This is a follow-up to my original year 2004 review of the Mosley TA33-WARC to report some accumulated experience. However, the bottom line for the Mosley’s performance over the years remains: An Exceptional Product!
During its fifteen years in the air, the TA33-WARC has always performed consistently and reliably. “Contacts-attempted, contacts-made,” from out west to China, and across the world to Serbia and Croatia in the east (with 100 watts!). For the HF bands from 20 meters up, it’s my station’s principal antenna; there’s seldom a need to switch.
In recent years a set of frequency sweep tests with an acquired Vector Network Analyzer on all of the TA33's operating bands indicates very acceptable performance. SWRs at the extremes of each band are easily manageable by the transceiver’s internal “line flatteners” (i.e. “tuners”). Even now, if I were to make any change in the Mosley’s tuning it would be only to lower the 20 meter band “passband” just a bit from where it presently is.
But I do not mean to suggest that the years have been entirely trouble free, and there is a cautionary message in this. Out here in “Kawl-lee-forn-knee-ya,” we don’t get a lot of wind and snow to harass our aerial aluminum, but sometimes we do get it. Earlier this year we had some hellacious winds, probably the most extreme in my forty-five years of living in this location.
I fretted through the long, clanking night. In the morning I popped out into the back yard and glanced skyward. The TA33 still rested horizontally atop the still upright 45 foot tower! I breathed a sigh, but that was caught short after a second glance. One-half of one of the Yagi elements was loose and dangling free from the boom, pointing vertically at the ground.
Inspecting from the tower top, the situation was obvious. One of the two “WARC bands” add-on aluminum tubes had slipped out of its plastic insulator blocks on the mast supports and was now prevented from falling only by an attached phasing line! The symmetrical opposite half of the same element was still intact.
More importantly, a check of all the other plastic insulator blocks indicated that as a result of wind-caused vibrations over the years, all the mounting bolts and nuts had loosened to various degrees! But the dangling element was the only one that had dropped its bolts entirely.
The situation was easily remedied. After repairs were completed, a recheck with the VNA indicated no change in the RF performance of the antenna. Back in service “as good as new.”
Two small cautions here. First, if constructing a new TA33-WARC, consider whether to “Locktite” (or equivalent) the assembly nuts as a precaution. This can avoid future problems, but with the possible elimination of the opportunity for performing a future re-build (replacement parts are available). Or, if the Yagi is already operational, at minimum consider a maintenance trip up the tower to check and tighten all the mounting clamp hardware (along the boom). “Just in case.”
My Mosley has been in the sky for a decade and a half, and “it will not be moving anywhere” in the future. This one is a “lifetimer,” and then perhaps it will provide even more service for the fortunate ham who gets it from my estate! In its size range, the Mosley TA33-WARC really is “that good!”
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Earlier 5-star review posted by W6LBV on 2004-12-06
The TA-33 is an old, conservatively-designed “classic Yagi,” intended to provide a basic level of performance. And it does (see below). But the real “story” here is in the hardware itself.
My TA-33-M-WARC was ordered early in 2002 and was installed on a 45' steel lattice tower over the 4th of July holiday that year. It has been in continuous service (without the slightest problem) since then.
Mosley was very late in delivering the antenna (the order to delivery time was about 5 months). However they provided an explanation and kept me informed about progress. The “situation” they faced was that they had just received a huge military antenna order (for the ramp-up to Gulf War II), and were in process of converting from civilian to military production. Plant space, materials, and personnel were all being redirected. The company was working six to seven days per week to make production goals. My antenna was, apparently, one of the last Amateur products to ship before production ceased.
I inferred that, since the raw stock inventory at Mosley was being redirected as well, the Amateur antennas were being built with commercial grade metal stock. Receipt and unpacking of the “kit” left no doubt in my mind about that! Compared to typical Amateur antennas on the market, this is rugged hardware! It’s entirely understandable why 35 year old TA-33s are still “up and running” in their original installations. If you want it to be so, this is a “lifetime” antenna.
To let my antenna reach its full potential, some care was taken with the feed system. The main feed line is a 60' run of Andrew LDF-4 (½" hardline), with Andrew Type N connectors. The top jumper is an 8' length of RG-214, and the bottom jumper (into the shack) is 10' of Andrew FSJ-1 (1/4" SuperFlex). All materials were brand new. Overall, at 30 MHz there is probably less than 0.5 dB of line loss through the run, and it will easily handle 1 kW on all its operating bands.
As soon as installation was finished and the dash into the shack was made, SWR proved to be less than 1.8:1 (generally much less) across the 5 operating bands. During the past 2 ½ years the overall match produced only one problem, traced to an N-connector which needed to be remade. The antenna itself has been perfect.
Performance has been excellent. More times than I can remember, while operating ssb with 100 watts from the U. S. west coast I’ve gone into “mini-DX pileups” to Europeans and have been called back by them first, before mid-West stations were called. I cannot verify (through measurement) the published operating specs on 10-15-20 meters, but I have no reason to believe that it does not meet the specs (+7 dBd forward, 20 dB front-back). Comparison with tuned long-wire antennas shows a considerable advantage to the Mosley. The 0 dBd forward gain spec on 12 and 17 meters is not really troublesome and often isn’t even noticed. When the MUF supports these higher bands, the gain is less necessary and the rotatable bi-directional pattern of the single dipole is still appreciated.
This antenna fills a niche: a “use it forever” modest-sized HF Yagi that will stand up to weather and always perform. As stated in the other review, it won’t necessarily put your signal first into the latest Dxpedition, but then again, if you are skilled, it just might! Overall, an awesome company and product. |