FM Portable Shootout: Bauhn ADS215 versus Degen DE1121

The following post is a ‘quick and dirty’ portable receiver shootout between the Bauhn ADS215 and Degen DE1121.

The DE1121 was chosen as the contender as it is consistently the most sensitive radio this writer owns, offering outstanding performance on weak FM signals. Whether playing with FM signals on a mountain top, or in a beachside apartment or garage surrounded by steel & concrete… if a (more preferable) component tuner absolutely cannot be utilized, this portable radio shines the brightest.

Sensitivity data for the Bauhn ADS215 dual band receiver is NOT available, so a comparison test is one crude and fun way to gauge significant differences in receiver performance.

Methodology

Since both radios offer FM reception, this band is to be the subject of the test. To avoid potential interference from the mains power supplies, battery power was used. The telescoping monopoles on both receivers were used. It is important to be fair and perform the test with considerable urgency. Transient propagation changes over time affect VHF/FM receiver testing. Anomalies such as jet reflected signal improvements may distort results.

The Degen radio was tested first. The Bauhn radio was tested immediately after; perhaps five minutes had elapsed. Seven provincial FM signals were tested for 45 seconds each. The test was repeated the next day to ensure that potential propagation changes during the test had NOT affected the preliminary test.

Characteristic	Bauhn ADS215	Degen DE1121
Price	Sale $30 retail	From $91 delivered
Availability	Exclusively through ALDI stores	Exclusively through online merchants
Tuner	Gyro Signal 1128 (Taiwan)	Toshiba TA7358AP (Japan)
FM Sensitivity	N/A	Better than 5 microvolts for a signal with 30 dB S/N at 98 MHz
IF and Selectivity	Stock: Digital Processing of analogue IF	Custom modified: 180 kHz + 56 kHz Murata filters
Origin	China by Tempo Australia	China by same parent as Tecsun
Coverage	DAB: 174 – 240 MHz, FM: 87.5 – 108 MHz, Radio Data System, 50 kHz steps, RDS: PT, PS, RT & PI data	Longwave:  50 kHz – 521 kHz, Medium wave: 522 – 1719 kHz, Shortwave: 1700 kHz – 30 MHz, FM: 70 – 108 MHz, 10 kHz steps
Telescopic Antenna	80 cm Stainless Steel	90 cm Stainless Steel
Batteries	4 x AA	3 x AA
DC Supply	5 volts, 600 mA	6 volts, 300 mA
Inputs	Headphones	Headphones, Auxiliary Audio, External FM Antenna
Speakers	Single, 1 watt	Single, 77 mm diameter

Comparisons with other DAB+ receivers

Surprisingly, the Bauhn receiver offers superior sensitivity on the FM band than the far more expensive Pure One Mini and Bush BR10DAB. The latter contains Frontier Silicon’s Venice 5.1 module, which was released in the third quarter of 2008. That module was also included in the Yamaha TSX-120 Ipod dock and many other receivers. At that time, Frontier Silicon manufactured 80% of the chipsets, modules & platforms for over 300 DAB receivers.

Commerce & economics graduates are taught that purchase price is a guide to what the market will bear, NOT necessarily quality. That is certainly applicable for this product!

Notable features of the Bauhn receiver

 

Unlike the latter two receivers, internally generated spurious interference was absent on the FM band on the Bauhn DAB+ receiver. By accident, this tester discovered that the Bauhn ADS215 will in fact decode PI codes, making it advantageous for long distance FM (DX) enthusiasts as PI codes. DX enthusiasts use these unique station identification codes since this parcel of RDS data will decode most readily.

Accessing PI code data seems to be a hidden feature (aka Easter Egg) of the receiver. Certainly, there is no mention of such capability in the instruction booklet. To access the PI code mode, simply hold down the INFO button for about five seconds or longer. This is the radio’s software menu. Continue to press the INFO button until the current FM station’s PI code is displayed. Once PI code mode is activated, tuning in 50 kHz increments can be performed as per usual.

Weak Signal in MHz	Distance in Miles	Bauhn ADS215	Degen DE1121
89.1	86  (15 kilowatt ERP)	No signal	Mono
91.5	88  (1 kilowatt ERP)	No signal	Negligible signal
92.5	45	Mono	Stereo
96.1	85	Poor signal	Stereo
100.9	143	Indoor interference	Mono
102.9	45	Negligible signal	Mono
107.3	90	Mono	Quieting Stereo

Sensitivity

The sensitivity results compiled in table two (above) suggests that unsurprisingly, a dedicated FM radio (as usual) will outperform a DAB+ radio. Similarly, high-end DAB+ component tuners do NOT take advantage of the compromised FM section of the DAB+ modules, but employ a dedicated FM tuner module for optimal reception.

Brief word on DAB+ 

This mode was NOT tested thoroughly on this occasion, since this receiving location suffers no coverage deficiency. However, the Bauhn ADS215 is an extremely capable performer on DAB+. These transmissions are the primary choice for digital radio broadcasts outside of the Americas, which uses IBOC (In Band On Channel).

Many forum correspondents report the Bauhn ADS215 to be the most sensitive DAB+ receiver they own.  British hi-fi manufacturer AudioLab uses the same DAB+ module as this radio in their high sonically rated 8200T component tuner, according to the service manual.

DAB+ versus FM

The penetration of DAB+ continues in Australia and is expected to reach 16 percent of households by June 2014, according to PwC estimates. With new spectrum allocated to DAB+ in regional areas (now that analogue high band VHF television has been switched off), the future of digital radio broadcasting offers great potential across the continent.

Anecdotal reports suggest DAB+ programming in this country may have improved. At the very least, the discussion of DAB+ station content seems to be flourishing like never before! Unfortunately, the use of low bitrates to broadcast specialist music stations may continue to be problematic for those listening on component tuners within hi-fi installations.

Summary

The FM performance of DAB+ modules seems to be improving each year. The FM performance of a DAB+/FM combination radio might still NOT meet the onerous portable demands of long distance FM enthusiasts. Earlier articles listed below focus heavily on that very topic, and attempt to explain why some of these individuals may prefer custom modified portable FM radios such as the Degen DE1121.

The test results indicate that the Bauhn ADS215 is likely to provide satisfactory FM performance. Ideally this radio is suited to those listeners who suffer from patchy DAB+ reception, which means the fallback radio entertainment becomes analogue FM broadcasts.

Further reading

AudioLab Component tuner

AudioLab Component tuner Review – Adobe Reader document

Bauhn ADS215 discussion on Whirlpool forums

DAB chips to be in smartphones

DAB radio’s reception gaps proved to be a matter of life or death – Telegraph (UK)

Degen DE1121 detailed specifications – German export version

Degen DE1121 user reviews – Translated Russian

DE1121 Block Diagram – Adobe Reader document

GyroSignal Technology DAB+  tuner modules

Indicative sales prices for DAB+ radios

Kaito KA1121 detailed specifications – North American version

Toshiba TA7358AP FM front end – Adobe Reader document

Related blog articles 

Bauhn ADS215 satirical shootout

Inject your DAB+ portable radio with steriods

Portable FM radios favoured worldwide – Digital Signal Processing versus a Conventional IF section

Receiving Sporadic E reception with portable receivers

Survey of portable receivers used by European enthusiasts

What if analogue FM radio ended in the United States?

‘Tis the season for beer (Part 2)

This is now what the finished product looks like:

Along with brewing, the publication of radio articles on this blog will resume over summer without interruption. Three articles will be published which loosely focus on surviving long distance FM reception without an external antenna. It is a situation many enthusiasts find themselves in from time to time, especially during the summer vacation period.

Forthcoming radio articles include:

• Simple DAB+ FM portable receiver shootout;
• Easy improvements to portable FM receiver antenna performance &
• FM DXing without an external yagi antenna.

Christmas & New Year wishes to all readers. The Festive Season can be a stressful time of the year, but let’s hope everyone can slip in some relaxation. ‘Tis the season for beer, after all! Try not to fight too much with family & friends! 🙂

‘Tis the season for beer (Part 1)

This blogger first started brewing beer in 1998. Due to other commitments, the hobby was unintentionally discontinued after 2005. Perhaps priorities changed?

Nothing messes up a tidy kitchen faster than brewing, especially when using vintage equipment designed back in glorious 1990s!

The first brew to contemplate ‘back on the trail’ needed to be as simple as possible.

Compared to previous brews, relatively inexpensive commercial ingredients were chosen, for example… no heating of grain on the stove. Nothing hard core or even remotely ‘expert’ was to be attempted on this occasion. After an extended absence, it was more important to try and re-acquaint oneself with the fundamental techniques of temperature control and sterilization. Minimizing equipment failure is also a factor at this point due to the age of the kit.

Pale Ale recipe

1.7 kilograms Cascade Imperial Voyage Pale Ale

1 kilogram Ultra Brew fermentable sugars

15 grams Cluster Hop Pellets (steeped for 20 minutes)

1 packet Dry Yeast (supplied with can of concentrate)

3 litres freezer-chilled Spring Water (to cool wort before adding yeast)

Tap Water

Key measurements 

Alcohol by volume	3.6 percent
Original gravity	1.040
Final gravity	1.012
Apparent attenuation	70 percent

Fermentation was complete after five days. The final gravity measurement taken with the hydrometer at this point remained unchanged for the next 48 hours. Bottling took place after seven days in the fermenter.

Temperature chart

DATE	DAY	MINIMUM	MAXIMUM
22	Friday	19.5	27.1
23	Saturday	21.9	28.1
24	Sunday	20.0	29.2
25	Monday	20.5	27.0
26	Tuesday	20.0	25.9
27	Wednesday	15.9	25.5
28	Thursday	17.1	26.6
29	Friday	18.6	29.3

Unfortunately, the beer sat in the fermenter at summer temperatures (maximum average 27 °C or 80 °F) a day longer than necessary. This was unavoidable as the bottling process takes two and a half hours in the cool of the evening. The exterior of the fermenter was cooled with ice during the final day prior to bottling. The cooling arrangements were implemented the night before, since the temperature forecast suggested the last day was to be the hottest of the month.

The bubbling had subsided after day five when the first hydrometer measurements were taken. On the final day (seven), the airlock continued to bubble (at most) every half an hour. The notoriously unreliable airlock should never be relied upon as an indicator exclusively!

The chilled, uncarbonated, unsweetened beer exhibits a dark maroon colour. Tasting suggests a slight resemblance to Newcastle Brown Ale. No strong ester characteristics were detected. Should it be left in the fermenter too long during high temperatures, beer may taste like ‘fuel’ or exhibit a solvent flavour prior to bottling. These harsh tones may dominate and ruin the flavour of the beer, even after aging.

During the bottling phase, commercial carbonation drops and a two litre Darwin stubby were used to save time. Priming 60-odd 375 ML bottles is old fashioned, but old habits die hard! 🙂

Why was an ale chosen?

According to Frey, Scheetz & Sheidy:

Ale is beer that is brewed using only top-fermenting yeasts, and is typically fermented at higher temperatures than lager beer (15 – 23 °C, 60 – 75 °F). At these temperatures, ale yeasts produce significant amounts of esters and other secondary flavours and aromas, oftentimes resembling those of apple, pear, pineapple, grass, hay, banana, plum or prune.

Daniel Stromwall, Andrea Lin & Chrissta Maracle offer further enlightenment:

If the wort brews at a higher temperature 10 – 2 (50 – 77 °F) using an ale fermenting yeast, the fermentation process will favor the production of esters and diacetyl compounds. The result is a beer that is fruitier and more robust in flavor while having higher sugar content and lower ethanol content than lagers.

In a nutshell, it is more difficult for high temperatures to ruin an ale when undertaking a potentially challenging summer brewing schedule. Bottle conditioning of this ale now requires at least four weeks in a cool dark place. The ale will be ready in time for Christmas, with additional aging to potentially improve the taste of the beer by the New Year.

Temperature data sourced from Bureau observations during the seven day brewing period, 22-29 November 2013. Thank you to all those kind folk, including master capper Fat Crap who shared the hard work!

Related articles

• Cascade Pale Ale (daniel.fragar.id.au)
• Cascade Pale Ale comes good! (beerblokes.blogspot.com.au)
• Bulk & pale, finally there (wemakehomebrew.com)
• Keep calm & brew up: How to home brew in 5 simple steps (kamerynevans1.wordpress.com)
• Return of an old kit, now colder (wemakehomebrew.com)
• The ale & the lager: The roots of all beer (mmc4120.wordpress.com)
• The problem with ESB: A treatise on beer styles (masterbrewerscorner.wordpress.com)
• Tasting: Nelsons Citra Pale Ale (halffullpint.wordpress.com)
• New beers bottled & fermenting! (darkstormbrewing.wordpress.com)
• Students craft own beer & drink it too (thewindcriesmaryyy.wordpress.com)
• Make me sweat! Cool tips for hot weather brewing (byo.com)