My 2020 Digi DX Marathon

In December 2019 I started experimenting with a new open source software for doing FT8/FT4 called DigiRite. It uses the WSJT decoder, but with a completely different user interface optimized for contesting.  It is also well integrated with Writelog.

I spent the first few months of 2020 doing lots of operation and beta testing.  The dev team was very responsive and the app kept improving. There was also the fun of learning the FT modes. FT is like having a contesting going 24/7. The QSOs are short and there is plenty of activity on all bands all the time.  I had a separate Writelog log going just for my digi QSOs and could see the number of contacts and DXCC on each band.

I was always pushing to see how to make rate on the FT modes. The only SO2R operation that I did was during the WW Digi DX Contest in August where I did about 16 hours trying to run with two radios. The rest of the year was a single radio.  I did use my amp most of the time (except 30m).

My operation was sporadic through the year.  There would be periods where I operated a lot and then weeks with nothing. I became unemployed in September and started operating more and at different times during the day. The country counts started to build.  I focused on trying to see how many bands I could achieve DXCC.  It was fun checking the bands, seeing new “multipliers”, and trying to figure out how to get their attention. With the whole world in quarantine, the digi frequencies were crowded!

I had not worked the WARC bands much before this year so one objective was to try to get my DXCC on those bands. I used my Cushcraft 40m beam on 17M. I couldn’t find an antenna that would work very well on 12M. I finished WAS on 30 meters and only need ME and NJ to finish it on 17M.

I made over 1500 QSOs in December.  In part because I could see the country counts getting close to 6BDXCC. 80 meters was the last band  to make it on the evening of Dec 30 when I worked VU,  UK8, and HP to get to 100 (while missing ZF and FG).

You may be interested in what is possible chasing DX on the digi modes for a year.

According the Writelog, I had 228.5 hours of digi operation. (Rate 31.5/hour)

Breakdown by band (not including dupes)

Band      QSOs     DXCC  CQ Zone
160M       352       72      22
 80M       961      100      31
 40M      1210      135      35
 30M       894      125      37
 20M      2089      143      40
 17M       424      117      29
 15M       600      103      29
 12M        10        4       6
 10M       297       49      20
  6M       369       12       5

Tot       7206      860

Worked on 8 bands: 5T5PA CO8LY J68HZ

Worked on 7 bands: 9Y4DG W1OP WB5BHS

Worked on 6 bands: A45XR J69DS N0AT XP3A YO9HP

Total of 177 different entities worked

Most worked countries (not including 6m)

      160   80  40  30   20  17  15  12   10    All      %
 K    124  244 383 231  379  62  79   6  151   2051    27.2
 UA    24  109  75  92  199  15   4        2    520     6.9
 DL    20   82  41  35  117  33  59        8    395     5.2
 JA         29  99  32  159   6  18        3    346     4.6
 I     16   31  33  30  116  20  35   2    4    287     3.8
 UR    22   62  48  32   80   8  11             263     3.5
 SP     6   36  22  29   86  16  15        5    215     2.9
 EA     5   22  36  23   65  16  23       17    207     2.7 
 F      9   24  16  21   50   7  19       21    167     2.2
 G      7   18   9  11   83   8  22        7    166     2.2
 UA9         6  17  48   92   2                 165     2.2
 PY     3   21  19   7   31   6  63        9    159     2.1
 PA     7    7  13   6   85   7  11        4    140     1.9
 VE    15   20  23  10   25   6   2        5    108     1.4
 ON     8   12  10   6   33   5   6        1     81     1.1 
 SV     7   12  13  12   22   3   9        1     79     1

One of my resolutions for 2021 is to help repopulate the CW bands. While FT8 is teeming with activity, and you can always see when the band is open and who is on, it is sad to tune across the CW segment and find no activity at all. FT is great for working DX, but it removes much of the human-to-human contact that helps build friendships and the shared experience that makes ham radio great.

Onward to a new year with less pandemic quarantine and more sunspots!

Randy K5ZD

Fixing my Intermittent 40-2CD

I put the Cushcraft 40-2CD 2-element 40 meter beam at the top of my tower in 1993. There are so many trees around the tower that we had to assemble the elements to the boom at the top of the tower. Actually it is at the top of the mast 10′ above the top of the tower! It lasted a long time before it started to be intermittent on receive.

John W2GD came up around 2016 and was able to climb the mast, get the beam in his hands, and rotate it so I could replace the feedline and feedpoint. It was less than a month later and the antenna started being intermittent on receive again. It mostly happened when the wind was blowing.

Just about the time John got the antenna reattached to the mast, I had noticed one of the loading coils looked mangled. It had a strange look like a bunch of birds had been pecking at the plastic. Since we had the antenna reinstalled, we didn’t pursue it.

The antenna kept getting worse and I would complain about it after every contest. In June 2020, Mark K1RX suggested that he had a fix that would solve the feedpoint problem and he was willing to help do the work. Mark does a lot of tower work for local hams and he is very good.

The feedpoint fix was to bypass the small through hole screws that Cushcraft used and replace it with some aluminum strap that went from the feedpoint, past the insulator, and out to the element. Mark came up with all the pieces from his junkbox. See photo below.

40-2CD Feedpoint “repair kit”

Mark climbed the mast and maneuvered the antenna so I could reach the feedpoint. I added the straps, reattached the coax, and then weatherproofed everything.

Fixing the 40m antenna feed point. (K1IR photo)

That mangled loading coil had also been bothering me for a few years. All attempts to get a photograph or better visual to diagnose were unhelpful. Since we had the antenna off the mast, Mark was able to get the coil to where I could reach it. Wow! Lighting damage. The coil had been vaporized on one end and the wire had unspooled. I had effectively been using a dipole in contests for 3+ years!

Lightning damage to 40-2CD loading coil.

I have collected a few 40-2CD elements over the years just in case something like this happened. We were able to find a good one in the junk pile and replace the fried one. I was excited to have that mystery solved.

A recent wind storm had caused the truss wire on the Hygain 205-CA 5-element 20 meter beam to fail. Since we were up there, we took on the job to replace the truss on both sides with new stainless cable. A 205-CA is a big antenna and the truss wires go out near the end of the boom. Mark had to remove one of the elements to get the antenna to lean over far enough so I could reach it. It took all of Mark’s strength to wrangle the antenna.

Mark K1RX removing the element.

The end result has both good news and bad news. The 40 meter beam now feels and sounds like a beam again. I.e., it has front-to-back and I have had a bit more success on 40 in the past few contests. The SWR curve is back to looking like it did when I first put it up.

The bad news is that the antenna is still intermittent at times on receive. Signals will fall about 20-30db when the antenna is not working. Sometimes transmitting with 100W is not enough to clear it. But, so far, a quick blast with the amplifier on always brings the SWR back in line and the signals up.

I climbed the tower one evening with a long pole hoping I could bang on things and find where the intermittent might be. With the antenna analyzer connected, I could see the high SWR. Banging and prodding did no good. I could not quite reach the loading coils. Only when I violently pumped the antenna up and down would the SWR intermittently come down.

This 40-2CD has the W6NL mods so it has been extremely durable at resisting wind and weather. Given the lightning damage on the reflector trap, there is no telling where the failure point is on the driven element. As long as transmitting will clear it, I will live with it. But, sometime next summer it will be time to make another try at finding the problem or replacing the element.

Thanks to Jim K1IR for serving as ground crew during the climb.

(l-r) Randy K5ZD, Mark K1RX, Jim K1IR (K1IR photo)

Setting Up WriteLog to Send K3DVR Messages

For several years I tried using the sound card in my station PC to handle voice keying. No matter how much I messed with it, I could never make it sound great. The audio would be too hot or too quiet. I did a contest at P40L where the voice keying was done using the Elecraft K3 built-in DVR module. It sounded great so I added the DVR to both of my K3 radios.

WriteLog has the ability to send commands to the radio. The commands can be triggered from the keyboard. It is not difficult to do, but it is not obvious and I wanted to have a record if (when) I need to do it again.

The first step is to tell WriteLog what radio commands to send. You do this by editing the writelog.ini file and adding a section Elecraft_K3_commands.

[Elecraft_K3_commands]
Macro_10=SWT21;
Macro_11=SWT31;
Macro_12=SWT35;
Macro_13=SWT39;
Macro_14=SWT37;SWT21;
Macro_15=SWT37;SWT31;
Macro_16=SWT37;SWT35;
Macro_17=SWT37;SWT39;

The K3 has a bunch of commands to do things like clear the RIT, go split, etc. See the Elecraft K3 programmer manual for explanation.

The next step is to connect the radio commands above to the messages. You replace the normal <msg#.wav> file with the link to the radio command. That uses %GK and the macro number. See below for how it looks in the SSB memory dialog.

If you want to program your DVR messages on the fly, you can add the Shifted SSB memories as well. Or you can just use the buttons on the front of K3 to do message programming since it is not something that you typically need to do often.

The memories are stored with the log so you will need to set them up for each new contest. Once you have it working for one phone contest, you can copy them in by using the Browse button on the memory setting dialog and select a .wl log file that is already set up.

That’s it, you’re done! Pressing the F1 function key will play macro 14, which is message M1 on my K3.

The best thing about this is that your audio through the DVR will always play with the same settings as the audio from your microphone.

Sending Commands with Keyboard Shortcuts

The example above is for using the internal K3 DVR to send voice messages. It is also possible to configure keyboard shortcuts to send other commands to the radio. For example, I set up a macro to command the rig to set VFO A = VFO B, then move VFO B up 1 Khz, then go into split mode.

As before, the first step is to add the K3 commands to the writelog.ini file. Here are some examples:

Macro_20=FR0;RC;XT0;LN0;SB0;BW0040;  
Macro_21=SWT13;SWT13;FT1;UPB4;XT0;  
Macro_22=SWT13;SWT13;FT1;UPB6;RT0;XT0;  
Macro_23=FR0;RT0;XT0;LN0;SW000;  

Notes:

  • SWT13 is a switch-emulation command that has the same effect as tapping A>B .
  • FT1 enters split mode.
  • The number 5 in UPB4 is not a value in kHz, but an index into the table of step sizes (in this case 1 kHz). VFO displacement, n: 0=1 Hz; 1 or not used=10 Hz; 2=20 Hz; 3=50 Hz; 4=1 kHz; 5=2 kHz; 6=3 kHz; 7=5 kHz; 8=100 Hz; 9=200 Hz.
  • RT0 and XT0 turn off RIT and XIT.

The next step is to use the keyboard shortcuts dialog to define which key will trigger which macro. In the example below, I have set the Ctrl+DASH key combo to send macro 21 to the K3.

The K3 programmer’s reference manuals are available online at https://elecraft.com/pages/programmers-reference-manuals

Contest Online Scoreboards

Contesting has traditionally been a very lonely sport.  You sit in your shack, make QSOs, and then find out how you did at the end.  That requires a lot of self-motivation to keep going when conditions are poor.

Over the past few years, I have been watching the online scoreboard while operating.  It gives me an idea of how I am doing compared to others.  There have been several times where I have operated many more hours than I intended just because I was chasing the next score above me on the scoreboard.  That is especially true when I am operating part time.  I sit down, see who is ahead of me, and then try to catch and pass them.  Fun little shot of excitement when the pass finally happens.  Especially if the other guy passes you back!

The ARRL and CQ have confirmed that watching a scoreboard during the contest does not put you in the Assisted category.  It is also a great way to keep a multi-op team motivated and engaged.  Even the ops that go home to sleep can follow the progress of the team.

All you need to add your score to the scoreboard is a popular logging software and an Internet connection.  One scoreboard I like to use is http://contestonlinescore.com (COSB), which is operated by Victor VA2WA.

All the details about how to set up your logger are available at https://contestonlinescore.com/blog/documents/  If you set up your logger to use the “score distributor server” then your score will be sent to other scoreboards in addition to COSB.

Once you have the logger broadcasting your score every 5 minutes or so, you focus on operating the contest.  The logger and scoreboard will work silently in the background.  I usually keep a small browser window open on the screen that is showing the scores for my operating category.  [Hint: Click on the small mobile phone icon near the top of the COSB page and it will take you to a page optimized for mobile phones.  That uses minimum screen space to show calls and scores.]

Give the scoreboard a try and see if you like it.  Scoreboards are definitely more fun when more people are contributing.

 

Battle of the Hams

One of the best descriptions of amateur radio contesting appeared in Sports Illustrated back in 1958. It was written by Bill Leonard W2SKE (SK) and takes the reader through a 48 hour DX contest. A great way for non-hams to understand the craziness, passion, and magic of staying on the radio for a full weekend chasing contacts from around the world.

http://www.si.com/vault/issue/41748/65/2

How much is using Assistance worth?

There is always a curiosity about how much of an advantage does one gain from operating Single Operator Assisted (with access to the DX Cluster spots) vs traditional Single Operator.

With the intense single op competition here in New England for CQ WW CW, we have some data points to help answer that question. K1DG and K5ZD have operated from the same stations over this period. K0DQ has been from two stations, but with similar results.  All three are hard core operators who make the most of their time on the air.  Given the scores are fairly similar over the years, we can assume the difference for the 3 single operator assisted entries by K5ZD is mostly due to DX spotting assistance.

year call Q Z C Hours SA HP ALL SO HP ALL
2008 K5ZD/1 3955 132 463 44.4 6,666,975
K1DG 3682 115 453 42 5,751,568
2009 K5ZD/1 3957 132 480 45.1 6,845,832
K1DG 3851 134 485 44.9 6,614,634
2010 K5ZD/1 4587 154 524 41.6 8,940,786
K1DG 4303 153 534 44.2 8,239,191
2011 K1DG 4795 163 582 45.3 10,189,365
K5ZD/1 4904 168 561 44.4 10,160,802
K0DQ/1 4910 159 541 42.5 9,703,400
2012 K5ZD/1 4647 167 629 41 10,523,916
K0DQ/1 4610 165 576 44.6 9,607,806
K1DG 4333 160 562 44.8 8,630,788
2013 K0DQ/1 5540 152 498 45.3 10,297,950
K5ZD/1 4945 160 547 45.6 10,050,712
2014 K5ZD/1 4993 190 697 44.3 12,768,365
K0DQ/1 5115 159 543 45.9 10,183,914
K1DG 4901 164 558 44.1 10,065,402
2015 K5ZD/1 4742 179 654 44.9 11,275,488
K1DG 4563 157 523 44.9 8,778,120
K0DQ/1 4870 143 495 44.1 8,723,374

In a post on cq-contest (May 26, 2016) where he presented this data, Doug KR2Q wrote:

…using assistance or being unlimited gets you more mults and hence a bigger score (relatively speaking).

All of the top guys (such as these three) use SO2R.  If you are SO2R and using your 2nd radio to find new Q’s (hopefully, new mults), when you tune using the not-assisted method you are “blind.”  You don’t know what your might find (which is fun).

When you are SO2R and use assistance on your second radio, you are not tuning “blind.”

You know just where to go to grab new mults.  So it would seem obvious that using assistance when SO2R would a higher mult and assuming you don’t neglect running on radio 1, a higher score.

I started doing SOA in CQ WW to have more fun and work more interesting DX.  I was tired of working 40+ hours and then learning there were many expeditions and rare stations that made several thousand QSOs that I never heard all weekend.  Having the cluster spots helped me find these stations as well as lots of other weak ones.  It is pretty cool to nearly achieve 5BDXCC in a weekend.

One of the great things about radio contesting is that we each get to determine our own goals and levels of competition.  I have enjoyed doing contests solo, but it is also a lot of fun to have the additional challenge of managing the non-stop stream of DX spots that the DX Cluster and RBN provide.

Convergence and Change – An Editorial

This originally appeared in the May 2016 issue of CQ Magazine along side the 2015 CQ WW CW results. It represents my opinion and not that of CQ Magazine or the CQ WW DX Contest Committee.

Many years ago the best DX and contest operators were hunters. They studied the bands, knew when the rare DX was most likely to be on, and could even recognize the sound of that rare station needed for a multiplier. As technology improved, stations got better and more capable. Personal computers entered our shack to help with logging and sending CW. With better equipment and more stations on the air, the game started to change from hunting to running.

In the mid 1980’s, Dick Newell AK1A invented PacketCluster® software that allowed operators to enter the call and frequency of a DX station – a “DX spot” – and have it announced to everyone connected to the VHF packet network. Suddenly we could have hundreds of others telling us where the DX was hiding. After some controversy, the CQ WW added the Assisted category in 1989 to place those using this new tool into a separate category.

In early 2008 a new innovation appeared. Alex Shovkoplyas VE3NEA introduced his CW Skimmer software. CW Skimmer is a multi-channel CW decoder that copies all of the callsigns in the receiver passband and displays them on the screen. It had amazing CW copying ability – especially when Software Defined Radios provided the ability to capture a full 96 KHz of each amateur radio band. It suddenly became possible to simultaneously copy and announce every station calling CQ on CW across all 6 amateur radio bands along with their signal strength!

Soon after, PY1NB and N4ZR began building out the Reverse Beacon Network (RBN). The RBN collected data from CW Skimmers around the world, made it available to DX Cluster nodes, and stored it in an archive. This concept was quickly adopted by contesters because it provided immediate knowledge of activity around the world. You could call one CQ and see your signal reported from every Skimmer where there was propagation. The archive was a rich resource for propagation and antenna evaluation.

This convergence of personal computers, Internet access, DX clusters, and CW Skimmer have changed the nature of CW contesting. Even the smallest station can now call CQ and be noticed. The top multi-operator stations have developed the ability to interlock multiple stations on a band so they can chase these Skimmer spotted stations in between CQs on their run frequency. Many single ops talk about the fun of doing all of their operating just by working stations found when clicking on DX spots.

Like it or not, the CQ WW CW (and contesting in general) has certainly been impacted by this convergence. Having so much information has helped more people have more fun – generating even more activity and QSOs for everyone. It has also made it more difficult to police the line between the single operator working alone and those who are using the assistance of DX spotting. Anyone who has received a ham radio license in the last 25 years doesn’t know amateur radio DXing without the DX Cluster.

We have to remember that contesting is ultimately a game played using the ionosphere and our ability to hear far away signals with our own ears. Enjoy the tools, but never forget that our real purpose is to build and test our skills as radio operators. Given our history of technology innovation, when does it make sense to accept convergence and recombine the single operator categories – giving everyone access to spotting information?

 

Elecraft K3 Settings

I have two Elecraft K3 radios that I use for SO2R.  I am creating this page to record all of the various settings in the radios so I can find them if needed.

N1EU recommended settings for best pileup performance:

AGC SLP 000  (maximum slope, instead of horizontal)

AGC THR 014  (so AGC doesn’t kick in until signals are very strong)

AGC DCY Soft

AGC PLS nor

AF Gain is adjusted so the loudest signals are tolerably loud (around 9PM) and RF Gain increased until weakest signals are readable (around 3PM).

 

Bob, N6TV, recommends the following K3 settings:

First set CONFIG:TECH MD ON to un-hide some AGC settings. Set TECH MD OFF when finished, to eliminate useless options from appearing in the SubRx display choices (PLL1, AFV, dBV, etc.)

AF GAIN LO — Cuts audio hiss. May not work with all headphones. OK on Heil.

AF LIM 20 — Only takes affect when AGC is OFF (rarely used)

AGC DCY Soft — Reduces AGC-induced IMD, recommended for pileups

AGC HLD 0.05 — Slow AGC hold time (50 ms). Reduces AGC-induced IMD, recommended for pileups. Works with AGC-S only.

AGC PLS NOR — Loud static pulses do not pump AGC.

AGC SLP 010 — A pretty “flat” AGC response curve. I may move this lower since pileups of loud guys can blend together, but I like this setting because it saves my ears.

AGC THR 010 — AGC kicks in at about S-8. Signals lower than THR behave as they would with AGC OFF ( +1 dB of RF = +1 dB of audio)

AGC -F 120 — Factory default fast AGC decay rate (recovery time). Higher = faster. Faster can be bad.

AGC -S 20 — Factory default slow AGC decay rate (recovery time). Higher = faster. Faster can be bad.

RF GAIN at 3 O’Clock or less on noisy bands

AF GAIN never higher than 3 O’Clock

AFX OFF

NR OFF

NB OFF

RIT OFF

XIT OFF

FL1 to FL5 BW set to match labeled filter bandwidth exactly, not wider or narrower.

Use AGC-F for CW.

Use AGC-S for SSB.

CW Pitch 500 (or to taste)

IF shift centered (on CW)

500 Hz InRad 8-pole filter on CW

2.8 kHz 8-pole filter on SSB (1.8 8-pole when bands crowded, must move IF SHIFT lower for pleasing audio)

Use XFIL button to toggle between filters and reset the IF shift, rather than NOR (hold) button

PREamp ON for 15m and up, OFF for other bands

 

My current settings for other items:

AF GAIN Low

AF LIM nor 030

EXT ALC Off t -4.0

LIN OUT nor 020

RS323 38400 b

TX ALC On

TX DLY nor 008

TX GATE On 10

TX MON Fast

TXG VCE 1.5 db

VFO CRS 0.1

VFO CTS 200

VFO FST 50

Rope for Wire Antennas

There was an interesting exchange of views on the topic of ropes for wire antennas on the Yankee Clipper Contest Club email reflector this month. I wanted to capture some of the discussion for later reference.

On Feb 5, 2016, at 1:02 PM, Lars KE1J asked:

My dipoles came down today due to the heavy wet snow. Clearly the rope I used was not strong enough. Any suggestions for a good rope that can hold some wire antennas?

de K1LI:

The MastrAnt rope that guyed the towers at WRTC2014 was spectacular.

I’d think you’d worry more about trees pulling each other down than you would about this rope breaking!

And, they were a corporate sponsor of WRTC2014, which puts them high on my list of “go to” vendors.

Widely available at US ham equipment distributors, like DXEngineering.

You can see their products at:    mastrant.com/en

de K1WCC:

There is a store in New Bedford, R&W Rope Works, that sells all kinds of rope. They opened their warehouse a few years ago to sell surplus rope, I went there, they had large amounts of all kinds of marine rope. I bought some 3/16″ dia. braided dacron, about 500 ft. and it’s tough and strong, designed for sunlight and abrasion resistance. I think they have a store there now, or, order online. My dipoles are still up, (just worked St. Helena with one of them) despite being coated with ice and snow right now.

I’m more concerned about wire strength.

https://rwrope.com/

Also, Davis RF is now in the rope business.

http://www.davisrf.com/dacron.php

Henry  K1WCC

de N2GZ:

I have been using Dacron rope sourced from davisrf.com. I bought a lot of it (savings in bulk) and im going through it slower than i thought I would.

I employ a technique that lends itself to rapid rapiers:

Using a heavy (5/16 or greater) rope, I install a loop in each tree that will support the ends of my antenna. The loop is tossed over the support branch and is joned at a welded stainless ring of approximately  1 inch ID,

1/4 inch wire diameter. Mcmaster part 3769T74 or similar. a smaller ring would probably be fine. A swivel sheave could probably used here with added expense.

I then use  a smaller rope, usually 3/16 diameter to support the antenna.

Shorter and lighter antennas require less tension to deploy, so a smaller rope could be fine here for shorter dipoles.  This rope is passed through the welded stainless ring (or sheave).

The antenna is raised first by moving the steel ring to the top of the tree, and securing in place by tying off the loop of heavier rope at the base of the tree. Then the smaller antenna support cord is tensioned to position the antenna as desired.  When deployed this way, there seems to be far less abrasion on the rope that passes over the tree branches, and the the rope that is likely to break is the one supporting the antenna. Should it fail, simply lower the ring/sheave with the loop of heavy rope and replace pull up a new antenna. Far easier to do rapidly, no need to get the cannon/slingshot out and no amount of luck is needed to get the rope placed as you had it before.

Sometimes it is desirable to install a fuse (smaller diameter rope) between the antenna and antenna support rope. so that it breaks in a specifiedspot, allowing your rope to be reusable without intermittent knots.

Greg, N2GZ

de W1HIS:

Yes.  _Wire_ rope beats any organic (natural or synthetic) fiber rope; however, wire rope must be broken up by insulators, and insulators don’t pass through pulleyvery well.

The best organic fiber is polyester.  No other organic fiber resists sunlight well.  Only one other organic fiber, namely Kevlar, creeps less than polyester.  (By creeping, I mean extending under sustained load.)  However:

  • Kevlar does not resist sunlight well, so it requires a braided polyester jacket.
  • Kevlar absorbs up to 7% of its weight in water!  It is a lousy dielectric.
  • Kevlar does not resist abrasion as well as polyester.  Although a braided polyester jacket would protect Kevlar fibers from external, or “surface” abrasion, Kevlar’s resistance to “internal” abrasion or fatigue due to repeated flexing is poor!
  • Kevlar is quite brittle.  A shock breaks it easily.  A falling tree branch would be much more likely to snap a Kevlar rope, than a polyester rope.

Last but not least, black Dacron/polyester double-braid rope is relatively inexpensive.

IMO, nothing matches black-jacketed Dacron/polyester double-braid rope.  The braided jacket protects the unpigmented, _straight_ (not twisted), fibers that provide the tensile strength of the rope.  The lack of twist is important because a twisted rope untwisted and extends under a sustained load.

You should buy rope whose rated (breaking) strength is ten times the sustained load (tension) it must endure.  I control the tension in a rope by hanging a lead weight on the free ends of the rope, which is fastened at one end and passes through a block to the hanging weight at its opposite end.

You should reduce wear on ropes by using pulleys (a.k.a. “blocks”) with large diameter sheaves (wheels).  After years of replacing rope worn out by 2”, 3”, and 4″-diameter sheaves.  I now use only 5” and 6” diameter sheaves.

Thus, I have gotten years of service from ropes, despite hurricanes, nor’easters, ice storms, and tree branches falling on my antenna and its supporting ropes.

For several years I have bought black Dacron/polyester double-braid rope from <http://www.synthetictextilesinc.com/supportham.html>.

-Chuck W1HIS

Note:

(1) Nylon does not resist sunlight well.

(2) Under tension, a Nylon rope grows longer, and longer, and longer.

de W1EQO:

Using an insulator between a nylon rope and the wire helps a lot.

The problem is we hams mostly use a class of wire antennas known as “standing wave” antennas (dipoles, verticals, yagis) vs another bunch called “traveling wave” antennas (loops, folded dipoles, resistor in the center folded dipoles, etc).

Standing wave antennas are characterized by an end (or ends), beyond which current does not flow. This is commonly called the “end effect.”

The end effect determines the feed point impedance of a standing wave antenna.

So, attaching a resistive chunk of nylon rope to the end of a dipole changes the feed impedance or VSWR. Also it is an absorbing extension to the wire, which I would expect, reduces the amount of radiated RF. Possibly even worse, the resistive value changes with weather and time.

Placing an insulator between the wire & rope mitigates this problem

Jim, W1EQO

de KI1H:

After the flurry of emails on the subject of rope last week and seeing my beams bowing to the weight of the heavy snow, I deciding to do a little research.

As was mentioned, Kevlar is resistant to stretch but not UV stabilized unless jacketed.

I did find a source for a material that stretches less than 1% at 30% load ( at 1/8″ that is 750 lbs load).

Look at the link below.

http://www.samsonrope.com/Pages/Product.aspx?ProductID=872

I called the manufacturer and it’s non-conductive.

OZ1AA Visit

I was very honored to have Thomas Andersen OZ1AA stop by today on his around the world bicycling adventure. The odometer on his bike was at 40999 Km.  That’s more than the distance around the world at the equator!

Thomas is currently riding from the bottom of South America with the goal of reaching Newfoundland.  Follow his blog with amazing photos and commentary at www.cyclingtheglobe.com.

Thomas OZ1AA visited on August 21, 2015

Thomas OZ1AA visited on August 21, 2015

Thomas OZ1AA on August 21, 2015

Thomas OZ1AA ready to get back on the road

Thomas OZ1AA on August 21, 2015

Thomas OZ1AA and his trusty Bianchi

IMG_2661

40999 Kilometers since the start of his journey in Denmark more than 3 years ago!

Thomas OZ1AA on August 21, 2015

Thomas OZ1AA on his way

 

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