LNA4HF Review
LNA4HF Review
Hello and welcome to my review of the LNA4HF.
What is it?
LNA4HF is a Low Noise Adapter, or a preamplifier, designed for use with RTL-SDR HF up converters or any other HF receiver. Since many homebrew designs of HF up converters don't use any kind of RF amplification, this little device will amplify HF signals and you will be able to hear more than before.
Specifications.
DC power supply: 6-12 V (5V with a jumper)
Consumption : 18 mA
Frequency range : 150kHz - 30MHz
Gain : 18-20 dB
NF : 1-2 dB
Dimension : 25x25 mm
First Impressions.
The seller is very friendly and nice. You send him an email and then he will give you the details. Shipping took about a week or so from Croatia to Lithuania. You pay for the item when it arrives, which is incredible. The item was inside an envelope, wrapped in some bubble wrap. Once I took it out I was amazed. The LNA4HF is tiny. Really tiny. And it is built very well. Mine was without SMA connectors, so I mounted the LNA in a small Altoids tin and added F type connectors because that's what I had on hand. I use 5V from the USB connector for convenience.
Performance.
I am using an RTL-SDR based on the R820T tuner with a homemade HF up converter based on this design: http://hamradio-builder.hamhacker.org/HFUpConverter Since it is a very simple design, the performance is poor. However, with the LNA4HF performance has been greatly increased. I will say this now - if you are using a Ham It Up, or any other up converter without a preamp, get the LNA4HF. You will be happy. It performs amazingly well, it is nicely built, small and quite inexpensive, considering the performance. Here are some comparisons (same gain was used on the specific frequency with and without the LNA4HF):
But it's not perfect.
Soon after I got the LNA4HF, I accidently killed it with ESD (electrostatic discharge.) I connected a small dipole to the antenna socket and my USB devices disconnected. Everything continued to work fine after I replugged them, but the LNA4HF died. However, the seller is lovely. I sent him a message and he offered me two options: I either send him the LNA4HF back and he repairs it; or he sends me the MMIC and I replace it myself. I chose the latter. He sent me the MMIC and the voltage regulator. Free of charge. I replaced both components and everything is working fine again. So there really is just one negative thing I have for this device: no ESD protection on the input. I strongly suggest you read this article (http://www.rfm.com/products/apnotes/esd.pdf) and add ESD protection yourself. I grabbed a BAV99 from an old damaged RTL-SDR and now I feel safe.
Wrapping things up.
Why are you still reading this? Get one! And I also recommend ESD protection of course. The seller also makes LNA4ALL, which is designed for 28 to 2500MHz, you may want to look into that as well. Overall, I am very happy with this tiny little device, as you may already tell, and I can't wait for more products made by the same guy.
Website with details: http://lna4hf.blogspot.com/
Rating: 9/10
Thanks for reading and 73 from CrysisLTU!