Read More
Seen this product cheaper elsewhere?
Call 0345 2300 599The Sirio GPA 66-108 is a tunable 1/4 wave ground plane base antenna covering 66-108MHz.
Designed for base station service, the GPA 66-108 provides omnidirectional vertical performance across the low VHF range. It is suitable for applications within its supported frequency range where a compact, robust, mast-mounted ground plane antenna is required.
The antenna is made from non-corrosive aluminium and assembled on a strong die-cast base for easy, secure installation and reliable outdoor performance. Frequency adjustment is carried out using the supplied tuning diagram.
The GPA 66-108 is fitted with a UHF female SO-239 connector and is designed for mounting on masts from 35-40mm (1.38-1.57in) in diameter.
Key Features
- 1/4 wave ground plane base antenna
- Tunable across 66-108MHz
- Omnidirectional 360° H-plane radiation
- Linear vertical polarisation
- 50 ohm unbalanced feed
- 0dBd / 2.14dBi gain
- VSWR less than 1.2:1 at resonant frequency
- 500W CW maximum power handling
- UHF female SO-239 connector
- Non-corrosive aluminium construction
- Strong die-cast base
- Stainless steel, chromed brass, nylon, and aluminium materials
- Suitable for 35-40mm (1.38-1.57in) mast mounting
Typical Uses
- Low VHF base station installations
- 66-108MHz applications where authorised
- 4m band installations where correctly tuned and permitted
- Fixed monitoring and communications setups
- General omnidirectional VHF coverage
- Mast-mounted base antenna installations
Electrical Data
| Specification | Details |
|---|---|
| Antenna type | 1/4 wave ground plane |
| Frequency range | 66-108MHz, tunable by diagram |
| Impedance | 50 ohms unbalanced |
| Radiation, H-plane | 360° omnidirectional |
| Radiation, E-plane | Beamwidth at -3dB: 86° |
| Radiation angle | 0° |
| Polarisation | Vertical |
| Gain | 0dBd / 2.14dBi |
| Bandwidth at VSWR 2:1 | 6.5MHz at 66MHz |
| VSWR at resonant frequency | Less than 1.2:1 |
| Maximum power | 500W CW |
| Feed system / position | Direct / centre |
| Connector | UHF female SO-239 |
Mechanical Data
| Specification | Details |
|---|---|
| Materials | Aluminium, chromed brass, nylon, stainless steel |
| Wind load | 54N at 150km/h |
| Wind resistance | 150km/h (93mph) |
| Wind surface | 0.05 sq m |
| Height | Approx. 1930mm (1.93m / 6.33ft) |
| Radial length | Approx. 1080mm (1.08m / 3.54ft) |
| Weight | Approx. 700g (1.54lb) |
| Mounting mast diameter | 35-40mm (1.38-1.57in) |
Installation Notes
The GPA 66-108 must be tuned for the required operating frequency using the supplied tuning diagram.
As with any base antenna, final performance will depend on installation height, mast position, surrounding structures, grounding, feedline quality, and correct assembly.
Shipping:
We have several shipping options for our products, including next-day and Saturday/Sunday delivery for certain items. Please see these options at checkout.
Returns:
If you have any equipment that needs to be returned to Martin Lynch & Sons, please fill out the form below:
Upon receipt of goods you have 14 days to return goods however the goods must be returned in original packaging and care must have been taken with the goods you wish to return. Under distance selling regulations you are not entitled to any refund on carriage charges or modification charges made at your request. Large items cannot be returned if they have been assembled, unless faulty.
Warranty Terms and Conditions
Outside of the 14 faulty return period, returned items cannot be accepted, unless covered by manufacturer's warranty. We will repair as much as possible on site however in exceptional circumstances products may have to be returned to the manufacturer of distributor.
For repairs/replacements under manufacturer’s warranty for any item please download a ML&S return form from the link above and return to ML&S with the faulty product.
International Warranty information
Warranty service for items we sell is available in the U.K. only, unless otherwise noted. It is your responsibility to pay freight for returned items to the U.K. and back to you for desired warranty coverage. All of our NEW products come with a minimum 12 month warranty, (Yaesu & Icom 24 months), with up to 90 days on second-hand equipment. Items returned for service must state "returned goods for repair" on the return air waybill or U.K. import customs duties apply and will be added to your invoice. For more info about returning items please contact our customer help desk, [email protected]