Routing Coaxial Cable
This is probably one of the most common questions that I receive, “How do I route my coaxial cable?” First off, DO NOT PANIC! Elk Antennas have to follow the exact same rules of physics that all other antennas have to follow. You want to efficiently route your feedline to not interfere with antenna – particularly driven elements. On a Log Periodic Dipole Array (LPDA) antenna, every element is driven! They may not all be active at every moment, but like keys on a piano they still are able to function whether you play them or not. If you put metal objects, and that includes feedline, near the radiating elements of any antenna, it will act as a parasitic element. It will change the performance, pattern, and SWR of the antenna. Perhaps only by a little bit, but it could profoundly affect the antenna in ways that you will not like.
We recommend, when vertically polarized, that you run the coaxial cable out to the side, then down the mast or tower. If you are horizontally polarized, then run the coax down about 18 inches and over to the mast or tower and down to your radio.
I am asked if it is possible to run the feedline along the boom and out the back? The answer is sure. Many people do this for the benefit of handheld operation, or for mounting the antenna from the rear. Can it affect your SWR? Likely! It also is likely not be be devastatingly bad, so it is a compromise you may wish to choose.
What should I do if I am operating handheld – like with satellites? My mind goes to two main answers here. The first is that I let the coax and normally a short jumper cable attached to my HT flop around to a certain extent. I have not noticed serious deleterious effects because of this practice. I seem to be able to scan for DX signals, perform direction finding, and work satellites with this method alone.
The second recommendation is to install a 90 degree RF adapter and run coaxial cable right along the boom assembly. I hold it in place with cable ties (zip ties). This works just fine, looks sharp, and gives me the piece of mind that I am doing everything that I can to get the most out of my antenna! That being said, I personally use the “let the coax flop around” method more often…
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Element Color Schemes
Here are the color schemes for the banding of elements on each Elk Antenna. We are starting from the front of the antenna (the end of the boom assembly with the RF connector).
Elk 2M/440L5 (UHF, N-connector, uncoated, black powder coated “Black Beauty”)
1. Black Elements (no color bands, shortest elements)
2. White Elements
3. Yellow Elements
4. Green Elements
5. Red Elements (longest elements)
Elk 220L6 (UHF, N-connector, uncoated, black powder coated “Black Beauty”)
1. Yellow Elements
2. Black Elements (no color bands, shortest elements)
3. Black Elements (no color bands, shortest elements)
4. Blue Elements
5. White Elements
6. Red Elements (longest elements)
Elk 440L8 (UHF, N-connector, uncoated, black powder coated “Black Beauty”)
1. Purple Elements (shortest elements)
2. Green Elements
3. Yellow Elements
4. Black Elements (no color bands)
5. Black Elements (no color bands)
6. Blue Elements
7. White Elements
8. Red Elements (longest elements)
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After years of operation, my Elk’s SWR is now very high!
Before we let any Elk leave our shop and do its noble work somewhere on our big blue marble, we test it and make sure it is going to work for you. At some point, I often receive calls in the range of 15 seconds to 15 years after purchase with customers that find their Elk has a really high SWR. I am going to tell you a little secret about antennas – if built and maintained well, they are amazingly simple devices. There are no batteries. There are very few things that can burn out. Historically, the biggest danger to Elk Antennas is your OM or XYL backing over it with the motorhome. The next leading cause of failure are hurricanes.
There are two ranges of high SWR that customers contact me about. The first is in the 1.8:1 to 3:1 range. In most of these cases, there is an issue with one or more elements. An element may have become loose, or some corrosion may have accumulated between the threaded element insert and the threaded element screw. This is generally a really easy fix.
The next range of high SWR that I get calls about (less often) is the 10:1 to 20+:1 SWR range. In most cases (perhaps all?) this is not an issue with the antenna, per se. Here are some items to look at to help troubleshoot the problem.
1. Is the coaxial cable “hamfest special” coax? I don’t want to be the bearer of bad news, but so much of the coax – I’m talking the really cheap stuff – that you pick up at hamfests and swap meets is just not good. I am not talking down to you – I am with you on this. I purchased plenty of it myself only to find that the construction did not lend itself to truly being coaxial cable. I have cut some open only to find a single strand of wire running along where there ought to have been braid. Many customers swap out for known good quality cable and their problems go away.
2. Is the RF connectors (UHF (PL-259) or male N-Connector) screwed on properly to your radio/antenna analyzer and to the antenna. Before you just answer “Yes!”, do yourself a favor and give it a thorough inspection. Many times, the center conductor on your coax does not make contact with the connectors on your devices. You may have to do a continuity check with a VOM (volt-ohm meter, multimeter). N-connectors often make the best connections you could ever hope for, but they can also give you a false sense that they are screwed on tight and that not be the case.
3. Check that the elements are screwed on tightly.
4. DO NOT USE LOCTITE “RED” OR EQUIVALENT! Loctite “red” is a wonderful product to use when rebuilding the differential in your Jeep. It is not such a great product on your Elk Antenna where you want to pass alternating current. There is a place for anaerobic adhesives on your Elk, but there is a dielectric value to each product. Loctite “red” will allow the least amount of current to flow, Loctite “blue” will allow a little more, and Loctite “purple”, while still possessing dielectric (insulating effects) properties, allows the greatest amount of current to flow. I have had customers literally kill their Elks by saturating the element screws with Loctite “red”. The good news was the elements did not fall off! One customer – a decade ago – returned the antenna but had to hacksaw off the elements for shipping…
5. DO NOT PUT WOOD OR OTHER FOREIGN OBJECTS INSIDE THE ELEMENTS! I am not sure why someone would do this, but this has happened a few times. The claim is that it prevents water from getting into the elements. Well, a little bit of water is not usually an issue. However, wet wood adds a capacitive effect to each element and rendered the antenna – well, odd! So, do not put wood in your elements.
6. When connecting your antenna to an antenna analyzer – make sure you are using the correct RF connector for the band you wish to test. This has come up maybe two dozen times where otherwise really smart people have used the wrong analyzer input to test their Elk and received really high readings. Initially, I get called some really rude names, and sometimes they even hang up on me (pretty much never though). However, after re-inspection, they confirm that was the problem and their antenna is “fixed”.
7. When testing your antenna, you do not want to have metal objects – or even you – right next to the antenna. This will change your SWR and the antennas pattern. On a proper antenna range, the ideal is to have ten wavelengths of your testing frequency between the antenna and anything that may affect its performance. Ten wavelengths is not too bad for a VHF/UHF antenna, but if you are building a 160 meter antenna, you may have to rent a flat state for a weekend…
8. The black rubber end caps on the elements actually have an affect on the antennas performance. If you are missing an end cap or two (or three), it’s not the end of the world. The SWR and pattern of the antenna will change a little bit, so please keep those on. After the dual-band Elk 2M/440L5 was designed and tested to as close to perfection as could be attained, it was reasoned that rubber end caps should be added to protect the users eyes and other body parts. No one wants to see core samples of radio operators. Once they were added, the characteristics of the antenna changed, and the element lengths had to be slightly redesigned.
9. I only saw one of these, but the wire on the center conductor of the antenna’s RF connector could have a cold solder joint. Check it with a VOM, and email me. It will be taken care of. You can certainly re-work it yourself, if you like melting metal.
10. The length of the elements matter! Because the length of the elements matters, it is important that you put them on in the correct pattern. On both the dual-band Elk 2M/440L5 and the 70 cm Elk 440L8 antennas, the elements can be installed simply by feel. The antennas are set up like arrowheads – where the shortest elements are at the front (by the RF connector) and they get successively longer as you install the elements to the rear. The 1.25 meter Elk 220L6 antenna is a little different. The very first pair of elements in the front are not the shortest – but the second shortest. Why? Because to make this antenna resonate well with a two-foot long boom assembly, it was necessary to create what would otherwise be called a Log-Yagi antenna.
11. Check your coaxial cable for water intrusion. This can be challenging to find, but your antenna analyzer may be a great tool for this.
12. Remember, not all antenna analyzers are equal. Most will have your SWR fluctuating around. You may seen and SWR bouncing around from 1:1 to 1.6:1. The reality is your antenna is not magically changing, but your antenna analyzer actually is. Your antenna analyzer is a transceiver radio that injects a signal and does a number of tests – really quickly – to determine your SWR. All things being equal, and SWR should not be bouncing around, at least not due to the static devices of an antenna and feedline. If you are in an RF rich environment while testing, then all bets are off. You may ask me, “What are you using?” Well, I have one of just about every antenna analyzer that has been introduced in the last 20 years. My quick (and seemingly accurate) goto device is the Comet Antenna Analyzer. When I need more detail, or am actively designing new antennas, then I use a spectrum analyzer, signal generator, and return loss bridge. I have a couple of MFJ analyzers. I think they are pretty nifty because of their rich features and the price, but not as stable or accurate as several other devices that I have.
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Horizontal Polarization – why?
Many, if not most of the stations that you may wish to work are likely to be vertically polarized. Vertical polarization is where the elements of the antenna pointed towards the sky and towards the ground (half up and half down). The front of the antenna is the end of the boom assembly with the RF connector attached.
I told you all that to tell you this… If you can operate with horizontal polarization (that’s where the elements are pointed out to the side and the front of the antenna is the end of the boom assembly with the RF connector), you can reduce the amount of QRM (man-made electromagnetic interference) and QRN (electromagnetic interference from natural sources – Sun, cosmic noise, God yelling at you, etc.) Can you always orient your Elk horizontally and get the benefits of horizontal polarization? Well, no. You need to work stations that are also operating with horizontal polarization. Well, who does that? Many contesters – especially those running Single Side Band. However, if you can get another operator to agree to work horizontally polarized with you, then you can reduce the noise in the neighborhood by up to 20 dB. Your antenna is not going to work better, but it is a lot more practical to have a QSO (contact) when all your neighbors are not talking loudly.
Are there other kinds of polarization? Well, of course there are – but we will talk about that in another FAQ.
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Does it matter if the elements are out to the side or if they are pointed towards the sky and towards the ground?
It does matter where the elements are pointed on most every antenna ever built – and Elk Log Periodic Dipole Array (LPDA) antennas are not the exception. Many stations that you may wish to work will be vertically polarized – that is where the elements are pointed up towards the sky and toward the ground. You will want to match the polarization of the station you are working in order to efficiently send and receive a signal. Most all repeaters, base stations, mobile radios, and HTs are vertically polarized. (See the section on horizontal polarization for details on that).
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Where is the front of the antenna?
The “front” of the antenna is the end where the RF connector (UHF (SO-239) or N-connector) is located. Think of the antenna like an arrowhead, and point it at the station you are trying to work.
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