If you've already read our guide to the SACAA ADS-B Out mandate, you know you need to equip. The question we get most often from South African owners after that is a lot more practical: which Garmin transponder? Almost every ADS-B enquiry that reaches our Lanseria workshop comes down to two units, the GTX 335 and the GTX 345, plus a compact Trig alternative for lighter and experimental aircraft. Here's the real difference between them, what each one costs to fit, and how to work out which one is right for your panel.
ADS-B "Out" versus ADS-B "In": the distinction that decides which unit you need
Both transponders satisfy the SACAA's ADS-B Out equipage requirement: they broadcast your aircraft's GPS position, altitude, velocity and identification on 1090 MHz so ATC and other suitably equipped aircraft can see you. That's "Out." The GTX 345 goes further and adds ADS-B "In." It receives a live picture of nearby traffic and, on the 978 MHz UAT frequency, subscription-free NEXRAD weather, METARs, TAFs and NOTAMs. The GTX 335 does not receive any of that; it only transmits.
In other words: if all you need is to be legally seen by ATC, the 335 does the job at the lower cost. If you also want traffic and weather in front of you in the cockpit, genuinely useful over the Highveld in summer, you need the 345.
Garmin GTX 335: the straightforward compliance upgrade
The GTX 335 is Garmin's one-box, one-swap answer to the mandate. It fits the same 1.65-inch avionics slot as your existing Mode S or Mode C transponder, and is available with an optional built-in WAAS/GPS position source, so no separate navigator is required to meet the positioning accuracy the mandate demands. It's IFR-certified, solid-state, and FAA-approved for installation on hundreds of aircraft types, which is why it's the unit we fit most often on straightforward compliance jobs.
For panels where space is at a premium, or where you're pairing with a G1000® or GTN™ 750/650 series system that can already handle squawk code entry on-screen, the remote-mount GTX 335R tucks the transponder itself out of sight and frees up panel real estate, including a diversity-antenna configuration for aircraft that need dual top/bottom antenna coverage.
Garmin GTX 345: Out and In, with weather and traffic on your display
The GTX 345 carries the same Out-compliance as the 335, in the same footprint, but adds dual-link ADS-B In reception on both 1090 MHz and 978 MHz. Once fitted, you can see other ADS-B traffic and subscription-free weather on a compatible panel display, or stream the same picture wirelessly via Garmin Connext to Garmin Pilot, ForeFlight Mobile, or an aera® 660/795/796 portable, useful if your aircraft doesn't have a dedicated MFD to show it on.
As with the 335, a remote-mount GTX 345R diversity variant is available for panels that need the space, or for integration behind a G1000 or GTN 750/650 flight deck. For most owners flying regularly into busy circuits around Lanseria, Grand Central or OR Tambo airspace, the traffic picture alone tends to justify the jump from the 335.
Flying experimental or a lighter airframe? There's a compact option too
Not every aircraft has the panel space or the budget for a full GTX installation. We also stock and support the Trig TT23 compact transponder range, along with the associated ADS-B bundles. It's a lighter-weight, smaller-footprint path to compliance that's popular on experimental and LSA-category aircraft. Because pricing on the Trig range depends heavily on the specific kit and options fitted, get in touch for a like-for-like quote against the Garmin options above.
Already ADS-B Out compliant? Two ways to add traffic and weather without a new transponder
Not every enquiry we get is a first-time upgrade. Plenty of operators already have a compliant Out-only transponder and just want the situational-awareness benefit of In, without replacing what's already fitted and working. Two options that don't require swapping your existing transponder:
- AIR Avionics AT-2 dual-band ADS-B receiver and the ATD-80/57/11 panel or external-mount traffic displays: these add ADS-B In reception and a dedicated cockpit traffic picture alongside your existing Out-only transponder.
- Garmin GDL 50 portable ADS-B receiver: a non-installed option that streams traffic and weather to a compatible tablet or portable, for owners who want the benefit without a panel modification.
Indicative component pricing (South Africa)
Unit pricing only. This excludes installation labour, which varies by aircraft type and panel layout. Request a quote for an installed price.
| Unit | ADS-B | Mount | From (ZAR, ex. install) |
|---|---|---|---|
| Garmin GTX 335 | Out only | Panel | R58,600 |
| Garmin GTX 335R | Out only | Remote (diversity) | R66,123–R114,267 |
| Garmin GTX 345 | Out + In | Panel | R99,222 |
| Garmin GTX 345R | Out + In | Remote (diversity) | R135,423 |
| Garmin GDL 50 | In only (portable) | Portable | R13,541 |
| AIR Avionics AT-2 | In only (receiver) | Panel/external | R18,526 |
Installed at Lanseria by an authorised Garmin dealer
As Garmin's largest authorised avionics dealer in Africa, we install and certify both the GTX 335 and GTX 345 series at our Lanseria facility, on certified and experimental aircraft alike, alongside the Trig and AIR Avionics options above. If you're not sure which unit fits your panel, your budget, or what you're already flying with, our team can size the right option before you commit to a part number, rather than leaving you to guess from a spec sheet.
Or contact the team directly at sales@aeronautical.co.za or +27 11 659 1033.
Aeronautical Aviation (Pty) Ltd is based at Hangar 202, Gate 7, Lanseria International Airport. SACAA AMO No. 1033. Garmin Platinum dealer and the largest accredited distributor of Garmin in Africa. The only certified Dynon dealer in South Africa. Clinton Carroll is a qualified pilot and the founder and CEO of Aeronautical Aviation.
