Voltage check of LAA+ bias-t
This should be around 0.7 V below the input voltage due to the reverse polarity protection diode.
You can check the voltage at the amplifier end of the coax. With the amplifier disconnected this should read the same voltage as that coming out of the Bias Tee unit.
If the LAA++ is working OK on HF frequencies then it is working.
I don't know your location but many areas of the world don't have long wave broadcast stations.
My location is Ontario, Canada. Grid FN03.
HF doesn't seem to be affected though. Plenty of signals there.
I've just switched the loop over to a 60cm diameter hula hoop with a solid copper wire running through. It's not the thickest though.
Fine for hf..
Rig up a 1m diameter loop ( lash it up) and see if any better..one would expect it to be..
To check if voltage is at end of cable ( amp) volt meter from centre pin to outer of coax..expect circa 11-13v depending upon cable length and V from psu..
As Chris said..if working on hf then amp works..i bet loop too small.( ie i use crossed parallel loops of total dimensions 2 x 2 m for low bands..) 60cms is good for ( CIRCA) 10mhz above.
Like these? How do you check the voltage with that? I was thinking of a multi-meter. Stick the red lead on the center pin and the black on the shield. Well, something like that anyway.
I love those "green" adapters! So useful for temporary and
experimental hookups when you don't want to solder up cable
assemblies. I've got a pile of them with male and female ends for
RCA jacks, male and female ends for BNC connectors, 2 and 3-cond
3.5mm plugs and jacks, 1/" plugs and jacks, 6-cond RJ-11/13
phone plugs and jacks, 8-cond RJ-45 "Ethernet" plugs and jacks,
and 6-pin mini-DIN "PS/2" plugs. I just keep finding more types
of connectors packaged this way on Amazon!
I use the RJ-45 male plugs to break out RJ-45 mic jacks on
radios, when experimenting with sound card interfaces. I make
temporary attenuators for both audio and RF by screwing down 1/8th
watt resistors between male / female RCA or BNC pairs. I have
used a pair with male/female XLR connectors, with resistors
in-between, to create one-of-a-kind attenuators for my audio
Just so convenient to be able to whip up these setups in the
field, without soldering.
Stephen H. Smith wa8lmf (at) aol.com
EchoLink: Node # 14400 [Think bottom of the 2-meter band]
Home Page: http://wa8lmf.net
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Chris did mention that with the voltage coming from the bias-tee of the SDRPlay devices that the LAA++ is limited to a minimum of 500 kHz.
It will be about size of half a shoe box if old school..if old school it is a linear power supply..ie not switched mode..= no rf noise.
As will be second hand just get it checked over before using.. ( unless competent to do so yourself.)
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