The March 2013 issue of QST has another Antenna Tuner test by Joel, W1ZR. This article is a good read because it also describes the ARRL's newest test method for antenna tuners. ONE OF THE BIGGEST MI
my thoughts on antenna tuners is they will not change an antenna but they will fool your rig into seeing a load. not matter what that swr if it is high with the tuner the swr will still be high behi
Al, I agree on the caps and the coils. The usefulness of the Johnson design took a big dive in the 1970's when transistorized rigs and then the WARC bands came in. The TX side of its tank circuit was
Rick, TNX for the spreadsheet - it's an interesting read. What I gleaned in a quick analysis is that while they aren't as convenient, the "old school" link-coupled tuners (in this case, the Johnson M
Agreed, the term "antenna tuner" doesn't really tune the antenna but more correctly matches the load, being a combination of antenna and feedline, to a suitable impedance to which the radio can deliv
I'll take an air-wound inductor over a toroidal inductor any day, space available. The typical loss in an air-wound inductor is IR loss where a toroidal has IR loss plus eddy current loss. I know one
Bob, your idea is very sound. But..not always possible. It's one thing when we are talking about a monoband antenna, but it's quite another when we speak of one antenna for working 7 bands. Balance T
Another advantage of those old link coupled transmatches is their ability to reject out of band signals...they pretty much function as a band pass filter. Rick, TNX for the spreadsheet - it's an inte
That may be too broad a generalization. While I haven't crunched the numbers for specific designs, I recently completed VNWA measurements of all the bandpass filter boxes I could get my hands on for
Hi Bob, Are you using the Johnson Matchbox to go from unbalanced (coax) line to balanced, and then your balanced L net between the feedline and the Johnson? I suspect not, but then what are you using
ANTENNA TUNERS ARE LIKE GOING TO THE DENTIST... Nobody wants to go there, but if you have to, you're really glad they are there. And you really don't want one that is not a good one. ________________
Jim, Is that really comparing apples to apples? In the case of the bandpass filter, you have a (hopefully) 50 Ohm signal passing through the coil. Considering that the bandpass filter is inserted in
Sure. Efficiency is efficiency. Power is dissipated by current flow through resistors. The greater the power applied, the more we must be concerned with it, and the heating produced. The W3NQN design
Pretty high Q values can be achieved if you choose the toroid mix and the winding spec carefully. For example, according to the Micrometals Q Curve Application Information book a T200-6 core wound wi
Steve, this thread seems to have taken two paths: 1) "balanced tuners" (which is what it was initially about) and 2) "Toroids vs. air-core coils in general." Focusing on the original topic, balanced
I was responding specifically to the comment from K4TAX: "I'll take an air-wound inductor over a toroidal inductor any day, space available. The typical loss in an air-wound inductor is IR loss where
THANKS STEVE, I KNEW WE WERE ON DIFFERENT PAGES. I ALMOST FULLY AGREE WITH YOU. In fact I do it exactly like you do it (L-Network and external 1:1 balun), but that's because I can't find (and can't a
Before we put this thread to bed, one final comment on the ARRL's test methodology. Knowing that an 80m dipole fed with openwire can present an impedance of 2K to 3K Ohms to the matchbox when trying