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50 November 2010

quires only basic soldering skills and would

be a good first project for those interested in

hands-on construction.

The Review Setup

I tested the receiver using two antenna

systems. The first was a high end antenna

system that consists of a homemade eight

element, right hand circularly polarized

Yagi with an antenna mounted preamp and

low loss hardline coax from the antenna

to the shack.

The antenna is mounted on

a computer controlled azimuth/elevation

(az/el) rotator system that automatically

tracks the satellite. This antenna system has

been developed over the years and gives con-

sistent horizon to horizon, noise free imagery.

The second antenna was a starter system

that consisted of a homemade turnstile an-

tenna with a run of 75 feet of RG-8X coax

with and without an antenna mounted pre-

amp.

The display software was WXTOIMG

running on a typical laptop computer.

From the Box to First Image

The review receiver came with the op-

Reviewed by Mark Spencer, WA8SME

ARRL Educational and Technology

Program Coordinator

I have been a user of the NOAA polar

orbiting satellites sending automatic picture

transmission or APT imagery for years.

Additionally, during the ARRL Teachers

Institutes, I encourage teachers to use these

NOAA satellite signals and their imagery in

their classrooms. A number of TI graduates

have installed satellite ground stations at

their schools and share imagery and weather

observations across the county.

For hams interested in exploring the sat-

ellite facet of the hobby, the NOAA satellites

are an excellent resource because their VHF

signals at 137 MHz are relatively strong.

They are easy to receive with basic equip-

ment, and a variety of computer software

packages (many freely available) make the

display of the imagery from space a snap.

The typical received image is illustrated in

Figure 2, which was produced during this

review. Though you can receive the NOAA

signals with a regular 2 meter FM radio or

police scanner tuned to the 137 MHz chan-

nels, quality reception of the APT signals

requires a wider receiver bandwidth than

FM voice. A receiver designed for APT

reception gives far better results.

Overview

The Hamtronics R303-137 receiver

is a replacement for the successful R139

weather satellite receiver that I have used

for many years. It’s is a weather satellite

adaptation of the Hamtronics commercial-

grade VHF FM receiver. The R303-137 has

four frequency synthesized channels that

cover the NOAA satellite frequency plan

and it has an IF bandwidth that is optimized

to receive APT imagery.

The receiver is not a plug-and-play unit

and comes as a circuit board only. The user

installs and solders interconnecting cables

and wires to connect the board to a 12 V

power source, antenna, speaker and com-

puter sound card. (You can mount it in a

suitable enclosure if desired, but that’s not

necessary.) Putting the receiver on the air re-

Bottom Line

With a little work, the R303-137

weather satellite receiver board

offers a great way to receive fasci-

nating weather satellite images.

The eight element Yagi antenna is detailed

online at www.arrl.org/ariss-tracking-

interface. Though the dimensions are for

2 meters, the antenna is easily scalable for

137 MHz. Contact WA8SME at mspencer@

arrl.org if you would like the dimensions for

the weather satellite version of the antenna.

The documentation refers to the turnstile anten-

na design as published in the ARRL Weather

Satellite Handbook (unfortunately this excel-

lent resource is no longer in print). If you

would like the details of the turnstile antenna

referenced and used in this review, contact

WA8SME at [email protected] and request

an extract that includes the information.

The display software used in the review can

be downloaded from www.wxtoimg.com.

Hamtronics R303-137 Weather Satellite

Receiver Board

Figure 2 — This image was received with

the R303-137 connected to a Yagi antenna

and mast mounted preamp.

tional power supply cube and a few pages of

documentation. The documentation, though

it appears Spartan, is well written and con-

tains all the information you need to set

up and connect the receiver to the external

parts required for operation. Following the

directions, it doesn’t take long to solder the

required wires to the through hole solder pads

and make connections to the power supply,

speaker, computer sound card and antenna.

Channel selection is made by jumper-

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