LNR PRECISION ---> QUAD BAND END FED HALF WAVE WIRE ANTENNA. -- VE3AB Earl Andrews - NEW REVISED ARTICLE: (OCT 2-2014). I previously had two wires attached to the matchbox in effort to try and get multiband version. Basically..that attempt late Sept-- FAILED -- the old article..with my ideas is still available at this link if you wish to refer to it for information. Hamelectronicsmagazine.com / earlandrews.com **** mirror sites **** since 2005 FREE ON-LINE MAGAZINE and mail order parts as well! Oct 2-2014 - rainy day up here in Northeastern Ontario. A good day to do some antenna work! -- Antennas always work better when installed or modified in miserable weather - or so..the saying goes. My previous attempt to install the Quad band LNR matchbox with dual radiating elements was a failure. THE ORIGINAL ARTICLE (NOW TITLED LNR FAILURE IS STILL AVAILABLE AS A REFERENCE PAGE (link here old article). There is too much interaction between the two elements. So..I lowered the matchbox portion and feed with my rope and pulley system and cut off the 17 meter (18 mhz) element and then I trimmed the remaining element and tied it off to my fence post. NOW..it exhibits very good SWR readings on 20 meters and not bad on 10 meters. SEE ALL THE PHOTOS OF THE SWR ANALYSER READINGS BELOW. This article has just been updated 19- December 2014.
The TV tower and mast. TV tower is self supporting up to about 27 ft and then there is about 10 feet of 1.5 inch mast above the tower. A couple of rope and pulley arrangements are used. 1 is for the QUAD band LNR precision antenna. The other rope and pulley I will use later on. - I have an LNR Precision 20 meter 200 watt matchbox I could put up as a second antenna but..i already have 20 meters covered with the QUAD matchbox antenna. I only had about 40 foot or so for a straight run of wire off the tower sloping to Europe (more or less) so I modified the LNR 40-20-10 (25 watt antenna) using the coil and the dimensions to build a 40-20-10 with the old loading/isolation coil but using the new LNR QUAD matchbox. What I have now is a short antenna that works well. Lately (December) I have been working stations on 40 meters close to me ie Sudbury ON. (about 100 miles east of me) and Ottawa and getting very good reports on 40 m ssb on the Transprovincial net 7.055. Good strong reports of S-7 from Ottawa and 10 over 9 from Sudbury. This new (modified) end fed antenna has been working well. I was using my Ten Tec Argonaut 515 on ssb with about 5 to 6 watts output for those reports. I want to do some more contesting with qrp with this new antenna.
ABOVE: UGLY DUCKLING end fed half wave matchbox. It seemed to work fine and SWR curves around 28 mhz were quite good. The full 2 page article is available at this link here. A single band matchbox is not all that hard to build. The multiband matchbox is a mystery though. I did not break the seal to peep under the hood of the new QUAD BAND MATCHBOX. I do plan (however) to saw into the old 40-20-10 matchbox and take a look at the arrangment. I want to try and build one for fun. Actually, there is experimentation (see you tube videos) and some images on the web where one fellow cut open the matchbox. Above: at the far end of the wooden fence at the east end of my yard. You can see a vertical antenna stored on hooks on the fence. My yard is a pretty nice yard for a city lot. It is about 60 ft wide and about 125 ft deep. One of the bigger and flatter yards in Elliot Lake. This coil is about 80 uh or so. I could (and maybe will) make a coil for my LNR Quad band antenna but this commercial version is rugged and light weight and I prefer it for that reason. The coil is sufficiently high inductance and impedance that it seems to divorce itself from 20 and 10 meters (for the most part) so that the 32 foot main radiator still works well on 20 and 10 but with inductor allows 40 meter resonance-- and it seems to work (as an antenna) quite well through my eperiences with the LNR (PAR) 40-20-10 ef 25 WATT version. December 2014 update: I am very well pleased with it on 40 meters. Getting good reports. Id say it might be about as good as a full size dipole or fairly close to that. I have no other comparison antenna however and this is just a practical guess. This is the coil from my previous antenna - The LNR Precision 40-20-10 antenna. The 40-20-10 can only take about 25 watts of applied power. The weak link is the capacitor inside the matchbox. I would think that the 150 pf cap in the matchbox would crack if 100 watts were applied to the matchbox on a regular basis. Below a picture from below the antenna going up towards the feed point. The coil and the tag end of the antenna are visible. The matchbox can be made out next to the antenna mast.
The loading coil (however) looks like it could take 100 watts no problem. So.. I transplanted this coil into the new LNR QUAD antenna and created the best features of both antennas. Its on a pulley system and can be lowered in a minute or so. There is a second pulley up the tower and I planned to get another LNR precision antenna up and sloping in the opposite direction but that will have to wait till spring now. THIS IS A SHOT OF THE LNR PRECISION (MODIFIED) QUAD BANDER. IT now is a 40-20-10 (41 ft) loaded wire. Works great on 40. I can run 100watts into this antenna but (lately) I have been using it on the low end of 40 with my ARgonaut 515 barefoot at only 5 or 6 watts output.
This is the antenna I now am using. The LNR QUAD bander with the shorter dimensions (modified) and with the LNR loading coil about 33 ft from the matchbox. The coil is not visible in this picture. The antenna is sloping in the direction of Europe. The antenna works fairly well on 20 meters to the west as well. I will be doing more testing this winter. SWR readings of the "new" 40-20-10 (and maybe some other bands) antenna!
LOOKS LIKE THE LOADING COIL is working good now on 40 meters! -- I have checked in on Thursday night 7.117 to the Great Lakes Slow CW net on 40 meters at 9 pm. Got decent reports of 579 or something along those lines. I was using about 20 watts with my IC-718. I lowered power from 100 watts because the check ins are mainly qrp operators. I could use my tuner and try 60 meters as well. Looks like it might work there too with a bit of persuasion.
Some persuasion and I might have an antenna that will get me on the other amateur bands like 10 mhz. The 40 meter SWR curve is better..more broadbanded than I would have thought. THE REASON I MODIFIED THE ORIGINAL LNR PRECISION QUAD BAND ANTENNA - I did not use the full 66 foot or so radiator with the tuning stubs is because of the layout of my backyard and the space I had to work with. I only have one tall support (my tower and mast) and the antenna would have to be a SLOPER OFF THE TOWER. The LNR quad band tuning stubs would not work all that well because of the stubs not being able to hang down perpendicular to the antenna element. So I modified the LNR quad bander with parts from the LNR 40-20-10. On 10 meters.. the SWR curves are not all that good. I will just use a tuner for 10 meters.
Below: the 20 meter curves are very good. This antenna is quite broadbanded on 20 with good low SWR. Up on 18 mhz the SWR is up around 3 to 1. It could be pressed into service for 18 mhz with a tuner..but I might keep the power down to around 50 watts out so as not to burn out the coil or perhaps even a component in the QUAD matchbox. THE SWR CURVES are better than I had anticipated. 20 meters looks like a real winner. SWR is flat with a dummy load as well! - The real test of the pudding is in the eating! - I will be on the air with this antenna during the month of October and November. Below: the far end of the antenna. You can see quite clearly (if you look hard enough) the 40 meter coil towards the end of the antenna. Also visible..the blue weed whacker line I use to tie off the far end of my wire antennas. I may make some tweaks depending on performance OR.. I may leave it alone if it peforms well. Even if I have to use a tuner to tune the thing.. it might be a good all round general purpose wire antenna.
The antenna requires only one tall support and slopes off the tower. It is broadside to Europe in one direction and the other direction..i guess it is broadside to Russia or maybe Alaska. I have another antenna I can put up the tower with a pulley and rope..but for now.. I have only the one wire antenna up. You can also see my 33 foot vertical in the right of the picture. Because it is vertical and off to the side.. it should not interfere with the LNR quad end fed wire. -- I have a QST article handy in my shack right now.. that shows how to use a small amount of inducatance
at the base of a vertical..to get two bands from the vertical..either 40 and 17 meters OR.. 12 meters and 30 meters. -- Perhaps..I will go with the 12 and 30 meter vertical. I will have to modify the current vertical a bit by shortening it to around 23 ft or so. That way..i will have quite a few bands covered with my wire and vertical antenna system. MY main rig is an IC-718 I bought used. I also have older Ten Tec Argonauts and FT301s I play around with. I also have a plan (right now in the back of my head) to add a top loading coil onto the 23 foot vertical which will give me a short vertical on 80 and the loading coil should not upset the 17 and 30 meter operation of the vertical. --- STAY TUNED and I will be doing some more antenna work in the spring and will write it up in this magazine. JUST A BIT OF ADVERTISING NOW -- MY NEW WEB SITE IS www.nettyelectronics.com (NETTY ELECTRONICS) is the company name. I just started this tiny mail order parts company. It is run out my home in Elliot Lake. You can visit this new site by clicking this LINK HERE. I sell toroid cores and other radio parts and it helps pay for the hobby. It is a "hobby business"of sorts. Just got the Ontario Business licence here 2 December 2014. This magazine "hamelectronicsmagazine.com" will continue on but as a separate entity from the business side of the house. 73 and thanks for reading. Earl VE3AB NAVIGATION LINK BACK TO HOME PAGE hamelectronicsmagazine.com click here for home page NOTE: I have been in correspondence with Dale Parfait.. the developer of the PAR end Fed (in conjunction with LNR Precision) and I have made a suggestion that they offer the type of modified version of this antenna (for single support small city lot or portable use). 73 earl ve3ab Feb 5-2015