Re: [Elecraft] Baluns wires feeders (oh, my!)
There is a simple way to measure the efficiency of a balun, make two of them and connect them back to back. Measure the power fed to them and the corresponding output power. Obviously this doesn't take a mismatched antenna into account. ___ 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] Baluns wires feeders (oh, my!)
Dave G4AON wrote: There is a simple way to measure the efficiency of a balun, make two of them and connect them back to back. Measure the power fed to them and the corresponding output power. Obviously this doesn't take a mismatched antenna into account. I did just that about this 5 years ago. I used two MFJ tuners connected by the 4:1 baluns in each. I fed one from my MFJ Antenna Analyser and hooked a 50 ohm resister to the other tuner. I measured the voltage across the resistor with a RF probe. Alas I can't locate the paper where I wrote down the results. Over the bands the loss was around 10-15% I recall and I thought that was about what I expected. 73 Karl K5DI ___ 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] Baluns wires feeders (oh, my!)
I ask this as a question - Putting baluns or UN-UN back to back checks that both have the same ratio and can check efficiency if they are transformers such as what is used on beverages. How does this check if it is working well as a balun? As an example, a straight piece of coax with ferrite beads on it could be treated as one or two baluns back to back. But just checking power at the end versus power going in would seem to check the efficiency of the coax but not tell you how much, if any RF was on the outside of the shield. Please correct me if I am all wet. 73, N2TK, Tony -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Dave G4AON Sent: Saturday, October 07, 2006 2:54 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Baluns wires feeders (oh, my!) There is a simple way to measure the efficiency of a balun, make two of them and connect them back to back. Measure the power fed to them and the corresponding output power. Obviously this doesn't take a mismatched antenna into account. ___ 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
[Elecraft] Switching Supplies
Hi John I was warned against switching supplies when I was building the K2. However, I'm cheap. I bought a Radio Shack 20A switching supply. I don't have a spectrum waterfall monitor but I receive signal reports that are not just good but very good on SSB and no negative comments on CW. John AB8O ___ 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] Baluns wires feeders (oh, my!)
N2TK, Tony wrote: I ask this as a question - Putting baluns or UN-UN back to back checks that both have the same ratio and can check efficiency if they are transformers such as what is used on beverages. How does this check if it is working well as a balun? As an example, a straight piece of coax with ferrite beads on it could be treated as one or two baluns back to back. But just checking power at the end versus power going in would seem to check the efficiency of the coax but not tell you how much, if any RF was on the outside of the shield. Please correct me if I am all wet. Hi Tony, you missed the question. We assumed the balun's were made properly. The task was to measure the loss through them. 73 Karl 73, N2TK, Tony -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Dave G4AON Sent: Saturday, October 07, 2006 2:54 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Baluns wires feeders (oh, my!) There is a simple way to measure the efficiency of a balun, make two of them and connect them back to back. Measure the power fed to them and the corresponding output power. Obviously this doesn't take a mismatched antenna into account. ___ 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] T7 winding: Does the relative starting postion of the secondary winding matter?
I am building SN:5750. I have searched the archive to answer this but not found one. I have wound the primary and secondary (20 turns and 5 turns). When I finished, I noted that I started the first turn of the secondary has more turns of the primary in front of it vs. the back of it. I was concerned that this might hurt its performance because it is not balanced. Does it matter? Thanks, 73, Chuck - K3TNT ___ 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] Baluns wires feeders (oh, my!)
The usual approach to measuring the loss of any device like this is to measure the heat. Basic physics - the first law of thermodynamics - tells us that the energy going into the device will equal the energy going out. The question is how much of that energy emerges as RF. In this case there is only one other significant form of energy involved: heat. (Yes, if the device is arcing over there will also be light and sound, but I'm assuming it *seems* to be working okay; no arcing and buzzing G.) So you put the device into a very well insulated test chamber. Dense urethane foam is commonly used for this. Then it is operated under the exact conditions you want to evaluate (high SWR through a BALUN at normal power levels, etc.) and the heat rise in the chamber is noted on an accurate thermometer over a specific period of time. Then you can calculate how many watts of RF were turned into heat. Not into doing the math? You can figure it out empirically by putting a resistor in the box with the device, let the whole thing return to ambient after measuring the temperature rise over time operating the device under test. Then do not apply RF to the balun (or tuner or whatever you're testing) but instead put DC current through the resistor sufficient to raise the temperature the same amount in the same time. The power dissipated by the resistor (volts times current) will be equal to that lost from the balun, ATU or whatever. Obviously, it might take several runs to find the exact value but you can learn something very useful from a limited test. For example, if you run 10 watts through a balun and the temperature goes up 2 degrees in 10 minutes, then you put 1 watt through the resistor and note that the temperature goes up more than 2 degrees in 10 minutes, you've demonstrated that the loss is less than 1 watt, since that amount of loss would cause a faster temperature rise. Does all that sound like a little bit much for a test on a quiet Saturday afternoon? That's why most Hams ignore the whole issue, hoping that the losses aren't too high. That's easy to do since in most on-air operating, especially on HF, a loss of even 10 dB is hard to spot unless once can do side-by-side testing with a distant station. So unless the losses are truly large, we'll never know for sure they are occurring. And if they are, we notice that the balun feels warm, the cores of the toroids cracked, or it arced over, Hi! On the other hand, arranging these experiments and working through them are a wonderful way to better understand not only Ham radio, but your equipment and physics as well. 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
Re: [Elecraft] OT: Argonaut help needed
Silk purse from a sow's ear? 73, Doug W6JD -- Original message -- From: Vic K2VCO [EMAIL PROTECTED] Does anyone have a schematic for the TT Argonaut 515 (not the 505 or 509!) that they can copy or scan for me? Naturally I'll pay any expenses involved. Yes, I know that Tentec sells manuals for $25! They should adopt the wonderful Elecraft practice of making them downloadable for free. I've been able to pick one up reasonably and I want to see if the strong-signal performance of the rx can be improved. It will never be a K2 (or perhaps even a K1) but it reminds me of my first really modern radio, the Tentec 540. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ 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] OT: Argonaut help needed
[EMAIL PROTECTED] wrote: Silk purse from a sow's ear? First of all, I want to thank the several people who have helped by sending me scans of the Argonaut 515 schematics or who have offered to copy the manual. I really am overwhelmed by the kindness of K6VNL, K0EVZ, K4ZM, W2XS, and others. I don't think the 515 is exactly a sow's ear. It is a single-conversion design, like the K2, and Tentec abandoned the mickey-mouse practice of multiplying the VFO output that they had used in the 509 in favor of a pre-mix scheme to provide the injection frequencies. The 9 MHz IF came with a 4-pole filter, which was probably a poor choice. Some owners replaced it with the better 8-pole filter from the 540, which has been done to my radio. My plan is to see what I can learn in the process of evaluating the performance of the receiver in this radio and trying to improve it. The modular construction should be a help in this. -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco ___ 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] KXB3080 Review
My Short Takes review, A 30 and 80 Meter Module for the Elecraft KX1 CW Transceiver, will appear in the November, 2006 issue of QST. It is available now for download to ARRL members at: http://www.arrl.org/members-only/prodrev/. 73, Bruce Prior N7RR ___ 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] T7 winding: Does the relative starting postion of thesecondary winding matter?
Chuck, The notion of balance on a toroid at these frequencies and these low turn-numbers is a pretty loose thing. For the K2's kind of transformers and inductors (apart from L31) it is more important to get the winding sense right and to make the winding leads to emerge from the core such that they go into the PCB with short runs, than it is to sweat over making the windings precisely arranged. Cheers, Marshall, WA3VPZ -Original Message- I am building SN:5750. I have searched the archive to answer this but not found one. I have wound the primary and secondary (20 turns and 5 turns). When I finished, I noted that I started the first turn of the secondary has more turns of the primary in front of it vs. the back of it. I was concerned that this might hurt its performance because it is not balanced. Does it matter? Thanks, 73, Chuck - K3TNT ___ 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] question
Anybody know the correct hand mic for the TS 440s? will a MC 43 mic work as well? I am checking in advance. Thanks, John KF7OM ___ 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] KXB3080 Review
On Sat, 7 Oct 2006, Bruce Prior wrote: My Short Takes review, A 30 and 80 Meter Module for the Elecraft KX1 CW Transceiver, will appear in the November, 2006 issue of QST. It is available now for download to ARRL members at: http://www.arrl.org/members-only/prodrev/. 73, Bruce Prior N7RR This is a very nice review, however you might want to tell people before hand that ARRL membership and log in account is required. ___ 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 CW Net Announcment
Good Evening, Once again my nephew left with his truck full of wood and his uncle weary! However, we hung a lot of drywall, a few panels of wood on the back of the house, moved a great deal of boxes, and got the mirror mounted on the back of one of Pat's antique dressers. My dream of a work area dedicated to electronics, robotics, and firmware development is very close indeed. One more week and I will have a continuously damp pad in my soldering station. All of the kits I've collected over the past year will start going through the assembly process. Quite a few projects which have been put on hold will go from dreams, to design, and then to reality. I plan on learning a great deal and documenting my way through the process. When spring comes along I will have quite a pile of firmware tools for my next embedded project. I have been listening to 160, 80, 40, 30, and 20 meters over the past week. I have also started work with my CW mentor once again. We had a number of good skeds on 20 meters. Hanging drywall and pounding nails has left my hands stiff but a good hour long chat session gets some of the kinks out. When the conditions are good we run as fast as I can form sentences. I strive for good spelling and grammatically correct sentences. This does not always happen ;) Maneuver tripped me up on Friday as an F14 decided to make a great deal of noise over my house performing some odd stunt. The conditions on 20 meters were good in the morning on Friday and 40 meters was very good last night. I hope both of those happy states will hold for tomorrow's nets. If you have some free time and would like to listen or participate you are most welcome. If you have recently built a KX1, K1, or K2 and want to see how well it works please tune us in. Please join us: Sunday 2300z (Sunday 4pm PDT) 14050 kHz Monday 0200z (Sunday 7pm PDT) 7045 kHz Until tomorrow, Kevin. KD5ONS ___ 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 CW Net Announcment
Kevin wrote: One more week and I will have a continuously damp pad in my soldering station. Is there any truth to the rumor that you positioned the soldering pad under a leak in the roof? Seriously, Kevin, you've been in an inspiration to everyone who has suffered a sudden and devastating loss. Thank you and keep up the great work! 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
RE: [QRP-L] WA3WSJ: Bead-Wire Antenna
Hi Ed, I find your SWR readings a bit contradictory to my antenna modeling in EZNEC. Modeling 4 radials 17.28' each and a radiator of the same length with the radials 7' off the ground and the ends and the feed point and feed end of the radials at 10 feet I get a SWR of about 1.6 to 1. If I change the radiator to a 40' length and feed it the exact same way and heights I get a feed impedance of 325 ohms and a reactance of -1147 Ohms for 14.06 MHz. which isn't what I would call acceptable. For 7.04 MHz I get it near perfect with SWR of 1.19 to 1, at 59.5 Ohms and -1.169 Ohms reactance. Very Nice. 30 meters comes out at 10.12 MHz with 283 Ohms and +828.7 Ohms reactance. SWR of 54.2 to 1. Not very nice. So, unless you are running a tuner and that was the best your tuner would adapt the antenna to your rig, then I can see where you got your numbers. Either way, the antenna on any band except 40 meters is not going to radiate very well UNLESS you install the tuner AT THE FEED POINT of the antenna so the COAX is not contributing to the losses in the system. Even then I would recommend looking at the radiation pattern and angle of attack for that antenna and see it is what you wanted. A 20 meter ground plane antenna as I first described has a very nice single lobe pattern with an angle of attack of 20 degrees and a very acceptable SWR. On 40 meters with the 40' radiator it runs 22 Degrees angle of attack so again, a nice antenna with a very nice SWR. Make the entire antenna as a 40 meter ground plane (double the 20 meter wire lengths with same height above ground) and you get 1.12 SWR will NIL for reactance and the same attack angle of 22 degrees. Very close to your 40 foot radiator model. So, how did you get your SWR readings? Tuner or No Tuner? And located where? Best 73 72 Michael Baker K7DD [EMAIL PROTECTED] -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Edward R. Breneiser Sent: Friday, October 06, 2006 7:55 AM To: elecraft@mailman.qth.net; [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: [QRP-L] WA3WSJ: Bead-Wire Antenna Hello all, I received lots of emails concerning my Bead-Wire Antenna. I've decided to post on the reflectors rather than send out to each Individual op. Here's what I did to make my antenna. I went out to my local craft store called The Rag Shop and bought a 40' spool of flexible bead wire. This stuff is very strong, has a clear tough plastic coating over it, but won't take solder. My wire has seven strands to it. It comes on a plastic spool that's about 2.75 in diameter and 5/8 thick. It even has a clear plastic cover that snaps over half the spool to keep the wire etc on the spool. The wire measures .012 in diameter so it's very small and light. In fact my 40' of wire and 40' fishing line with spool weighs-in at less than 1oz! I tie one end of the bead wire to 40' of 30lb test fishing line. On the on the fishing line I tie a loop. I tie about an 1 loop on the end of the fishing line so I can attach a 1oz lead sinker. The sinker is one that is egg shaped and has a wire loop at the top. In the field I simlpy slip the fishing line loop through the wire loop and double back over the sinker. This makes for a solid tie that can be taken off easily anytime. This sinker makes it easy to throw up the bead wire into a tree too. At present I use three ground radials each 16' in length made from #26 black stealh wire. I plan to make my ground radials out of the bead-wire too to save on space and weight. I tried this setup yesterday in my back yard with my KX1. On 30m I had 4.0W out with a 1.0:1 swr. On 20m I have 3.8w out with a swr of 1.2:1 and on 40m I have 2.8w out with a swr of 1.1:1. My entire trail radio package weighs-in at 1.6lb. Here's what I use on the AT: Radio: KX1 with 30m option Battery: Powerizer 11.1V 1800mah 3-cell Lithium Polymer ~4.5oz Antenna: Bead-Wire Ant. Attached with 2-post to bnc adapter Paddle: AT Paddle Mini (plugs directly into KX1, 3.5mm stero plug) The entire package stores in a small camera case! p.s. You can buy silver coated bead wire to solder to, but it's expensive! 72, Ed,WA3WSJ __ QRP-L mailing list Home: http://mailman.qth.net/mailman/listinfo/qrp-l Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[EMAIL PROTECTED] -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.407 / Virus Database: 268.13.0/465 - Release Date: 10/6/2006 __ QRP-L mailing list Home: http://mailman.qth.net/mailman/listinfo/qrp-l Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[EMAIL PROTECTED]
Re: [Elecraft] Elecraft CW Net Announcment
Ron D'Eau Claire wrote: Kevin wrote: One more week and I will have a continuously damp pad in my soldering station. Is there any truth to the rumor that you positioned the soldering pad under a leak in the roof? Seriously, Kevin, you've been in an inspiration to everyone who has suffered a sudden and devastating loss. Thank you and keep up the great work! Ron AC7AC Heck, Kevin's industriousness is an inspiration to everyone *whether or not* they've suffered any loss. How he does it is a mystery to me, but I enjoy his reports immensely! 73, Kevin and Ron and the Elecrafters in the world! Joe, W2RBA ___ 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
