The MINI (1/4th) W3EDP – A Special Design for a Balcony Down South

Much as any boat, a radio-amateur antenna design is always a compromise between performance (efficiency, in the case of an antenna) and what is possible and feasible or even convenient and available.

In CX-Land (Grid Loc.: GF25id), using callsign CX7RT, I operate /QRP/P mostly from a small balcony in a 4rd floor apartment (facing NW). My preferred antennas there have been the Alexloop and end-fed dipoles. With the aid of a small (2.40m long) “Tacuara” (a local bamboo-like cane of just the perfect size, found in the flotsam at the beach) I have been rigging, as inverted “V’s”, PAR EndfedZ dipoles for the 10m or 15m bands spanning the entire front of the apartment (5.7m). The maximum wire length for this arrangement is abt. 7m.

During last summer up North, I have explored the use of a portable wire multiband antenna not requiring counterpoise wires on the ground: the 10-80m W3EDP ( The W3EDP is 85′ long, which limits its deployment in small quarters. In an effort to further adapt its concept for operation in restricted areas I proposed the W3EDP “Junior” (a 1/2 version of the full W3EDP) and have used it with success as a stand-alone vertical ( and as an inverted “V” in the standing rigging of a small boat (

It did not escape my attention that a 1/4th version of the W3EDP would be 21 feet long (6.4 meters), i.e., almost the perfect length for an inverted V spanning the front of CX7RT’s apartment. All that was needed was a piece of thin wire 16.75 Ft. long, a twin-lead leftover 3.5 Ft. long, some connectors, a few pieces of shrinking tubing and some soldering and voilà: the Mini W3EDP was already wrapped in “eight’s” around a Staedtler HB2 pencil, ready for the trip down South.

Similar to its two bigger sisters, the Mini requires a tuner (I use the Elecraft T1 remote) and in theory, because of the high impedance of the parallel transmission line, it also requires a 4:1 unun. Between the unun and the coaxial I’ve been adding a toroidal choke to prevent any possibility of common currents.

In theory this mini version of the W3EDP should also have some interesting behaviour in several of the bands. Any W3EDP-like antenna can be viewed in three different ways: a) as a single wire end fed via a parallel line 1/4th its length, b) as an end-fed wire with a single counterpoise 1/5th its length juxtaposed to its proximal section or c) as a wire antenna fed off-center at 1/6th its length from one of its ends with both arms also juxtaposed. Depending on each of these views the antenna could be resonant in different frequencies. According to a) the Mini W3EDP may correspond to a full WL in 10m, and Half a WL in 20m; according to b) it may be a full WL in 12m and 3/4 WL in 17m; and according to c) it might be a WL and a half in 10m, a full WL in 15m and 1/2 WL in 30m. The following graph obtained with the Mini-VNA antenna analyzer directly from the 4:1 unun (no choke or coax) shows that the antenna resonates best close to the 10m band (SWR=1.5:1; Z=35 Ohms) and that SWR values (without tuning) remain below 50:1 throughout most of the HF portion of the spectrum (SWR:green; Z:blue):

Mini W3EDP.jpg

Does it work? Well… a multi-element Yagi-Uda it is not… but the Elecraft T1 tuner does readily tune it in all bands from 80m to 6m at SWR values of less than 1.5:1. Also, in the recent CQ WW RTTY it allowed the logging of 21 QRP contacts (several of which have already been confirmed in eQSL and/or LoTW): 16 in the 15m band and 5 in the 20m band. Five of the QSOs in 15m were transcontinental: 2 in Europe and 5 in North America. All these QSOs have been posted in ( and uploaded to LoTW and eQSL. Given current propagation conditions, particularly in the high bands (SFI<90) most of the credit has to go to the QRO stations contacted. However, some credit ought to also be given to the brave Mini W3EDP.

And yes, in the picture above, the blue spot between the big hotel on the right and the white building on the left is the Río de la Plata (River Plate)… Here is a better view of it from the top of the Pan de Azúcar (Sugar Loaf), which I climbed just to take this picture. CX7RT’s QTH is right in the middle, to the left of the white tall building, and the point at the left is “Cape Joy”, thus named by Sir Francis Drake during the circumnavigation of the “Pellican” (later renamed as “Golden Hinde”). According to Michael Turner who retraced Drake’s world voyage (see: “In Drake’s Wake – Volume 2 – The World Voyage” by Michael Turner, Paul Mould Pub., First Ed. 2006): “Cape Joy is the headland under which nestles the town of Piriapolis.”





Alchemist “Energies” and Poor HF Path Prediction in the South Atlantic


When the Uruguayan tycoon Francisco Piria (1847-1933) undertook the creation of a seaside resort at the image of those in the Italian Riviera (where he had spent part of his youth) he insisted that the area he had chosen for it in Maldonado had “special energies”, something that befitted well both his alchemist ideologies and his real-estate marketing genius. However, though unknown to him, perhaps there was some justification for those ideas.

The name that Francisco chose for his resort was “Heliopolis”, but it has been known since as “Piriápolis”. Within a few days CX7RT will be back in Piriápolis (where he spent part of his youth). From his QTH there (GF25id) CX7RT likes to probe the HF bands with QRP/P signals and small wire antennas. In the past three years and in as many months he has logged from there short of 300 QRP/P QSOs ( However, he noted that HF propagation predictions (using VOACAP) have not been too helpful in determining the best conditions for DX skeds and QSOs. Here is a possible reason: Piriápolis as well as all Uruguay and large portions of Brazil and Argentina, are within the “South Atlantic Anomaly”, a large and growing patch on the surface of the Earth with low strength in the geomagnetic field due to the fact that in that zone the axis of the magnetic dipole of the Earth is furthest away from its surface (

As a result, in this part of the South Atlantic, the Van Allen Belts (toroidal-like pockets of charged “high-energy” particles held around the Earth by the geomagnetic field) are closer to the surface of the Earth – (would modern alchemists wish to argue that this proximity of the Van Allen Belts might have been the source of the “energies” invoked by Francisco…?). In this zone the inner Van Allen Belt reaches as close as 200 Km from the Earth surface instead of the 500 Km of its general altitude elsewhere.

Also, normally, the inner Van Allen Belt touches the outside of the F2 layer (the main layer responsible for the retutn to Earth of HF electromagnetic waves). However, within the “South Atlantic Anomaly” area it reaches underneath it and its relation with the F2 layer is inverted ( The general opinion seems to be that this condition does not affect HF propagation ( However, this seems difficult to visualize given the above considerations.

Stefanus Jansen van der Merwe, in his superb Master dissertation thesis (University of Pretoria, 2011) entitled “Characterisation Of The Ionosphere Over The South Atlantic Anomaly By Using A Ship-Based Dual-Frequency Gps Receiver”  ( states that “The abnormal behaviour of the ionosphere makes inter-continental high frequency (HF) propagation difficult to predict over this region.” He provides data showing that HF paths predicted on the basis of electron density maps generated from mobile GPS observables are better than those based on the IRI model (, which does not appear to be “well defined for the southern hemisphere” because of the lack of enough ionosonde data for the area.

Therefore, the “South Atlantic Anomaly” might affect HF paths more than is usually accepted and current HF path predictions may be less reliable in this area than in other parts of the World. Given the geographic span of the “South Atlantic Anomaly”, it is more likely to affect HF path predictions for stations within its boundaries, namely South America and South/West Africa. Hence, if you fail to hear CX7RT’s signal from Piriápolis, it could be because of its QRP nature and/or his use of small wire antennas. However, it could also be due to the “South Atlantic Anomaly”, something that may not be completely accounted for in HF propagation prediction models, and – who can say…? – which could also be contributing to  the local “energies” that make Piriápolis such a compelling place…



Because She and I Still Can


On September 6, after four hectic days (one for cleaning the garage and making room for the boat stuff, another emptying the boat an bringing all the gear home, a third removing the sail and bringing the dinghy to the garage, and a fourth to get the trailer, haul the boat out of the water, remove the motor from the bracket, retrieve the fenders at the dock, tow the boat to the yard and snug her under her tarps) Sassy Gaffer was once again on the dry, ready for the Winter. Normally she would have stayed afloat for another one or two months, but a pending trip down South forced an earlier date for a last visit to the ramp.

In spite of the many things that could have gone wrong, only one did: while disassembling the hinge at the base of mast (to remove the slugs at the luff from the track and fold the sail away), the top of the mast slept forward from the gallows bracket braking beyond repair the lens of the anchor light. The original lens was an Aqua Sail Series 25 Standard all-around lens and a replacement was quickly found at the local chandlery. While the brand, the model and the size were a perfect match to the original, the position of the notches for anchoring the lens to the base of the light did not (go figure!). So next season the base of the light will also have to be replaced.

This season, Sassy was launched on May 11 but did not get her sail until May 20. She was provisioned on the 26 and on May 27 she had the first sail up-river. One week later, on June 3rd and 4th was the second sail upriver for a first overnight and “portable afloat” at “Horaceville”. Two weeks later, on June 17 and 18, was her third sail upriver and second overnight, this time on the lee of Aylmer Island. This trip included the activation of the island (CIA ON-295) as well as its historic lighthouse (ARLHS CAN-897). The fourth sail was on July 14 sailing together with “Bay Hen” in the context of the Small Boat Messabout. August 19 and 20 was the fifth sail up-river, to Pinhey Point, for a third overnight at the anchor and an initial deployment (vertical) of the W3EDP Jr. antenna. Two days later, at the marina, the same antenna was successfully tried as an inverted “V” using the spars of the boat. And on August 27 took place the sixth and last sail of the season, to be “self-marooned” in Aylmer Island and participate in the W/VE Island QSO Party.

Hence, after 119 days afloat, “Sassy” was away from her dock for nine days, with three full nights spent swinging at the anchor.

– Why?, you may ask…
– Because she and I still can…

Another CXpedition

From September 15 to October 20 2016, VA3PCJ, VE3DTI and VE7PCJ will be in CX-Land, hosted by CX7RT at GF25id. They hope to be QRV/QRP on occasions and contribute to CX7RT’s effort in the CQ WW RTTY. For skeds, please contact VA3PCJ (but don’t hold your breath given current propagation conditions).


A Duck in a Mad River Party in Ohio

A year ago (August 22 2015, to be more precise) VA3PCJ paddled his inflatable Sevylor “Rio” to Upper Duck Island (FN25el), set on qualifying the island for the Canadian Islands Activators (CIA) program.

August 22 2015 was also the date that the Mad River Radio Club had set for the 2015 Ohio QSO Party.

In order to attain qualification, receive a number and be included in the database of the CIA program, 25 QSOs had to be logged operating from the island.

Of the 33 QSOs that VA3PCJ logged that day from Upper Duck Island, 27 were made in the context of the 2015 Ohio QSO Party.

That same day Upper Duck Island became “ON-296” in the CIA database.

A year later, the following certificate was received from the Mad River Radio Club:

OHQP 2015 Certificate

Self-Marooned in an Island with only a W3EDP and a KX3

On Saturday August 27, 2016, in addition to the regular and occasional stations on the air, several radio amateur contests were raging simultaneously in the High Frequency portion of the spectrum all over North America: Kansas QSO Party, OHIO QSO Party, Hawaii QSO Party, YO DX HF Contest and the W/VE Islands QSO Party.

I had participated in all these in the past and decided to give it another try from the very same island that I had qualified a year ago: Aylmer Island, ON-295 – the “Dead Chest Island” of the Ottawa Valley. This is a small rocky island in the middle of the Ottawa River about 7 Km NW of the Deschènes Rapids. Being a water-locked island it is only accessible by boat. I had planned to sail to the island on Friday but couldn’t. Hence I sailed at dawn the same Saturday, and had the opportunity to take some unique pictures of the marina before sunrise (and also to dodge the Pokemon Go players that roam the park around the marina later in the day). ­­­­­­

Aylmer Is. 2016 01

I anchored some 50 Ft. from the South shore of the island in 7 Ft. of water and proceeded to transfer the equipment (and myself) to the Sportyak dinghy. After a few oar strokes and a quick assessment of the area I decided to set the “shack” on the west side of the island under the shade of a young American Elm and not much older Manitoba Maple and Silver Maple trees. I rested the S9 telescopic mast on the Elm and brought the twinlead to the 4:1 unun connected to the Elecraft T1 mini-tuner “remote”. A short RG-58 coax lead to the KX3.

Aylmer Is. 2016 02

For furniture I had the rather comfortable Swedish “WalkStool” and a small “TravelChair Side Canyon Aluminum Folding Camp Table”. The first contact was made at 9:30AM local time and the last was logged at 16:12 also local time.

Around 16:00 dark clouds started to roll in from the NW and I decided not to spend the night in the boat, and not much later than 19:00 (local) I was recovering on the deck of the club house with a Barking Squirrel Lager in one hand and an elk burger in the other.

The W/VE Islands QSO Party log from Aylmer Is.(ON295) shows 48 QSOs: 4 QSOs island-to-island: NS-003 St. Paul Is. (SSB, 20m), GA-031L Pine Is. (SSB, 20m), NC-019S Colington Is. (CW, 20m) and WA-003S Camano Is. (SSB, 20m), 3 QSOs with NPOTA stations, 11 QSO in the OHQP, 25 IN THE KSQP, 2 SKCC QSOS, 2 QSOs DX (DL&YV – the DL was in the YO HF DX contest), and one QSO with Vicente LU4DNC (which for a moment made me dream of having reached Tierra del Fuego: he was /W4, in FL). With a total of 18 Multipliers and 92 Points my tentative score estimate is of 1656. And I have still Cabrillo’s to submit for the KS QP, the OH QP and the YO HF DX.

The very special QSO with Ben KV4RH was already reported in a previous article in this blog (

Not bad for an old sailor self-marooned in an island with only a W3EDP and a KX3.

A single man on a dead man’s chest—
…Yo-ho-ho, and a KX3!
CQ and the devil be done with the rest—
…Yo-ho-ho, and a W3EDP!

Rare Species in the Mer Bleue Conservation Area

“Mer Bleue” is the name of a large peat bog in a conservation area in southern Ontario, part of the Greenbelt of the city of Ottawa. It is the remnant of a sea, the Champlain Sea that formed when the glaciers melted, close to ten thousand years ago. Ecologically it is similar to ecosystems in the Arctic, much further north. Used for bomb practice during WWII, it is now a protected ecological enclave. The bog mat is made of thick peat, heath and small black spruce and tamarack trees. In the mat several rare plants survive in spite of the extreme acidic environment: sphagnum moss, sundew, pitcher plant, rare orchids, bog rosemary, Labrador tea, cotton grass, blueberry. The fauna is also rich: snowshoe hare, beaver, muskrat, mink, a diversity of birds and waterfowl as well as some much rarer and unique species such as the spotted turtle (Clemmys guttata) and the Fletcher’s dragonfly (Williamsonia fletcheri).

Occasionally, the bog is also visited by another rather rare and possibly dwindling species: Radius amans (radio amateurs) of the QRP/Portable variety. Two specimens (VA3QV and VA3PCJ) were seen in the bog area this afternoon (Aug 29 2016), probing the HF propagation from picnic tables near the bog traildeck. VA3QV used his vintage FT-817 and the PAR EndFed Tribander operating digital with his NUE PSK 31 modem. VA3PCJ brought with him his KX3 and the W3EDP Jr. and was able to log CW QSOs with three other DX (distant) specimens of the same species: XE1RX (Mexico, in 15m), OM5XX (Slovakia, in 17m) and YT9M* (Serbia, in 17m), thus adding two new bands to the successful spectrum of the W3EDP Jr. antenna.


* Zoran YT9M has confirmed since both in eQSL and LoTW