Re: [Elecraft] Auto Tuner Wish List
Mike, Trouble with that is you can't predict which of the 8 capacitors will be connected. It may be the ones from only one side of the output bus. My original breadboard, now scrapped, used just one relay per capacitor and I found that the circuit was badly out of balance when *no* capacitors were connected ... just the capacitance of the wires running to one side of all the capacitors was causing it. The other reason I use two capacitors, one on each end of each capacitor, is that it puts two sets of relay contacts in series and so divides the voltage that each switch experiences. I worry about voltage breakdown under high swr conditions when the voltage node occurs near the tuner and the two switches in series just doubles the ability of the tuner to survive that stress. My antenna is a full wave horizontal loop for 160M which is a very forgiving antenna to match. I feed it with ladder line and find that with all of that wire out there the voltages and currents do not seem to build up as badly as can happen with shorter antennas which are much more of a challenge for a tuner .. especially when operating at higher power. What works for me may not work for others. Don K7FJ < Don, < Rather that switching both sides of the caps, what about alternating which side they are connected to and which side is switched. That < shouldkeep things fairly well balanced and cut the relay count in half. < 73/72 - Mike WA8BXN __ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Auto Tuner Wish List
There is acompany out of Germany that has made such a device for years... it's very well built, but very expensive. Larry N8LP Ben Hofmann KB1AHR wrote: John W2XS, I have been wondering about a balanced L network auto tuner for some time now. No one is making one that I know of at this time. Like you, I thought it would be great for the Elecraft guys to produce a kit for it. And Don K7FJ, I would be very interested in following your progress in building one of these as you described in your post. Here's my wish list. 1) Balanced output using a balanced L network with 2 set s of inductors and one set of capacitors. 2) Current balun at input. 3) Programmable and switchable to be able to use unbalanced line as well by: switching the balun out of line, and bypassing one set of inductors to effectively be the same tuning circuit as the presently available L network autotuner. 4) At least 2 antenna inputs (even better 3) each separately programmable and switchable for balanced or unbalanced as stated above. 5) 160m - 10m capability. 6) Bypass function. 7) 150w power handling minimum. 8) Maybe an option kit to add an analog meter if the user wants one. 9) Same algorithm as KAT100, where it searches for the best match, not just an "acceptable" one. 10) Function to auto-retune when a certain (user selectable maybe) SWR threshold is exceeded. 11) Integration with the K2 "TUNE" and "ANT 1/2" functions as the KAT100 does 12) Selectable Ability to use stand-alone with other non-Elecraft rigs 13) A kit So Wayne, Eric, what do you think? Another idea might be to sell production rights to manufacture an assembled version. I bet lots of people who maybe don't like kits would be interested in an assembled one. This thing has the potential to be marketable to a very much larger customer base than elecraft's current product offerings. Of course I'd buy the kit, and use it faithfully with my K2 (s/n 4429) which is very close to completion by the way. -Ben KB1AHR ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Auto Tuner Wish List
John W2XS, I have been wondering about a balanced L network auto tuner for some time now. No one is making one that I know of at this time. Like you, I thought it would be great for the Elecraft guys to produce a kit for it. And Don K7FJ, I would be very interested in following your progress in building one of these as you described in your post. Here's my wish list. 1) Balanced output using a balanced L network with 2 set s of inductors and one set of capacitors. 2) Current balun at input. 3) Programmable and switchable to be able to use unbalanced line as well by: switching the balun out of line, and bypassing one set of inductors to effectively be the same tuning circuit as the presently available L network autotuner. 4) At least 2 antenna inputs (even better 3) each separately programmable and switchable for balanced or unbalanced as stated above. 5) 160m - 10m capability. 6) Bypass function. 7) 150w power handling minimum. 8) Maybe an option kit to add an analog meter if the user wants one. 9) Same algorithm as KAT100, where it searches for the best match, not just an "acceptable" one. 10) Function to auto-retune when a certain (user selectable maybe) SWR threshold is exceeded. 11) Integration with the K2 "TUNE" and "ANT 1/2" functions as the KAT100 does 12) Selectable Ability to use stand-alone with other non-Elecraft rigs 13) A kit So Wayne, Eric, what do you think? Another idea might be to sell production rights to manufacture an assembled version. I bet lots of people who maybe don't like kits would be interested in an assembled one. This thing has the potential to be marketable to a very much larger customer base than elecraft's current product offerings. Of course I'd buy the kit, and use it faithfully with my K2 (s/n 4429) which is very close to completion by the way. -Ben KB1AHR ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Auto Tuner Wish List
I was by no means criticizing any other auto tuner with the Auto Tuner Wish List, including Elecraft's. The reason for the wish list in the first place was to express the desire for a BALANCED tuner - by design - not an unbalanced tuner by design with a balun on the output. I am sure the KAT100 (etc.) are great tuners, and can match a wide range of loads. But my wish is that another set of inductors would be added to make the design inherently balanced. The meter and switches are optional, of course, but they were on my "wish list". But, as those great philosophers the Rolling Stones say: "You can't always get what you want." (I used to play that for my kids when they asked for something). 72, John W2XS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Auto Tuner Wish List
Funny you should ask. That is almost exactly what I want except I want mine to handle at least 500 watts (with *my* antenna anyway) and fit in a K2 case. I am designing and building my own. So far I have a fairly neat breadboard operating and when I am ready all of the assemblies of the breadboard will fit right into the K2 case. I am about to order the components for the controller and should have that built up and installed in two or three weeks. The controller will be a Basic Stamp BS-2sx PIC, some octal latches, an A/D converter and miscellaneous frequency measuring components, optoisolators, relay drivers, etc. The breadboard is for verifying that the capacitors, inductors, and relays can handle the stress. For testing only it is controlled by a diode matrix switched by a single pole rotary switch. My design uses Form A reed switches (the *big* ones) with about 500 turns of #38 magnet wire wrapped on them to form the relays I need. There are 32 of them because each of the capacitors are switched in by a pair of relays, one at each end of each capacitor to maintain balance by decoupling *both* ends of each capacitor which is not in use. The little latching relays as used by Elecraft would be a whole lot quicker and easier but they would not handle the voltages I expect at higher power levels. My design has a homemade balun at the input, two strings of inductors, and a single set of capacitors to form a 'balanced L-network' ... at least that is what I call it. There are 8 capacitors with the smallest 5 pF stepping up binarily (X2 at each step) so that the PIC can switch in any value from 0 to 1275 pF in 5 pF increments. Each bank of inductors works in the same way with 0.25 microHenry as the smallest increment. I have a forward and reverse current monitor at the input identical to the one in the K2 100W amp but I have not decided if I will go to the trouble of putting in a LCD display for SWR, power, band/frequency, etc. None of that is really needed but it would be kind of nice to duplicate the general appearance of the K2 with an LCD display. If anyone is interested in following my progress (or lack thereof) let me know and I will provide occassional updates. Don K7FJ Here is what I would like in an auto tuner. 1. Balanced Output for ladder line - two sets of inductors and one set of capacitors (like the Rich Measures roller L design). The inductors can step along in parallel. No control software changes are needed - just another set of inductors and relays. The capacitors can switch between the input and output depending on the load impedance. 2. A current balun on the input side of the tuner driving the 2 sections of inductors. 3. 160m to 10m operation. 4. Matching range somewhat better than the Johnson Matchbox. 5. A rating for 150W max. power output. 6. A switch for bypassing the tuner and connecting the ladder line directly to the output of the balun. 7. A peak-reading, illuminated power-output meter. 8. A 4-position input (rig) selection switch. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] Auto Tuner Wish List
In defense of the KAT100 Tunerwhich I do not believe was being attackedbut, in its defense. I have come back to the fact that the LC or CL antenna tuner is a very good tuner concept. See recent articles in QST. The LC tuner is quite the tuner once you understand what it is doing and how it works to your advantage. The KAT100 has never missed a match since I have owned it and when I say never missed a match...I am not talking about perfect antennas. It even matched a longwire very well and it radiated too. In otherwords, I made contacts right and left with the KAT100 matched longwire. I made the contacts on 160, 80, 40 and 20. The 130 foot (or so) hunk of wire even matched oon 15 and 10 meters. Yes, it would have been nice for the KAT100 to have a watt meter and extra antenna ports, but I have found it is excellent very excellent ... the way it is designed. Elecraft was very thoughtfull in design...making it easy to use...and it matches a very wide range of impedances. Because of my experience with the KAT100, on my other station I have been foolling around with a high powered LC matching systems that can take 1500 watts. Again, the matcher tunes in all. You just have to make sure you use 20 watts or so to find the match because moving the alligator clip from coil turn to coil turn at 1500 wattshurts. The LC Match is not new...I used it years ago in my college days in my basement appartment to have a station with 70 foot of 18 bell wire using a cold water pipe as ground. Worked well then too. Old is still good. Lee - K0WA Common sense is in short supply - get some and use it - Lee Buller ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
[Elecraft] Auto Tuner Wish List
Here is what I would like in an auto tuner. 1. Balanced Output for ladder line - two sets of inductors and one set of capacitors (like the Rich Measures roller L design). The inductors can step along in parallel. No control software changes are needed - just another set of inductors and relays. The capacitors can switch between the input and output depending on the load impedance. 2. A current balun on the input side of the tuner driving the 2 sections of inductors. 3. 160m to 10m operation. 4. Matching range somewhat better than the Johnson Matchbox. 5. A rating for 150W max. power output. 6. A switch for bypassing the tuner and connecting the ladder line directly to the output of the balun. 7. A peak-reading, illuminated power-output meter. 8. A 4-position input (rig) selection switch. Right now, I have the following set up: Outside: Ladder-line fed Cobra Ultralite 160m to 10m antenna. On the desk: Johnson Matchbox for 80m to 10m. Drake MN75 with Elecraft balun on the output for 160m. It also has a bypass switch. Ceramic knife switch to switch the ladder line from one tuner to the other. Heath coax switch to select one of four inputs (2 rigs and 2 boatanchor receivers). Autek WM-1 peak wattmeter. Everything works fine, but takes up a lot of precious room on the desk. (I could put more boat anchors there!). Having a one-box, balanced auto tuner with those options would be great! IMHO, of course. John W2XS ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
