Comtek PR-72b Personal Companion Receiver - GRADE DB
PLEASE CHECK OUR OTHER SALES FOR MORE OF THESE MODELS IN DIFFERENT GRADES AS WELL AS M72 TRANSMITTERS AND UNITS WITH DIFFERENT FREQUENCIES
This sale is for 1 only PR-72b receiver. The pics may show more than 1 but again this sale is for 1 only unit. Batteries are not included. We offer these units as working and in condition as according to our own grading system. They are not offered with any warranty and can not be returned.
We have a few of these to sell and they are in different grades. All have been exhaustively tested, adjusted & graded as to performance, range, output levels and cosmetic appearance. All input connectors for monitoring have been adjusted as required for a tight fit. All output connectors are mono only, if you require monitoring in L & R you will need to use an 3.5mm Stereo to Mono adaptor. All battery covers clip into place and all units are fitted with the A Frequency Crystal (72.1 MHz). None of the units have breaks or cracks.
We have 2 versions of the PR-72b, the difference between them is in the volume knob, this is either a low surface type or a larger knob. Some of the low surface types have lost their knob and need adjustment by flat screwdriver or your thumbnail.
Remember, this is a used radio receiver, we have gone out of our way to test and adjust and accurately describe the condition of these units, your own findings may vary from ours. We can not control this. You may find that the PR-72b you buy from us differs from one you already have, again we are unable to control this. We would ask that you accept that we have done all we can to set these up, test & adjust and do not post negative feedback if you are not entirely happy. These units are probably the most tested and best described used PR-72b units available on the market right now and are priced fairly.
AVAILABLE GRADED UNITS
- A - None, we would consider A grade to be brand new and these are not.
- B - Unit is complete, has an Obstacle Range of 15-20M and a Line of Sight range of 30-50M, volume Knob is complete
- C - Unit is complete, has an Obstacle Range of 15-20M and a Line of Sight range of 30-50M, volume Knob is missing or turns 360 degrees with no Stop but works ok
- D - Unit is complete, has an Obstacle Range of 10-20M and a Line of Sight range of 30-50M, volume Knob is complete
- E - Unit is complete, has an Obstacle Range of 10-20M and a Line of Sight range of 30-50M, volume Knob is missing or turns 360 degrees with no Stop but works ok
Cosmetic Condition Grade
This grade relates only to cosmetic appearance, some units are yellow in appearance.
- A - None, we would consider A grade to be brand new and these are not.
- B - Slight discoloration, some marks and scratches
- C - A lot of yellowing of the case, some marks & scratches.
Summary of Grade Description
Units are graded firstly with Performance Grade then with Cosmetic Grade, an example is:
D - Unit is complete, has an Obstacle Range of 10-20M and a Line of Sight range of 30-50M, volume Knob is complete
B - Slight discoloration, some marks and scratches
COMPLETE SPECIFICATION SHEET
The PR-72b Companion receiver is a high performance miniature receiver. And due to its excellent performance and many available options, this versatile receiver may be used for many applications - IFB and professional studio communications, personal cueing, industrial communications, and individual auditory assistance, to name a few. Also, because of its extended frequency response and low noise level, the PR-72b is a convenient receiver to use with portable tape recorders.
The PR-72b incorporates the latest state-of-the-art technology offering low power consumption for longer battery life (up to 40 hours). Special features include an LED battery condition indicator, automatic on/off power switch, battery charging access through the output jack, slide-open battery compartment, and no external antenna - only the output cable extends from the receiver.
The following options are also available: plug-in channel selector, external microphone input for specialty applications, switch for two-channel operation and an independent on/off switch. Moreover, the PR-72's small size and light weight make it easy to carry in a pocket or pouch.
Audio Outputs : 2.5 volts RMS, adjustable volume control nominal load 50-600 ohms (100 ohms nominal)
Connectors : 1/8" mini jack (locking plug optional)
Indicators : LED battery condition indicator
Audio Frequency Response : 100 Hz to 10 kHz with M-72 transmitter
Operating Radio Frequency : Single channel, 50-215 MHz
Frequency Stability : .005% crystal controlled
RF Sensitivity : 1 µV for 20 dB of quieting
Adjacent Channel Rejection : -55 dB with 50 kHz channel spacing (72-76 MHz)
Image and Spurious Response : At least -60 dB (72-76 MHz)
Ultimate Quieting : Better than -65 dB related to output
Bandwidth Acceptance : Up to 30 kHz deviation
Antenna : Intergral with output cable (no external antenna)
Current Drain : 14 mA nominal
Battery : 9 volt alkaline Eveready 522 or equivalent or optional 9 volt nickel-cadmium rechargable battery
FCC Compliance : Certification under Part 15
Dimensions : 1 1/16" X 2 1/4" X 3 1/4" (27 mm X 57 mm X 83 mm)
Weight : 4 ounces (110 grams) approx.
COMTEK PR-72B TEST PROCEDURE
Comtek M72 Setup - Obstacle Test
- Wireless Microphone plugged into a PC Line output, set to 50% output level, generate constant tone
- Fitted with a 30 cm whip antenna
- Battery voltage between 8.2 to 9V
- Set upright on desk next to PC
(POINT A - 4M) - Room with gyprock walls on timber frame, wooden door closed M72 4M from door.
(POINT B - 12M) - Garage style roller door 8M from wooden door.
(POINT C - 13M) - Outside garage roller door
(POINT D - 19M) - Sedan car parked behind roller door 6M from roller door
(POINT E - 24M) - Driveway behind Car +5M
(POINT F - 29M) - Driveway behind Car +10M
Comtek PR-72b Setup
Input connector checked for electrical connection and tightness, adjusted if needed for tight fit
Battery voltage between 8.2 to 9V
Fitted with small personal Sony headphones
Walk tested to behind car (18M)
Signal monitored for quality and background noise when moving & when stopped and move unit for optimal signal
All units worked perfectly to POINT C - 13M
Some units experienced some choppy noise and hiss between POINT C - 13M and POINT D - 19M
These units are labelled OBST 10-20M When stationary at this range they are clear.
Units that were relatively clear to POINT E - 24M to POINT F - 29M are labelled OBST 15-20M. When stationary at this range they are clear.
Line Of Sight Test
M72 & PR-72b taken outside and tested facing each other with no obstacles. Units were relatively clear up to 30M even when moving. At the 30M mark they became choppy depending on transmitter antenna orientation and receiver orientation. This choppiness was more pronounced when walking between 30-50M. At 50M all units were able to hold a clear signal when stationary and units moved to optimise reception.
Output Level Tests & Adjustments
M72 connected to SQN Mixer with constant tone, output volume of M72 fixed to around 50%
PR-72b connected to input of SQN Mixer in the same room as M72
PR-72b Headphone volume set to Maximum
Noted input meter position to determine output level of receiver, set a reference for one PR-72b at 0 dB
All PR-72b receivers connected to SQN Mixer and internal output pot adjusted to bring to 0dB level
All PR-72b are now outputting the same level of signal at MAX volume setting