A dish for Es’Hail-2, QO100

Last year I experimented with using a 13cm band yagi for the up-link and an LNB strapped alongside my horn on the dish I use for terrestrial work for the down-link.

I’ve now put a dish up for the Qataris’ Es’Hail-2 satellite. It is a 1.1m off-set PrimeSat dish.

Prior to putting it up,¬† I had bodged a bit of aluminium¬† box tube to take the dual-band feed. I checked the dish’s focus with a few stick-on mirrors and the sun as an light source. There did seem to be a bit of distortion in the dish, though it looked in excellent condition, with no visible damage. I may be able to squeeze out this distortion using the braces for the LNB arm.

Bearing in mind how windy it gets here I’ve used belt and braces in mounting the dish. I decided not to get the larger 1.3m dish. I felt the 1.1m dish would be easier to manoeuvre¬† up to the roof and also it would be less affected by wind. I’ve used two steel chimney lashings to hold two brackets. I decided the usual aluminium pole might not be up to the job, so I set a section of steel scaffold pole in the brackets. The dish’s two clamps are fixed to the bottom of the pole. In case of the dish clamps somehow working free, there is a third clamp at the bottom of the pole to stop the dish dropping off.

I’ve fitted braces to the LNB arm to hold the arm steady in the wind.

Being low down on the chimney and on the easterly side of the house, the dish is in the lee of the strong westerlies and south-westerlies.

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The 13cm patch antenna in the bigger plastic box is not really working as circularly polarised. It is more like linear, effectively from a dipole, but the return loss is quite good. The patch is fed with a shortish length of Ecoflex 10.

The LNB has a bit of “satellite” coax taking the signal back into the station. I found the connectors on my thin “WiFi” coax were very poorly fitted. I use this to carry the 27 MHz reference oscillator signal to the LNB. I soldered a proper SMA connector on the LNB end of the cable. An LNB lens takes the signal rom the dish which is then piped along a short length of copper waveguide (22mm domestic copper pipe) into the LNB. The waveguide is held by pipe clips mounted on short lengths of stainless steel studding. The LNB has a bit of a twist on it in an attempt to optimise the match to the polarisation from the satellite.

I sealed all the connections with self-amalgamating tape.

See Dual Band Feed construction.

Note: I had originally mounted the N-type socket for the patch feed with the socket mounting flange inside the plastic box, but this meant the N-plug did not mate reliably, so I re-mounted the socket on the outside of the box.

5-April-2020 Low Bands contest

In spite of the nearby high pressure, conditions were very poor. On 23cm band I failed to work Gordon GI6ATZ and only just scraped a contact with Richard GD8EXI. I failed with Pete GM4BYF.

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I worked some of the usual suspects on 13cm in the 2.32GHz sub-band.

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And the usual suspect in the 2.30GHz NoV sub-band: Keith G4ODA. Unfortunately, I didn’t get the points for this contact as I entered his callsign as G40DA. Spot the difference. I didn’t!

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28-December-2020 SHF UKAC

This was my first UKAC this year. The Microwave Modules 70cm transverter wasn’t working on PTT for some reason and was defaulting to RF Sense, so I struggled a bit on 13cm. It is nice to have 13cm going again. I need to improve the Noise Factor of the pre-amp in the box on the pole, but that will have to wait until the weather calms down.

It was all pretty local stuff on 13cm:

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It was even more local on 3cm:

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26-Nov-2019 SHF UKAC using 13cm and 3cm bands

I hopped about between both bands. On 13cm it was was nice to work Pete G4CLA again. Keith G4ODA was my best DX (longest distance) at 117 km. So my contacts were all pretty local really. I used 25W into the coax to the antenna box, so the Andew amplifier was under-driven.

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On 3cm, my initial contact was with Peter G3PHO. Our usual reflection point worked well to get round the hills. Keith G4ODA was my best DX (longest distance) on this band.

The rain was in the wrong places for rain scatter.

Denis G3UVR was much easier to hear on 3cm than on 13cm, and the dish is mounted a bit lower down than the 13cm yagi.

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26-November-2019 – my first contact on the 2.30 GHz NoV band

With the SG-Labs 13cm transverter in a box indoors, I can use a sub-band switch on the front panel of the box to switch between 2.30, 2.32 and 2.4 GHz. At 1870 MHz, the LO (Local Oscillator) frequency is rather low for the Microwaves Modules 70cm transverter (1870+430=2300 MHz) as I have not reprogrammed the SG-Labs transverter, so I thought the configuration might not work on the 2.300 to 2.302 GHz NoV band. I had configured the K3 with a 2300 band setting to generate the correct frequency on 10m band Intermediate Frequency (IF) feed to the 70cm transverter.

Using my Tiny VNA as a signal source, I found I could receive in the 2.30 GHz band.

I tried a contact on transmit with Keith G4ODA. It worked easily! Keith’s signal was very strong. I was using the Andrew linear amplifier producing about 50W, feeding the 40 el Wimo yagi through some metres of Ultraflex-10.

Really the SG-Labs transverter needs re-programming to give a more appropriate LO frequency, but it is nice that something works on the NoV band for the time being.

UK radio amateurs can apply for an NoV here for the 2.300-2.302 GHz band.