Another advantage of the 40 & 20 dipoles is that the 40 dipole should load up well on 15 (while it is still hanging in there prop wise). Will have some gain and the main lobes will be closer to the wire than broadside, so watch the orientation for DX coverage. I put up a G5RV at my vacation home and it loads with a tuner on 80 to 10. Has some gain on the higher bands ,keep in mind that nulls go along with the gain main lobes.
W3OU Steve -----Original Message----- From: Don Wilhelm <[email protected]> To: CRAIG SCHROEDER <[email protected]>; elecraft <[email protected]> Sent: Mon, Dec 7, 2015 6:41 pm Subject: Re: [Elecraft] Advice on First HF Antenna Craig, For the home station, your first consideration is build or buy. It is quite easy to build a pair of dipoles, one for 40 and one for 20 if those are your most desirable bands. Get some wire, and some good coax and a good common mode choke for each antenna and use the ARRL handbook section on dipoles to build your own - it is not difficult. Look at what you have for antenna supports - the higher the better, but for 40 meters, 50 feet is a suggested minimum for good performance. If you have only one support that high, an inverted Vee works nicely. Use resonant dipoles center fed and feed with 50 ohm coax. Low loss RG8X is almost as low loss as RG8 but not as heavy. If you are going to run power, use the RG-8 or RG-213 right from the start. With a single tall support, for an inverted Vee configuration, position a 40 meter radiator at right angles with a 20 meter radiator and feed both with a single feedline. Being placed at right angles to each other, there is little if any interaction. Get the ends of the inverted Vee radiators up as high as possible - if you can get the ends up to the same height as the center, that is great - you will have a pair of dipoles, so much the better. Put the dipoles up, cut a bit long from what the "formula" tells you, and then trim it a bit at a time for the lowest SWR or for a reactance of zero should you have access to an antenna analyzer at the midpoint of your operating frequency. If you have room for another dipole, consider adding a multiband antenna such as a G5RV so you can explore bands other than 40 and 20. Use a good common mode choke at the antenna feedpoint (for the G5RV at the junction of the parallel feedline and the coax). You will need a tuner for a G5RV or most any other multiband antennas. If your horizontal space is limited, try a vertical. I can recommend the GAP Titan, being a halfwave vertical, it needs no radials. Mount the base 10 feet off the ground so the loop for 40 meters is above head level and use a good common mode choke at the feedpoint. This is just for starters on your antenna quest. That quest is an ongoing exercise for most hams. Do not strive for the "best" antenna for starters, just get something up in the air and start operating - with time you will be able to determine how you want to improve your antenna farm. For portable QRP operation, take a look at the End Fed Halfwave antennas offered by LNR Precision - They work and they have a good "trail friendly" lightweight version. An EFHW can be easily deployed with one end in a tree and the other end near the transmitter. If your field operations are more of the picnic table variety than the backpacking type, then consider a 32 foot heavy duty telescoping pole to hold up the center of an inverted VEE antenna. Tie the center of a dipole antenna to the top of the pole and push it up - anchor the pole to whatever vertical support is available with bungy cords. Extend the radiator ends out to whatever bushes or other supports are available. So my suggestion is to start simple with homebuilt dipoles or other wire antennas, then grow your antenna farm after you get on the air and determine what you really want, and that may be a 150 foot tower with stacked rotating beams sometime in the future. If you have space and want "beam" antennas using wire, consider 4 130 foot wires spaced 45 degrees apart (total of 180 degrees spread) and you will have V-beams that can be steered - a very effective beam on 20 meters, but does require some feedline switching to select the pair of radiators to properly direct the radiation (it is bi-directional). 73, Don W3FPR On 12/7/2015 5:13 PM, CRAIG SCHROEDER wrote: > I am pretty new ham and a brand new KX3/PX3 owner excited to try my hand at > DX'ing! If you were buying your first HF base antenna, primarily looking for > performance on 20 and 40 meters, what would you recommend? Also, what do you > suggest as a high performance field antenna for QRP? > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
