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The Sierra Radio Systems SIR-331 is a four port remote coax relay module for the Sierra Station Controller range.
Also known as the CX-1, this module can be used to switch one radio between four antennas, or one antenna between four radios. It is intended for HF and 6m operation, covering 1-60MHz, and provides a flexible RF switching option for remote HF stations, contest stations, repeater sites, receive systems, and automated shack installations.
The SIR-331 uses latching relays, so the selected port remains in its last state even if power is removed from the module. It also uses break-before-make switching, releasing the current connection before making the new one, while the built-in firmware prevents two relays from being active at the same time.
The module can be controlled through the Sierra DCN, or Device Control Network, and also provides momentary pull-to-ground inputs for external pushbutton or electronic port selection.
Key Features
- Four port HF and 6m coax relay module
- Also known as the CX-1
- Switches 1 radio to 4 antennas or 1 antenna to 4 radios
- Intended frequency range of 1-60MHz
- Suitable for 160m through 6m operation
- Maximum power handling of 100W
- Insertion loss less than 0.05dB on HF
- Port isolation typically between 53dB and 65dB across the HF band
- BNC RF connectors
- Latching relay design
- Retains last selected position if power is removed
- Break-before-make switching
- Firmware prevents multiple relays being active at the same time
- Control over Sierra DCN
- Manual control possible using external momentary pushbuttons
- Multiple modules can be used together for larger switching arrangements
Typical Uses
- Switching one HF radio between up to four antennas
- Switching one antenna between up to four radios
- Remote HF station antenna selection
- Contest station RF switching
- Automated shack antenna switching
- Receive antenna selection
- Repeater or remote site RF path switching
- Expanding a Sierra Station Controller installation
Station Controller System Role
The SIR-331 adds RF coax switching to a Sierra Station Controller system.
It connects to the Sierra DCN, using RJ45 style connections and network-style patch cables. The DCN connection is used for module communication and system power distribution between compatible Sierra modules.
Although the connectors are RJ45 style, the DCN ports are not standard Ethernet ports and should only be connected to compatible Sierra Station Controller modules and accessories.
Switching Arrangement
| Mode | Description |
|---|---|
| 1 radio to 4 antennas | Select one of up to four connected antennas for a single radio |
| 1 antenna to 4 radios | Select one of up to four connected radios for a single antenna |
| Disconnected state | All relays may be placed into a disconnected state |
| Expanded switching | Multiple SIR-331 modules may be used together for larger switching systems |
Specifications
| Specification | Details |
| Brand | Sierra Radio Systems |
| Model | SIR-331 |
| Product type | Four port HF and 6m coax relay module |
| Alternative name | CX-1 |
| Switching format | Single pole, four position |
| RF ports | 4 |
| Frequency range | 1-60MHz |
| Typical coverage | 160m to 6m |
| Maximum power | 100W |
| Insertion loss | Less than 0.05dB on HF |
| Port isolation | 53-65dB across the HF band |
| RF connector type | BNC |
| Relay type | Latching |
| Control method | Sierra DCN or external momentary pushbuttons |
| System type | Sierra Station Controller |
Important Note
This listing is for the SIR-331 Four Port HF and 6m Coax Relay Module only.
SIR-310 host adapter, installation kit, DCN hub, coaxial cables, antennas, radios, power supply, pushbuttons, control wiring, and other accessories are not included unless stated otherwise.
The SIR-331 is rated for a maximum of 100W. Please ensure it is suitable for your station power level before installation.
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.
A suitable 10-18V DC supply is required when the module is not being powered through a Sierra DCN connection from the SIR-310 host adaptor.
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.