More Work On the 10GHz Beacon Monitoring System.

 Today I got the 10GHz RX beacon monitor outdoor work done:

- extended the stacked fiberglass mast by about 60cm, and got a modified LNB mounted just under the feed point of the 2m/70cm vertical used for monitoring "Raketten" (a local 2m/70cm cross band repeater), and turned the LNB in the correct direction, close to WSW.

- got the cables in through the wall, so the utility room window can be closed properly again. 

- connectors for the RX system and the reference frequency system (F-connectors)

- a satellite signal splitter for the 25MHz signal was sufficient to supply both the beacon monitoring system and the QO-100 system  with a decent temperature stability.

Future improvements: 

- Improving the reference frequency generator(s). Will probably use, initially, a 25MHz ref for the beacon monitor LNB and maybe a second 25.xxxx ref for the satellite RX, providing an IF of 434MHz, so a "proper" receiver can be used. I have TCXO(s) for those two frequencies. 

- converters for both LNBs for using amateur band receivers (2m, 10m, maybe 6m) as base receivers. Mostly for use with better CW filters than the AR-8600s have (they have no CW filter, and a rather poor SSB filter - Whether they can be replaced/improved I do not know - also lowest frequency step is 50Hz, too much for serious weak signal work - even good narrow filter CW work).

Another 10GHz Experiment. Murphy Canceled.

The OZ7IGY beacon has been reinstated on all bands but 2m (That one needed repair after the power cable had been cut by someone digging at the site.

Today the weather was quiet, so around noon I repeated the experiment with the LNB on the 13m telescopic mast.

This time the signal came up immediately with rain scatter, and a bit of tone now and then. 

The signals have been there for at least an hour now. Is it, maybe tropo scatter ? The rain radar does indicate some light rain in the area around the beacon.

The test needs to be repeated on a dry day.

This test indicates that it would be interesting to have a rotatable ,low gain antenna, system for 10GHz, for monitoring. A 10 - 15dB horn antenna is not too large to fit on top of a rotating structure. 

After an afternoon of testing, the signal is mainly (rain?) scatter, not much tone. 

The LNB has been lowered to about 9m, scatter signal still there.

After the end of rain scatter, with the LNB lowered to about 9m, the signal is very weak, coming in and out of the noise, but it is mostly there. Given the temperature drift of the LNB 9750MHz LO, it can be tricky to find the beacon. It looks like it needs just 10dB more gain, then the signal will be there, almost constantly. 

Final experiment today:

Lowering the LNB to about 3.6m, and moving it to a position where the trees at the other end of the garden do not block the view in the direction of the beacon. The signal is quite weak, but generally audible. With the LNB pointing towards OZ7IGY, the OZ9GHZ beacon in a direction about 60 deg. offset is quite audible, with S-meter deflection.

While writing this, sitting in the other end of my living room, I can hear the OZ7IGY from the speaker, quite clearly. I suspect there is a little bit of evening tropo, because before dark the signal was barely audible, but with a stable receiver and a good CW filter it would be 100% readable.

I have achieved another goal in phase 1 of my 10GHz activities, hearing OZ7IGY on a more regular basis, all with a very simple receiving system:

- a PLL-LNB, unmodified

- a bias tee for the LNB

- a "scanner" receiver, the AOR AR-8600 receiver.

I am quite happy with today's results.

The next step will be using modified LNBs w/connection for an external reference frequency (25MHz). Then, possibly more gain and a rotating receiving system.

A Failed 10GHz Experiment, Murphy's Law. Then Some Success.

 Todays experiment was setting  a LNB up, taped to the 12.5m fibreglass telescopic mast. Tried to listen for the OZ7IGY beacon on 10GHz. Still not audible, landscape, or maybe its radiation pattern, combined with the low gain of the raw LNB is the most probable reason. OZ9GHZ, as expected, is still quite strong - no surprise because there is an even better path to it with this set-up. (See below for the real explanation)

The mast is leaning on the old (no longer) rotating antenna, and initially toppled. Now a bit better "trapped" between the old 6m antenna and the 2m antenna radials, so it should stay up for the day.

It turns out that the OZ9GHZ beacon is audible, even when the signal has to go through the neighbour's roof (thatched), so it is likely a bit of a scatter signal. The signal was quite good, readable all the time.

It turns out the OZ7IGY test was in vain, because later I noticed that all the OZ7IGY beacons I have disappeared. A friend reported that the beacon(s) disappeared around noon, and I did the test in the afternoon. So ... I will have to redo the test another day when OZ7IGY is in operation. Let us just say that this was an example of Murphy's Law in action.

The LNB was then brought indoors, placed on the window sill of a window facing the OZ9GHZ beacon. The signal is much weaker, but still audible, and because the LNB is indoors, the drift of the local oscillator is much less. Opening the window increased the signal considerably (10 - 20dB). Double glazing is not good for 10GHz signals.

In conclusion, monitoring the OZ9GHZ beacon is quite easy at my place. I should probably make a permanent setup for this, maybe with a RTL-SDR for decoding and monitoring the 10GHz beacon band in the Southern direction.