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

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

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

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

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

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

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

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

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

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

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

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

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 © 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 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

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

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.

Creative Commons license

Creative Commons license - Click here for details

Photographs may be freely used for non-commercial activity, provided attribution is given. Should readers choose to use those photos elsewhere, please link back to this page or attribute this blog as the copyright holder. Please click on the photos to access higher resolution shots (2048 x 1536 pixels).

Advertisements

Revisiting the Realistic PRO-2006

Around 1990, Tandy Corporation introduced the Realistic PRO-2006 programmable scanner. It was manufactured for Tandy by General Research of Electronics, Inc. (GRE) in Japan. It is also known in Europe as the Commtel COM-205 or Handic 0080 (below), according to Javiation.

Handic 0080 aka PRO-2006 © 2011 Wanderlinse

This triple conversion receiver offers microprocessor-controlled VHF, UHF and FM reception. A rooftop antenna or whip (supplied) is connected via the BNC antenna connector. The scanner sold for a retail price of $400 in the United States.

Realistic PRO-2006 © 2014 FM DXing at WordPress

There are plenty of modifications that can be undertaken for this scanner. These include the ability to tap the discriminator output or the 455 kHz third Intermediate Frequency (IF) signal for SSB demodulation. An HF receiver or modern outboard conversion hardware (such as RadiØKit-2 in combination with open source Dream software) is required to demodulate the SSB from the IF signal.

Being relatively lightweight, the PRO-2006 offers genuine potential during field trips at summits. The scanner is easily operated using an inexpensive, lightweight and rechargeable Sealed Lead Acid (SLA) battery.  A battery with a capacity of nine Amp hours (Ah) is more than adequate for this scanner. A handheld MP3 recorder featuring line-in recording can be connected to Tape Output on the rear of the scanner to permit monophonic recording of reception, including FM broadcasts.

Realistic PRO-2006 supplied antenna © 2014 FM DXing at WordPress

FM broadcast band tuner module

The PRO-2006 incorporates two 280 kHz, two 455 kHz ceramic filters and a 48.5 MHz crystal filter. Wide FM mode is designed for analogue FM and TV audio only.

Realistic PRO-2006 tuner module, rear unit perspective © 2014 FM DXing at WordPress

The PRO-2006 has two 10.7 IF bandpass filters in the FM section (above). These are both marked 10.7A, suggesting a 280 kHz bandwidth. The part number is Murata SFE10.7MA5W-A. The bandwidth of these filters is too wide to discriminate FM stations spaced 100 kHz or 200 kHz apart on the contemporary congested FM band.

PRO-2006 partial schematic © 1990 Tandy Corporation

KA2243N (IC1)  is the IF amplifier/detector Integrated Circuit (IC). The first 280 kHz filter (CF1) leads directly to pin 1. The second 280 kHz filter (CF2) leads to pins 4 and 6. The HA12413 IC may be substituted for the KA2243N.

This tuner module incorporates the IF coils and the Quadrature/detector discriminator coil for both 48.5 MHz (T1, T2) and 10.7 MHz (T3, T4).

FM broadcast band performance

The nominal 30 decibel FM sensitivity ‘design specification’ for the PRO-2006 is 3 microvolts for frequencies from 25 – 520 MHz. The FM broadcast band falls into this segment.

Radios featuring a Si4734 digital AM/FM radio receiver IC, such as those manufactured by Tecsun, offer approximately equal sensitivity as the PRO-2006 scanner in Wide FM mode. It is impossible to make entirely accurate comparisons between the Silabs’ Digital Signal Processing (DSP) based receivers and conventional tuners, since the company use differing units and test conditions to measure sensitivity. However, the nominal 30 decibel FM sensitivity ‘design specification’ (below) from Tecsun, applicable for radios such as the PL-300WT & PL-606) is better than 3 microvolts for frequencies from 64 – 108MHz.

Tecsun specifications © 2014 FM DXing at WordPress

How to access the tuner module

Unscrew the two, top positioned screws on the rear of the scanner. Remove the top plastic cover top to expose the ‘linear printed circuit board’, PC1. Remove the metal cover of the tuner module (below), which is located second from the right.

PRO-2006 interior modules © 1990 Tandy Corporation

Replacing wide 280 kHz filters in the PRO-2006, PRO-2005, PRO-2004, PRO-2035 or PRO-2042 scanners is likely to be as simple as the modification to the Philips FM1216-based tuner module, used in television tuners such as the Winfast TV2000XP. An excellent resource for this modification is GBPPR Projects.

Realistic PRO-2006 frequency display © 2014 FM DXing at WordPress

Mating the PRO-2006 with a Software Defined Radio (SDR)

After filter replacement, tapping the 10.7 MHz IF (both mods are described at GBPPR Projects) may enable the 10.7 MHz output from the scanner to be manipulated with DSP functionality in an SDR. Unfortunately, readers wishing to do so are ‘on their own’ because the writer does not own a compatible SDR (such as the SDR-IQ). It may be instructive to watch the video Gough Lui made. He taps the 10.7 MHz IF of the PRO-2021 scanner into the Winradio Excalibur SDR. Peter employs the same principle in his video.

A more inexpensive alternative may be to use a High frequency (HF) upconverter in combination with a cheap RTL-SDR receiver. Such upconverters are available for under $50. Unlike the cheap RTL-SDR receiver itself, an upconverter will tune into the 10.7 MHz output frequency from the scanner. There are side effects in this approach, which potentially include a 10 decibel loss and the limiting dynamic range of the RTL-SDR receivers.

Pairing the scanner with an SDR offers hobbyists the opportunity to extract the maximum potential audio quality out of FM broadcasts or International Radio and Television Organisation (OIRT) broadcasts on 66-74 MHz still on-air in Eastern Europe.

Creative Commons license - Click here for details

PRO-2006 photographs may be freely used for non-commercial activity, provided attribution is given. Should readers choose to use those photos elsewhere, please link back to this page or attribute this blog as the copyright holder. Please click on the photos for higher resolution shots (2048 x 1536 pixels).

Sangean PR-D8 recorder on AM: Crude review

The Sangean PR-D8 is a two band portable radio for Medium Wave (MW) and FM. The radio is designed to easily record radio broadcasts, wherever one may roam. The test unit was purchased from Amazon dot com. Carriage took two weeks via USPS First Class International postage.

How does recording work?

Press the ‘Rec’ button for five seconds on the unit and the tuned station is recorded to an SD card. The end product is a relatively high resolution 192 kbps MP3 file that can be immediately shared via the internet. Modern computers typically furnish SD card readers as a standard feature. For older computers, USB ‘all-in-one’ card readers can be purchased (for next to nothing) to access the recordings encoded to the SD card.

Recording screen including dual VU meters - Sangean PR-D8

ADVANTAGES

Excellent recording fidelity at 192 kbps bitrate. Digital artifacts may be audible if the 128 kbps encoding quality is chosen.
Accurate recording level meter suits both radio and line-in recordings.
Fully customizable timer recording and alarm functions. May be used as an alarm clock.
Tuning stations is user-friendly. Easy to navigate, review and delete clips.
Well designed instruction manual which is readable & written with satisfactory grammar.
Excellent build quality. Strong likelihood of maintaining value in the secondary market.
Compatible with modern SD cards, including smaller breeds via an adapter. A 32 gigabyte HC Class 10 card was used in test.
Satisfactory sensitivity on MW. The 20 kW broadcast Premiere (1ère) 666 kHz Noumea is received with this radio on a daily basis at 920 miles. As is the 50 kW broadcast Radio New Zealand National 567 kHz Wellington, at a distance of 1,565 miles. Antenna is a 11.5 x 100 mm ferrite bar inside the unit.
Satisfactory sensitivity on FM. 4JJJ 99.3 MHz Biggenden was received on a daily basis at 143 miles. Antenna is a telescoping antenna, sited directly above the MP3 recorder.
Tuning increments can be selected to suit the listener’s region.
Includes quality AC power supply for indoor use. Satisfactory battery life whilst recording (up to 10 hours).
Full suite of features. Twin (stereo) microphones suit outdoor recordings. Line level audio output is provided in addition to the standard Headphone output.
Reasonable FM sensitivity when connected to an external antenna.

 

DISADVANTAGES

NOT recommended for portable FM recordings. Please refer to the detailed discussion in the body of the article.
Wide filters are NOT suitable for separating all FM stations 200 kHz apart. The FM selectivity may be improved by a simple ceramic filter mod. Such a project voids the warranty & requires a conventional front end design.
Expensive purchase price relative to offerings made by the group that produces the Degen/Tecsun portable radios.
No provision for external antenna, but this can be circumvented with minimal effort.
No signal meter although a stereo indicator is included.
The inclusion of the 64 kbps bitrate recording option seems superfluous. Those recordings exhibit significant compression artifacts, to the point of the clips NOT being usable.

Love AM? This may be the radio for you

The author of this review has a bias towards FM. With that disclosure out of the way, the most fundamental flaw of the design is not catering for FM recording enthusiasts. Why make the MW section virtually immune to interference when encoding recordings, whilst not doing the same for FM? It seems bizarre for Sangean to pursue such a strategy. Did (former) Prime Minister Kevin Rudd or Opposition Leader Tony Abbott (now Prime Minister) help design this ill conceived recording radio? And why can’t Turnbull (Communications Minister) can fix it?

MW enthusiasts vastly outnumber FM enthusiasts. Effectively FM listeners ‘lose out’ since the manufacturer seems to have designed a recording radio to satisfy the largest segment of consumers.

Recording mode & Backlight - Sangean PR-D8

According to C. Crane:

Traditionally AM radio is very difficult to record into MP3 format because of unwanted noise generated by the digital components inside the radio. The PR-D8 overcomes this problem by using good circuit craftsmanship techniques.

This radio does cause some interference when recording weak MW signals from an external tuner, even in ‘Recording Pause’ mode. This symptom seems to be easily solved by moving the component’s passive indoor MW loop well away from the recording radio, using a higher gain loop (especially an amplified variety) or an outdoor antenna.

For those seeking to purchase this radio for the sole intention of MW recording, this receiver performs admirably and would be recommended primarily for this purpose.

Samples of MW recordings

873 kHz talk: interstate fringe signal

1242 kHz music: fringe signal

1368 KHz music: interstate fringe signal

Recording mode & Backlight - Sangean PR-D8

 

Further reading

Enthusiast Review – Herculodge blog

Customer Reviews – Amazon & C.Crane

The author acknowledges the assistance of David in the composition of this review. Photos of the Sangean PR-D8 may be reused under a Creative Commons license. Simply link to this blog or attribute the blog in a photograph mouse hover or caption. Medium Wave distance calculations calculated using coordinates from Asia Waves.

Portable FM radios

European hard core FM enthusiasts tend to use the Grundig satellite 700, Eton E5 (Grundig G5), Degen 1103 (Kaito 1103), Grundig satellite 3400, Grundig satellite 500 & Sangean ATS-909.

These radios require a filter modification in order exceed the selectivity of modern radios with Digital Signal Processing (DSP). Usually replacing the last 150 kHz or 180 kHz filter in the Intermediate Frequency (IF) circuit for a 80 kHz variety does the trick. In unmodified form, the radios rarely provide equivalent selectivity of a DSP radio.

Sangean ATS-909 worldband receiver © 1996 Mysid

Sangean ATS-909 © 1996 Mysid

So why do European enthusiasts go to this trouble? Apart from the obvious fun of learning about the internal circuitry of the particular radio, in this blogger’s experience there are overwhelming advantages in ‘modding’:

  • better performance 200 kHz above local stations;
  • better separation of stations spaced at 100 kHz;
  • better sensitivity due to the narrower filters; &
  • ability to plug in an external antenna (without a plague of images) due to sophisticated attenuation switches.

DSP based radios such as the Tecsun PL606 probably still offer better immunity from strong signals, a key feature of the Silicon Laboratories’ (Silabs) tuner design. For example, at a high rise apartment tower within 20 kilometres (12 mi) of a major FM broadcast site, the Degen DE1121 will start to overload before the Tecsun PL300WT (Grundig G8) will. It is also hard to overlook a Silabs design for the convenience factor: it is a functional radio ‘out of the box’.

De1103 © 2007 Igor K ico.livejournal.com

De1103 © 2007 ico.livejournal.com

In the field

The chief problem with portable radios is that all receivers tend to overload near mountain tops. This can be immensely frustrating. What tends to happen is the listener is increasingly likely to inadvertently make mistakes. Whether it is mistaking images for legitimate stations or missing weak signals (because the weak stations are covered up by distorted images) the experience is often not rewarding!

For this reason, this blogger argues that a portable radio has a limited role to play for field trips. Their use is primarily suitable for inaccessible terrain or very remote areas perhaps 30 kilometres (19 mi) away from broadcast sites. Perhaps this suggestion is a controversial and extreme stance?  (It is important for every writer to remember that enthusiasts often hold strong views. Respect these differing opinions. Entering into robust on-line debates typically ends with instances of dysfunctional behaviour and worse case scenario, a loss of friendships).

Importantly, using a portable radio in a popular location makes it likely for others to think the listener is strange. As this difficult hobby is supposed to be about enjoyment and fun, no one needs to be ridiculed in public. The trick is to switch to a cricket or football broadcast – pretend that is the reason for lugging the radio. Of course, this writer does not need to pretend, although listening to cricket matches (hell, even briefly) can be tiresome when Australia exhibits poor form!

Nonetheless, it’s yet another reason to stick to the safety of a car receiver. Moreover, by using a car radio, a better antenna may be utilized (in many cars, a proper monopole). Car tuner performance makes listening far more comfortable, especially with regard to inter modulation distortion (IMD) – the unwanted mixing of two or more stations. Protection from adverse temperature extremes, in particular summer heat and thunderstorms cannot be lightly dismissed. For example, air conditioning is essential for comfortable mobile DX in cities and towns along eastern Australia.

For everyday use in high rise dwellings, the weaknesses of portables become much less evident. In fact, packing a portable in the luggage is a simple way to turn a potentially boring trip into a DX opportunity.

De1121 © 2010 nice.kaze.com

De1121 guts © 2010 nice.kaze.com

Favourite FM portable

The beauty pictured above and below is the DE1121. Despite the relatively high purchase price, the modified Degen DE1121 is the blogger’s favourite! The designers did made some mistakes; flaws include a complicated user interface and relatively poor build quality. However, this modified radio provides superior FM performance compared to DSP-based competitors with both indoor and outdoor antennas.

Little wonder that Degen’s sister DE1103 remains so popular amongst European FM enthusiasts. Between 76-108 MHz, the DE1103 features better 12 dB SINAD sensitivity than the Sangean ATS-909, that is 0.5 versus 1.8 microvolts.

De1121 station labelling © 2013 FMdxing

De1121 station labelling © 2013 FMdxing

Features of the DE1121 include:

  • Station labelling (all stations can be labelled using a computer);
  • Three level signal attenuator;
  • External antenna input;
  • Full length telescopic FM antenna;
  • 128 kbps MP3 recording (with noticeable artifacts);
  • MP3 playback;
  • Direct frequency entry;
  • Audio Input from other portable radios (to permit recording);
  • High sensitivity tuner (virtually identical to the DE1103);
  • Full aluminium tuner shielding  &
  • SSB decoding up to 30 MHz.
De1121 © 2010 nice.kaze.com

De1121 accessories © 2010 nice.kaze.com

De1121 © 2013 FMdxing

De1121 © 2013 FMdxing

De1121 © 2013 FMdxing

De1121 backlit © 2013 FMdxing

Recommended reading

2012 comparison of portable shortwave FM receivers by Universal Radio (Archived PDF file)

DE1121 world band receiver review by Dave N9EWO

Is DXing a hobby only for the rich?

Mt Canobolas Sharx in-car band scan by Dr Nobody (No longer available)

Portable DSP pain at Point Glorious by FM DXing

European data is compiled from tropospheric loggings in 2012. Enthusiasts who provided loggings reside in Belgium, Finland, France, Germany, Holland, Italy & Poland. This article was updated in December 2013.

Photos from the field

This gallery shows that setting up an FM antenna for long distance radio listening in an apartment is easy.

These three photos show the temporary placement of an antenna at Noosaville despite metal intrusions on the balcony. Antennas work optimally in free space, but the world is not perfect!

View of the rear balcony from ground level - Noosaville

Close up of the antenna - Noosaville

Close up of the antenna - Noosaville

This is how the receiving equipment was accommodated inside the apartment in this Noosa suburb. Please watch a partial bandscan here.

Tuner set to 4ABCFM 98.5 - Noosaville

At Pelican Waters, the balcony was more ‘accommodating’ of a friendly yagi companion! A prettier view makes these four dull antenna shots far more palatable as well!

View from the Front Balcony - Pelican Waters

View from the Front Balcony - Pelican Waters

View from the Front Balcony - Pelican Waters

View of the front balcony from sea level - Pelican Waters

This is how the receiving equipment was accommodated inside the apartment in this Caloundra surburb. Please be sure to watch the videos here.

Tuner set to 2ABCFM 98.7 with DVB receiver  - Pelican Waters

Note the pirate flag at this nearby caravan park.

A pirate radio flag at a caravan park

The same principles loosely apply for long distance reception of UHF DVB-T. In fact, setting up a UHF antenna for long distance television viewing in an apartment is even simpler. If that’s ‘the go’, a phased array is a good choice. The phased array is extremely portable and far less obtrusive than a collapsible yagi. A phased array was used briefly at Pelican Waters (the suburb pictured above) and was far more effective than the rooftop antenna to receive distant translators — supplementary ‘relay’ broadcasts.

Free to reproduce
Photos from the field by FMdxing is licensed under a Creative Commons Attribution-ShareAlike 3.0 Australia License.

The shire

Laguna Lookout, Noosa Heads

Laguna Lookout is located in the Headland Section of Noosa National Park. Altitude information is unknown, but utilizing Bonzle, it is crudely estimated that Laguna Lookout has a height of 105-131 metres above sea level.

Below is a boarding video recorded by Plummet Longboarding. The ride starts from the summit of the Laguna Lookout.

The view is not bad, either! Gwirionez documents the panaroma concisely.

Idling in the crowded Laguna Lookout carpark for about two minutes, stations including Radio National from Coffs Harbour (distance: 437km, azimuth: 183°) & Rockhampton (distance: 392km, azimuth: 318° – much weaker) were receivable on the Blaupunkt Twinceiver. Other tropospheric scatter audible during the rain was from Bundaberg & Passchendaele (distance: 269km, azimuth: 207°). Note all other stations from Coffs apart from 99.5 MHz are blocked by local broadcasts on the Sunshine, Cooloola & Fraser Coasts.

Images from the local Sunrise Road translator site (distance:10km) & Cooroy’s Black Mountain (distance: 24km) were significantly problematic throughout the shire. Based on the brief scan undertaken, no such issues were noted at this lookout.

Mount Tinbeerwah, Tewantin

The altitude of Tinbeerwah is 265 metres above sea level. It is a favoured destination for climbers. But for the biggest thrills, it is best traversed using a unicycle!

Alas, in the two trips made to the lookout, the most popular activity observed was much simpler… Watching the sunset.

Bruce C documents this thoroughly in this video.

At the higher sections on the Mount Tinbeerwah walking track (leading to the summit) Rocky’s Radio National on 103.1 MHz (distance: 384km, azimuth: 320°) was audible via troposcatter.

The Dabbler’s Dream™ portable receiver (on steroids: modified with an extended telescopic antenna) revealed no traces of Coffs Harbour. Considering that aforementioned local sites are 5km & 13km away, that is probably no surprise. Consider the impeded portable performance experienced by this blogger at Cooloolabin Dam.

It seems certain that RN heard on the portable was definitely the Rocky broadcast (rather than a mistaken image of the local 20 kW broadcast) because other Rockhampton Mount Hopeful broadcasts were also audible with heavy fading in the Tinbeerwah carpark using the Twinceiver.

In-car video of Coffs (distance: 438km, azimuth: 181°) was recorded at Lake MacDonald’s Mary River Cod Park upon darkness. Lake MacDonald adjoins Tinbeerwah. With any luck, the documentary evidence will be uploaded by the end of the week. In these suburbs, jet scatter along Lake MacDonald Drive, Cooroy-Noosa & Sunrise Roads seemed to occur between 5-6 pm daily.

Radio path data sourced from FM Scan.org using the Locate Yourself Precisely algorithm. Videos sourced from Youtube.

Portable reception

Here are some long distance catches received during the last fortnight using the Tecsun PL-300WT portable radio. The radio is equipped with an extended telescopic antenna and was used inside the house beside the window. Strong images from 4SBS Radio appear on the radio at this city location.

Sporadic E

Azimuth: east
Maximum distance: 1,635 km

Nouvelle-Calédonie 1ère 88.5 Loyalty Islands
Nouvelle-Calédonie 1ère 89.0 Nouméa
Nouvelle-Calédonie 1ère 90 Dumbéa

© 2012 France Télévisions Interactive

Plus an unidentified station on 91.5 MHz, possibly RFO 3 Nouméa.

Tropospheric Ducting

Azimuth: south
Maximum distance: 340 km

2MRR ABC Local Radio 92.3 Coffs Harbour
2ABCFM 97.9 Coffs Harbour

© 2012 Australian Broadcasting Corporation

Colour code:
Stereo signal on peaks
Received over local station from the north or south coast