[Elecraft] Elecraft: Z Match Tuner and K1
Hi folks, first thanks to the guys who responded to my previous query on the Z match. Well I built the thing and it works (the one shown on this site http://www4.tpgi.com.au/users/ldbutler/SingleCoilZMatch.htm). But here are some questions for you experts: I am using a 130 feet end fed wire with a counterpoise (not sure how long it is) and have managed a reasonable match (1.5 or less SWR) on 80/40/30/20. The tuning is very sharp and I will be looking for slow motion drives for the variable caps. My main query is what is the best procedure for finding the match, it's been a bit hit and miss so far. I think the best way is first set both caps for best rx, then with the K1 set for 5W, key the K1 adjust the main tuning cap for max output (measured by my power/swr meter between the K1 and the tuner) , then adjust the other cap for minimum SWR, then back to the main tuning cap for max power and so on. Have I got this right? I seem to get close with this technique but it doesn't always find the right settings and I spend many minutes trying this and that (and heating up the K1 output!). Also quite often the power and K1 current draw shoots right up (up to 2 amps) and at other times the K1 output seems to drop (is this the K1 protecting itself due to high SWR?). Eventually I will get some vernier drives and make a note of the exact settings but maybe I'm not using the best technique. This is the first tuner I have built so I'm feeling my way a bit. Any hints would be most appreciated. 73's Martin M0KWV K1 #1534 Why not take a look at our Web site? http://www.simoncarves.com * The information in this email and any attachments may contain privileged and/or confidential information intended solely for the use of the individual or entity to whom it is addressed. If the reader of this email is not the intended addressee, or the employee or agent responsible to deliver it to the addressee, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify me by telephone or email and delete all copies immediately. * ___ 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] Elecraft: Z Match tuner
Hi Guys, I have moved my shack to an upstairs bedroom and consequentially I will need to feed my 130 feet wire at the end rather than at the centre (it was a dipole fed with coax). I want to work 80/40/20m. I have made some open wire feeder (about 15 feet) to get me from the chimney to the bedroom and have left one end of the open wire feeder open circuit. I think I am making a Zepp antenna. Now to match this arrangement to my K1 on the above bands, I want to build a tuner. I have just been looking at the design on this web site (http://www4.tpgi.com.au/users/ldbutler/SingleCoilZMatch.htm) and it looks just the ticket. It is suitable for balanced lines and would allow QRO up to 100W in the future. Before I commence construction I just want to check that it will match the very high Z of an end fed half wave wire. Any thoughts. Martin M0KWV K1 #1534 Why not take a look at our Web site? http://www.simoncarves.com * The information in this email and any attachments may contain privileged and/or confidential information intended solely for the use of the individual or entity to whom it is addressed. If the reader of this email is not the intended addressee, or the employee or agent responsible to deliver it to the addressee, you are hereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please notify me by telephone or email and delete all copies immediately. * ___ 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] Elecraft: Z Match tuner
Martin, To be a Zepp antenna, the parallel feedline would have to be an odd multiple of a quarter wavelength, and that quarter wave a;so serves in place of a 'counterpoise wire', so your 15 feet is a futile effort in that regard. Just as well to use a single wire for the 15 feet to the end (and thaat makes your end fed antenna 15 feet longer too). You will also need something for a ground reference from your 2nd floor shack location. A ground (earthing)wire will have length to it and that causes it to NOT be a good RF Ground. You may have to resort to using a counterpoise wire cut for each band. Cut one insulated wire to 66 feet (80 meters), another to 33 ft (40 meters) and another to 16 ft (20 meters). Connect one end all of these wires to the ground point on your tuner, and fan out the other ends as best you can. Keep the far end of the wires insulated and away from reach of people and pets because they will have high RF voltage on those ends. You may have to trim the wire length a bit to make them resonant on each band, but doing so will eliminate RF in the Shack. 73, Don W3FPR -Original Message- Hi Guys, I have moved my shack to an upstairs bedroom and consequentially I will need to feed my 130 feet wire at the end rather than at the centre (it was a dipole fed with coax). I want to work 80/40/20m. I have made some open wire feeder (about 15 feet) to get me from the chimney to the bedroom and have left one end of the open wire feeder open circuit. I think I am making a Zepp antenna. Now to match this arrangement to my K1 on the above bands, I want to build a tuner. I have just been looking at the design on this web site (http://www4.tpgi.com.au/users/ldbutler/SingleCoilZMatch.htm) and it looks just the ticket. It is suitable for balanced lines and would allow QRO up to 100W in the future. Before I commence construction I just want to check that it will match the very high Z of an end fed half wave wire. Any thoughts. Martin M0KWV K1 #1534 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.344 / Virus Database: 267.11.13/126 - Release Date: 10/9/2005 ___ 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] Elecraft: Z Match tuner
Don is right, about needing 1/4 wave of feedline (or an odd multiple thereof) so it will act as a transmission line transformer to convert a high impedance at the antenna to a low impedance at the rig. But that also requires a high impedance feed at the antenna. That is, an antenna 1/2 wave length or a multiple of 1/2 wavelength long. The true Zeppp is, in reality, a single-band antenna! His suggestion about just running a single wire is spot on in my book. You'll want to arrange a counterpoise (either tunable for a 1/4 wave long wire for each band). With a good, long wire like you have it won't be hugely important as far as the efficiency of the antenna is concerned, but it will serve to keep the rig at RF ground! Indeed, the nearer your antenna is to a multiple of a 1/2 wave on each band, the more efficient it will be. Ron AC7AC ___ 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
