Second Remote Base

A second remote base is under way.  This is a de-commissioned tower from a business I once owned.  The landowner called when the new company said they no longer needed the tower.  My suggestion was to donate the tower for non commercial ham radio use and they went for it.  I will pay the landowner reasonable fees to use his land and for electricity.  Here’s what it currently looks like.  That white road is pointing toward Europe.  Nice, right?

The plan is minimalist.  We will put a 20′ aluminum mast at the top of the 30′ tower providing a total height of 50′.  At the tip will be a light weight dipole cut for 20 meters made from two 16′ Jackite fiberglass poles (http://www.jackite.com/product_info.php?cPath=41_44&products_id=98).   A dipole at 50′ models very well and should have lots of gain for DX on top of a hill that slopes down toward Europe.  Ground conductivity is good in the area, too.  It should give us the productivity on the high bands we are  lacking at the first remote base.  In 2002 this was the very first tower for our wireless ISP. It’s had a lot of communications pass through it in it’s 14 years of commercial use. Now in retirement we hope it will see a lot of DX.

Wish List

The remote base is currently working 100 per cent as designed and one could be very happy with it for a long time.  However three concerns have surfaced in the first full week of operation.  These concerns could just be kept in the back of one’s mind and not acted upon or a timetable could be set up for upgrades.  After all this is the main station now.  Here is the list of concerns starting with one that has already been blogged about.

The 20 meter antenna is weak.  It is an inverted vee with the apex at 39 feet.  It’s model shows a gain of 4dBi over average ground at 15 degrees take off angle.  It’s signal gets beaten out by almost any other station in a head to head contest to work a DX station.  First item on the wish list is a better antenna—higher, more gain at 15 degrees. A hex beam might be a good solution. (Cost, $500)

Next concern is one that was discovered last night when trying to work Iran, EP2A, on 40 meters CW.  It is a rare country and there was a huge pileup last night for the current dxpedition. The receiver on the Kenwood TS-480 was hopelessly swamped by the strong signals of the pileup overpowering the puny front end with it’s poor dynamic range.  It was a little spooky in the sense that the receiver was tuned to 7.019 MHz but there was no static, no background noise, no EP2A signal.  It was as if  a large attenuation had been inserted in the coax.  It was very very quiet.  Disabling AGC made no difference. Front end overload completely shut down the receiver. That was caused by the strong pileup signals.  Rob Sherwood’s receiver test web page (sherweng.com) shows the TS-480 has a dynamic range of 72 dB at 2kHz.  For comparison an Elecraft K3 has a dynamic range of 101 dB, roughly 1000 times better (30dB).  The Kenwood is ok for JT65 because even when there are pileups the signals are never extremely strong. For serious DX chasing with incredibly strong pileups the TS-480 just doesn’t cut it.  Second item on the wish list is a replacement transceiver. An Elecraft K3 might be a good solution.  (Cost, $800 for a K3-zero [already have a K3 ]).

Third concern on the wish list is more battery reserve.  Once the sun quits powering the solar panel the station can run on it’s batteries for approximately two hours before discharging to 50 per cent. Then the station needs to be shut down for the night to avoid shortening the life of the batteries.  Calculations for battery reserve had been only a guesstimate. It’s clear more is needed.  The panels on the other hand seem to be very adequate because the batteries are typically recharged by mid morning each day.  Third item on the wish list is to double the battery capacity. Two more Walmart group 29 marine batteries should be a good solution. (Cost, $200)

Total estimated cost, $1500.  Next wish:  wish there was an extra $1500 hanging around.

May 12, 2016 Update to each item –  Batteries are doing ok if the system isn’t allowed to run all the time.  There is plenty of operating time available as is. (I went ahead and added a third deep cycle marine battery in June.)

As for receiver overload it doesn’t happen with the JT modes, just DXpeditions on CW.  Those are infrequent.   Never the less the remote software for the IC-7300 is on order and should allow using the IC-7300 at the site if that becomes more necessary. ( When I tested it the remote software worked ok for CW and SSB but was a total failure for digital.  The remote congested the data channel and the digital signals we choppy.)

And finally the 20 meter antenna upgrade has been given some more thought.  See the separate new post with the full story. (I put the phased verticals on hold when I got the second remote base working for 20 meters.)

 

 

 

Not So Fast

This morning 20 meter European DX is rolling in like crazy but not a single station I call comes back to me.  It’s not the old test tone problem because pskreporter shows stations spotting me in Europe.  I can only conclude my antenna isn’t big enough.  What about a hex beam?  It would get out a lot better and still be a top hat for the low band vertical.  The seed of thought has been planted.  Maybe I could get some of this juicy DX to hear me.

Examine what was happening above a little deeper.  I heard a Czech station call CQ and I called back.  At the same time, another U.S. station was calling him, KD2EIP which we can see and apparently one we can’t see in Russia, RV3DBK.  The Czech heard the Russian and came back to him.  My signal was clobbered by a New York station and a Russian station.  A bigger antenna might not have made any difference.  Probably nothing I could do here could overpower two stations closer to the Czech Republic.  I have to learn to think of it as a DX pileup where finesse and operating skill are the best way to beat out big gun stations (for example, “tail ending”).  OK, back to the pileup. Hex beam is on hold for now.  JT65 has become so popular every day seems like a weekend contest.  It’s not like the early days when I once worked England with 100 mw.  Here’s another example from this morning.

OZ1DSD, Denmark, calls CQ and I call back.  Apparently KK5AA calls him, too, and the Denmark station comes back to KK5AA.  I lose out.  Next SQ5WAF, Poland, calls CQ and I call him back.  So does a station in Spain, EA3ATJ, and the Polish station comes back to the station in Spain.  I lose out again.  Next a station in Bulgaria, LZ5UF calls CQ and I call back.  And he doesn’t come back to anybody. He calls CQ again and I call and he comes back to no one.   I lose again.  Born to lose.  But I’ll keep trying and maybe just maybe a little bigger antenna could compensate for being so far west.  Sorry about the whining.

Remote Base Breaks The Rules

An interesting phenomenon has occurred.  It appears the remote base is making contacts above the Maximum Usable Frequency.  MUF is 18 MHz and the remote base just worked two different stations on 21 MHz using JT65.  Refer to the screen snaps below.  In the first frame notice the lines highlighted in red.  Those are packet exchanges with the WOQL Remote Base.  Clearly good contacts with excellent signal reports with time stamps between 2143Z and 2156Z.

Here is a screen snap of the Digisonde Ionogram at Boulder, Colorado at 2150Z, the same time as the contacts, showing the MUF is 18 MHz.

Any explanation?  This needs to be dug into deeper.  Is JT65 that good?  Was the MUF in South America higher at the time than it was in Boulder?  Does MUF need to be redefined?  Is it just all magic anyway?

 

September, 2017 Followup:   QST article calls this phenomenon “an above-the-MUF mode of propagation”. October 2017, page 46 by K9LA.

Successful Antenna Completion

April 15, 2016 – Tax Day and the day we got the antenna project completed just before another spring snow storm.  It looks remarkably similar to the drawings.  The relay is in a little gray box mounted on the front of the SG-230 tuner.  Radials are more visible here.

Final height is 39 feet. In the picture below notice the EF-20 vertical is now located on one of the guy poles to the left.

It was very windy ahead of the storm while we were trying to do the lift and insertion.  With one more section to go we decided the wind was putting too much stress on the upper sections and stopped before we had another catastrophe. We ended up only 1 foot below our goal of 40 feet. The project is ready for on-the-air testing and a good snow storm is always a good time to test an antenna.

Back To The Drawing Board

Some days you eat the bear and some days the bear eats you.  Success is going from failure to failure with enthusiasm.  I know. You’ve heard ’em all.  This was one of those days.  Time to redesign.   When the pole was up to about 45 degrees one of the fiberglass sections snapped.  As it came crashing down around me two more sections snapped when they hit the ground.  Three sections are broken and replacements are not available on ebay.  The picture below is NOT how it’s supposed to look.

The ladder was being used as a gyn pole raising fixture and it did it’s job very well.  Fiberglass camo poles just aren’t strong enough to lift their own weight when they’re longer than 8 sections.

Aluminum sections are the only type I could currently find on the market forcing a switch.  Ladder line won’t work inside aluminum and that dictates we switch to coax.  We’ll need a balun at the top.  More weight to raise.  Otherwise the design will stay the same. Aluminum poles are on order.  Hopefully aluminum sections will be strong enough. Work is on hold til they arrive.  Meanwhile…

Thursday, April 14, 2016 Update –  I’m having second thoughts about switching to aluminum and coax.  I’d be much happier if I could figure out how to get the original design working.  Today I found a company on the Internet that says they have fiberglass army poles.  I think fiberglass will work if I lift the pole one section at a time from the bottom like a telescoping pole.  I’ll make the mounting post taller so the top clamp holds the pole at about 5 feet above ground.  Then I can slip in the next section and raise the pole.  Repeat until the proper height is reached.  I will loosen the guys enough each time to allow raising the pole one section but not enough to allow the pole to fall over.  I tried this method for the remaining unbroken poles in the picture below and it seems to work.  It only needs 3 more sections inserted at the bottom.

Oops. I called to make sure the company that advertised fiberglass poles really had them.  They do but the shipping is $48.00.  I passed.  (After about passing out.)  Still hoping for fiberglass, I will try to repair what I can and reuse the broken sections.  Lonely and waiting for attention the half done support pole awaits.

 

 

The article below might be one reason why I had second thoughts about going to coax.  This is stolen from KV5R’s web site which I highly encourage one to visit:   http://kv5r.com/ham-radio/ladder-line/

 

Ladder Line

Copyright © 2002-2015 by Harold Melton, KV5R. All Rights Reserved.

Why Use Ladder-Line?

To efficiently feed a non-resonant multi-band antenna.

Antenna Mythology

Resonance

First, let’s dispel the greatest myth in antenna theory: Antennas must be “resonant” to be efficient. Baloney! It just ain’t so!

Please recognize that an antenna need not be resonant in order to be an effective radiator. There is in fact nothing magic about having a resonant antenna, provided of course that you can devise some efficient means to feed the antenna. Many amateurs use non-resonant (even random-length) antennas fed with open-wire transmission lines and antenna tuners. They radiate signals just as well as those using coaxial cable and resonant antennas, and as a bonus they usually can use these antenna systems on multiple frequency bands.

ARRL Antenna Book, Ch. 2

As long as the length of the antenna is at least a half-wavelength at its lowest intended frequency, its efficiency is well over 90%, just like a resonant dipole. The problem is getting power to it—coax is very lossy (due to dielectric heating) unless terminated into its characteristic impedance, and this effect is what leads most hams to erroneously believe that non-resonant antennas are inefficient. But the problem isn’t non-resonance, it’s high SWR on coax.

On the other hand, ladder-line does not suffer from high losses at high SWR, so may be effectively used to feed an antenna that may, at various frequencies, present the feed-line with any SWR from 1:1 to ~10:1. So, with ladder-line, you can completely forget about resonance and SWR, until you get to the radio, where you use a tuner to make the match to 50 j0 ohms.

To compare mismatched feed-line losses we have to start with the antenna’s feed-point impedance, and the line’s impedance, then calculate the SWR, and finally, the loss of each feed-line-type at a given frequency and length.

For a worst-case example, feeding a voltage node (like running 40 meters on an 80 meter dipole), let’s say the feed-point impedance is 3500 ohms. With 100 feet of RG-8 coax at 7 MHz, that’s a whopping 65:1 SWR, with a total loss of 78%. With 600-ohm open-wire line, the SWR is only 5.8, and the loss is 3%! Then, if we switch to 80 meters, the impedance is 50 ohms, the SWR is ~12:1, and the loss is 7%. In this case, 450-ohm line would be even better, because the SWR only varies from about 9:1 at 50 ohms to 7.7:1 at 3500 ohms. The total losses for 100 feet of 450-ohm windowed ladder-line, at 9:1 SWR, ranges from 5% at 3.5 MHz, to 14% at 28 MHz, and again, that’s at the worst-case mismatch points.

So we see that ladder-line is not only better for non-resonant antennas because of its much lower loss at high SWR, but also because its characteristic impedance places it nearer the center of the antenna’s impedance range, from lowest (odd half-waves) to highest (even half-waves).

Antenna Upgrade

This week we are installing the antenna upgrade based on earlier modelling of the so called “Compromise Antenna”.  Below are sketches to further clarify the relay-controlled High Band and Low Band operating modes.

Per the model there should be 4 dB gain on the new antenna at 15 degrees take off angle.  We terminated the guy ropes on 6′ poles to keep from entangling cattle.  This is grazing land.

 

 

Below is an ugly whiteboard snap of the relay circuit.  When the relay is relaxed the system is configured for the high bands.  When it is activated the system is configured for the low bands.  The spare position on the Remote Power Monitor provides the power to activate the relay.  It can be toggled on and off over the Internet with the Power Monitor.

 

Progress so far: Note the new camo poles are mounted on the same base as the original PAR EF-20 which is still in place. A welded wire fencing radial is visible on the ground.  This project is about half completed. Three more camo pole sections are yet to be added to get up to 40 feet. The EF-20 will be moved to one of the guy-poles so we can compare performance  between the old and new antennas.

 

 

Port Forwarding

Before we get too far ahead discussing antennas we need to address the very important subject of configuring software for port forwarding.

Port forwarding is necessary for getting through the firewall on the router at the remote site.  Otherwise when the I.P. address of the remote base is entered the packets would get blocked by the firewall.   Remote Rig is the device that needs to be reached behind the firewall.  Other devices might have been added like we did (the Remote Power Monitor ).  Entries need to be made for each device using unique port numbers.

Find the page where port forwarding is configured on your router.  On our Linksys it was under the “Applications and Gaming” button and then under “Single Port Forwarding”.  First enter the “Application Name” which is what the device will be called by.  Our Remote Rig is being called Rem Rig.  In the next column is the port number chosen arbitrarily.  You can chose any port number you want that is available. ( ISP’s block certain ports ). We chose 81 because it’s the next port after web pages ( port 80 ) and it’s not being used by other services.

In the next column the port number used by the Remote Rig is entered.  This is normally Port 80 because it is the Remote Rig’s web page. Port 80 displays the internal web page and this is what we want to access.  Here is what our port forwarding page looks like.

We also need to reach the ports used for sip and the voice packets on the Remote Rig.  Those ports are 13000 through 13009.  Those can be put in one at a time on the Single Port Forwarding Page or all at once with one entry on the Port Range Forwarding page as shown below.

 

For the Remote Power Monitor we chose the next available port number which is 82. We will forward port 82 to the Monitor’s port 80. It does not require any other ports because all the information is displayed on the Monitor’s web page.

To reach the Monitor from any place on the Internet we type in the I.P. given to us by our ISP followed by a colon and the port number.  Let’s say, for example, we had been given 72.7.12.24.  We would use our web browser and type in 72.7.12.24:82.  Up pops the Remote Power Monitor main page.

At some point we need to find out what the I.P. is that our ISP has given us.  This can be done by going into the router’s status screen and looking at the Internet or WAN address.   If the first number begins with a 10, 172, or 192 more work needs to be done.  Those are private I.P. addresses behind a firewall and you need a public address.  You must obtain a public i.p. from you Internet Service Provider and there will likely be a fee involved.  The fee we pay is $10 a month.

Although we haven’t tested it there might be a way to save the fee and get around the firewall by using proxy sites.

Earlier we found the I.P. address of the Remote Rig.  That information is located in a “dhcp table”.  The router will have a button somewhere to display the table. On our Linksys the button is located right on the front page and it’s called “dhcp reservations”.  Remote Rig was not named so we had to obtain the (12 character) MAC address from the physical label on the Remote Rig and then search for that mac address in the dhcp table.  For us the i.p. address is 192.168.3.134 (It later changed to 192.168.3.147).  Beginning with a 192 is ok here because we are on the LAN side behind the firewall and that’s where private addresses are used.

And now we’ve discussed port forwarding and hopefully shown how easy it is.

Here’s what Morningstar says about port forwarding on their web site:

There are many different router models, so we cannot provide specific direction in this document for configuring port forwarding. However, the website:

http://www.portforward.com

provides a comprehensive list of routers and instructions for port forwarding.

A Look At The Comet CHA250B Antenna

Comet Antenna, of Japan,  developed a 24 foot vertical antenna for HF that requires no radials, is multi band, and I picked up one at a recent hamfest.   How good is it?  Reviews on the Internet are mixed which means even though some people hate it others love it.  Why?

It is extremely clean looking with no top hat radials or spines or traps to break up the visual lines.  It has a mysterious matching device at the base.  Not mentioned in the sales brochure and almost buried in the instructions is an important note that might be a clue as to it’s love-hate reviews.  This antenna must be mounted a minimum of 35 feet above ground.  How many reviewers had their antennas mounted correctly at 35 feet or more? From the Comet instructions:

Aha.  The secret to this antenna is to put it ridiculously high, use the coax and mast for a counterpoise, and let the coax or the mast do the radiating.  It is marketed as a small yard solution awkwardly worded this way on the Comet web site:

“if you live in an antenna restricted area and must manage with antenna or space restrictions or you simply wish to operate incognito you will be forced to make significant antenna compromises. The CHA-250B will make the most of these circumstances!”

A 35 foot mast with a 24 antenna adds up to 59 feet tall.  Does a 59 foot vertical equal incognito?

Enough of the negativism.  One must get past the surprise of the height requirement and just think of this is as a 59 foot vertical antenna.  The Comet CHA250B is a 59 foot vertical.  How does it model in EZNEC?   Will it work some DX?  Our reference antenna is a full size quarter wave ground mounted vertical with lots of radials over average soil.  We care most about the gain at a take off angle of 15 degrees and secondly how “full” the pattern is.  That is, does it have serious nulls that would compromise operation. Here is a view of the antenna with rf current modeled at 14.1 MHz.

Let’s run through the bands and I’ll make comments starting with the toughest of all, 160 meters.  A gain of 0.77 dBi on 160 is quite respectable.  And there are no nulls.  Nice.  This should work some DX on top band.  This is roughly equivalent to a full size quarter wave vertical. HOWEVER, I’d be skeptical of a model showing a 24 foot antenna having a .77 dBi gain on 160.

Next band up is 80 meters which often proves to be the hardest band when it comes to 5BDXCC.  The pattern here looks good, too, with -0.21 dBi.  Again, I am skeptical of the model.

Now for the esoteric band, 60 meters.  Pretty good again. Very usable.

How does it do on one of the most popular bands, 40 meters?  Can a person work some DX here?  Yes, as long as the band has gone long, very long.  This band has one of those dreaded serious nulls above 30 degrees and stateside signals will be missing.  No NVIS either.  A person will need a separate 40 meter antenna to work domestic stations.  On the other hand interference from strong U.S. stations should not be a problem when working DX.  This is the first band where the pattern is not ideal.

Moving on up through the bands, next is 30 meters, the first WARC band so far.  The pattern looks good here.  Good gain at 15 degrees and a nice plump pattern the rest of the way.

The big one, in fact the biggest one for working DX, the 20 meter band.  How does it look?  It’s not equivalent to a beam but it holds it’s own against a quarter wave vertical. It also has plenty of plumpness for higher angles, too.

Now for the upper bands beginning with the WARC band, 17 meters.  Wow, even a dB of gain here.  A little disappointing above 45 degrees but otherwise a usable band. Critical frequency never goes this high to allow NVIS contacts on this band, anyway.

Now we’re getting into what our grandparents called Ultra High Frequency, 21 MHz. How does it do?  Fine.  Like the 17 m band, we don’t have much high angle radiation but in the low angles used for DX it looks good.  And it has 2 dBi gain even.

Skipping 12 meters because we assume it will behave the same as 10 meters, here is a look at the “light” band (from the phrase, “DC to light”).   Ten meters is a very usable band on this antenna on the rare occasions the band is open.  Rooster tails are almost ready to appear but they haven’t yet.  Therefore no serious nulls. In addition we have almost 2 dBi of gain.

Overall it would be reasonable to assume this is a good multi band antenna usable for both DX and domestic contacts on almost all bands.  How in the world we can erect this at 35 feet is questionable.  The author’s or translator’s grasp of English is not strong as indicated by the use of the word “erectric” instead of “electric”.  Could it be that the author does not have a grasp of the measurement system and he (or she) actually means 35 centimeters or something else?  An attempt to find a copy of the instructions written in Japanese failed.  The thought was maybe there had been a failure in the translation if we could find the original instructions.  We will attempt to put this antenna up at 35 feet and see how it plays.  At that height it’s hard not to play well.

 

 

 

 

 

Happy Sunday

Finally the stars have aligned and we are having a happy Sunday afternoon watching the DX come in on 20 meters and seeing our signals posted over a large part of the world. This is only on 20 meters because we are still using only the PAR/LNR EF-20 end fed half wave vertical while we ponder antenna improvements.