Tuesday, September 29, 2009

A Compact Chinese Made QRP Transceiver with General Coverage Receiver: The HB-1A by BD4RG.

Thursday, September 24, 2009

Full Size Cans: Kanen KM-880 Wooden Headphones.

Technical Data :

Driver Units: 40mm
Frequency Range: 20-20.000Hz
Sensitivity: 104 dB ( at1 KHz, 1mW )
Impedance: 32 Ohms
Cord: Single-sided (separated)
Cord Length(approx): 2.1m
Jack: 3.5mm, nickel-plated

First Impressions :

The headphone closely resembles the Targus wooden cans previously reviewed here. They come packed in a see through blister pack together with a microphone (Separate) which can be used with your computer sound card.

The Kanen KM-880 wooden headphones are a product of China and the price is ridiculous as they are being sold for US$15.50.

Right out of the box they sounded very good and I would say exceptional, exceeding the price value paid. They are great for bass head with a very extended and well controlled tight bass, no muddiness at all. The overall tonal balance was quite a surprise to me since the mid range was well balanced and the highs were nicely extended and crisp, the cohesion was good.

The plastic headband maybe a failing component later as I can foresee the plastic becoming brittle later on, but at such a low price who really cares! The wood appears to be similar to the Targus (maple???). Without any burning in these headphones sounded good out of the box and were pleasing to the ears, with furter burning they may open up even further.

I tested these using the Tsinghua University G&W TW-J1 SS headphone amplifier connected to a Sony D-NE730 discman and listened to them with only one disc that was on the study table at the time - "Mindi Abair's Come as you are", the saxophone rendition throughout Mindi's album sounded very sweet and seductive.

I did not notice any discomfort and in fact found them quiet comfortable and light. For under US$16.00, I would say go for it - you get a pair of wooden cans which sound not at all bad.

Alinco DJ-G7 Tri-band Handheld Transceiver (144MHz, 430MHz and 1.2GHz) plus General Coverage Rx.

The Alinco DJ-G7 is a Tri-band amateur radio handheld transceiver covering the 144Mhz, 430MHz and 1.2GHz bands as standard, plus it has a general coverage receiver for SW reception in AM.

It comes with it's own charging cradle powered from a wall wart transformer. Two independent VFOs, dual independent controls, up/down scanning, dual independent displays, main and sub transceiver toggling functions, call, repeater offsets, memory, scope, mode, tone, CTCSS, priority, memories, step, power output - the functions just go on and on.


144MHz 5W / 430MHz 4.5W / 1200MHz 1W
FM Tri-band Handheld Transceiver
Manufacturer's Details on the transceiver:

Get ready for action as you hear signals that you may never have heard before.
The DJ-G7 tunes 0.530-1299.995MHz continuously, and you can enjoy full duplex receive in combination with the amateur 144/430/1200MHz bands. AM and WFM modes allow you to hear the aviation and broadcast bands and with the broadcast preset memories and built-in AM bar antenna radio listening is easier than ever. Enjoy a variety of scan modes and options that include Time -set scan, 50 pair of programmable scan memories, Timing adjustable priority scanning and Alinco's patented Channel-Scope?visualize the presence of radio signals on the display. There are also two modes of bug detector functions.
*Restrictions may apply to frequency combinations for Full-duplex QSO.

Customize the DJ-G7 to your personal preferences.
Set the parameters to suit your needs and likes. Choose the display language (English/Japanese) lamp function and display contrast and brightness. Select Auto-Power Off / Battery save function. Turn sounds (beep, bell, end beep) on or off. Set the transmitter for VOX / TOT / BCLO. Control the DTMF burst timing, link your scan banks, set priority scan-timing and memory skip functions and more. Personalize the DJ-G7 to make it, "YOUR DJ-G7".

About IPX7 Designation
The IPX7 designation provides for limited waterproofing of the radio. The specifications are immersion in one meter (approx 3ft) of still sweet water for up to 30 minutes. This compatibility is factory guaranteed for a period of one year provided all the jack covers are securely in place, any accessories connected must be genuine Alinco water-proof accessories and the radio has not been disassembled by the customer. The factory has tested and made the equipment compatible to IPX7 certification during engineering. However, please understand that this equipment is NOT certified IPX7 compliant but is designed to remain operational when used in rain, severe weather or in accidental cases of dropping it in water when used in extreme conditions and is in no way stating that you should attempt use the radio under water or submerge the radio for cleaning. Warranty will not cover radios that are water / salt damage due to negligence or misuse of the product.

Frequency range:
E-version TX/RX: 144.000 - 145.995MHz / 430.000 - 439.995MHz / 1240.000 - 1299.995MHz
AM/FM/TV(analog) broadcasting bands

T-version TX: 144.000 - 147.995MHz / 430.000 - 449.995MHz / 1240.000 - 1299.995MHz
Sub-band RX: 0.530 -1299.995MHz
(Cellular frequencies 824.000 - 849.995MHz, 869.000 - 894.995MHz blocked on T-version )
TX: F2D/F3E (RX only:WFM,AM)
Memory channel:
1000 channels + 1 call channel per ham bands+50 programmed-scan pairs+100 dual-memory+100 priority+100 serch-pass
Antenna impedance:
50 ohm unbalanced
Frequency stability:
+/- 2.5ppm
Supply voltage:
DC 7.4V (EBP-73 Li-Ion battery pack) / DC 4.5 - 16V (external regulated source)
Current consumption:
(Typical value)
TX approx. 1.6A/144MHz, 1.8A/430MHz, 0.8A/1200MHz
RX approx. 200mA
Battery save (1:4) approx. average: Dual 56mA / Single 50mA
Temperature range:
-10 to +45 degrees C. (+14 to 113 F)
(WxHxD Projections exclusive): 60 x 115 x 30 mm or 2.36 x 4.53 x 1.18 in.
(Antenna/EBP-73 inclusive): Approx. 296 g /9.55 oz
Power output:
DC13.8V: 144MHz/430MHz 5/2/1/0.3W,1200MHz 1/0.3W
EBP-73: 144MHz 5/2/0.8/0.3W, 430MHz 4.5/2/0.8/0.3W, 1200MHz 1/0.3W
4 x AA cells (Max): 144MHz 2W, 430MHz 1.5W, 1200MHz 0.5W
Variable reactance
Spurious emission:
-60db or less
Max. Deviation:
+/- 5kHz
Mic. impedance:
2K ohms
Double-conversion super heterodyne (NFM,AM)
Single-conversion super heterodyne (WFM)
144/430MHz ham-radio bands -15dBu or better
1200MHz ham-radio band -13dBu or better

Sub-band receiver (Best values):
AM (10dB S/N):
Lower than 50MHz -1dBu
50MHz and above -6dBu
FM (12dB SINAD):
30-470MHz -15dBu
470MHz and above -7dBu
76-470MHz -6dBu
470MHz and above -3dBu
Intermediate frequency:
Main-band FM 51.65MHz / 450KHz
Sub-band AM/FM 50.75MHz / 450KHz
Sub-band WFM 10.7MHz
AM/FM -6dB 12KHz or more / -60dB 35KHz or less
WFM -6dB 130KHz or more / -60dB 300KHz or less
AF output:
400mW (8ohm 10%THD)
Specifications subject to change without notice or obligation. Specifications apply to Amateur Radio bands only. Permits required for MARS use. Product intended for use by properly licensed operators. Wide band receive related specification is for T-version only.800MHz cell-phones frequencies blocked on T version. RoHS compliant.

  • EBP-73 Li-Ion Battery Pack 1200mAh 7.4V
  • EDC-173T Drop-In Charger (120V/T-version)
  • EDC-173E Drop-In Charger (240V/E-version)
  • EA-163 Antenna
  • EBC-23 Beltclip
  • Handstrap
    (Please be advised that EDH-35 dry-cell case is not included in T and E packages.)
  • EDC-36 ------------ Cigarette Cable with filter
  • EDC-43 ------------ Cigarette Cable with charger
  • EDH-35 ------------ Dry Cell Case
  • EDS-10/EDS-14 --- Plug Conversion Cable
  • EDS-11 ------------ Cloning Cable
  • EME-32A ---------- Earphone/Mic (heavy duty)
  • EMS-62 ------------ Speaker Mic
  • ERW-4C ----------- PC Interface Cable (Serial)
  • ERW-7 ------------- PC Interface Cable (USB)
  • ESC-50 ------------ Soft Case

Friday, September 4, 2009

Classic Collector's Premium Communications Radio: Japan Radio Company NRD-515.

The Japan Radio Company NRD-515 is a classic collectors communications radio still held in very high regard by DX'ers and seasoned SWL'ers even today. When it was first introduced back in the 80's the basic radio was fetching US$1,200 plus (option filters, speaker etc.). Today secondhand it is still fetching well over US$1,100 a piece depending on what options and configurations come with the radio. These radios are literally snapped up as soon as they appear on the secondhand market and there is no shortage of people waiting on the waiting list to try and get one.

Yours truly is also in the fortunate position of owning one of these receivers in pristine, almost mint condition with the matching NDH-518 external memory units. I will over the course of the next two weeks or so be talking about this great receiver and what makes it so special and sought after and even today. Before I get launched in to the nitty gritty I will leave you with some photos and a video from you tube.


The Japan Radio Company is a long established company since 1915 and is considered one of the oldest and largest electronics manufacturing companies in the world. Employing over 3,000 workers, JRC is a respected expert in such areas as marine radio equipment, mobile and satellite communications, fiber optics, radar, navigation equipment, and avionics systems. Therefore, it should be no surprise that JRC's line of communications receivers are held in high regard and so highly sought after for their excellent and outstanding performance, dependability, ergonomics, and ease of use.

Over the years, JRC has manufactured a fine line of consumer grade shortwave communications receivers. Beginning with the NRD*505 and ending with the NRD*545, not to mention also a fine line of amateur radio transceivers. Japan Radio Company has incorporated state-of-the-art features into a unit designed with excellent sensitivity and to be operated with ultimate user comfort. This NRD-515 is no exception and is typically sought by collectors that are fond of it's design and capabilities and exceptional performance with no compromise. According to Fred Osterman in his book "Shortwave Receivers Past and Present" the NRD-515:

"is robustly built and straight-forward to operate. This receiver remains popular with utility DXers, tropical band enthusiasts, and general shortwave listeners. The '515' has nearly a cult-like following. Clean lines, easy operation, a solid feel and outstanding performance come together in this radio."

Interestingly, the 515 sold in the late 70's thru the mid 80's for about $1,000 to $1500....a tidy sum of money in those days. Extra features such as the memory unit and additional IF filters would push the price even higher. When new models come out, typically older shortwave receivers, like most consumer products, lose much of their original value. However, the 515 in good condition is a true exception with selling prices remarkably stable even 25 to 30 years later have remained high. There are many reasons for this.

First of all, the receiver is truly built like a battleship The receiver front panel and cover are made from heavy gauge steel and designed to last. The only plastic is found are on the various knobs and feet with the balance of the receiver is all constructed of metal - no compromise, period. Even the top of the range receivers and transceivers today cannot boast this!

Secondly, the 515 was made during an era of mostly analog dial readouts that could tune to within 5 kHz or maybe even 1 kHz. However, the red LED readout of the 515 could literally tune to a resolution of 100 Hz...an achievement unparalleled by other consumer equipment from that era and almost unheard of. Only military spec. equipment could brag about such extremely high resolution tuning. Other Japan electronic manufacturers of the era were beginning to release some models with digital readouts, but again, the resolution was only as good up to about 1 kHz.

Tuning on the 515 is accomplished using a variety of knobs. The user would determine which one of 30 MHz bands they would like to tune and move the large MHz dial into that position. JRC used a optical rotary encoder that is extremely durable. Then actual tuning to the specific frequency would occur with the large right main tuning knob, or if faster tuning was desired, using the toggle tuning switch that is located at about 2 o'clock to the main tuning knob. For most tuning, this method is sufficient. However, if tuning on SSB or for RTTY, JRC also included a fine tune control that they called the delta control. This control deviates by about + or - 3 kHz and allows for extremely precise tuning.

The 515 is a extremely stable receiver. Drift after about 30 minutes of warm-up is reported to be less than 50 Hz per hour, but avid users report that they rarely have to re tune. This stability is uncustomary for this time in the consumer market and unheard of.

A nice feature found on the 515 is the pass band tuning. This control coupled with the receiver's excellent dynamic range allowed the operator to frequently eliminate considerable, if not all, of the side band interference. When used in conjunction with the optional installed filters, the 515 becomes a fantastic unit for searching out those weak signals. The choice of filters is not mode dependent and this gives the user an extra degree of flexibility in use.

General Specifications:

  • Coverage from 100 kHz to 34000 kHz
  • Installed filters of 6 / 2.4 / .6 / .3 kHz
  • Noise blanker
  • Delta Tune (RIT) of + or - 3 kHz
  • BFO + or - 2 kHz
  • RF gain
  • AGC fast / slow / off
  • UP / Down tuning
  • Pass band tuning + or - 2 kHz
  • S-meter
  • 1/4" Headphone jack
  • Ext. speaker jack
  • Line out jack
  • Attenuator -10 or -10 dB
  • BC preselector / tune
  • Mute and monitor functions for amateur radio use