Reflections at Lake Poona, Great Sandy National Pk & Rainbow Beach

Lake Poona bush walking (sans 4WD)

Lake Poona is accessible from Freshwater Road just west of Rainbow Beach. The lake comprises part of the Great Sandy National Park (NP). The park comprises some 220,000 hectares according to Bonzle and is tentatively World Heritage listed. The colourful Great Sandy NP (below) is sandwiched between Fraser Island & Tewantin – Noosa.

4WD vehicle driving south of Rainbow Beach © 2014 FM DXing

The Lake Poona walking track starts at the Bymien picnic area (map). This area is accessible via a loosely graded dirt road which is officially deemed suitable for 2WD vehicles.

To access the lake, a challenging walk (4.2 km / 2.6 mi return) is required. There is no direct vehicular access to Lake Poona. With a couple of short breaks, the walk took 43 minutes for its first half. Based on alitmeter readings, the elevation rises from 183 m (600 ft) to well over 240 m (787 ft) through the mid-point of the walk. Because of small rocks that are loose underfoot on the track, undertaking the walk is particularly challenging in the dark, even by torch light! It is therefore recommended to leave the lake and commence the return half of the walk at least half an hour prior to sunset.

Who is this tool at Lake Poona? © 2014 FM DXing

The colour of the water in Poona Lake (above) is distinctive. It forms as a result of tea tree leaves that fall into the water. The pristine lake tastes good; the home brewed ale afterwards in the apartment… even better! This blogger roughly estimates that the lake is at least 226 m (741 ft) wide and 574 m (1,883 ft) long…  assuming seasonal rainfall maintains its capacity! The expansive lake can be easily seen from an aircraft. Fishing enthusiasts should be aware that reports suggest that fishing in Poona Lake is unlikely to be a fruitful endeavour!

4WD driving permitted on Rainbow Beach © 2014 FM DXing

The walk, which culminates at the south east corner of the lake, seems to be surprisingly unpopular. Even on a busy summer Sunday, with the Rainbow Beach patrolled surf beach ‘pumping’ nearby (above), only two thirty-something walkers were seen during the course of the walk.

Expansive Lake Poona © 2014 FM DXing

Despite the obvious potential (above), there was no swimming undertaken on this occasion due to lack of time. The time of arrival was 5:30 pm. About three minutes were spent on a brief survey of FM radio reception. This act of madness was done discreetly, when nobody else was around.

Only very rudimentary portable radio equipment (below) was able to be taken on the bushwalks. Frozen water bottles, insect repellent, a ‘smart’ phone (apparently?), torches & two video cameras take precedence!

Tree hugging radio at Lake Poona © 2014 FM DXing

At the lake, signals from Bundaberg (93.9 MHz, N), the Darling Downs (100.7 MHz, SW) & the Gold Coast (89.3 MHz, S) at a distance of 224 km (139 mi) were clearly audible on the Tecsun PL-300WT (below). The 80 kW FM western ‘beasts’ broadcasting from Biggenden (116 km / 72 mi) were so strong the signals were bleeding onto adjacent channels such as 99.5 MHz. Jet-scattered transient signals from Coffs Harbour were NOT receivable at the lake. Tropospheric Index: light blue.

The highest point of the walk is roughly about one kilometre from the lake. At this point is a grassy clearing of about 25 square metres (269 square ft) with a basic selection of log ‘seating’ to recharge one’s depleted physical ‘batteries’. Unfortunately, the towering trees nearby attenuated FM signals at this area. This seemed to negate the benefit of the higher altitude, as signals listed above that were clear at the lake were noticeably absent.

Tecsun PL-300WT radio at Lake Poona © 2014 FM DXing

Great Sandy NP radio observations

In contrast to Lake Poona, at two locations a short drive away, Coffs Harbour’s RN on 99.5 MHz would ‘boom in’ via jet reflection at this time of day. These were accompanied by daily late afternoon showers which were likely indicative of flat atmospheric conditions. These two trips are detailed below:

A third of the way (3 km / 1.9 mi) to Neeb’s Waterhole (map), the tour was forced to stop on a hill (where the road parts in two directions) that is roughly estimated to be 50 m (164 ft) ASL using Google Earth. Access to the waterhole was previously possible via Mullin’s carpark through Cooloola Way with a 4WD vehicle (that is, four-wheel drive or SUV, sport utility vehicle) but is now closed for repair to all traffic due to severe flood damage, which necessitated turning the vehicle back.

On this hill in Cooloola Way, the extensive 4WD metal body (below) was used as a highly effective ground plane. The radio was placed on the high roof of the vehicle. The Tecsun radio battery ground was connected to the roof and the telescopic antenna fully extended vertically. The base of the telescopic antenna is NOT touching the metal roof, only the ground wire does.

4WD beach route between Middle Rocks & Double Island Pt © 2014 FM DXing

This yielded far better results than the 4WD factory radio. As seems to be commonplace, the Toyota’s telescopic antenna was too short. The FM telescopic wasn’t captured on film, but is probably only two-thirds of the length of the portable receiver’s telescopic antenna. Worse, the factory receiver did not feature sufficient selectivity for the modern congested FM band.

Although worthwhile for long distance FM reception, this ‘portable on the roof’ approach unfortunately yielded this crazed enthusiast dozens of insect bites that affected ‘sleep quality’ for the remainder of the vacation!

The highlights were Stanthorpe (103.3 MHz, SW) & Coffs Harbour (99.5 MHz, S) at distances of 302 km & 476 km (286 mi) respectively. A ‘rebelliously-strong’ signal from Beaudesert (90.5 MHz, S) was a pleasant surprise at 210 km (130 mi). It’s hard to maintain interest when insects are feasting on the back of one’s knees, but signals towards the north & west seemed lacklustre with nothing obvious further than moderate strength Bundaberg, 146 km (91 mi)! Tropospheric Index: unknown.

At the Tin Can Bay Volunteer Coast Guard (map), a simpler arrangement was used since a conventional vehicle was able to be used. Obviously this is more convenient (translation: ‘bite free’ comfort) & yields superior results to a portable receiver sited in the ‘middle of nowhere’, although perhaps it does not offer as much ‘quirky’ enjoyment. Again, a Blaupunkt ‘Sharx’-enabled radio with an amplified Shark Fin (an appropriate match for pun enthusiasts?) was effective, as is regularly used.

Overlooking Tin Can Inlet west of Rainbow Beach © 2014 FM DXing

The car was driven to a parking space overlooking Snapper Creek near the Coast Guard’s antenna arrays (above). At this spot, Bundaberg (93.9 MHz, N) & Brisbane (104.5 MHz, S) were strong. Satisfactory reception was possible from Redland Bay (100.3 MHz, S), Ipswich (94.9 MHz, S), the southern Gold Coast (95.7 MHz, S), Beaudesert (89.7 MHz, S), Cherbourg (94.1 MHz, W) & Coffs Harbour (99.5 MHz, S) at a distance of 491 km (305 mi). North-western signals from Gladstone (93.5 MHz) & Rocky (103.1 MHz) at respective distances of 287 km & 348 km (216 mi) were weak. Tropospheric Index: dark blue.

Great & Sandy but dense terrain

The Great Sandy NP comprises many ranges of dense rainforest. Not only does this result in exhausting 4WD driving for relatively inexperienced drivers (like this long-suffering writer) but these terrain characteristics also pose a significant obstruction for long distance FM reception towards the south at Rainbow Beach.

Leisha track entrance to beach © 2014 FM DXing

Conversely, it is highly likely that this is also the reason for the FM reception deficiencies at Noosa towards the north, discussed in previous posts. Tewantin – Noosa is located near the southern boundary of the park. One afternoon, when checking briefly on the 4WD on the beach near the Freshwater camping & day use area (below) a haul of southern stations were found. These included the Gold Coast and were easily detected in flat conditions. Freshwater’s facility is NE of Teewah Beach, accessible by 4WD.

Freshwater track entrance to beach © 2014 FM DXing

Much like Noosa, reception to the north west is obstructed by mountains. Fishing, surfing, swimming, walking, backyard cricket or drinking is probably a more fulfilling way for prospective campers to pass the time in this part of the park (below) than playing with a portable FM receiver!

Driving north towards Rainbow Beach © 2014 FM DXing

Located NE of Freshwater camping & day use area is Double Island Point Conservation Park. Atop a cliff is the popular lighthouse attraction, accessible via walking track (below). The Double Island Point lighthouse has operated since 1884. The ‘light’ which guards passing ships from the rocky headland is supplied via solar electric panels. The lighthouse is an official weather station, often featured on television.

Lighthouse cliff track, Double Island Pt © 2014 FM DXing

Rainbow Beach accommodation (sans 4WD)

Rainbow Beach (below) has a ‘party-like’ tourist atmosphere. To this writer, this felt reminiscent of Airlie Beach, the gateway to the Whitsunday Islands without the oppressive tropical summers. Granted, there is not the variety of restaurants & nightlife the Airlie Beach destination offers. Both destinations share the same sub-tropical climatic classification.

Rainbow Beach © 2014 FM DXing

Rainbow Beach seems particularly popular with Dutch, German, Polish & Swedish twenty-something tourists. During the week, the location (cue The Specials’ classic, please deejay) almost resembles a ‘Ghost Town’!

It’s probably unsurprising as there is barely one school and no major supermarkets in the locality, with the overwhelming emphasis on tourism. Nearby Tin Can Bay seems to be the business, residential & recreational fishing and hub of the region.

Rainbow Beach to the south east, including Double Island Pt © 2014 FM DXing

Rainbow Beach’s weekday ‘slumber’ (above) is perhaps ideal for exploiting Rainbow Beach’s wonderful potential for FM reception. It is remote! How remote? The only local broadcast is a one watt Christian FM narrowcaster; on MW it is Classic Hits 4GY. The region only requires 75 watt digital television translators.

Tropospheric Ducting: Pack a yagi or get high!

Even during instances of ‘fair’ tropospheric ducting in mid-March (Autumn), distant reception is awesome. These were indicated by a light blue colour on the Hepburn tropo forecasts, easily viewed via even the most rudimentary cellular phone. (Conditions were confirmed after the vacation ended using the Marine Tracking peaks on the graphs at Gladstone).

Long distance FM reception from the north west as far as Mackay (687 km / 427 mi) is possible at Rainbow Beach. Just as rewarding is hearing the numerous low-powered mine relays from the same azimuth, rebroadcasting commercial stations Zinc (aka 4CC), Sea FM, Rebel & Breeze.

In total, 92 FM stations were logged at Rainbow Beach over three evenings. These included two re-broadcasts of cable television sporting channels, typically servicing large caravan parks.

As mentioned above, the obstructive nature of the Great Sandy NP at Rainbow Beach enable FM broadcasts from Gladstone (292 km / 181 mi) to obliterate those on the Sunshine Coast (100 km / 62 mi). This is a very pleasing terrain side effect, since the Gladstone broadcasts emanate from a low-elevation site with a tenth of the power of the coast stations!

Access to a collapsible three or five element FM yagi (from $45) is recommended for receiving pleasant ‘quieting’ signals from the north west (such as Mackay) in Rainbow Beach. Not all accommodation may be ideally suited for the placement of a ‘stealth antenna’. Huh? Essentially, a stealth antenna in this context refers to the erection of a tripod-mounted small yagi on the balcony during darkness between 7 pm – midnight. A folded dipole resting on a balcony’s glass or wooden table may suffice. (The dipole is easily detached from a surplus five or eight element FM yagi).

Carlo Sandblow to the south, including Double Island Pt © 2014 FM DXing

Rainbow Beach’s elevated region is characterized by a gradual rise from beach level (i.e. the Pacific Ocean) to 87 m (285 ft) near the Cooloola Drive reservoirs. These water towers adjoin the extremely popular Carlo Sand Blow lookout (108 m / 354 ft ASL), so these are easy to spot! The Sand Blow is pictured above & below.

Unless one is lucky enough to secure scarce accommodation located around here (the author did not), experimentation with a portable receiver’s telescoping monopole antenna is virtually guaranteed to be frustrating as the effects of a federal budget! Unlike many holiday locations, at Rainbow Beach there are simply no towering high rise apartments on offer. Typically towers partially offset the performance of a ‘lossy’ telescoping antenna.

Carlo Sandblow to the south, including Double Island Pt © 2014 FM DXing

Provided one pays attention to the hilltops and gets mobile, there are still plenty of other alternative methods to ‘get in on the action’. In fact, one evening the Mackay stations were even audible via tropo in the car, albeit only on the western crests of Rainbow Beach Road. Reception from this north western azimuth seems optimal when this road transitions into Tin Can Bay Road, approaching Wolvi near Gympie. Signals from Mackay were typically heard just above the noise floor.

Distance calculations computed using FM Scan, with base (apartment) reception undertaken with a Yamaha TX-930 component tuner.

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Butchering the Winfast TV2000XP for FM DX

Please consider the risks involved with modifying a tuner before proceeding with any project. The author shall not be liable for any loss or damage whatsoever (including human or computer error, negligent or otherwise, or incidental or consequential loss or damage) arising out of, or in connection with any use or reliance on these instructions.

The Leadtek Winfast TV2000XP is a Peripheral Component Interconnect (PCI) card to receive FM and analogue television broadcasts. The card also provides analogue video capture functionality via an S-video input. At the heart of the card is the Philips FM1216 / PH hm tuner. The module may be used in a number of other manufacturers’ analogue TV and FM cards, including:

• Hauppauge WinTV FM;
• AverMedia AverTV Stereo Edition Desktop TV Personal Video Recorder &
• Conexant Fusion 878A Easy TV.

The tuner includes the following Philips’ integrated circuits:

• TDA5736;
• TSA5523;
• TDA9809 &
• TDA7040.

Since analogue television is ‘done and dusted’ these cards (below) may be classified as redundant technology. Accordingly, most sell for less than 10 bucks on Ebay!

The card may be used with Dscaler noise reduction software for weak signal detection, such as low VHF band Sporadic E in regions where analogue television is still operational. Because of the wide frequency coverage, Klaus Hirschelmann suggests the tuner offers potential to receive International Radio and Television Organisation (OIRT) broadcasts still on-air in Eastern Europe.

According to Philips:

The tuner [Automatic Gain Control] AGC for both TV and FM radio operation is generated with a novel AGC detector which measures the [Intermediate Frequency] IF signal level directly at the tuner IF output pins. As opposed to the conventional AGC detector, this new circuit allows a higher take-over level and offers superior immunity against tuner overload.

The tuner offers satisfactory strong signal immunity. Performance is markedly better than the E4000, R820T or FC0013 tuners used in a Realtek Software Defined Receiver (SDR) or a Silicon Laboratories’ Si4734 based portable receiver connected to the same rooftop antenna. Philips’ tuner typically features an Image Rejection of 65 decibels for the FM band. In terms of benchmarking, a Yamaha TX-930/950 component tuner features a more favourable 90 decibels. AM Suppression – the ability of the tuner to reject AM signals, is specified at 38 decibels.

Whilst the tuner features interference suppression, the separation of FM stations is not up to contemporary requirements. When Philips Components designed the tuner, Digital Signal Processing (DSP) was at its infancy. These days, DSP based tuners are perhaps taken for granted. Whilst away interstate recently, this blogger noticed that even a cheap TDK Ipod dock supplied in the apartment featured a DSP FM tuner!

The scheduled timer recording functions for recording (above) on the TV2000XP is a boon. Therefore, it is a shame that the tuner is not suited to a congested FM dial. When it was used for television recording, the software accompanying this product worked flawlessly.

The tuner does not permit a listener to separate fringe stations 100 kHz apart, and to hear several stations without interference from strong local stations, it was necessary to off-tune 50 kHz to prevent audible interference. Fortunately, sensitivity seemed fine, for example daily reception (a 26 kW broadcast) out to 208 miles (335 km) was possible with a modest combination rooftop antenna without a preamplifier. Sensitivity for a weak signal with a 26 dB signal to noise ratio is 2.24 uV, compared to a Yamaha TX-930 with a more favourable 0.8 uV. Most tuner software (including Leadtek and Hauppauge) features a five segment signal strength meter.

After quite a few drinks one night the author decided that it would not hurt to rip the tuner module open and see what was inside! It was no risk, because a replacement card is dirt cheap. Worst case scenario, if secondhand supplies dissipate, one can simply solder in a new tuner module, pictured below.

The fact the aluminium lid of the Philips FM1216 / PH hm tuner module could be easily plied open was a surprise. What was inside was even more interesting. Staring up at this ‘butcher’ were two 230 kHz Murata ceramic filters and one ceramic discriminator. The block diagram (below) shows the role of the two 10.7 MHz IF filters.

To aid easy identification of components (in this case, the existing filters), it is recommended to refer to an online source such as Bruce Carter’s Ceramic Filter page.

Was this ‘elderly beast’ a candidate for a filter butchering? Hell yeah! Hence this article is basically another instalment of the ‘narrow filter modification’ project. It never gets old. 🙂

Because the rear of the tuner module cannot be easily accessed, the existing wide filters are perhaps best removed from the enclosure… by force! Pliers were – again – used to ‘throttle and crumble’ the existing filters, easily identifiable by the Murata logo. The replacements are soldered in place of the old ones.

The tuner module features a large Printed Circuit Board (PCB) as illustrated on the left half of the photograph above. Even ‘old eyes’ are unlikely to encounter problems with such a simple project. This is a five minute project requiring little equipment, consisting of:

• general purpose pliers;
• a soldering iron;
• solder;
• desolder braid (optional);
• philips head screwdriver (optional) &
• replacement 10.7 MHz filters of one’s choice.

Mike Bugaj is another enthusiast who enjoys ‘butchering’ FM tuners as much as this blogger! He prefers to change one filter first and test performance before proceeding with replacing the other wider filters. This blogger takes the same approach. One of the two 230 kHz filters was removed and a 80 kHz filter soldered in its place. The butchering is not pretty (below), in fact it is possibly one of the ugliest mods ever performed… ‘but she works!’ Stations 100 kHz apart can now be heard, whilst the distortion levels of FM broadcasts remain satisfactory.

Whilst not mandatory, a preamplifier improves sensitivity. As mentioned above, the module may not be up to component tuner standards for weak monophonic or quieting stereo signals.

For the finishing touch, it is recommended to purchase a few ferrite suppression chokes to clip onto the coaxial cable (above) to minimize Electro Magnetic Interference (EMI) problems from a desktop PC. The blogger can recommend jteam Electronic Components. Their chokes (below) were posted quickly from Perth, Western Australia and were very inexpensive compared to retail supplies.

To minimize interference from the desktop PC, so as to maximize FM tuner sensitivity:

• A CRT computer monitor should NOT be used;
• Internet routers should be switched off;
• Remove all unnecessary or unused leads connected to the desktop computer such as USB extension cables &
• Use RG-6 Quad Shield Coaxial Cable for all connections from the tuner to the antenna wall plate.

A recommended source for replacement 110 kHz narrow ceramic filters is Greg Gortman of Lexington, Kentucky. International carriage is available from these sources. Prior to publication stocks were available.

Klaus Hirschelmann notes that the tuner module features an Multiplex Output for RDS use. Whilst this blogger has not tried it yet (perhaps after the Ashes test cricket series) the Data and Clock signals (found on pins 13 & 14) can be fed via a shielded cable to the Line Level Input on a sound card. In theory, this should enable RDS decodes with RDS Spy software, illustrated above and below.

For those craving more experimentation, H. Chew suggests the Philips tuner can also be used as an SDR under a Linux operating system. Polish enthusiasts have even built the module into a ‘stand alone’ RDS component tuner!

Specifications quoted above may not necessarily be indicative of performance. There is nothing preventing manufacturers from using different test signals to make measurements in an effort to improve performance specifications for marketing purposes.