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 Updated  11 Aug '11

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  The MicroWave contacts we made
 

IW9ARO operating at 10GHz

IW9HJV operating at 10GHz

Johnny

Andrea

While being very far to set  new records, we had great fun with every single contact we tried. Even at the first test from a corner of a room to the opposite one, you feel the challenges of being a microwave operator. Everything can go wrong when your key equipments are homemade, and non-extensively tested.  But the first difficulty, here in Sicily, has been to find other hams active on 3cm. That's why we have setup two complete 10GHz rover stations to make our experiments on this band.

Here we keep a Log of the 10GHz contacts we have been able to establish with our equipments, together with a photo gallery and some comments we like to share with you.

Date Time
UTC
MHz Mode QRB
[Km]
Operator(s) Location Grid POS ALT TX
PWR
Ant,
Gain
my
RST
Photos Notes
01/03/09 9:30~
10:00
10369.2 USB, FM 41 IW9ARO, IW9GUR Augusta (SR) JM77OG N3716.680'
E1512.790'
20m 100mW 40cmDish,
28dB
5/9+ 1 2 3 4 5 1
IW9HJV, IW9CRG Pedara (CT) JM77MO N3736.950'
E1503.007'
600m 50mW Small Horn,
10dB
5/9+ 1 2 3 4 5
10/04/09 10:00~
11:00
10369.1 USB, FM 378 IW9ARO, IW9GUR M.ti Nebrodi (ME) JM77HW N3756.858'
E1437.769'
1200m 100mW 40cmDish,
28dB
5/9+ 1 2 3 4 5  2
IW9HJV/I8 Roccamonfina (CE) JN61XH N4118.150'
E1358.989'
900m 50mW 43cmDish,
28dB
5/9+ 1 2 3 4 5 6
11/08/09 06:30~
07:15
10368.2 USB 61 IW9ARO Agnone Bagni(SR) JM77NI   3m 100mW 40cmDish,
28dB
5/8 1 2 3 4 5 3
IW9HJV Giardini-Naxos (ME) JM77PU   3m 50mW 43cmDish,
28dB
5/8 1 2 3 4
23/04/11 08:00~
09:30
10368.11 USB, FM 390 IW9ARO/IT9 M.ti Nebrodi (ME) JM77HW N3756.858'
E1437.769'
1200m 1W 40cmDish,
28dB
5/9 1 2 video 4
IW9HJV/I0 Terracina (LT) JN61OG N4117.05'
E1314.87'
5m 300mW 43cmDish,
28dB
5/9 1 2 3 4 5
07/08/11 13:10~
13:50
10368.2 USB, FM 207 IW9ARO/IT9 Mt. Etna JM77LQ N3741.92'
E1459.66'
1800m 1W 40cmDish,
28dB
5/9+   5
9H1GB/P Malta JM75GU     110mW 40cmDish 5/9+  
07/08/11 13:50~
14:10
10368.2 USB, FM 208 IW9ARO/IT9 Mt. Etna JM77LQ N3741.92'
E1459.66'
1800m 1W 80cmDish,
34dB
5/9+   5
9H1FX Malta JM75FU     200mW Slotted 8dB 5/9  
                             
                 

Notes:

1. This was our first true 10GHz contact and first on-air verification of our stations, just after completion of Andrea's transverter that, at that time,  had not the GPS lock circuit yet. The locations chosen were perfectly LOS, with easy eye-aiming, and in fact the contact was done easily with strong signals also in FM and with low-gain antennas. But we didn't know yet that our equipments would work! This first experiment was so smooth and encouraging that, immediately after, all our doubts disappeared and we both felt that those 41Km weren't that much at all. Our thanks to IW9CRG that has offered the large terrace of his penthouse located on the south side of Etna volcano, and to IW9GUR who, despite of his his leg recovering from a surgery, has actively participated with his experience from DX-peditions and field-days.   

2. This very successful long-range contact was not "scientifically" programmed. Andrea's location was simply the highest place close to the town in Campania where he and his family were spending Easter vacations. Without any experience, we did not know exactly where to look for the Sicilian location, so we made our best guess identifying  a site on the highs of Monti Nebrodi with a good visibility of the Tirrenian coast, with Eolie Islands at the horizon.  According to the simulations we did, about 140Km of sea would be below LOS, but we have been positive-thinking... and lucky. This time Andrea had a dish to increase the antenna gain, and also the GPS frequency lock was implemented in his transverter. But unfortunately GPS signals were jammed in his location, therefore also this time we had to play for a while to find each other. The FT817 has been a big help in this task because it is able to send continuously a Dih-Dah sequence with a simple trick: just set it in CW mode with the internal auto-keyer enabled, and afterwards short to ground both dot and dash pins of its paddle jack (or simply insert a stereo earphone that practically acts a a short). By continuously transmitting and slightly moving the dish, one station got better chances to be caught by the other.
Once established the contact, signals were above 9 most of the time using 40cm dishes at both sides, allowing also a relaxing FM talking. The contact was still possible using a small pyramidal horn  (13dB) at  Monti Nebrodi side, but in SSB only with a weak S1~3.  
In this "expedition" Andrea has been helped by his brother-in-law Carmelo (non-ham, but really precious). Johnny got a strong support by Davide IW9GUR, who has always been enthusiast about these new microwave experiences.

3. Just a summer exercise from our respective holiday locations, but with a little bit of risk because we both were at sea level and  LOS slightly obstructed by headlands in two points. Nevertheless, the direct path contact has been done easily, plus an interesting and successful experiment using as a reflector the large rocky hill of Taormina, about 1Km NE, behind Andrea's location.

4. Also this year Andrea moved to I8 for his Easter vacations, so it was time to try again the big jump...  Both transverters were significantly upgraded in power, and oscillators were locked to an internal OCXO to avoid bringing the extra load of the GPS disciplined references. To make things less easy,  this time Andrea drove his car to I0 to set his equipment on the beach of Terracina (LT), just few meters above the sea. Johnny went again to the location in Monti Nebrodi at 1200m. QRB was slightly below 400Km, and the forecast of tropo index  in the south Tirrenian sea was 2 (fair). Despite of that, signals were very strong also this time, and the QSO has been like talking at the telephone, also in FM. Sporadic, deep fading was observable, but the communication has never been lost. The OCXOs, previously tuned in the lab with the GPS reference, have been proven very stable, and fine tuning has been rarely necessary. We had the time also to stop the QSO and make an on-the-air check of the CW beacon recently built by Johnny, running 150mW in a low gain sectoral horn antenna. The beacon was transmitting from Johnny's location in Monti Nebrodi and was received 5/5/9 by Andrea in Terracina. Here is a short video of this QSO.

5. First QSO with stations outside Italy (and different from Andrea IW9HJV!). The contact was done easily at first try (QRB is not challenging) but this contact has been important to test  a new 80cm dish and to learn more microwave DX techniques from a new /P location.  

What we learned...

Apart of the common-sense rules you may easily imagine, like "bring also a  spare battery and don't forget to charge both the night before", there are a few lessons we learned during our few experiences as 10GHz ham operators, and we like to share them with you.

 - Not rely too much on GPS frequency reference: this system guarantees a very high absolute accuracy, but also keep as spare a well-calibrated alternate frequency standard because your GPS receiver might be jammed by strong TV or other transmitters close to your site.
- Plan in advance the talkback channel: in the 400Km range you can rely on a well-positioned VHF or UHF repeater,
 as we did, but before leaving to the sites don't forget to study which are the best repeaters to try, if they are not QRT and which sub-audio tone they need to be keyed (if any). Store all those repeater settings in the channel memories of both talkback radios. 
- Cellular phones can also be a good (even while expensive) back-channel for longer ranges, but not rely too much: there could be no GSM coverage where you are going to operate
- Plan in advance one or two microwave frequencies to operate on, and store the corresponding IF frequencies in both IF radios: this avoids calculations and/or misunderstandings when on-site. You will have many other things to think about.
- Study in advance and bring a note of the azimuth values from both locations, and don't forget a good magnetic compass (yes, is common sense, but is so important...).
- When outdoor, you normally run with batteries and your lab is not with you. A very useful thing we have put in our transverters is a simple meter to check the battery voltage and the TX power: if you are building a transverter don't consider it as an accessory gadget. 
- Similarly, on the field, you might need to check if the transverter is able to receive correctly. When no beacons are in range, ground noise/sky noise can theoretically help, but we noticed that by ear is a  very thin difference to catch. Without the antenna, it is much easier instead to hear the noise difference between terminated/unterminated antenna port: bring a 50ohm termination with you.
- Setup a system to continuously transmit a characteristic signal. You can use a looped voice recording in your MP3 player, or a CW keyer with memory. A PC needs a lot of power, space, and it's the very last tool we would suggest. Bottom line, if you have an FT817, use a 3.5mm-plug stereo  earphone (read above).


If  you are interested to get more details or to arrange a sked, feel free to drop an e-mail at our e-mail address

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The projects presented in these pages are our own design and have been tested and verified by ourselves at the best we can. However, they might be inspired by concepts, ideas, solutions coming from known-art or free resources on the Web. We provide them as  reference designs to skilled hobbyists and technicians  who are willing to reproduce them for non-commercial use. Your results might be different from ours and we cannot be considered responsible for that. Similarly, we are not responsible for any damage or injury you might incur while building, assembling or using the equipments, projects or ideas presented in these pages. The firmware embedded in our projects is our property unless differently stated and when available in the Download Area it is license-free only for non-commercial purposes.  

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