Reflections about a remote mediumwave listeners station

Left: The terminating resistor of currently 820 ohms is waterproof in an HT tube. The connections are mounted on lamp terminals, without much effort to remove.

Center: Middle: The mast top in 7.50 meters, to the left of K9AY mast. An aluminum tube of 4 m length carries the tip, attached to the plum tree with clamps, freestanding.

Right: The 9:1 balun also resides in an HT pipe. The 4m long mast made of aluminum stands with only 2 guy wires in a ground pipe, which once served as a prop for a parasol. I still wrap my balune myself ...

For the 40 m long wire I use galvanized uninsulated electric fence wire with a diameter of 1mm. Source: 1000 m / < 33 €

Shot 1: Flag-Loop. The noise level is near -138 dBm, signal at -105.3 dBm. Direction 80°.
Shot 2: K9AY. The noise level is near -130 dBm, signal at -107.1 dBm. Direction 35°.
Shot 3: 50 m longwire. The noise level is near -127 dBm, signal at -108.5 dBm. Direction 30°. Connected two CMCC.

It looks a bit better than I suspected in the last post. The antennas were for comparison without preamplifier.

Note: A precise statement can not be derived from this, all antennas should have had the same direction.

The loop has a total circumference of almost 40 m and closes the gap between northeast and southeast of K9AY. The top of the mast is 7.50 m high. The direction of reception is 80° across the northern Indian subcontinent, via Southeast Asia, western Australia and the New Zealand South Island, huge targets for MW-DX.

The loop can be relocated with a few simple steps, if necessary. For Central America reception, only balun and resistance are reversed. As it is rather quiet without a suitable preamplifier, it is amplified by the RPA-2 from DX-Engineering. This brings 17 dBm, which is still 10 dBm below the noise figure of the the K9AY or the 50-longwire.

The flag loop was built according to the pattern of FO0AAA, but is twice as large. The audible front-to-back ratio is better than K9 and longwire, as is the directivity. It was the only antenna that audibly filtered Palangkaraya, Indonesia at 3325 kHz (31.9.2019, 17z).

So much wood for an antenna that is suspended relatively quickly. Some preliminary work is nevertheless necessary for the measurements to be correct.

More additions to the loop will bring time. Now I'm curious.

Within 2 days I received this confirmation from AIR Northeast from Gantok Sikkim, via @mail. The often disturbed reception was on 30.8.2019 between 1629 and 1659 z on the frequency 4835 kc in acceptable quality possible. Antenna: 210 ° / 30 ° 50-m long wire. Thanks to D K Tripathi, Assistant Engineer at AIR Gantok for this nice confirmation from India.

Left: In the HT box at 4 m height is a Beverage Antenna matching set. The HT box was overhauled and re-waterproofed.

Middle: the CMCC was connected to the HT box with a 75 ohm coax cable at a distance of 5 meters. The ground rod is a discarded water pipe.

Right: a poplar serves as a holder for 3 long wire antennas, each 50 m in length. Not shown: a 2nd CMCC 5 m away from the receiver.

How are the CMCCs? First tests brought a significantly reduced QRN under thunderstorm disturbances.

Common mode choke coils act as a simple wire against push-pull current (signal), while acting as an inductor against common mode current (noise).

The kit, concerned on the HAM radio, contains all the necessary materials to quickly assemble a CMCC box. Only a 16mm drill for the PL jacks and another narrow drill bit for the screw feedthroughs are required, apart from the soldering iron. The box is IP55 certified and can be waterproof if you work carefully on the holes. The three central ferrite cores are shrink tubing sheathed, the associated thin coax cable is cut to the correct length sufficient. For a tech-savvy hobbyist, the assembly is easy, even if as in my case the instructions are missing and can not be delivered on request. The substitute transmitted by the manufacturer images of the open finished box could not help. In particular, I could only do the screwing with a number of washers at its own discretion. Since the screw connection also affects the water resistance of the box there are a few points deduction at this point. Also because the screws are not retractable as shown on the website, but come as slotted screws therefore. Another point loses the box due to an oversized wing nut that does not want to fit on any of the screws. Replacement by post was announced after a prolonged contact with the manufacturer.

Two of the boxes are inserted into the coax cable, one 5 m from the antenna's feed point, the other one 5 m from the receiver entrance. From the earth connection of the box a grounding line must be applied to the ground spike. These are not included in the kit. The earth connection is small in size, more than a 1 mm Ø line does not allow the eye with the pin. The wing nut would dress better if one had chosen a larger one. At this point, you can only rework yourself and realize your own ideas of a good ground connection.

The kit cost on the HAM radio 27 €, so 54 bucks for 2 CMCC boxes + a can of cold beer for free, which you can easily drink away while writing the many emails to the manufacturer.

The CMCCs significantly reduce thunderstorm disturbances. The 50-m antenna now has 4 grounding points.

There were exciting days on the medium wave. In addition to the usual stations from South America such as Radio Bethel, Vaughan Radio and Radio Buenos Aires popped to sunrise other rare stations from Argentina, Peru and Bolivia. Also the Harbor Lights of the Windwards can be regularly recorded at 1400 kc.

Here is my complete logbook of the last days:

2019-07-05
1400 0201 GRD Harbour Light of the Windwards, Carriacou/Tarleton Point (cpm) ID 7538 km
950 0250 ARG CNN Radio Argentina 950, Buenos Aires/Bella Vista (df) ID [SDRCONSOLE3, 50 m LW 210° RPA-2 AM/7686 Hz/-60.0 dBm] 11537 km
1470 0300 PRU Vaughan Radio, Lima/Pantanos de Villa (lim) 10752 km

2019-07-04
1400 0220 GRD Harbour Light of the Windwards, Carriacou/Tarleton Point (cpm) [SDRCONSOLE3, 50 m LW 210° RPA-2 USB/2800 Hz/-84.0 dBm] 7538 km
1350 0301 ARG Radio Buenos Aires, Burzaco (ba) NA 11542 km

2019-07-03
1400 0221 GRD Harbour Light of the Windwards, Carriacou/Tarleton Point (cpm) ID This is the Windward Islands [SDRCONSOLE3, 50 m LW 210° RPA-2 AM/5512 Hz/] 7538 km

2019-07-02
1400 0301 PRU OBX4W Ecco Radio, Lima (lim) ID Ecco Radio, NA 10753 km
1500 0301 PRU Radio Santa Rosa, Lima/San Miguel (lim) ID 10745 km
1350 0304 ARG Radio Buenos Aires, Burzaco (ba) NA ID Radio Buenos Aires [SDRCONSOLE3, 50 m LW 210° RPA-2 AM/5000 Hz/-60.0 dBm] 11542 km
1470 0304 PRU Vaughan Radio, Lima/Pantanos de Villa (lim) 10752 km
1570 0304 PRU Bethel Radio, Lima (lim) 10732 km
920 0311 PRG ZP1 Radio Nacional del Paraguay, Asunción/Capiatá (asu) typ. Mx after endless talks in Sp. 10642 km

2019-07-01
1400 0239 GRD Harbour Light of the Windwards, Carriacou/Tarleton Point (cpm) 7538 km
1390 0300 USA WEGP, Presque Isle (ME) [SDRCONSOLE3, 50 m LW 210° RPA-2 USB/2800 Hz/-72.0 dBm] 5399 km
1560 0300 USA WFME, New York/Queens (NY) 6174 km
1570 0300 PRU Bethel Radio, Lima (lim) 10732 km
1560 0303 BOL Radio Luz del Mundo (La Paz), La Paz (lpz) ID Radio Luz del Mundo [SDRCONSOLE3, 50-m longwire 210°, RPA-2 LSB/2159 Hz/] 10520 km

2019-06-29
1350 0155 ARG Radio Buenos Aires, Burzaco (ba) nice signal [SDRCONSOLE3, 50 m LW 210° RPA-2 AM/7880 Hz/-54.0 dBm] 11542 km
870 0237 ARG LRA1 Radio Nacional, Buenos Aires/General Pacheco (df) prers., talk abt. Buenos Aires 11519 km
950 0250 ARG CNN Radio Argentina 950, Buenos Aires/Bella Vista (df) ads abt. BA, CNN ID 11537 km
920 0254 PRG ZP1 Radio Nacional del Paraguay, Asunción/Capiatá (asu) nice signal 10642 km
790 0255 ARG LRA22 Radio Nacional, San Salvador de Jujuy (jy) // 870 11011 km
700 0300 ARG LV3 Radio Córdoba, Córdoba (cb) NA 11563 km
1470 0300 PRU Vaughan Radio, Lima/Pantanos de Villa (lim) 10752 km
820 0302 ARG LRA8 Radio Nacional, Formosa (fm) pres., NA 10749 km
750 0503 VEN , Caracas (dcf) ID 8101 km