KX1 help
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Howdy,
I am new to amateur radio and just upgraded to General a few months ago and have some basic questions on a power supply for the KX1 and how to make a wire antenna. I am going to add the auto tuner and the optional 80 and 30 meter board later. So as far as a power supply can I use an old AC adapter as long as it is within 8 to 14 VDC and if so how should it be connected to the connector for J1. Or would a commercial type application be a better choice. As far as the antenna is concerned what type of wire should be used and how is connected to the connector. I hope that as I start building my kit that these answers will be a little more obvious but I am trying to get as much information as I can before I start building. Thanks, Ed KE7HGA _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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Ed,
First welcome to a great hobby. I would advise against using that 'old AC adapter' - those wall warts are usually not regulated and the no-load voltage often soars to 1.5 times the voltage shown on it, and at high current loads, the voltage sags a lot. For home station use, you will likely accumulate several things that run on a "12 volt" power source - that is actually a 13.8 volt power source, the voltage of a fully charged lead-acid '12 volt' battery like that found in an automobile. So my recommendation is that you get a regulated power supply that is rated for at least 3 amps (I would actually suggest one that is rated at 12 amps or more, you will eventually need it). Put a 2 amp fuse in the power cord to the KX1 to protect it near its maximum current draw plus some reserve. As for the antenna, there are several choices to make - what bands do you wish to use it on? Is this an antenna for portable use or will it be a permanent part of your home station? A half wavelength dipole fed with coax is the simplest antenna, but the coax fed dipole is a single band antenna. - there are ways of using it on multiple bands - traps, or extra half wavelength wires for the other bands spaced away from each other - use a 1:1 balun at the antenna feedpoint. Alternately, you can feed the dipole (single wire cut for the lowest band) with ladder line and use a balun in the shack to convert to an unbalanced line and connect it to the KX1 with a short length of coax. - you will need a BNC connector at the KX1 end. The KX1 autotuner does not have a lot of range on 80 meters, so get the antenna plus feedline as close to 50 ohms resistive on 80 meters as you can. If you use a 135 foot wire and feed it in the center with a length of 450 ohm ladder line that is 122 feet long (an electrical half wavelength), you will come pretty close to a 50 ohm load at the shack end of the feedline, and the tuner should handle it on the other bands. If you want additional information about antennas and transmission lines, I would refer you to the ARRL Handbook (every ham should have a copy). You may also find the Antennas, Transmission lines, and Tuners article on my website www.w3fpr.com informative. Yes, build your own antenna, it is a lot of fun to experiment with antennas, and it is much less expensive than the prices charged for pre-built antennas. Some even tout very impressive specs, but that is a stretch of someone's imagination, the basic laws of physics must apply, and some of the ads stretch that truth. (Rant off now!). 73, Don W3FPR Edward Doyle wrote: > Howdy, > > I am new to amateur radio and just upgraded to General a few months > ago and have some basic questions on a power supply for the KX1 and > how to make a wire antenna. I am going to add the auto tuner and the > optional 80 and 30 meter board later. So as far as a power supply can > I use an old AC adapter as long as it is within 8 to 14 VDC and if so > how should it be connected to the connector for J1. Or would a > commercial type application be a better choice. As far as the antenna > is concerned what type of wire should be used and how is connected to > the connector. I hope that as I start building my kit that these > answers will be a little more obvious but I am trying to get as much > information as I can before I start building. > > Thanks, > > Ed > KE7HGA > > Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by EMD
Welcome to a very fine hobby Ed. As far as a power supply is concerned you
didn't exactly specify what type of AC adapter you are planning on using, but if it is a wall wart, I would advise against it. Most of them have no voltage regulation and if the voltage swings high enough above 12 V you could damage your radio. Lack of recognition is also likely to result in chirp on your signal. I think a much better choice would be a small regulated power supply. I have an inexpensive one from RadioShack which I have had for years and has successfully powered a number of small items. An antenna is a simple thing to build and put up. I would suggest using something like 14 gauge copper coated wire. It's length can be determined by the formula 468/frequency, choosing a frequency somewhere in the middle of the CW band of interest. Once you have the overall length, simply cut the wire in two. You can use an insulator for the center of the antenna. Then attach the end of each dipole wire you just cut to each end of the insulator. Then solder the center conductor of your coax to one of those wires and the shield to the other wire. Solder the other end of the coax to a PL 259 plug and you should be done. After you have upon the antenna up in the air key up the rig and check the SWR if it is too high, that is above 2.0, choose a frequency near the bottom of the band and key the rig while looking at the SWR reading. Then move to the top of the CW band and key it again noting the reading. If the SWR reading is higher at the top of the band that was at the lower end, your dipole is too long. Trim off a few inches from both ends of the dipole, keeping the amount of trim the same, and take the reading again at a frequency in the middle of the CW band. If the SWR has improved you are on the right track. If it is at least below 1.5:1 you may wish to leave it at that. Achieving a 1.0:1 exact match is not all that important. However, if the SWR is still above 2.0:1 trim off a bit more from each end and see what happens. If the SWR reading at the bottom of the band is higher than the reading at the top of the band, your dipole is too short. If you wish to lower the SWR you will have to solder some wire of equal length to each end. That is not the best idea because you must be careful when attaching the lengths of wire to make a mechanically secure connection or the antenna is likely to come apart during the first windstorm. I forgot to mention that the ends of the dipole should be attached to insulators and then to a rope which you can use to secure the antenna to a convenient tree branch or other support. I suspect the foregoing was a lot more than you really wanted to hear, but I remember my first ham experiences when every bit of information I could get was helpful. You may wish to invest in an ARRL antenna book or handbook. Both have a wealth of information for the new ham as well as more experienced hands. Best of luck. I hope to hear you on the air soon. Bruce-W8FU -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Edward Doyle Sent: Monday, January 05, 2009 12:58 PM To: [hidden email] Subject: [Elecraft] KX1 help Howdy, I am new to amateur radio and just upgraded to General a few months ago and have some basic questions on a power supply for the KX1 and how to make a wire antenna. I am going to add the auto tuner and the optional 80 and 30 meter board later. So as far as a power supply can I use an old AC adapter as long as it is within 8 to 14 VDC and if so how should it be connected to the connector for J1. Or would a commercial type application be a better choice. As far as the antenna is concerned what type of wire should be used and how is connected to the connector. I hope that as I start building my kit that these answers will be a little more obvious but I am trying to get as much information as I can before I start building. Thanks, Ed KE7HGA _______________________________________________ Elecraft mailing list Post to: [hidden email] 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: [hidden email] 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 |
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In reply to this post by EMD
> [..] Solder the other end of the coax to > a PL 259 plug and you should be done. I believe the jack on the KXV1 is a BNC connector. Right? Not sure what the PL-259 gets you. Converting from PL-259 back to BNC is just another RF-speedbump. It might not matter though. I tend to try to avoid converting coax connectors and instead put on the connector for the application. On the coax, here's what I thought, but I could be mistaken: For portability I was going to mention RG-316, it's O.D is just less than 0.100" and therefore really light in the backpack, but the matched loss is substantially higher than other selections. I haven't tried RG-303 (Belden 84303) but the O.D. is only 0.170" and the matched loss is just a bit less than half of RG-316. (1.2 db at 10Mhz per 100ft, 4.1db at 100Mhz per 100ft) compared to RG316 (2.7db at 10Mhz at 100ft and 8.3 (wow) db at 100Mhz at 100ft). Your rig is going to be operating at frequencies lower than 20m so 1.2db at 10Mhz per 100ft would be ok with me, If you use a feedline that is 40ft or so or less from the portable antenna (backpacking situation) that would be just fine. There's other narrow O.D. coax listed in table 19.1 of the ARRL handbook, RG-400 also has a narrow O.D. and decent loss values. Just depends on how much weight you want to carry with you, availability of connectors for the various coax. If weight isn't an issue, I'd go with RG8-X to get started, not the absolute best coax but cheap and fairly good dB loss figures for the bands you can work with the rig you have. -jeff _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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If it is a BNC connector, then obviously that is the connector to use.
Unfortunately, I do not have that radio. The K2 does have the PL 259 type connection and so I apparently wrongly assumed so did the smaller radio. It was certainly never my intention to suggest that one used an improper connector and then convert to what is actually needed. Bruce-W8FU -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of W7BRS Sent: Monday, January 05, 2009 2:38 PM To: [hidden email] Subject: Re: [Elecraft] KX1 help > [..] Solder the other end of the coax to > a PL 259 plug and you should be done. I believe the jack on the KXV1 is a BNC connector. Right? Not sure what the PL-259 gets you. Converting from PL-259 back to BNC is just another RF-speedbump. It might not matter though. I tend to try to avoid converting coax connectors and instead put on the connector for the application. On the coax, here's what I thought, but I could be mistaken: For portability I was going to mention RG-316, it's O.D is just less than 0.100" and therefore really light in the backpack, but the matched loss is substantially higher than other selections. I haven't tried RG-303 (Belden 84303) but the O.D. is only 0.170" and the matched loss is just a bit less than half of RG-316. (1.2 db at 10Mhz per 100ft, 4.1db at 100Mhz per 100ft) compared to RG316 (2.7db at 10Mhz at 100ft and 8.3 (wow) db at 100Mhz at 100ft). Your rig is going to be operating at frequencies lower than 20m so 1.2db at 10Mhz per 100ft would be ok with me, If you use a feedline that is 40ft or so or less from the portable antenna (backpacking situation) that would be just fine. There's other narrow O.D. coax listed in table 19.1 of the ARRL handbook, RG-400 also has a narrow O.D. and decent loss values. Just depends on how much weight you want to carry with you, availability of connectors for the various coax. If weight isn't an issue, I'd go with RG8-X to get started, not the absolute best coax but cheap and fairly good dB loss figures for the bands you can work with the rig you have. -jeff _______________________________________________ Elecraft mailing list Post to: [hidden email] 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: [hidden email] 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 |
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In reply to this post by EMD
Edward,
Welcome. I have been a Ham for many years, but I am just getting back into the hobby. I don't have an HF rig, so right now I am building the KX1 just as you, so I thought I might have a couple of thoughts. I am a "soldering robot" who can follow directions well - but I don't understand a lick of electronics theory!
For power, I just went down to the local battery mart and purchased a 12V SLA battery, similar to the ones used for security system backup batteries. Then I just have alligator clips that attach to the batter, a fuse inline, and the J1 plug at the other end.
Because I live in an antenna restricted neighborhood, I am opting for the PAR Electronics End-Fedz antenna. It is very discrete and I could easily take it down if needed. Plus it will work when we go camping. They have gotten good reviews and they are priced in my budget.
I am currently working on Section 2 of the construction manual. I hope to have this section completed this weekend. It is very fun to build, and so far simple if you follow the directions.
As you have seen, the guys on this list are a HUGE help if you run into trouble!!!
Let me know if you have any questions.
Burke Jones
N0HYD
Olathe, KS
On Mon, Jan 5, 2009 at 11:58 AM, Edward Doyle <[hidden email]> wrote: Howdy, _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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In reply to this post by Bruce McLaughlin-2
Bruce McLaughlin wrote:
> If it is a BNC connector, then obviously that is the connector to use. > Unfortunately, I do not have that radio. The K2 does have the PL 259 type The base K2 uses BNC. Generally though, all amateur antennas are compromises, and there is a lot of mythology on the subject. Other than that you really need at least a full halfwave at a reasonable height, everyone will have different idesa, and some people will try and sell you very compact antennas and claim they are as good. To take things to extremes, for a simple, halfwave, dipole aerial, you probably want superconducting wire, connected directly the antenna connector, with the radio suspended several thousand feet in the air, with wireless (possibly optical fibre) control of keying and return of audio. Obviously you will need to use batteries. Even replacing the superconducting wires with fat silver ones, that is unrealistic and may not be optimum for some propagation conditions. Your antenna will be dictated by how much you can afford, and where you can place it. (Even with the extreme case quoted, you might want a balun, and a free space dipole is more like 75 ohms than the 50 ohms design load.) -- David Woolley "The Elecraft list is a forum for the discussion of topics related to Elecraft products and more general topics related ham radio" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> _______________________________________________ Elecraft mailing list Post to: [hidden email] 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 |
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