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Call 0345 2300 599The Sierra Radio Systems SIR-335 is a two port RF watt meter control module for the Sierra Station Controller range.
Also known as the WM-1, this module allows compatible WaveNode RF sensors to be integrated into a Sierra Station Controller system, providing remote monitoring of forward power, reflected power, and SWR from the Station Controller dashboard.
The SIR-335 supports one or two active RF power monitoring sensors, allowing two RF paths to be monitored from a single control module. Any combination of compatible HF, low-power HF, or VHF/UHF WaveNode sensors can be used, making it suitable for HF stations, QRP setups, VHF/UHF systems, repeaters, and remote installations.
The module can provide periodic power measurements, streaming data with a refresh rate of less than one second, and repeater keying and monitoring functions. It also includes PTT input and PTT output connections, allowing transmitter activity to be monitored and, where required, keyed for testing.
Key Features
- Two port RF watt meter control module
- Also known as the WM-1
- Integrates compatible WaveNode RF sensors into a Sierra Station Controller system
- Supports 1 or 2 active RF power monitoring sensors
- Measures and reports forward power
- Measures and reports reflected power
- Allows SWR monitoring through the Station Controller dashboard
- Supports periodic measurements
- Supports streaming data with less than 1 second refresh rate
- Can be used for remote repeater keying and monitoring
- PTT input for monitoring transmitter status
- PTT output for transmitter keying during testing
- Compatible with HF, low-power HF, and VHF/UHF WaveNode sensors
- Control over Sierra DCN
- Suitable for remote stations, repeaters, and station monitoring systems
Compatible WaveNode Sensors
The SIR-335 requires at least one compatible WaveNode RF sensor or directional coupler. The sensor is not included and must be purchased separately.
Suitable sensors include:
| Sensor Type | WiMo SKU | Typical Use |
|---|---|---|
| HF-1 | WN-2.HF | HF operation up to 2kW |
| LP-1 | WN-2.QRP | Low-power / QRP HF operation up to 60W |
| UHF-1 | WN-2.UHF | VHF/UHF operation up to 300W |
Any combination of compatible HF and VHF/UHF sensors can be used at the same time, up to a maximum of two sensors connected to the module.
Typical Uses
- Remote RF power monitoring
- Forward and reflected power monitoring
- SWR monitoring through the Station Controller dashboard
- Remote HF station monitoring
- Repeater power monitoring
- VHF/UHF station monitoring
- QRP or low-power station monitoring with the correct sensor
- Monitoring amplifier output power
- Monitoring antenna system performance
- Remote transmitter test keying where appropriately configured
Station Controller System Role
The SIR-335 adds RF power monitoring to a Sierra Station Controller installation.
It connects to the Sierra DCN, or Device Control Network, using RJ45 style connections and network-style patch cables. The DCN connection is used for module communication and can also provide system power when connected to a suitable Sierra Station Controller host or powered DCN system.
The Station Controller can poll the watt meter module and update the dashboard. A power measurement can also be triggered from the dashboard when required.
Although the DCN connectors are RJ45 style, they are not standard Ethernet ports and should only be connected to compatible Sierra Station Controller modules and accessories.
Connections and Functions
| Function | Details |
| RF sensor ports | Supports 1 or 2 compatible WaveNode RF sensors |
| Measurement types | Forward power, reflected power, and SWR monitoring |
| Measurement modes | Periodic measurements or streaming data |
| Refresh rate | Less than 1 second in streaming mode |
| PTT input | Monitors transmitter active status |
| PTT output | Can key transmitter for testing where correctly configured |
| Control method | Sierra DCN |
| System type | Sierra Station Controller |
Specifications
| Specification | Details |
| Brand | Sierra Radio Systems |
| Model | SIR-335 |
| Alternative name | WM-1 |
| Product type | Two port RF watt meter control module |
| Number of sensor ports | 2 |
| Active sensors supported | 1 or 2 |
| Supported sensor types | WaveNode HF-1, LP-1, and UHF-1 |
| Measurement data | Forward power and reflected power |
| Dashboard support | Sierra Station Controller dashboard |
| Control method | Sierra DCN |
| PTT support | PTT input and PTT output |
| System type | Sierra Station Controller |
Important Note
This listing is for the SIR-335 Two Port RF Watt Meter Control Module only.
At least one compatible WaveNode RF sensor or directional coupler is required. The RF sensor is not included and must be purchased separately.
SIR-310 host adapter, installation kit, DCN hub, power supply, RF sensors, coaxial cables, antennas, transmitters, amplifiers, and other accessories are not included unless stated otherwise.
A suitable 12V DC supply is required when the module is not being powered through a Sierra DCN connection from a suitable Station Controller host or powered DCN system.
The Sierra DCN uses RJ45 connectors and network-style cables, but DCN connections are not standard Ethernet connections. Do not connect DCN ports directly to normal Ethernet network equipment.
Shipping & Delivery
We offer UK and international delivery services, including next working day and selected weekend options for eligible orders. Available services, prices and estimated delivery times are displayed at checkout.
Delivery Information
Delivery options depend on the parcel's size, weight, contents and destination. Express and weekend services are subject to availability and cut-off times. Oversized or exceptionally heavy items may require a specialist delivery quotation.
Returns & Cancellations
To arrange a return, please contact ML&S or complete our returns form. You may also exercise your statutory right to cancel by email or another clear statement, without completing the form.
Changed Your Mind?
Under the Consumer Contracts Regulations 2013, most purchases made online or by telephone can be cancelled within 14 days of receipt.
You must notify us of your cancellation within this period and return the goods within a further 14 days.
Please handle all goods with care. Returned items must be in a resaleable condition, complete with their original packaging, and all supplied accessories.
You may inspect goods as you would in a shop. Handling beyond what is necessary to inspect them may result in a lawful deduction for diminished value.
Exceptions
Modified Equipment & Reversal Charges
Additional return conditions may apply to equipment modified at the customer's request, including wideband transmit or receive modifications.
ML&S may charge a reasonable fee to reverse physical modifications and restore the equipment to its original factory specification. Any such charge will be agreed in advance and deducted from your refund.
Custom-Made Cable Assemblies
Coaxial cable assemblies manufactured to a customer's specifications are excluded from the 14-day return policy and are non-refundable unless faulty.
Software & Labour Charges
Labour and modification charges requested by the customer are non-refundable once the work has been completed.
Computer software may only be returned under the 14-day return policy if it remains sealed and unopened.
Return Postage Charges
Customers are responsible for the direct cost of returning unwanted or incorrectly ordered goods, where permitted by law. You may arrange your own suitable return postage or use one of our optional prepaid services.
Standard Parcels
Royal Mail Return Label
£5.95
Per parcel
For eligible standard-sized parcels, subject to Royal Mail restrictions. Free collection included.
Larger Parcels
DPD Return Label
£7.95
Per parcel
For larger or heavier parcels and any shipments with batteries.
Collection Service
DPD Collection
£25.00
Per parcel
Available upon request for eligible addresses, subject to availability.
Prepaid return charges will be confirmed before booking and deducted from your refund.
These prices apply to eligible UK mainland returns. Oversized items, specialist products and returns from other destinations may require a separate quotation. Estimated return costs will be disclosed before purchase.
Faulty or Incorrectly Supplied Goods
Return postage charges do not apply to faulty, damaged or incorrectly supplied goods returned under statutory rights. ML&S will arrange a free return in these circumstances.
Refunds
Refunds are processed without undue delay following receipt and inspection of returned goods, and no later than 14 days after we receive goods returned under statutory cancellation rights.
Refunds will be issued to the original payment method. Any prepaid return postage charges or lawful deductions for diminished value will be itemised.
Warranty Terms & Conditions
New Equipment Warranty
Minimum 2-Year Warranty
All new products supplied by ML&S carry a minimum two-year warranty against manufacturing defects, excluding batteries, which are covered by separate warranty terms.
Some manufacturers provide extended warranties, such as the three-year warranty available on eligible Yaesu equipment. Any additional coverage is subject to the manufacturer's terms and conditions.
Our workshop may assess and repair faulty equipment on site or refer it to the manufacturer or an authorised service centre where necessary.
Warranty exclusions may include batteries, normal wear and tear, accidental damage, misuse and unauthorised modifications, as specified in the applicable warranty terms.
All warranties are provided in addition to your statutory consumer rights against ML&S, which are not limited by the warranty period.
International Returns & Warranty
Unless otherwise stated, ML&S warranty servicing is carried out in the UK. International customers must contact us before returning goods to confirm shipping and customs requirements.
International customers are responsible for return postage unless the goods are faulty and ML&S has been notified within a reasonable time.
ML&S accepts no responsibility for additional charges resulting from incorrectly completed customs documentation. Any additional duties charged to ML&S as a result will be billed to the customer before return of the goods.
Need Help With a Return?
Our team can assist with returns, postage arrangements, modifications and warranty claims.
Nothing in these terms excludes or limits your statutory consumer rights.








