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GRAVES TX power down.

Suddenly today at about 10:20 UTC no more echoes from GRAVES transmitter have been received at my meteor receiver. A Christmas time maintenance?


Shortly before a strange activity has been captured from my receiver some Hz upper the usual meteor frequency.Meteor20161228092933 Meteor20161228093242 Meteor20161228100849

Meteors Radar

In these last days I focused my free time to meteors radar by French GRAVES VHF Radar transmitter. The new page is here: Meteors Radar.

On this page you can find a 3 minutes auto-refresh picture almost real time. Just under a statistics image of received meteors signals.

At the moment the system is composed by a desktop PC with a simple RTL-USB SDR receiver and a LPDA V-UHF antenna.

I hope to better optimize the quality of my receptions to get best reports.

What the page shows?

I must for first thanks mister Simon Dawes that shared the original Conditional Action for SpectrumLab that I modified for my purposes.

At the top of the page we can see the 3 minutes real time grabber image. The center of the image is at about 143.050 MHz: the GRAVES transmitter frequency.
For any positive sample you can read some data just after the meteor echoes:
Date&Time, Signal strength, Noise, Frequency, Time Length, S/N ratio.

Just under there is an image of RMOB Lab (Radio Meteor Observatory’s On Line) where my system sends data for colorgramme compilation.

At the bottom a 6 hours plot shows a pair of parameters analized in the time domain: the Signal Strength of the echoes and the Time Length of the same echoes. It’s so possible to see at a glance not only the quantity of events but also the strength of them.
Strength is in dB (absolute and not relative to noise floor), Time is a number derived from Conditional Action cycles, so 25 is about 6 seconds. Only longer events than 6 seconds are saved into the images gallery.

U3S stuck :(

Just now my U3S transmitter is blocked in TX condition as is possible to see in the next picture:


DK7FC grabber

The continuous line over 475.740 is my signal more than one hour long. The problem is that it was an unmanned operation and I’m not at home now. Strange is that the U3S doesn’t seems to have a whatchdog for a hard reset of the system in these cases.
It’s probably caused by high antenna SWR because of windy night.
In the next days I will build a web remote control at least to remote reset the TX and eventually turn off the amplifier.

As Rick IW4DXW said to me: “A good test for your amplifier, HI”

A small summary of the last months

Here follows a PDF doc where is possible to see all my unique stations transmission report on WSPR MF band, they are in descending order of distance. I still didn’t compiled a ranking by country but it’s easy to see how many DL and G are in the log.

Senza nome 1

My first TA MF!

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km mi
2016-09-27 02:40  IK0VVE 0.475692  -29  0  JN61km  0.05 WD2XSH/17 FN42pb 6626 4117

Grabbed Iceland on 630m

Finally my signal came out from continental Europe reaching Iceland.


44 stations copied my signal and 3 times TF3HZ received my weak signal:

Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
 2016-09-19 22:16  IK0VVE  0.475774  -28  0  JN61km  0.05  TF3HZ  HP94ad  3355  330
 2016-09-19 22:08  IK0VVE  0.475775  -25  0  JN61km  0.05  TF3HZ  HP94ad  3355  330
 2016-09-19 22:00  IK0VVE  0.475774  -25  0  JN61km  0.05  TF3HZ  HP94ad  3355  330

The distance of 3355 Km is a new record for my 100W transmitter and the “clotheshorse” antenna in MF. For sure conditions were very good and no strong thunderstorms over the Europe last nigth as two nights before.
This good outcome is probably due to antenna improvement, last year was very difficul for me to reach England and impossible be heard from Norway, now it seems to be a daily practice.

136 kHz… finally!

Last night was my second “serious” TX test on 136 kHz, transmitted Opera32 mode after an upgrade to the matcher.

To tune the antenna on 136 kHz I’ve build a couple of inductors over two hand cleaner soap bins. The first one was wound with enameled copper wire of about 1 mm diameter, the second with PVC copper wire of 1.5 mm diameter.

The first has an inductance of 2.2 mH while the second is around 400 uH.20160910_231203


Inserting one bin into the other I’ve reached the needed inductance to work with my antenna on 2200 meters. 20160910_231625

Moving up and down the two bins I’ve reached a coarse value just to use my variometer for tuning. The maximum value that I can reach is about 4 mH.

In the next photo the final layout of entire matching system for 630 and 136 kHz.20160913_082035

From left: remote controlled variometer (for fine tuning), matcher, 136 kHz tunable coil. The next step will be to remote switch the two bands from my radio room.

QRSS10 & WSPR dual transmission last night.

Due the lack of public MF grabbers on the net, last night I’ve tried to receive my signal in qrss10 with remote WebSDR system. I alternated the two transmission mode so to have an idea about where my signals were received.

With great surprise receiving myself on Twente WebSDR my signal was audible and even a bit stronger than IQ2MI signal (used always to compare mine). The audio record follows:

My signal is on higher frequency because WebSDR software uses reverse CW.


3rd August solar storm MF observation

For the expected solar storm of last 3rd August, I’ve planned a continuous 72 hours transmission of my MF station as QRSS10 beacon since 1st of August afternoon.
I’ve monitored my signal on the MF grabber of Stefan DL7FC, comparing it with IQ2MI signal, downloading for the 72 hours a picture any 10 minutes.
Nothing strange appeared over the pictures, signal was about the same for all days like before.
Only to note that IQ2MI signal appear over the grabbers at about 1800 UTC (sun set at my QTH) while mine about 40 minutes later. The same in the morning, my signal disappear 40 minutes before IQ2MI signal.

Here another picture with IK1HGI signal, too:

WhatsApp Image 2016-08-03 at 23.27.25

Even though I’m 500 Km farther from Stefan my signal seems quite solid.

Increasing TX antenna capacitance

This is my umpteenth upgrade to the TX antenna to try to get better general performance and get the possibility to work on 136 kHz without tons of electrical wires outside the terrace.
The new layout is drawn in the next basic picture:
newAntI’ve passed from 4 top wire and a single vertical tube to 6 wires as in the picture. The hat is always 13 meters long (I don’t want to go over the neighbour roof) but now also six wires come down to about 10 meters to the variometer.
The capacitance was raised from 235 pF to 310, not bad. The only doubt is about the vertical side that is not exactly vertical and it shows an angle of about 75/80° to the ground.

100_4559The telescopic pole by now is not more a radiating part of the antenna, this simplified my life because I don’t need to insulate the base of the pole for high voltages.
This is the usual photo of the whole antenna with an Unidentified Flying Object up on the left:

Now the target is to tune the antenna for the 136 kHz that should it be possible with a 4.4 mH coil.