Joe (VO1NA), last night (27.28 Sep) your sigs were very good when I switched on at 2305UTC and received "NA" very clearly. Then you sent "RDI" which had some frequency wobble. This was followed by a
Chris, I have been following your exploits with getting going on LF tramsmit. You certainly have a very good signal for the relatively low RF input so there is actually not a lot wrong with what you
Good conditions and activity last night on the 136kHz band. My Op32 transmission at midnight UTC last night produced reports from nine countries, including LA, SM, EW6, SV, SP and EA. I also received
Well, that makes sense if (as I suspect) your impedance is a few tens of ohms, ie you barely need a transformer (at least for matching purposes). de Mike ==
Your scope match measures the current in the feeder. This is not the same as that in the antenna which may be a different impedance - which is why you need a matching circuit (eg transformer). You c
The transatlantic frequency for Eu stations is 136.172kHz plus or minus a couple of Hertz. As you say, Eu stations listen around 137.777kHz for intercontinental DX. Mike, G3XDV ==
Another solid 136kHz band transmission from VO1NA, mostly strong with some fading. A long CQ call lasting from when I started watching at 0205 until he faded just after sending "QSX" at 0740UTC. The
I agree with Stefan. A transformer (using a suitable core material such as 3C90) gives you more flexibility in the future It also provides the opportunity to isolate the RF ground from the mains supp
Chris, my 3C90 transformer has about 16 turns on each winding. (I say approximately as I need to adjust by a turn or two between summer and winter due to absorption/detuning by trees. I would suggest
Well, I specified the core type as Chris was originally using a different type, but of course the size is relevant. The diameter is 55mm and I use two cores, one on top of the other, to reduce heat.
To all intents and purposes a short (in wavelengths) vertical attached to an arrangement of horizontal wires is a simple (capacitively) loaded vertical. The horizontal part will radiate, especially i
Opera 32 activity was high and widespread last night. My transmissions were reported by: DF2JP, DB1EPO, PA7EY, TF3HZ, SP5XSB, SV8RV, EW6BN, G3XKR, EA5DOM, DF6NM*, DK7FC*. IS7SLZ*, YO/4X1RF*. (* = OPD
Very interesting reception of VO1NA last night on 137kHz Opera32. Firstly, for a long period those stations in the west of the UK (GW0EZY, G3XKR, G4WGT, G8HUH) seemed to have much better reception th
Chris, What receiver are you using? By how much does the background noise go down when you disconnect the antenna (ideally replacing the antenna with a 50-ohm resistor)? Do you have any local QRM? Ar
Chris, You should not need to use the 's' meter on HDSDR when taking relative readings. The (wideband) waterfall display is already in decibels - just place the cursor at the position you want to mea
Hmmm. Interesting. You don't show DCF39 (I wrongly called it DCF38 before) as it is outside your passband. However you show HGA on 135.42 at 40dB above noise. I see it at 59dB above noise and that co
My antenna came down in the recent gale (the wires,not the poles so no harm done). It will take a few days to restore it. I may be able to run a temporary receive antenna in the meantime. Mike, G3XDV
