Introduction
Working LEO satellites with small portable rigs is a lot of fun. Radios like the Yaesu FT-817/818 and the Icom IC-705 are extremely popular because they are lightweight, cover both 2 m and 70 cm, and are easy to use in the field.
But there is a catch: their receivers are not very sensitive on VHF and especially UHF. On weak satellite downlinks, this lack of sensitivity becomes a real problem. That is why external Low Noise Amplifiers (LNAs) are so valuable.
In this article, I want to share my first tests with inexpensive Chinese LNAs from AliExpress. These are globally available, very low cost, and could help hams everywhere — including those in developing countries — to improve their satellite reception dramatically.
This article will be continuously updated as I test more LNAs and collect measurement results.
Why LNAs Matter for LEO Satellites
When receiving weak downlink signals, the noise figure (NF) of the receiver is critical. A lower NF means that the signal is more audible above the noise floor. Unfortunately, the portable radios we love are not strong performers here.
Receiver Noise Figure Comparison
When I started experimenting with Chinese LNAs for LEO satellite operation, I quickly realized why they make such a difference. Many of the popular portable radios are simply not very sensitive on 2 m and 70 cm – especially when their internal preamps are switched off. The following measurements show clearly why an external LNA can be a game-changer, particularly for radios like the FT-818 or IC-705. By contrast, radios such as the IC-9700 and IC-910H already perform better out of the box, but even they can benefit from a good masthead preamp.
As the numbers show, the FT-818 and IC-705 suffer from significantly higher noise figures, especially with the internal preamp switched off. An external LNA is almost mandatory in these cases. In contrast, the IC-9700 and IC-910H already offer much better performance thanks to their low NF, though even they can benefit from masthead amplification / LNA.
Data compiled by DK9JC
Sources: AB4OJ, OZ9AAR, DL3JOP
First LNA Tested – 433 MHz SAW-Filtered LNA
This compact LNA includes a SAW filter at the input, powered via USB-C at +5 V.
- Manufacturer specs: Gain 23 dB, NF 1.2 dB
- My measurement: 18.2 dB gain on 70 cm (HP VNA)
- Price: €8.99
I mounted it into a Schubert tinplate enclosure and added BNC connectors for practical use.
Here is my measured result:
Measurement Setup
All measurements were carried out with a HP 8752A Vector Network Analyzer (VNA) covering 300 kHz – 3 GHz.
For the LNA with integrated SAW filter (8.99 € from AliExpress), I recorded the following results:
- 145 MHz: –51.4 dB suppression
- 435 MHz: +18.3 dB gain
- 1090 MHz: –22.2 dB suppression
- 1296 MHz: –20.0 dB suppression
This clearly shows the effect of the built-in SAW filter: strong suppression on 2m (145 MHz), a good usable gain on 70cm (435 MHz), and additional suppression in the L-Band.
Real-World Test – SO-124 FM Satellite
A few days ago I worked F5RRS on a low pass of SO-124 using a Yupiteru MVT-7100 handheld receiver that I had picked up second-hand.
- LNA off: I could not hear him at all.
- LNA on: easy QSO, very strong difference.
This was a night-and-day improvement, proving how effective even a simple low-cost LNA can be.
For context, the Yupiteru MVT-7100 is a wideband handheld scanner covering 530 kHz to 1650 MHz (RigPix, Manualzz). Despite being released in the late 1990s, its sensitivity on UHF (~0.5 µV for 12 dB SINAD at 435 MHz) translates to a rough noise figure of about 6–8 dB. That is actually in the same ballpark as the modern Icom IC-705 with its internal preamp switched on (~7 dB NF on 432 MHz, AB4OJ measurements).
The key point: although the IC-705 is a modern full-featured SDR transceiver for HF, VHF, and UHF, in terms of raw receive sensitivity on 70 cm the inexpensive Yupiteru scanner plus a small external LNA can perform surprisingly well. Without the LNA, the MVT-7100 struggled. With the LNA inline, it became fully usable for LEO satellite contacts—showing that low-cost gear, when combined with the right preamp, can rival much more expensive setups.
Second LNA – SPF5189Z Wideband
This is a tiny wideband LNA based on the SPF5189Z chip.
- Frequency range: 50–4000 MHz
- Advertised gain: ~20 dB
- Advertised NF: 0.6–1.0 dB
- Price: only €2.80
I have not tested it yet, but it will be fascinating to see how this ultra-budget design performs on 2 m and 70 cm.
Third LNA – 0.3 dB NF Broadband
This model claims to cover 100 MHz to 6 GHz, with 20 dB gain and an extremely low 0.3 dB noise figure.
- Price: €21 (including shipping)
- Delivery time: about 1 week
- Specs: 0.1–6 GHz, 20 dB gain, NF 0.3 dB (claimed)
This LNA was recently tested in CQ DL magazine and reviewed in detail by DD1US: 📄 DD1US Test Report (PDF)
According to his findings, the performance is indeed impressive for such a low-cost device. My own tests are pending and will be added soon.
Operating Tips
One advantage for satellite operators is that many of us already use two rigs (for example, two FT-817s). In that setup, the LNA can simply stay permanently in front of the receive-only rig, while the other radio is used for transmit. No switching or relays are needed.
Conclusion
The first tests clearly show that even very inexpensive LNAs from AliExpress can transform the satellite performance of radios like the IC-705 and FT-817/818.
- The €8.99 SAW-filtered LNA already enabled a successful SO-124 QSO that would not have been possible otherwise.
- The €2.80 SPF5189Z LNA and the €21 0.3 dB NF broadband LNA are next on the bench.
For less than the price of a pizza, you can add several dB of sensitivity to your satellite station. And because AliExpress ships worldwide, these tools are accessible not just to hams in Europe or North America, but also to operators in developing countries.
This post will be continuously updated as I test more LNAs and publish new results. Stay tuned!
