recently I decided to hook up the trusty Tecsun 660 Shortwave radio to the outside 21 meter long wire urban wire antenna for some SWL
in metropolitan Adelaide. as this was a working system in 2017
but got only noise & Interference from 1MHz up to 18MHz thinking it was a loss of the impedance transformer grounding by a earth wire failure.
I did re-test the external antenna and its indoor impedance transformer circuit, transformer grounding and the coax . however no fault found in the antenna
so I decided to build a passive 0.5 to 30MHz tapped coil antenna tuner box with attenuator for receiving shortwave in the hope that this may help?
however I decided post to the forum. before wasting any more time and money on SWL
I have not used the shortwave radio for a year or two and new LED street lighting may have something to do with it?
see image here is the outside 21 meter long wire urban wire antenna setup I use. its a copy of the Technical and historical site SWL antenna design.
this was ok back in 2015 when I did first got the Tecsun 660 and needed a good SWL antenna.
I will also note that a 891KHz AM signal is so strong it will drive the multimeter continuity test piezo buzzer as a speaker
I get ABC Adelaide radio station 891 kHz AM on my multimeter piezo buzzer. even though the station is on the other side of the city .
Hello jonovid, here are some thoughts
First of all, LED street lights may generate noise, but then those lights should be off in the morning, so if they're the source of noise, you should notice some difference in the morning, also, if the very strong signal from ABC Adelaide was already there in the past and didn't cause issues, then you may exclude it from being the cause, otherwise for sure, such a signal may overload the frontend of your receiver making it deaf
Anyhow, you may run a quick test by disconnecting the PL660 from the external antenna and checking if, using the internal one, you're able to pick up something; you may also drive to some "quiet spot" and test reception there, those tests will at least tell you that the 660 is working and isn't causing issues
Given that the 660 is working, the next step would be checking the antenna, you wrote that till 2017 it worked, but you hadn't used it for some time, so the antenna may have some issues; start by checking if the various connections at both ends (receiver, coax, antenna, grounds) present oxidization or problems, in case use some deoxit to clean them, also open the unun and the transformer boxes and ensure everything inside is ok; if that doesn't solve the issue, then it may be due to either the antenna wire being damaged (e.g. if using an insulated wire, the wire may be broken at some point and the insulation layer may be keeping the antenna up) or the buried coax being damaged; to run a quick check, try connecting the 660 directly to the antenna transformer (using your adapter box), if the reception works this way, then the issue may be due to a damaged coax otherwise you may want to lower the antenna and inspect it (as a note, I'd add a second pulley at the feedpoint side too, that would help lowering the antenna and checking it)