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Auteur Topic: Inaugural Distance Records on 135 GHz, 243 GHz and 324 GHz in VK.  (gelezen 3372 keer)
Eene de Weerd PA3CEG
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« Gepost op: Oktober 21, 2011, 10:44:19 »

Gents – this posting to advise the 135 GHz, 243 GHz and 324 GHz Microwave Bands have been activated in VK3 today, Friday 21/10/2011.
Despite the most unfavourable weather conditions.. Michael – VK3KH and I went out to Casey Sports arena in Cranbourne, east of Melbourne to test a pair of new Transverters that I had just finished building.
Our initial On Site testing over a 10 Metre path was to check the functionality of the gear.
We started with 324.48 GHz. Signal Reports for our SSB signals were 5+9 both ways. At this time, I'm unsure if we in VK have any allocations in this Band segment. There have been recorded Amateur QSO's on 322 GHz in the USA and Europe.
The next frequency we activated was 243.36 GHz. Signal Reports were 5+9 +10 both ways. Our final frequency was 135.20 GHz, again with 5+9 +10 both ways.

Having seen such big signals over our 10 Metre path, we decided to try our luck with an optimistic 400 metre path.
We failed to hear anything on 135 GHz.

This was not surprising with all the recent wet overcast weather, water sitting in puddles in the nice green grass and the very high Relative Humidity at the time.
Tests over a 200 metre path yielded much the same results. Nothing heard. Clearly we had too much atmospheric attenuation.
A 100 metre path yielded mixed results. We heard our 135 GHz Ident signals but they were so very weak that SSB was going to be impossible. Despite much effort to optimise our Dish pointing and the gear sensitivity.. the signals finally disappeared as the afternoon passed.
On each series of Tests using non Amateur Band Frequencies, we noticed that conditions (propagation) for these upper Microwave frequencies were changing very fast - even over these relatively short paths.
As the afternoon progressed towards 1600 hours local, it became somewhat chilly. With time running out, we decided to run our last tests over a 25 Metre path.
Our 135 GHz QSO was 5+9 both ways. The 243 GHz QSO was also 5+9 both ways. Our final QSO on 324 GHz was 5+5 from Michael to my 5+2 report.

All in all it was a very successful day despite the obvious poor weather. Amazingly, the QSO's we achieved on these 3 widely spaced Band segments were achieved by this single pair of Transverters.

At this time, we have not decided whether to claim Australian Distance Records for these 25 Metre QSO's. Clearly with some better weather and accompanying low Humidity, these distances will certainly be improved on.

A full Write-Up on the Equipment used will be published shortly. Suffice to say that the hardware is very similar to the 78/122 GHz Transverters I built previously. This time the "pump" source is 27.04 GHz. So, the 5th harmonic is 135.2 GHz, 9th harmonic is 243.46 GHz etc.
Our VK9NA Website at www.vk9na.com has more information on the techniques used. Related articles will also appear in DUBUS 4/2011.

Cheers,

Alan – VK3XPD
Michael – VK3KH.
Gelogd
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