Hello everyone! It was a former student who opened this feed, but I took on his work with CCERES Ground Station, and I would like to follow up on this subject.
We bought a new LNA for the 430 - 440 MHz band (this one) and installed it back on the station, so that now the line is the following:
The signal level with and without the LNA is exactly the same. My feeling is that the surge arrester (or the adapter I use to connect it) somehow blocks the DC line, and the LNA is not powered. However, I tested both components with a multimeter and there seems to be continuity… The arrester I am using is a Diamond SP3000: do you think it is suitable for such and application, with this kind of RF path? Does it seem like a reasonable possibility that it is blocking the power supply? And lastly, how risky it is to keep the antenna on the roof of a building without this type of protection? It might be a silly question, but I have no idea of the consequences that it might have if I simply remove it
Any suggestion on how I could proceed would be appreciated! Thanks
As the frequency range in the datasheet shows they should pass DC up to 3000 MHz so it should be possible to pass LNA power , which runs on DC voltage as that datasheet shows.
What comes in mind is, if you are going to connect the surge arrester somewhere inline with the system you would need another adapter, either N male male or a short cable male male ? If so, where you able to check that adapter if it functions as designed? Maybe the tip of one of the male connectors is to short / broken / missing / disconnected ?
Hi, thanks for the suggestion! I had thought about that too, and I have tested for continuity also the male-male connector between the surge arrester and the LNA, but it seems to work – both tip to tip and external ring to external ring show no resistance. I have also substituted it with a short cable, and still no signal… Do you know if there’s any other useful way for testing these components?
Next step would be a testing cable with a , for example, 12 volt 3 watt light bulb. A voltage meter can check for DC but does not run current through the line. If you connect the light bulb to the points you expect the preamp to be powered you can check the voltage (drop) if there is actual current running. Check in front of your surge arrestor, and check after the arrestor and see if that makes a difference.
12 V 3 Watt should drawn 0,25 Ampere, if your LNA power does not supply that much you can run a 1 Watt bulb / led for the same check
