Tuesday, April 29, 2014

Simple Ham Radio Antennas: A 5/8 wavelength vertical ground plane. Post #272

According to Edward M. Noll (W3FQJ), "The 5/8-wavelength vertical is a preferred length for the best low angle radiation."  For the higher HF bands (20 through 10 meters), this antenna is easily assembled and requires a small quantity of wire, some ceramic insulators, a suitable mast, 50-ohm feed line or 450-ohm feed line, a simple ground radial system, and a sturdy antenna matchbox or ATU.  Multiband use between 20 and 10 meters is possible with 450-ohm ladder line, ATU, and a balun, while good single band use can be obtained with 50-ohm coaxial cable and an inline or base antenna "tuner".

So, let's build a simple 5/8 wavelength vertical for the 10 meter amateur radio band, centering on 28.4 MHz.  This frequency is at the mid-point of the SSB allocation for Technician Class licensees.  The antenna was built at my new home in the Puna District on 18 April 2014.


Using the general formula, 585/f (MHz)=L (ft), our vertical element will measure out to 20.59 ft/6.28 meters.  I rounded the length to 20 feet, 7 inches.  Each of the four slanting radials will be a 1/4 wavelength long or 8.23 ft/2.51 meters.  I rounded off the length to 8 ft, 3 inches.  I used some spare #22 AWG hookup wire for the antenna elements and the radial system.

Four ceramic insulators and nylon rope to tie off the radials.

Five, 5-ft/1.52 meters wooden stakes.  One stake would support the fiberglass mast and the four remaining stakes would support the slanting radial elements.

One 33-ft/10.06 MFJ telescoping fiberglass mast.

One "ladder lock" center connector to support the 450-ohm feed line.

50-ft/15.24 meters of 450-ohm ladder line.

One W9INN 4:1 current balun.

One Drake MN-4 antenna transmatch.

Station equipment:  patch panel in the shack window, low-pass filter, Heathkit Dummy Load, Ten-Tec Argosy II transceiver, solar charged battery power supply, microphone, key, log, miscellaneous connectors, several 3-ft/0.91 meters RG-8X patch cords with UHF connectors, and a "counterpoise" bundle consisting of 1/4 wavelengths of wire for 20, 15, and 10 meters.  The bundle will be connected to the ground lug of the Drake MN-4 antenna transmatch.  I also have a station ground consisting of a 8-ft/2.43 meters long ground rod connected to four 33-ft/10.06 meters buried radials.

Nylon ties, nylon rope, tacks to secure the 450-ohm feed line to the garage wall, and various tools.


The antenna was built on the ground a later raised into position.

I attached the vertical element to the tip of the MFJ mast and ran the wire to a point approximately 12-ft/3.65 meters above the base of the mast.  The wire was secured to the mast with nylon ties and vinyl electrical tape.  Each radial segment was attached to a ceramic insulator.  A small length of nylon rope was tied to each insulator.  This rope would be used to tie off the radial wires to  nearby wooden stakes.

At the 12-ft/3.65 meter point of the mast, I attached the "ladder lock" device and threaded the ladder line through the appropriate holes in the connector.  One lead went to the vertical element, while the other lead went to the four sloping radials.  All connections were soldered and covered with several layers of vinyl electrical tape.

I carefully hoisted the fiberglass mast onto its support stake.

I then spread out the sloping radials in a uniform pattern (every 90 degrees) and secured each radial to a pre-positioned 5-ft/1.52 wooden stake.  The ladder line was led off from the mast at a 90 degree angle and attached to the outside shack wall.  Even with a little sag in the line, the feed line was kept approximately 10-ft/3.04 meters above ground, well out of the way of children, visitors, and pets.

The ladder line was connected to the wall mounted W9INN 4:1 balun.  Three-feet/0.91 meters of RG-8X coaxial cable ran from the balun to the patch panel in the shack window.  A 6-ft/1.82 meters length of RG-8X coaxial cable with UHF connectors ran from the patch panel  to the Drake MN-4 antenna transmatch.  The Argosy II, low-pass filter, and the Heathkit Dummy Load were interconnected with 3-ft/0.91 meters lengths of RG-8X coax with UHF connectors.  A "counterpoise bundle" was attached to the ground lug of the ATU.


With the Drake MN-4 in the system, I was able to keep swr below 1.3 to 1 throughout  the entire 10 meter band.  Running approximately 15 watts from the old Argosy II, I got excellent cw reports of 579 to 599 and ssb reports of 56 to 59, depending on the time of day.

With a little careful tuning, the 5/8 wavelength 10 meter vertical can do an acceptable job on 20 and 15 meters--better if additional wire is added to each radial wire for those bands.  Ed Noll adds that "a vertical cut for 5/8 wavelength on 10 meters has an electrical length not too much shorter than this value on 15 meters, and it functions as a quarter-wave on 20 meters with just a little base loading."  Although what he says is generally true, I decided to keep this antenna for 10 meters only and not stress the old Drake MN-4 too severely.

As a side note, you can also use this antenna (with a "tuner") to work CB channels as well.  Many families in my new neighborhood have CB transceivers and I sometimes use an old Radio Shack TRC-23 CB set to talk with nearby families.

This was a fun and inexpensive project.  According to some antenna experts, you can expect a 3dB gain over a 10 meter dipole with this 5/8 wavelength vertical.


Noll, Edward M. (W3FQJ). 73 Vertical, Beam, and Triangle Antennas.  Editors and Engineers, Indianapolis, IN, 46268.  Seventh Printing, 1979.  pp. 34-35.

Orr, William I. (W6SAI) and Cowan, Stuart D. (W2LX)).  The Radio Amateur Antenna Handbook.  Radio Publications, Inc.  Box 149, Wilton, CT, 06897.  First Printing, 1978.  pp. 108-109.



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Aloha de Russ (KH6JRM)
Along the beautiful Hamakua Coast of Hawaii Island.
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Monday, April 14, 2014

Simple Ham Antennas: The Novice 40 meter delta loop. Post #271

During that brief period between getting my novice amateur radio license and moving on to the technician and general class license (1977-1983), I built several dipoles, inverted vees, and verticals.  All of these antennas worked very well, considering the lack of space I had at the time.  When my xyl and I moved from Honokaa to Laupahoehoe, we occupied a larger home and had more backyard space to place antennas.

Just before I passed the Advanced Amateur License exam, I built what I considered my best and "most forgiving" antenna--a full-wavelength 40-meter loop.  The loop displayed some gain over a dipole at the same height, needed only one tall support, and didn't require a ground radial system to operate efficiently.  Using balanced feed line, a 4:1 current balun, and a Drake MN-4 transmatch, I could cover 40, 20, 15, and 10 meters with one antenna.  Later on, when 30 meters became available to amateur radio operators, I used a MFJ-941-E Versa Tuner II and my spare rig (Ten-Tec Argosy II) to cover 30 meters.

Last weekend, I decided to recreate that first "novice" loop just to see if it was a good as I once thought it was.


Fortunately, all of the materials for this loop project were available on site.  Based on what I found in my antenna notebooks for 1979, I began to revisit this old friend who sat beside me on those damp tropical nights while I "pounded the brass" in the QRM-infested frequencies of the 40-meter band.

Design frequency:  7.127 MHz--one of the novice hangouts "back in the day."

Antenna:  Full-wavelength 40-meter delta loop.  Using the general formula 468/f (MHz)=l (ft), I came up with a length of 141 ft/42.98 meters).

Antenna wire:  I had three rolls of Radio Shack #18 AWG speaker wire in the shack.  That wire would serve as my antenna.

Three ceramic insulators--one for the top of the delta loop and the other two for securing  the corners of the loop.

One 33-ft/10.06 meters MFJ telescoping fiberglass mast.  The mast would support the apex of the loop.  Back in the late 1970s, I made a homebrewed 33-ft/10.06 meters mast out of pvc pipe.  This time, however, I decided to use the fiberglass mast to support the loop.

Five, 5-ft/1.52 meters wooden stakes--one to support the mast, two to support the bottom section of the delta loop, and two to keep the balanced feed line off the ground until it reached the wall of the shack.

One W9INN 4:1 balun.  The balun would be attached to the outside shack wall and would serve to interface the balanced feed line with the ATU.

Fifty-feet/15.24 meters of 450 ohm ladder line. This would serve as the antenna feed line.

Four alligator clips.  Two would be attached to the delta loop at the left hand, bottom corner, and two would be connected to the leads of the balanced line. I could connect and disconnect the feed line easily in the event of storms or other emergencies.

Twenty-five ft/7.62 meters of RG-8X coaxial cable with UHF connectors, which would run from the 4:1 current balun through a small hole in the window patch panel and onto the Drake MN-4 ATU or MFJ-941-E Versa Tuner II.

Small lengths (3-ft/0.91 meters) of RG-8X coaxial cable to interconnect the rigs (Swan 100- MX/Ten-Tec Argosy II), the Heathkit Dummy Load, and the low-pass filter to the ATU being used.

Various lengths of nylon tie off rope, nylon ties, vinyl electrical tape, and basic tools.


The full-wavelength loop was built on the ground and later raised into position.

The length of the delta loop was calculated for a frequency of 7.127 MHz.  The 141-ft/42.98 meters antenna wire was shaped into a equilateral triangle, measuring 47-ft/14.329 meters per leg.

Three ceramic insulators were used for the delta loop--one for the apex of the mast, one for the bottom right hand section of the loop, and one for the left hand bottom section of the loop.  Once I threaded the two free ends of the loop through the bottom left hand insulator, I soldered a small alligator clip to each end.

I soldered two small alligator clips to the end of the 450 ohm ladder line that would be attached to the loop clips as they passed through the bottom left ceramic insulator.  The feed line then could be connected/disconnected as conditions warranted.

I pounded in three, 5-ft/1.52 meters wooden support stakes.  One would support the fiberglass mast, while the other two would be spaced 47-ft/14.329 meters apart to accommodate the bottom leg of the delta loop.
With each support stake sticking 4-feet/1.21 meters above ground, there would be some space separating the bottom element of the loop and its connection to the 450 ohm feed line from the surface of the lawn.

I carefully hoisted the fiberglass mast onto its support stake, tied off the corners of the loop with nylon rope, and adjusted the loop for a uniform appearance.

I next drove in two more 5-ft/1.82 meters wooden support stakes to support the ladder line as it was taken to the 4:1 current balun on the wall outside the shack.

I connected the clip leads from the feed line to the clip leads at the bottom left hand corner of the delta loop, led the ladder line away from the left hand corner of the loop, connected the ladder line to the pre-positioned wooden support stakes (keeping the ladder line 4-ft/1.21 meters off the ground), and finally connected the end of the ladder line to the 4:1 balun on the outside wall of the shack.  The balun was approximately 6-ft/1.82 meters above ground level.

Twenty- five feet/7.62 meters of RG-8X with UHF connectors was attached to the balun and run through the patch panel and onto the Drake MN-4 transmatch.  To be on the safe side, I attached a "counterpoise bundle" to the ground lug of the Drake ATU.  The bundle consisted of a quarter-wave length piece of #22 AWG hookup wire for 40, 30, 20, 15, and 10 meters.


I was very pleased with the initial results of my old "novice" 40 meter loop.  With the Drake MN-4 and the MFJ-941E Versa II tuner in line, SWR across all bands was held below 1.1 to 1.  If you prefer to use this antenna for 40 meters only, a feed line made from 50-ohm coaxial cable and a 75-ohm matching section should serve you well.  Since I preferred to use the loop as a multiband antenna, I opted for the 450-ohm feed line used in conjunction with a 4:1 current balun and an ATU.

Local and DX contacts over the past few days have been excellent, with daytime 40 meter reports ranging from 56 to 59+ on SSB and 579 to 599+ on CW.  Twenty meters has been quite good, with signal reports ranging from 57 to 59 for SSB and 579 to 599+ for CW.  I was using the Ten-Tec Argosy II running around 30 watts.  Of course, results may vary depending on time of day and proximity to structures.

I plan to keep this antenna up for awhile, because it's so fun to use.  I may even add a director or reflector to increase its gain.  And best of all, the antenna was cheap, required no ground radial system, and needed only one tall support.





The recent ARRL Antenna Handbook also contains a good discussion of loop antennas.

You can also search for more information on the internet by referring to "Delta Loop Antennas".

Thanks for joining us today!  You can follow our blog community with a free email subscription or by tapping into the blog RSS feed.

Until next time,

73 de Russ (KH6JRM)

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.

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Wednesday, April 9, 2014

Simple Ham Radio Antennas: Time to head for the radio basement? Post #270

Those of you who follow my Amateur Radio News Blog (http://kh6jrm.com) on a regular basis may be aware of two related radio stories that will have a significant impact on the future of amateur radio and the rf spectrum that we share with other services.

The first article relates to comments made by FCC Chairman Tom Wheeler at the annual NAB convention today in Las Vegas, Nevada. In his speech before NAB delegates, Wheeler urged television broadcasters to abandon over-the-air transmissions in favor of streaming over the internet.  Wheeler says the migration to broadband internet would free up spectrum for the ever increasing demands of consumer electronics, from cell phones and iPads to mobile radio and other public services.  Already, VHF analog channels between channels 2 and 13 have moved to higher frequencies and now employ digital signals.  The now vacant channels won't remain idle for long, since these VHF allocations will be assigned to other services. The gradual appropriation of frequencies above 450 MHz for other users is continuing as consumer demand for broadband services grows.  Amateur Radio is just one of the services that could be impacted if the FCC decides to reassign frequencies shared by hams with other services such as the U.S. military.

The second article concerns the loss of amateur radio assignments in the 2.3 GHz and 3.4 MHz bands, which Ofcam (the UK equivalent of our FCC) has reassigned to what is called "new civil uses" in the UK.  Amater radio is a secondary user along with the military on these bands.  On 07 April 2014, the UK Ministry of Defense released 40 MHz of spectrum at 2.3 GHz and 150 MHz of spectrum at 3.4 GHz for other services, including broadband coverage for cell phone, internet use, and public service agencies.  Some of these new allocations will affect amateur radio frequencies between 2350-2390 MHz and 3410-3475 MHz.  The tiny slivers left of this spectrum will be assigned for amateur radio use by special permit only.

The object of these two seemingly unrelated articles is clear:  Amateur Radio is being excluded from bands above 70 cm (450 MHz) to make room for the anticipated expansion of Wi-Fi and other broadband carriers.  The amateur radio bands are being compromised  under the names of consumer demand and expediency.

This is a battle Amateur Radio will lose.  Why?  Simple:  money talks.  These UHF and SHF bands are worth millions to commercial interests.  The taxes alone will generate much needed revenues for cash-strapped governments.

This scenario reminds me of the spectrum battles fought by the ARRL and other amateur radio societies after World War I when the U.S. Navy and various corporations vied for control of the airwaves.  Thanks to the work of the ARRL and ham volunteers, the tide was turned.  A good account of this battle is contained in Clinton De Soto's book "200 Meters and Down."  It appears history is repeating itself.

Perhaps, amateur radio enthusiasts will be given the "radio basement" (VLF and MW) where radio once began.

Perhaps, the FCC is encouraging  amateur experiments and licensing below 500 kHz to prepare hams for the day when they will lose much of their current primary and shared rf spectrum to what ARRL cofounder HIram Percy Maxim called "The Commercial Interests."

Who knows? With the loss of international HF shortwave broadcasting, the loss of public support for MW AM broadcasting, and the new amateur radio allocations between 472 and 479 kHz, ham operators may find a "gold mine" in those soon-to-be abandoned MW and HF frequencies in the years ahead.

So, it may be a good idea to keep that HF rig and that simple 2 meter/70 cm HT around the shack.  These may be the only rigs operable on the realignment of frequencies that surely lies ahead.

In my less than humble opinion, all the efforts by UK amateurs to maintain their shared frequencies at 2.3 GHz and 3.4 GHz may have been in vain.  There's obviously profit to be made in withdrawing amateur radio frequencies and giving them to various public users.  As good as the ARRL and RSGB legal teams are, they will not be able to withstand the offensive from the broadband and internet industry.  Couple this trend with the growing opposition to antennas from HOAs and CC&Rs and you have a real mess on your hands, especially where emergencies occur.  When an emergency happens, you can count on our sophisticated cell phones, tablets, and iPads to give out when commercial power dies.  It may be trite, but the phrase "When all else fails, there is Amateur Radio" still rings true.

So, what do we as amateur radio operators do?  Keep operating on the frequencies and bands we do use. The old saying, "use it or lose it" comes to mind.  Be sure your local amateur radio club has a good relationship with civil defense and first responders in your community.  Have memoranda of understandings in place and be sure hams are included in emergency preparation plans.  Get trained in CPR, First Aid, and Emergency Response procedures so you will be viewed as a valuable human resource.  Become part of an ARES (Amateur Radio Emergency Service) group and get the necessary FEMA certifications.  Stay in contact with local, state, and national political leaders and keep them appraised of the community service you and your amateur radio club give to your community.  Work with local county and city councils to moderate antenna restrictions in your area.  And finally be prepared for emergencies.  Have a "go kit" in your home and vehicle.  Stay positive and proactive about amateur radio.  Do interviews with local media to spread awareness of amateur radio and the service it renders to our neighborhoods.  When I worked at a commercial broadcast station, I encouraged amateur radio clubs to come into my news studio for interviews and public service programs.  Finally, let all of us work together to preserve the operating privileges we do enjoy.  That means we must support the ARRL, RSGB, RAC, and the other amateur societies around the world in their efforts to protect our small slice of the rf spectrum.

The FCC and Ofcom have made it very clear:  Unless you can demonstrate a reason for using the rf spectrum, your portion of the radio pie will be auctioned off to the highest bidder.  All of that broadband space must come from a limited rf spectrum.  And three guesses where that easily available space will be found.  You guessed it--from the spectrum now used by the military and its shared users, including amateur radio.  We are seen as "easy pickings" by some.  Don't become a spectrum "victim".  If we don't get our act together, we're headed for the VLF and MW radio "basement."  It may be time to restore that old tube or hybrid HF rig, build a 472-479 kHz rig, and learn how to wind large induction coils for that VLF antenna.  We've been warned...it's time to act.

You can find the FCC and Ofcom articles by visiting my Amateur Radio News Blog at http://kh6jrm.com.

You can follow our blog community with a free email subscription or by tapping into the blog RSS feed.

Aloha es 73 de Russ (KH6JRM)

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.
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Saturday, April 5, 2014

Simple Ham Radio Antennas: The Ghost of Antennas Past--the simple vertical. Post #269

Over the past few posts, I've been describing some of the antennas I designed, built, and used during my days as a novice amateur radio operator (1977-1978).  Most of the working designs were copied into school theme books and saved for future reference.

One of my favorite homebrewed antennas was a simple vertical  antenna supported by a high tree limb terminating with a slightly angled ground plane consisting of 10 radials.  The antenna was designed for 40 meters and worked very well for contacts throughout the Pacific Rim and the mainland United States.

Last weekend, I decided to duplicate that antenna with some spare wire, ceramic insulators, coaxial cable, and basic tools.

As mentioned earlier, the process of moving to a new home often uncovers items you once thought were lost.  Such was the case here when I found several 50-ft /15.24 meters rolls of #14 AWG house wire in the garage.  That wire would serve as the vertical element and the rudimentary ground radial system.

To function properly, vertical antennas need a  radial system to supply "the missing half"of the antenna were they to be used as ordinary dipoles.

Fortunately, I had several tall Norfolk Pine trees in my back yard that could support a vertical wire.


My first vertical was cut so that I could operate cw on the lower portion of 40 meters (below 7.100 MHz) and the upper portion of 15 meters phone (approximately 21.240 MHz).  I wanted to save this antenna for when I became a general class licensee, so, by cutting the antenna for this length as a novice, I expected some SWR on the antenna.  When I added my Drake MN-4 transmatch to the system, the SWR was easily accommodated.

The 40 meter vertical antenna was built on the ground and later raised into position by a length of nylon rope.

My chosen design frequency was 7.088 MHz, the "watering hole" for many Hawaii amateur radio nets.  Using the general formula 234/f (MHz)=L (feet), I cut a length of #14 AWG wire measuring 33.01 ft/10.06 meters.  This would be the vertical element.

I also cut 10 pieces of #14 AWG wire for the radial system.  Although some antenna experts recommend that radials be cut approximately 5% longer than the vertical element, I decided  to follow my original plans and cut each radial wire to match the length of the vertical element (33.01 ft/10.06 meters).

I had 50-ft/15.24 meters of RG-8X coaxial cable with UHF connectors in a plastic storage box.  The coax would serve as my antenna feed line.  I also had a spare Budwig HQ-1 center coax connector to attach the feed line to the vertical element and the radial screen.

To support the vertical element and to terminate each radial wire, I found a dozen ceramic insulators in the junk box.  I would use one of the  11 insulators to secure the top of the vertical to a tree limb and the remaining insulators to tie off the radial elements to nearby tree limbs.

I had 100-ft/30.48 meters of nylon rope with a fishing sinker attached.  The rope would be attached to the insulator at the top end of the vertical element and shot over a convenient tree limb, taking the vertical element high into a notch approximately, 40-ft/12.19 meters above ground.

Once I had all the wire laid out on the ground, I soldered the vertical element to the + terminal of the center connector and soldered the radial wires to the - terminal of the center connector.  All joints were covered with several layers of vinyl electrical tape.

I attached a ceramic insulator to the top end of the vertical segment and to the free end of each of the 10 radial wires.

Before I attached the RG-8X coax to the center insulator, I made a 6-turn "choke balun" from the coax measuring approximately 8-in/20.32 cm in diameter. The coil was held together by nylon ties.  The coax was then attached to the center coax connector.

The nylon rope with sinker attached was tied to the insulator at the top end of the vertical element.  I then shot the rope over a limb about 40-ft/12.19 meters above ground level.  I slowly pulled up the vertical element into the tree notch.  The remaining part of the rope was secured to a nearby tree, so that the vertical segment stood straight up and down from the tree branch.  I made sure that the radial wires didn't get tangled as I lifted the vertical element into place.

The bottom of the vertical element was approximately 7-ft/2.13 meters above ground.  I then led each radial wire off from the center connector at a slight angle and tied off the end insulators to nearby trees or rocks.  The antenna resembled a low angle ground plane.

I fed the coax feed line through the nearby trees to the patch panel in the shack window.  A 6-ft/1.82 meters piece of RG-8X coax led to the Drake MN-4 antenna transmatch.  Short patch cords made from RG-8X interconnected the transmatch to the transceiver (Ten Tec Argosy II), dummy load, and low-pass filter.

I also connected a 33-ft/10.06 meter counterpoise wire to the ground lug of the Drake MN-4 transmatch.


Without the Drake MN-4 in the line, the SWR across the 40 meter band measured 1.5 to 1.  The SWR on 15 meters was a bit higher at 1.9 to 1.  With the transmatch in the line, I was able to get the SWR near 1.1 to 1 on both the 40 and 15 meter bands.  Although I could load the antenna on 20 and 10 meters with the Drake MN-4, I decided not to strain the old ATU anymore than necessary.  For 40 and 15 meters, the antenna worked very well, just like its predecessor back in 1977.  The antenna can be converted into a multiband antenna with the use of 450 ohm ladder line and a 4:1 current balun attached to the Drake MN-4.  I received good signal reports from both Hawaii and mainland U.S. stations.

This simple, inexpensive antenna was easy to build.  When I was a "wet behind the ears" beginner in amateur radio, this antenna delivered many enjoyable hours of excitement and discovery.




http://www. dxzone.com/catalog/Antennas/Vertical.



Thanks for joining us today!

You can follow our blog community with a free email subscription or by tapping into the blog RSS feed.

Aloha es 73 de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.

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