Författare: Lars Thunberg

432 MHz EME QSO

Inläggsförfattare Av Lars Thunberg
Inläggsdatum 2024/09/28
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Some time ago now – but I made two EME QSOs with DL7APV (now SK) in February 2023. I used my 2* 15 el LFA X-yagi and 40 watt output from IC-9700.

2.2 GHz Helix

Inläggsförfattare Av Lars Thunberg
Inläggsdatum 2024/09/21
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Some construction notes of my two 2.2 GHz Helix antennas I now using for my SatNOGS station and manual satellite RX.

The print scaffold set is from Dereksgc and i friend of mine did the printing https://www.thingiverse.com/thing:4980180

Construction notes from UHF-Satcom:
https://uhf-satcom.com/satellite-reception/s-band

The wire is from a RFC-400 coax cable center conductor – I just stripped one meter.

First set the wire to the printed support frame:

Then drill a hole in the reflector and mount a connector – I used both N-type and SMA-type.

In order to get good 50 ohm match I needed to solder a piece of copper tape according to the image below:

Then a lot of hot glue and UV protection spray to get it a little bit more water proof:

Finally mounted at the mast:

This is the SWR plot after mounting:

I can recommend Dereksgc Youtube channel for lot of videos about S-band antennas and RX:

https://www.youtube.com/@dereksgc

Amateur Radio

Internal and external LNA tests IC-9700

Inläggsförfattare Av Lars Thunberg
Inläggsdatum 2024/08/28
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Some test with the internal LNA (P.AMP) of the IC-9700 and external LNA. What combinations will give the best SNR? Note that all tests are done without any type of professional equipment – only by looking at the waterfall and listening with my ears.

I have used my VHF and UHF yagis and external LNAs Mini-2 and Mini-70 mounted just below the antennas. I have aprox. 16 meters of high quality LMR-400 cables between the IC-9700 and antennas/LNAs.

VHF – beacon SK1VHF at 144.447 MHz

Without internal P.AMP and external LNA	Not possible to hear beacon
With only internal P.AMP	Possible to hear beacon
With both internal P.AMP and external LNA	Better SNR but needed to reduce RFGain to get good SNR
With only external LNA	Best SNR! No need to reduce RFGain.

Note on VHF: The difference between using both internal P.AMP + external LNA and only external LNA is not huge, but is clearly audible.

UHF – beacon SK1UHF at 432.405 MHz

Without internal P.AMP and external LNA	Not possible to hear beacon
With only internal P.AMP	Possible to hear beacon
With both internal P.AMP and external LNA	Better SNR but needed to reduce RFGain to get good SNR
With only external LNA	Best SNR! No need to reduce RFGain.

Note on UHF: Almost the same result as VHF, but the external LNA gives better result and SNR compared to VHF.

Summary:

If you do not have an external LNA it is mandatory to use the internal P.AMP on the IC-9700 for very weak signals.
If you have a good external LNA mounted close to the antenna it is best to turn off the internal P.AMP to get best SNR.

Etiketter ic-9700

Amateur Radio

QO-100 SatRover fixed setup

Inläggsförfattare Av Lars Thunberg
Inläggsdatum 2024/05/05
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This is my final QO-100 fixed setup with the SatRover:

SatRover Mk 1 from PE1CKK
2.4 GHz Helix (as a part of SatRover)
LNB a part of the SatRover, feed with normal 75 ohms TV cable coax
60 cm dish from Triax (TD64) branded as Canal Digital
IC-705 as TRX
10 dB attenuator and a number of meters of Hyperflex 5 coax cable to make the output on 2.4 GHz at the Helix to aprox 100 mW (legal power limit in Sweden)