issue is, the insulator is riveted onto the tube (as seen in the photo above). So, it seems I will be touching base with Mosely looking for parts. If I wanted to get replacement traps from Mosely, they quoted me a price of $478.60 for this beam. Thankfully, replacement coils only run $39.50 each!  Living on a tight winter budget, you can sure guess which parts I will be ordering!

I would purchase another Mosley antenna in a heartbeat! It has done well but even the best antenna's have their breaking points. This beam has survived extreme cold, high wind gusts over 70 mph, ice, and more. In the end, it was RTTY at high power that did it in. You need to know the limits of your equipment. From the Mosley website, the following graphic below describes the limitations of the Mosley TA-34-XL antenna which I should have paid a bit more attention to prior to banging out a RTTY contest on legal limit high power all weekend long. I am proud to say, the beam did not fail until many hours of high power RTTY operating (actually, the last few hours). I can't see myself owning any other manufactured antenna during my ham career.

So, I can only hope that I can repair this trap and get it back in operation before the extreme cold and snow arrives. If not, I can always print this photo and keep it close as a grim reminder of what happens when you ask more from your equipment than it can take. My Ameritron AL-1500 might be enjoying the rest but I'm sure not enjoying the lack of activity. If I don't get this beam fixed, I may have to take up a new hobby for the winter as my 5BTV just ain't the same even though it's a good antenna.

Sunday, October 3, 2010

Fun Summer, Rough Winter

I live in a pretty windy area and it's common to receive 50-60 mph wind gusts here. Any issues with guying or antenna's that are not well constructed will show themselves in a matter of time. Just yesterday, one of my antenna's "bit the dust" and will no longer see action. This would be my Diamond 2m/70cm dual band antenna. While I was working in our kitchen, I heard a loud bang of something striking our metal roof. I have my HF beam lowered for troubleshooting and thought it may be on of my wire antennas that happen to be hanging low. Upon close inspection, I found that the 54 mph wind gusts took it's toll on my X500HNA.Snapped the fiberglass underneath the bottom element which sent the top part flying. After striking my roof, I found it laying on the ground near the back of our house. 

The Diamond antenna site states this antenna will withstand 90 mph wind with no ice. Well, apparently a common winter wind of 50-60 mph must equal 90 mph as my antenna failed this winter. Sadly, I don't have a spare on hand and this won't see a replacement until next summer. On the positive side, my long time friend and neighbors, KL1SF & KL1MF, have relocated to Arizona, so I would not be doing much chatting anyhow. But, with that said, I had plans of operating as a digi for APRS and now that will have to wait as well. I do have a Cushcraft 124WB that I may try to place in service but not sure I can beat the weather.

Continuing with my antenna saga, my HF beam appears to have a trap issue. Close inspection of the beam shows no problem and even though it has taken a much worse beating that my dual band vertical, it has held up wonderfully. Last year during a RTTY contest, I was running high power and my gut feeling tells me a trap received a bit more than it could take. Mosley's website has a trouble shooting guide and from what I have reviewed, my 15 meter trap(s) have failed. So, I have a note into Mosley to find out about replacements. Yes, I could take them off and fix them but I would like to have a spare set anyhow. I have a flat match on 10 meters but 15 and 20 are poor with 15 being a super high SWR. So, there is no doubt in my mind a trap failed due to an over active AL-1500 in one of my RTTY contest pursuits.

What does this all mean for my station?  I will be much quieter than normal this winter operating from my ground mounted vertical and a few wires if I can't beat the weather with getting my HF beam fixed. Possibly not a bad thing as I have lots of remodeling work to do around our house. I may have to find another hobby or actually, I was thinking of gutting my shack and remodeling it. A few other locations in our house have a higher priority but with the looming dark and cold season, I could get plenty accomplished if I gave up my normal contest weekends for remodeling. I will be on, but my signal won't be as strong and you probably won't find me on as often if my antenna repairs fail to beat the arrival of our normally harsh weather. 

In conclusion, I'm extremely happy with my Mosley TA-34-XL and it has withstood the extreme weather conditions we experience here in our part of Alaska. The Diamond however did not, and it will eventually be replaced. In the mean time, as you can see from the photo above, I won't need a wind sock as I will always be able to tell which way the wind is blowing as the guts to my Diamond will be flapping in the wind.