Part 1 Case Study: Reaching Distance of the 145.750 Mhz Aasvoelkop Repeater in the Southern Cape (Click on link.)
In the first part I looked into long distance RF contacts that were made via the Aasvoelkop Repeater, amateur radio mobile- and fixed stations. In the second part I will be looking at:
1. Possible coverage areas where long distance RF contacts can possibly be made during normal or flat conditions with the repeater but thus far these areas were left in limbo. Either because no radio amateur was mobile or the lack of a fixed amateur radio station in the plotted areas.
2. Coverage areas not generally accessible but might be when Tropospheric Ducting, Sporadic E or other means of propagation conditions are favorable.
3. Coverage areas were the repeater is accessible under normal or flat conditions.
Once again a bit of background is necessary. Radio Mobile Software is great to map the repeater coverage but
to ascertain how accurate the software is we need real live repeater
reports from different coverage areas under "normal" operation.
Admittingly there are many other factors (propagation, seasons, time of
day, weather etc.) that plays an important roll when conducting such
tests / experiments. This case study is nowhere close to any scientific study but none the less very useful as can be seen from Part 1.
For the purpose of these tests / experiments I made use of the following methods to illustrate the relative performance of the Aasvoelkop Repeater in areas where this repeater up to now was never heard or activated before:
1. Use of Radio Mobile Software as a tool for predicting the performance of the 145.750 Mhz Aasvoelkop Repeater.
2. The RF Line-of-Sight Tool to easily drag-and-drop locations and obtain point-to-point line-of-sight information anywhere using Google Maps. This RF Line-of-Sight tool is exceptionally helpful in mapping long distance radio communication coverage.
Once again we need to look at the following maps that show the repeater coverage area after new data was entered as a result of the upgrade undertaken. (Click on all image to enlarge.)
With all the foreword done it is time to look at certain very interesting areas from where radio amateurs might or might not access this repeater as mentioned supra.
1. Possible coverage areas where long distance RF contacts can possibly be made during normal or flat conditions with the repeater but thus far these areas were left in limbo. Either because no radio amateur was mobile or the lack of a fixed amateur radio station in the plotted areas.
Caledon Area and Radio Coverage:
Note: It should be possible to activate the repeater just outside Caledon direction Mossel Bay using a good gain antenna and at least 50 watt RF Power. Who will be the first to make contact from Caledon?
Kogelberg Mountain and Radio Coverage:
Note: This radio path is from Kogelberg Mountain to the Aasvoelkop Repeater. Anybody willing to climb the Kogelberg Mountain, setup a station and try to make a contact via the Aasvoelkop Repeater?
Struisbaai Area and Radio Coverage:
Note: This one should be quite easy. Any radio amateurs on holiday visiting Struisbaai or Agulhas you now have a repeater that you can excess and talk to radio amateurs all over the World.
Border between Western Cape and the Northern Cape: Fraserburg / Merweville Area and Radio Coverage :
Note: Now here might be a very interesting contact option. Fraserburg / Merweville is situated in the Great Karoo. The Radio Path Study indicated that there might be an "open line of sight path" in areas between Merweville / Fraserburg to the Aasvoelkop Repeater. If this is correct than the radio signals "cross" the Outeniqua- and Swartberg Mountains. The yellow (weak signal color) area indicate from where contacts are possible. One green (strong signal color) spot is also visible. These areas are mostly on mountains and ridges between Fraserburg and Merweville. It would be great to hear a station calling from this area to confirm that the models are indeed correct. This would make it the longest distance (209km) until now over mountains in accessing the repeater under normal or flat conditions.
2. Coverage areas not generally accessible but might be when Tropospheric
Ducting or Sporadic E propagation conditions are favorable:
Beaufort West Area / Molteno Pass / Carnavon:
Although the modules do not indicate any radio paths in the Beaufort West and Molteno Pass areas, Peet EI7JQ heard the repeater while mobile through the Molteno Pass between Beaufort West and Carnavon during his visit to South Africa recently. Unfortunately he could not access (TX) the repeater as his radio was not programmed with the necessary CTCSS code. It might be possible to make a contact from the Molteno Pass. (Red Dot in satellite image.)
Uniondale Potjiesberg Area and Radio Coverage:
Several areas of interest here but I would like to concentrate on the Potjiesberg area. The yellow (weak signal color) area indicate from where contacts are possible. The green (strong signal color) areas are also visible. The yellow and green indications are mostly in mountainous or ridges areas. Potjiesberg is situated about 10 km from Uniondale direction George and can be seen from the N9 road. In the past one could easily access the 145.600 Repeater from Dana Bay. It would be great to hear a station calling from this area to confirm that the Aasvoelkop Repeater is accessible from Potjiesberg, Uniondale area.
Table Mountain Area:
Note: No Radio Mobile image coverage to Table Mountain but a contact might be possible with a high gain Yagi antenna and at least 100 watts of RF Power. Above image is from the upper cable cart station on the mountain. Who are we going to hear first from Table Mountain?
Sir Lowry's Pass Mountain and Radio Coverage:
Note: Although better coverage higher up towards Hottentots Holland Nature Reserve there is sometimes the possibility of a reflected signal from the mountains. Why not try activating the Aasvoelkop Repeater when on top of the Sir Lowry's Pass while mobile towards Mossel Bay?
Bloemfontein Area:
Kimberley Area:
Luckhoff Area:
Orania Area:
Note: In my humble opinion it would be rather difficult to access the repeater under any normal or flat conditions. It might however be possible to make contact to and from these areas through the repeater under the following propagation conditions:
1. Tropospheric Ducting (Possible along the coast. Rare inland)
2. Summer Sporadic E (Fairly good chance during summer)
3. Temperature Inversion (Possible along the coast. Rare inland)
4. Aurora Scatter (Possible)
5. Meteor Scatter (Possible)
6. Tropo Scatter (Possible)
7. Airplane Scatter (Possible if the direction of the plane is correct.)
8. High-Level winds moving across mountains creating gravity waves and compressing the ionisation.(Never achieved but possible if you have large mountains and correct winds in your area. Experimentation necessary.)
9. Reflection from Mountains (Possible)
10 Moonbounce (EME) Would it be possible to access the Aasvoelkop Repeater or any other repeater by using Moonbounce (EME)? I am of the opinion that it should be possible. Has any radio amateur experimented with this possibility? (Never achieved but possible with some changes to the repeater)
3. Coverage areas were the repeater is accessible under normal or flat conditions:
Blands Drift, Herbertsdale Area + Radio Coverage:
Dana Bay Area + Radio Coverage:
George Area + Radio Coverage:
Hartenbos Area + Radio Coverage + Obstacles:
Note: There are several mountainous areas between the repeater and Hartenbos which prohibit communications in areas. However the 145.550 Mhz GRHub Network is connected to the Aasvoelkop Repeater and can be used to access the 145.750 Mhz Repeater.
Still Bay Area + Radio Coverage:
Oudtshoorn Area + Radio Coverage:
Mossdustria Area + Radio Coverage:
Mossel Bay and Heiderand Areas + Radio Coverage:
End
