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  1. KE8HNK's Blog

    A blog by KE8HNK in Member Blogs

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    KE8HNK

     

    20210429_202823.thumb.jpg.8166d0352be94090512bda8013b29187.jpg

    Imagine your at work and it is near the end of your shift, over the radio and buildings loudspeaker you hear the following message......

    "All second shift standby for an emergency announcement" 

    A few seconds go by and another announcement's made. 

    "due to civil disrest we are asking all second shift employees to stand by with third shift until further notice at which time we will provide further information" 

    Now you know that there had been some peaceful vigils and protests going on in the downtown area, but nothing to crazy, however once you flip on the news channel you find out that a few bad eggs decide to start a riot to the south of downtown. So you call your family and tell them to lock the doors and stay in the house. You know your wife or Fiancé's kids are at a restaurant nearby and you call her and say " Babe get a hold to the kids and tell them to get out of the area".

    She responds why? As she has been asleep and didn't know what is going on. 

    You respond they are rioting to the south and I know- CLICK all of a sudden your phone shuts off. 

    You desperately try to call her back but you get the message " All circuit's are busy try your call again later"  

    A few minutes later during a press conference you find out that the city had shut down cell phone service for 8 miles around downtown to help quell the riot's. You and your family live within the 8 mile range. You worry that your message didn't get through and you fear the worst as you watch the live news  reports from your desk computer. 

    What do you do next? 

    Fortunately for you, you, your significant other and two of your kids are a ham radio operator. 

    You go up to the roof of your building and call out on the local repeater that you guys chose to meet on should an emergency  happen. 

    You call out "KX9XOX to K7XIX" you wait a few long minutes and then you hear.

    " K7XIX to K9XOX" 

    You respond: "did you get my message and are the kids ok?"

    She replies: "yes and I was able to get ahold of our daughter and they left about 15 minutes before you called........" 

    You reply: " Good, I am stuck at work keep the radio on this frequency and I will let you know when I am on the way" ~She replies OK. 

    A few hours go by and things calm down you are released from your shift but you find out that cell phone service won't be back on till the AM. As you step outside of work and smell the scent of burning fires and tear gas you call out on the radio......

    "K7XIX to K9XOX I am on my way home" to which she replies "Ok I will be up when you get home".

    This actually happened in our home town (with the exception of the cell phones being turned off and using the radio). In a million years I never would have thought that it would happen here. Now before you go jumping on the bandwagon of they can't shut the cell phone off you need to know a few things. 

    The first is yes they can shut down or limit it to only 911 calls. 

    The second is they have done it before,

     On 8/11/2011 BART  in San Francisco shut down cell phones like that in the area of the stations as there was plans to disrupt the service. 

    The final thing you need to know is you should  be prepared for the inevitable no matter how thin the chance of it actually happening is, and if you have family that live nearby and doesn't have, or want a radio license a GMRS repeater system might not be a bad idea. 

    Now if you are a ham  hope this give you food for thought and if not maybe it will encourage you to get your license and develop a plan for you and your family. 

    Until next time, stay blessed ~73 

  2. QCWA-91 Blog

    A blog by WA8AHZ in Club Blogs

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    WA8AHZ

    As we approach another Thanksgiving, I note the following SK...

    Vic Clark, W4KFC, was President of the ARRL, and honorary member of the Vienna Wireless Society. He died the morning after Thanksgiving, 1983, after having just returned home from traveling on behalf of the ARRL. At the time, Chapter 91 was known as the Northern Virginia Chapter of QCWA. After Vic's untimely death, the chapter applied for, and received, the name memorializing Vic.

    Keep Vic and his extended family in your prayers this Thanksgiving

    Mike, WA8AHZ

  3. Knowledge

    A club blog for Antenna Installation Club | Sponsored by Mastrant

    • 3
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    Katerina01
    Latest Entry

    Ropes and Accessories

    By Katerina01,

    What difference is there between Mastrant Classic ropes (P, Q, S, C, R) and Mastrant-M?

    • The difference stands in parameters. Ropes from the Classic product line are the basic ropes optimized for a good price to performance ratio, whereas type M has approximately doubled strength and simultaneously half the stretch compared to type Classic. They are also lighter because the rope core is made from high-strength Dyneema® fibers.

    When is it better to use Premium rope (M) instead of Classic? 

    • When one needs the lowest weight and wind resistance (long ropes holding wire antennas, or supporting large beam elements, or expeditions where low weight is crucial). Also when the anchor points on the ground need to be placed close to the tower (less than 50% of the anchor height – depending on the type of tower – the higher stress needs to be calculated individually) and finally, for any big towers with big antennas.

    When I am looking at Dyneema ropes for maritime use, the strength eg. with 10 mm Dyneema is well over 10.000 kg, but your Mastrant M rope with a similar diameter has "only" 3850 kg strength, even the core material is the same. Can you explain why?

    • There may be several reasons for this difference. The first is that in Mastrant-M ropes, HMPE fibers form only the core. The braid (and any intermediate braid) is made of Polyester fibers, which have lower strength (but other necessary properties for which they are used). The reason may also be the methodology of measuring strength. Our declared breaking strength of ropes is strength really measured – each production series. It must be always 3% or higher than in our specification. There on the market is also another approach – the theoretical BS calculated based on the specification of Dyneema fiber and number of fibers (diameter). This theoretical strength is always much higher.

    What difference is there between Mastrant ropes and Kevlar ropes?

    • Kevlar, like Dyneema®, uses high-strength fibers. While Kevlar is made from aramid the Dyneema® is made from a special sort of PET. Kevlar is not UV resistant and its fibers tend to break when bending over a small radius.

    What about comparing Mastrant ropes with Phillystran?

    • Mastrant-P has about 80% of the strength of Phillystran of the same diameter. Mastrant-M has about 30-65% higher strength than Phillystran – but the bigger the diameter the smaller difference. Nevertheless, any Mastrant solution of any strength is many times cheaper.

    Can you compare Dacron with your ropes?

    • Our ropes have a cover made from polyester. Polyester is a material, and it is the same material as Dacron (brand name of polyester). Construction of the rope (number of layers, number of strands, fiber angle, manufacturing process, ...) is a different story – the design of Mastrant ropes is adapted so that the abrasion resistance is as high as possible.

    What makes Mastrant-M better rope for tower guys than pure Dyneema rope made for maritime use?

    • This question has several answers:
      • There are several types of Dyneema. Also, there are other producers (and brands) of HMPE ropes (the chemical principle of Dyneema). HMPE ropes are excellent, but they slightly stretch if they are in great tension for a long time. This property is called creep. This is not a problem for many applications: regular (e.g., once every 6 months) tightening does not matter, or the ropes are not permanently stressed (for example, masts where there is no permanently high tension, but only during strong winds).
      • In Mastrant-M we use a special version of HMPE fibers – Dyneema DM20. The biggest advantage is that it does not creep. Even though this material is much more expensive than older types of Dyneema or other HMPE fibers, stability is very important for guying so in 2013 we switched to DM20, and Mastrant-M was born.
      • For guying, there are usually important also mechanical features. Using two (or three in diameters 6 mm and up) layers of materials in the rope significantly increases mechanical durability. Also, pure HMPE rope is “slippery” (on touch).
      • If you are considering pure standard HMPE rope (Dyneema SK75, SK79, SK99, Nexsteel, ...), also consider our HMPE ropes D-F3.

    What is the expected lifetime of Mastrant ropes?

    • Like steel ropes producers, we recommend replacing them after 5 years of use. However, we have experience with flawless 15-year-old installations.

    Do I need to buy a complete reel? How long is the rope on the reel? 

    • Standard is 100m or 200m of rope on the reel. Some diameters are 31m on the reel. However, we can deliver any length you want (ropes longer than 200m are available on special order). The ropes of standard length are cheaper. Aside from standard ropes, we offer also “ready-made” ropes with thimble compressed-in on one end.

    Why don't you supply clamps with safety locking nuts?

    • We fully understand your concerns. In reality, if the clips are used properly – and that means properly tightened, it is not possible for the nuts to spontaneously loosen. The reason is that there is always strong counter-pressure caused by the elasticity of ropes. The fact is that the clips were designed by much smarter people than me without washers or locking nuts - and this applies to all types of rope grips. Also, we have never received any feedback that nuts were loosening when installed on the rope, on the other hand, losing nuts during transportation in a pack or pocket is quite common. My personal experience (OL5Y) proves that they will not loosen on the rope if properly tightened.

    Some definitions:

    • SWL — Safe Working Load
    • WLL — (Working Load Limit
    • BS — Breaking Strength
    • SF — Safety Factor
    • Wikipedia details here.

    Ropes and the sea salt - is it true, that in the marine air will collect sea salt in the rope braids and eventually will become conductive?

    • That is correct - it is true that once the rope gets wet from salt water, it can start to become partially conductive, which can affect the electrical performance of antenna systems. This is an occasional problem with insulators, by the way. However, in the 14 years of Mastrant's existence, we have satisfied hundreds of customers with antennas right on the shoreline, and as far as I know, this temporary change in conductivity has never caused a loss of satisfaction or confidence in our ropes.

    Are the BAYCO monofilament ropes better than your Mastrant ropes for guywiring a tower? It looks like the Bayco do not absorbe water.

    • Mastrant ropes are developed for anchoring masts, and the fibres from which they are made (Polyester, Dyneema) do not absorb water in the same way as monofilament. However, water can get into the rope, which is made of thousands of individual fibres. This occurs in a situation where the rope is "loose" - if it is taut, the wetting of the inside of the rope is negligible. The essential difference in favour of Mastrant type ropes is their mechanical properties and therefore their handling, ending, tensioning etc. It is therefore impossible to decide in general terms which solution is better for anchoring antennas. We recommend asking about the experience of users of our ropes in Italy.

  4. Official Community Blog

    A blog by K3MRI in General

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    K3MRI

    For years I’ve tried to define Field Day, not in an absolute, definitive or comprehensive way but rather, in a personal one. What does it mean to me? I have narrowed it down to two key added values, again, for me.

    First of all it is the camaraderie. I spend Field Day in a group setting. I do not operate alone. Secondly, more than the ‘contest’ aspect, even though it is technically not considered one, I find that Field Day is an exercise in ‘aggregation.’ Individuals, with different radios, different feedlines, antennas and power supplies, show up on the Friday or Saturday and are expected to magically make it all work together. Except for the most avid contesting clubs, there is little to no real preparation. Sure, so and so will bring the CW station, and so and so will bring the SSB station, but is there really any real pre-matching? Not really, and yet, it works.

    I’m sitting here at this year’s Field Day, with a group that has been together for 51 years, and yet, it’s as disparate as I describe above. Multiples of each needed item show up, and maybe because they’ve done it for years, everything somehow connects and they get on the air.

    If you think about it, this aggregation characteristic provides a foundation for many aspects of amateur radio. Of course, emergency responses are made possible by this quasi-instantaneous aggregation. So too do the more mundane public service interventions. Every year I participate in the Marine Corps Marathon. Over the past few years I’ve been attached to Net Control. Here again, ‘stuff’ shows up, and like magic, we have a net control station able to transmit to and coordinate with over one hundred portable and mobile operators.

    That’s it for now, I guess I should get ready for my own Field Day. And yes, I better remember what I ‘brought’ so that I take home what’s mine and not what’s everyone else’s.

  5. VWS Official Blog

    A blog by WA8AHZ in Club Blogs

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    WA8AHZ

    Join the Club’s Regular General Meeting starting at 7:00 pm, via Zoom Meeting.  The Zoom link is:    https://us02web.zoom.us/j/83906871573?pwd=V3l1UkZmSGZObGI5YkhLbGFYRzRUZz09   

     Forum – “Amateur Radio RF Exposure” Join the ARRL Learning Network pre-recorded presentation on Amateur Radio RF Exposure, by Dan Brown, W1DAN. Dan is the Eastern Massachusetts ARRL Section Technical Coordinator, and President of the Wellesley Amateur Radio Society.  In May, the FCC issued a new Rule and Order eliminating the decades-long “categorical exclusion” for mandated RF exposure calculations for most Amateur Radio stations.  Effective May, 2021 Amateurs must conduct detailed calculations of RF exposure for both controlled and uncontrolled environments, and have the calculations on file in the shack. After Dan’s presentation, there will be a short discussion.  Time: 7:00-7:30 pm

    Main Program -- “Mitigating Residential Heating, Ventilation and Air Conditioning (HVAC) RFI (Radio Frequency Interference)”  The mandated use of high-efficiency DC motors in HVAC systems poses new challenges for RFI mitigation in the Amateur Radio bands.  In this presentation, VWS member Roger, KM4LHZ along with Steven, W9SAN of the Fort Wayne (IN) Radio Club will explain the physical basis for these phenomena, present brief case studies in RFI mitigation, and discuss some common myths regarding HVAC RFI. Considerations for purchasing a new HVAC system will be given.  Roger experienced this issue first-hand when he recently updated his home HVAC system, and Steve is an electrical engineer at the Regal Beloit Corporation, specializing in RFI issues.  Time: 7:30 – 9:00  pm

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