MINI DX-PEDITION TO
SHOREHAM BEACH, WESTERNPORT BAY
By Bob Padula, Melbourne, Australia
Sourced to the EDXP DX-LOG, May 24, 2002
Hello to everyone!
My search continues for exotic midday LF DX signals during our Melbourne winter, and as the solstice approaches, propagation round our local noon (0200 UTC) is getting better and better on the 49, 41 and 31 metre bands.
Yesterday, May 24, which was "Empire Day", I visited the beach at Shoreham, a small hamlet on the north side of Westernport Bay, about 50 km south of Melbourne. The nearest town is Flinders, about 5 km to the west, and the take-away shop there serves superb fish and chips!
The main purpose of the trip was to get a collection of seashells for my aquarium, and the drive is about 75 minutes from here in Surrey Hills, mostly along the fast, smooth Westernport Highway.
I had been to the Shoreham foreshore a few times over the past year for some midday radio work, looking at both summer and winter propagation. It is possible to drive almost on to the surf beach along the track which passes through the small picnic ground, and it is reasonably free of power line interference.
I first went to Shoreham about 50 years ago, to the YMCA's summer boys' camp, which was adjacent to nearby Point Leo. That's where I played my first tennis game as a kid of 12. I can still remember the accommodation: in stifling hot canvas tents, with board floors covered in straw, four boys to a tent, and supported by communal facilities!
I guess that the camp was part of our sexual awakening, as we learned a few things there which would not be proper to repeat here...!
Nothing remains now of the Camp, or at least I couldn't find it - there has been moderate residential development in the area, but the beaches look much the same with nice views southward to Phillip Island in the distance.
However, I tossed the 20 m of antenna into the trees on the foreshore, cutting myself on a barbed wire fence designed to keep cows in, (and people like me out!)
Here is what I found from 0100 onwards...
This band was full of DX signals. Many Brazilian stations were audible, including some previously unheard this winter! These faded up at around 0115, and by 0145 were offering really good signals, and remained audible until their sign-off between 0245 and 0300. Some stay on air later for all-night services This Brazilin pattern was similar to last year, with these stations heard:
9515 R. Novas de Paz, Curitiba, audible after Iran signed off at 0130 co-channel, and quite good until 0230. Unheard previously this season!
9530 R. Novao Visa, Santa Maria, fade-in 0140 to 0230 when blocked by R. Tashkent opening on the same frequency. Unheard previously this season!
9565 R. Universo, Curitiba, fade-in 0130, audible to 0300
9615 R. Cultura, Sao Paulo, fade-in 0140 to 0300. Co-channel QRM DW-Trincomalee until that station closed at 0150
9630 R. Aparecida, Aparecida, fade-in 0140, brilliant level 0200 to sign-off 0230
9645 R. Bandeirantes, Sao Paulo, 0130 fade-in, to 0300
9675 R. Cancao Nova, Cachoeira Paulista, religious format, fade-in 0115, peaking to very strong 0200 to 0300
Other new DX signals heard on 31 mb at Shoreham:
9770 Radio Sri Lanka, English, quite strong 0125-0200 when co-channel BBC-Seychelles s/on
9505 VOA-Iranawela, Pashto, 0100-0200
9790 VOIRI, Tehran, Arabic service opening at 0230
9875 BBC-Cyprus, Pashto *0100-0200*
9890 VOIRI, Tehran. NF, 0200-0230* Pushto (moved from 96740 to avoid co-channel Egypt)
Signals audible 0100-0145 were:
6175 Voice of Vietnam via Sackville (unheard this freq until now!)
After 0200, the pattern is now stable, including 6120 Finland and 6190 Slovak Republic.
There are relatively few international stations actually operating in this band between 0000-0400.
The band is now open for this time span, and signals audible between 0100 and 0300 included:
7130 DW-Nauen 0000-0200*
7130 VOIRI Tehran *0230-0300 Pushto
7140 BBC-Skelton 0000-0300* Arabic
7155 RL-Wooferton Russian *0200-0300
7160 R. Tirana 0030-0200
7190 Unid, believed to be Radio Tashkent 0100-0130
7210 R. Ukraine International via Minsk 0100-0300*
7225 R. Romania International 0230-0300
7245 RL-Lampertheim Russian *0200-0300
7270 R. Tirana 0100-0130
7305 Vatican 0030-0130
7330 Russia 0030-0300
7365 VOA-Greenville 0100-0130 Spanish
7405 VOA-Greenville 0100-0130 English
Winter daytime reception on 6, 7, and 9 MHz is subject to many variations, and is a little different for each receiving location I have visited, even though all are close to Melbourne's smog and pollution.
Many of the stations are of course audible in Melbourne, but not as reliable, with only the stronger signals appearing above the external noise floor.
The small receiver performs well, but not as good as a full-scale, higher sensitivity machine with a proper dipole and noise-redicing balanced feeder. After all, these Sangean 808s and 909s are in reality portable radios, and we should not expect top performance from them. I do not use the Sangean at home, as it is mainly for "mobile" work!
External antenna positioning is important when going portable, and best results are when the wire is as high above the ground as possible. In fact, a vertical "long wire" tossed over a tree branch 5 m above the ground works MUCH better than a 20 m horizontal wire 1 m above the ground.
Beware of using wire fences as antennas - they may be several hundred km in length, but pick up is disappointing, being only a metre or so above ground level.
What is obvious from these picnic-DX-peditions is that there are four major limiting factors to receiving weak signals:
1. Power line noise (very high anywhere within 200 m of a distribution network)
2. Signal blocking by increased absorption of low angle stuff, due to high industrial smog layers
3. RF interference from household appliances, either directly by radiation, or via re-radiation from power lines. Drive underneath the 600,000 Volt major transmission lines and see what I mean!
4. Intense RF noise from electric trams and trains, neon signs, dimmers, movement actuated security lighting, industrial switching networks, and traffic light control equipment
From a home location, a dipole antenna, with a balanced feeder (so that noise pickup by the feeder is "cancelled out") are essential, or you are really wasting your time! The balanced feeder should be around 75 ohms (the characteristic impedance Zo of a simple dipole). Your folded TV antenna has a Zo of 300 ohms. The Zo of your plain old telephone cable is 150 ohms. An open-wire telephone line has a Zo of about 600 ohms (what you may still see in rural areas, two wires spaced about 50 cm apart, and used in professional monitoring "antenna farms")
Don't waste your money on 75 ohm coaxial cable for reception purposes - it's not balanced! The balanced feeder is important; ordinary plastic covered twin electric power flex is near enough to 70 ohms.
Your receiver should ideally have a balanced input at 75 ohms - sadly many current receivers do not. Think about using a Balun in such circumstances - beg, buy, borrow, steal, or make your own. Also you may use a passive antenna tuning unit which can emulate a Balun - very important for weak signal reception.
My monitoring work from these places near to Melbourne is always with the Sangean ATS-808A with about 10 m of wire. When I travel in Asia, the same gear is used, with the antenna into a palm tree. Hotels are useless! Bungalows are best, if physically isolated from the rest of the accommodation complex. For an antenna counterweight, use a coconut, or a Coke can filled with water!
Good reception on your next picnic DX-pedition or from home!