The following two postings refer:
1. Opgraderings aan die 145.750 Mhz Aasvoelkop Herhaler in die Suid Kaap (Deel 1)
2. Upgrading of the 145.750 Mhz Aasvoelkop Repeater Site in the Southern Cape Area (Part 2)
Now as with any repeater that gets installed or upgraded, there is always an interest to find out how far the repeater is heard and the distance it can be accessed to make an audible and reliable contact. The Aasvoelkop Repeater's "reaching" distance was and is a HOT discussion topic amongst the users of this repeater in the Southern Cape.
I found some very interesting information during my research to compile this posting. More on this later in the posting.
I again used Radio Mobile Software and added the RF Line of Sight Firmware to predict the performance of the Aasvoelkop Repeater after the upgrading of the repeater site and the antenna system.
The following maps show the repeater coverage area after new data was entered as a result of the upgrade undertaken. (Click on all image to enlarge.)
Now the 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. Now this is just what happened after the upgrading of the repeater. In my opinion April is one of the best months to do such tests or experiments without "interference" from some factors mentioned supra.
For this purpose of these tests / experiments I made use of the following methods to illustrate the relative performance of the Aasvoelkop Repeater:
1. Real Time Reports by Radio Amateurs that utilized the 145.750 Mhz Aasvoelkop Repeater either mobile or from a base station.
2. Use of Radio Mobile Software as a tool for predicting the performance of the 145.750 Mhz Aasvoelkop Repeater.
3. 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.
There was many local (short distance) reports forthcoming from radio amateurs in the Southern Cape. Unfortunately I cannot mention and illustrate all the reports as this will make for a very long posting. I have therefore decided to only mention a few long to extra long distance reports that were received from radio amateurs.
1. Real Time Swartberg Pass Contact: Still Bay to Swartberg Pass (Dolf ZS1DRP, Rassie ZS1RP and Johann ZS1AAC)
On the 24 April 2024 Dolf ZS1DRP called from the top (road peak) of the Swartberg Pass. Contact was established with Rassie ZS1RP and Johann ZS1ACC in Still Bay. All three stations could copy each other via the 145.750 Mhz repeater.
Radio Mobile / Google Image: Still Bay to Swartberg Pass (Dolf ZS1DRP, Rassie ZS1RP and Johann ZS1AAC)
RF Line of Sight Path: From the 145.750 Mhz Aasvoelkop Repeater to the Swartberg Pass Peak. Distance: 101.57 km. Note the clear path between the repeater and the Swartberg Pass Peak. The green line in the Radio Path Study indicate that there is a clear path.
2. Real Time N1 Dwyka River and Prins Albert Road Contact: (Kobus ZS1K, Johan ZS1I and Koos ZS5KDK)
On the 13 April 2024 Kobus ZS1K was heard calling from the N1 near Prins Albert Road and also when crossing the Dwyka River. Koos ZS5KDK called back but Kobus ZS1K did not hear Koos. Johan ZS1I then called Kobus ZS1K and he returned the call. A brief contact was made between Kobus ZS1K (Mobile N1) and Johan ZS1I (Mossel Bay) via the Aasvoelkop Repeater.
Radio Mobile / Google Image: (Kobus ZS1K and Johan ZS1I)
RF Line of Sight Path: From the 145.750 Mhz Aasvoelkop Repeater to the N1 Dwyka River and Prins Albert Road. Distances : 125.44 km and 135.91 km. Amazing that this contact was made. The Radio Path Study indicate that there are several mountains (obstacles) between the repeater and two stations. Also indicated with a red line. Please note the Blue and Green Antenna height indications in the Radio
Path Study has no effect on the study and is there for record purposes
only. However in the second Radio Mobile image one can clearly see that there is weak (Yellow) signal repeater coverage in the mentioned areas. This also indicate that Radio Mobile is quite accurate in its predictions.
3. Real Time N2 Humansdorp to Still Bay Road Contact: (Thys ZS1TBP, Rassie ZS1RP and others)
On the 21 April 2024 Thys ZS1TBP was heard calling from the N2 10km from Humansdorp direction Mossel Bay. He was at first scratchy but when he called again Rassie ZS1RP answered his call. Thys was so excited he nearly fell out of the MAN truck he was driving. Never since the upgrading was he able to access the Aasvoelkop Repeater from this location. A brief contact was made between Thys ZS1TBP (Mobile N2) and Rassie ZS1RP (Still Bay) via the Aasvoelkop Repeater. As Thys ZS1TBP was moving towards Mossel Bay several other stations contacted him. It would not be fair not to mention the fact that the Hepburn Propagation Prediction was very good on the day but not only that, it was also warm (38 Deg C) with several deep temperature inversions along the N2 motor way. The Radio Mobile Software was not far off the mark here but we must note that propagation on the day was very good.
Radio Mobile / Google Image: (Thys ZS1TBP and Rassie ZS1RP)
RF Line of Sight Path: From the 145.750 Mhz Aasvoelkop Repeater to the N2 Humansdorp Road. Distances : 266.43 km Note that the Radio Path Study indicate that there are mountain (obstacles) between the repeater and two stations. Also indicated with a red line. No open path but as already mentioned the Hepburn Propagation Prediction was very good on the day.
4. Real Time Anysberg to Still Bay Contact: (Nick ZS1ZAN, Johann ZS1AAC and others)
On a regular basis Nick ZS1ZAN is heard via the Aasvoelkop Repeater calling in on the Sonsakspan Net all the way from the Anysberg Area close to Laingsburg. Since the upgrading he has a far better signal coming into the Aasvoelkop Repeater from his location. A while ago a simplex contact was also made between Nick and Johann on 145.500 Mhz
Radio Mobile / Google Image: (Nick ZS1ZAN and Johann ZS1AAC Simplex Contact)
RF Line of Sight Path: From the 145.750 Mhz Aasvoelkop Repeater to the Anysberg Mountain. Distances : 112.02 km. Interesting to note the large mountain area between the Repeater and ZS1ZAN. Once again a red line indicating that there is no direct path between stations. Please note the Blue and Green Antenna height indications in the Radio Path Study has no effect on the study and is there for record purposes only.
5. Real Time Still Bay to Barrydale Contact: (Fred ZS5SAM (Div 1) and Johann ZS1AAC)
On the 18 April 2024 Fred ZS5SAM called from Barrydale using his homebrew constructed Yagi Antenna. Contact was established with Johann ZS1ACC in Still Bay. Although there was "rain" on the signal Johann ZS1AAC and Fred ZS5SAM had a short conversation on the 145.750 Mhz repeater.
Radio Mobile / Google Image: Barrydale to Still Bay (Fred ZS5SAM (Div 1) and Johann ZS1AAC)
RF Line of Sight Path: From the 145.750 Mhz Aasvoelkop Repeater to the Barrydale. Distances : 94.06 km. Although the distance is only 94km it is interesting to note the large mountain areas between the Repeater and ZS5SAM. Once again a red line indicating that there is no direct path between stations. I suspect a mountain reflected signal assisted with this contact. Looking at the "obstructions" one would say that a contact would be impossible. Please note the Blue and Green Antenna height indications in the Radio Path Study has no effect on the study and is there for record purposes only.
Other Repeater Coverage Maps: (Click on images to enlarge)
In Part two I will take a look at areas where the repeater might be heard and the distance it might be accessible to make an audible and reliable contact. In some instances the repeater was received from areas but no contacts were yet made as the depicted repeater coverage areas are in remote locations where there is no radio amateurs available. However one never know when a roaming/mobile radio amateur station might move through these areas and contact is then established. Some interesting "phenomena" will also be presented in Part 2.
Finally: A big word of thanks to all those stations, also those that were not mentioned in this posting that use the 145.750 Mhz Aasvoelkop Repeater in the Southern Cape. A big thank you must also go to all the Echolink and AllStar stations that connects to 145.750 Mhz repeater to use and to create activity on the two meter band. This is only the beginning. Johann ZS1AAC indicated that he is already busy planning future upgrades and installations in the Southern Cape. We are looking forward to see what he has in stall for the Southern Cape.
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