>To: steve.m.zettel@internet.nps.usace.army.mil
>From: jreid@aloha.net (Jim Reid)
>Subject: Which amplifier
>
>Certainly the 50% increase in output power does't seem to be
>much in dB on the receiving end, but many DXers amd contest
>people believe it makes a huge difference in their activities.
>Similar to arguments about antenna boom length for yagis
>and the benefits of fourth and fifth elements: as the boom
>is increased to the optimum for max gain, a 3 el yagi should
>yield, on about a 26 foot boom(0 .4 wav. lgth), about 7.7 dB gain
>over a diploe; a 4 el, on its' needed about 36 ft. boom, 8.5 dBd;
>and the 5 el on a 49 ft boom, 9.6 dBd. These are the text book
>best obtainable, supposedly, numbers.That's 2 dB gain from 3
>to 5 elements and a nearly doubling of the boom length, and
>a huge increase in weight, tower strength and rotator torque
>to buy! Is 2 dB ever noticeable? An S-unit increase is supposed
>to take a 6 dB increaase in signal strength. Well, again, the
>experienced and competitive operators think so, they sure
>spend the money to put them up.
>
>So is the 1.76 dB increase from 1000 to 1500 watts output
>a big deal. If you believe the 5 element monoband yagi
>group, it is! You add that to their 2 dB extra antenna gain, and
>they are almost 4 dB louder, and can hear a signal nearly
>4 dB weaker, than the little pistols can, with
>their 1kW and 3-el tribanders, (whcih, of course, also
>have a couple of tenths dB lost in tri band design
>compromises and trap losses.) However, the big guns still
>must go to a stacked pair of 5 el monobanders on those
>big towers to get to nearly a full 6 dB, or about one S-unit
>advantage over the ordinary guy. And most of the "big
>gun" contest stations do just that, and very proudly, to
>assure themselves they have the best and can be
>competitive.
>
>So, Steve, it really depends on what your goal might be, and
>of course, how much money you have to spend, and real
>estate available to mount many monobanders on several
>towers, as W4LPL and many others do.
>
>I guess unless you really plan to go the monobander route,
>and want to go all the way to the max., I'd see no real
>loss in usual amateur radio activity with a 3-500Z transmitter
>amplifier, Ten Tecs Centurian 422, say. If going all the way
>in time, then get the ceramic tubed Titan now.
>
>As for the Tec Tec transceiver, the Omni 6 is the top of the
>line just now, but I hear rumors of a new rig coming out in
>a year or so to coincide with the next pick up in DX'n
>etc. as the solar sunspot count and flux start up again in
>late l997. Ten Tec has been given lots of, " the VI is good,
>but do this, that and this also next time, and you'll have a
>real winner against the Japanese rigs." So we'll just have
>to wait and see. Both Kenwood, with the 870S and Yaesu
>with the 1000MP have made stabs at their next generation
>rigs, but their real new ones, again will probably not be
>released until at Dayton, in 1997. It was at Dayton in 1990
>that Kenwood introduces the 950SD, but then had to replace
>it with the SDX at the '92 Hamvention, so they also learned.
>
>Well, again, I have written more than you probably care to
>be reading, Steve, so will stop.
>
>73, Jim
>
73 and Aloha,
Jim Reid, AH6NB (Happily retired on the Island of Kauai)
Hawaii, USA Email: jreid@aloha.net
|