Keep in mind that while the "T" tuners can match a wider range they also can be mis-tuned into a mode where a lot of power is consumed in the coil yet all looks good. This can't happen in a PI network for instance. It's a good reason to have one or more RF ammeters around for monitoring your antenna current.
I prefer a link-coupled tuner like the MB for balanced loads, a parallel type tuner for end-fed wires and such, and a PI for coax-fed antennas. I can tune my Zepp from 80-10 including WARC bands with the MB. For 160 I can feed it as a "T" through a special link-matcher. You'll find many different opinions except that I think everyone agrees the MFJ tuners are very cheaply made. I have a 949 that I don't use that much... it's got flimsy components in it. Fine for say 100W I guess but no more. The switches feel flimsy too when you rotate them. I wouldn't recommend one that's for sure. 73, Mark W1EOF > -----Original Message----- > From: John Lawson [mailto:[EMAIL PROTECTED] > Sent: Friday, August 18, 2006 12:52 AM > To: [EMAIL PROTECTED] > Cc: [email protected] > Subject: Re: [AMRadio] Legal-Limit tuner advice....? > > > > > On Fri, 18 Aug 2006, [EMAIL PROTECTED] wrote: > > > > > In a message dated 1/12/06 8:31:16 AM, [EMAIL PROTECTED] writes: > > > >> On Wed, 11 Jan 2006, [EMAIL PROTECTED] wrote: > >> > >>>> > >>> Quick and dirty, just try grounding one side of your > ladder-line at the > >> input > >>> end and feeding the other side off the single ended output of > your ATU and > >>> see what happens. SWR figures might be better (but could > also be worse). > >> > > John, > > > > Did you ever try this? If so, what were the results? > > > Yes, I did - results not good at all, antenna would not tune and the > Transmitter complained at me bitterly... ;} I also built in a DPDT > knife switch in the feedline after the tuner - it's mainly for grounding > during t-storms, but I played around with various > (semi-calculated) values > of capacitors and coils... on 10 meters the use of various paralelled > caps made improvements, but tuning became very critical, and there's > nothing much that interests me up there - I *do* like to work 20M RTTY , > and have yet to try PSK32 into the Valiant. > > I'm still gathering facts, and the Listmembers have been quite > helpful - > everyone likes the Palstars, but the big Ten-Tec also has impressive > specs.... I intend on converting a broadcast transmitter for use in the > shack, so the Tuner needs to be able to withstand 100% duty-cycle at > Legal Limit. Ultimately I'll tune the feedpoint of the antenna itself, > and just run 50-ohm line from the transmitter out to the > "doghouse" if you > will. > > > Cheers > > John KB6SCO > > Who just shut the rigs off after a nice AM QSO on 80.... > >
