Long Distance 2m project

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Daniel Wee
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Joined: Wed 25 Feb 25 2009 8:00 pm

Long Distance 2m project

Post by Daniel Wee »

The idea is to try to make a 2m QSO from Singapore to Sarawak. For this, we will need to overcome the 25W power limitation so this means good yagis or arrays of yagis. It would also require elevation and information concerning potential tropo ducting opportunities.

This could be done in collaboration with the Sarawak Amateur Radio Emergency Services Society (SARES), or even with Miri and Indonesian counterparts.

https://www.facebook.com/saresswk/
http://arcsonline.blogspot.com/
http://marc.org.my/

Other long distance attempts:-

http://www.ok2kkw.com/kh6ku/ok1vr58eng.htm
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Distance-Records-11-September-2020.pdf
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Daniel Wee
Site Admin
Posts: 2317
Joined: Wed 25 Feb 25 2009 8:00 pm

Re: Long Distance 2m project

Post by Daniel Wee »

If we assume 25W output power (43.98dBm), and a receiver noise floor of -131dBm (best case -145dBm) of the ICOM IC-9700, along with a Cushcraft 10-element Yagi with a gain of 11dB (13.2dBi) and using RG58 (Belden 9201) with a loss of 0.492dB/3m - we get the free space loss of 184.5dB and a corresponding maximal distance of 276537km. This means that the theoretical distance is sufficient to cover the distance of Singapore to Kuching (725km), or Miri (1192km), Mt. Kinabalu (1512km), Cameron Highlands (437km), Gunung Ledang (172km).

https://www.rfwireless-world.com/calcul ... lator.html
http://www.sherweng.com/table.html
https://www.dxengineering.com/parts/csh-a14810s
https://www.dxengineering.com/parts/csh-a14820t
https://www.dxengineering.com/parts/csh-a13b2
https://www.qsl.net/co8tw/Coax_Calculator.htm
Daniel Wee
Site Admin
Posts: 2317
Joined: Wed 25 Feb 25 2009 8:00 pm

Re: Long Distance 2m project

Post by Daniel Wee »

Assuming we are able to get to the top of a HDB building - say 100m up, the line of sight distance is 35.7km and the radio horizon is 41.2km. That just isn't far enough to get a really long distance QSO. Even with both ends elevated by 100m, the total line of sight distance is only around 80km under the best conditions. We are clearly in need of some propagation condition help.

https://www.everythingrf.com/rf-calcula ... calculator
solomonbstoner
Posts: 1
Joined: Fri 25 Dec 25 2020 6:17 pm

Re: Long Distance 2m project

Post by solomonbstoner »

The tallest building in SG stretches up to 290m (Guoco Tower), but there doesnt seem to be access to the rooftop. Its "rooftop" garden is on the 2nd floor.
The highest publicly accessible building is the The Pinnacle@Duxton which stands 156m tall.

Using this calculator , the LOS distance is 44.5km, and radio horizon is 51.4km.
Im gonna see if the ITU P.528-4 software might give us more details in our link budget

https://www.itu.int/rec/R-REC-P.528-4-201908-I/en
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