28 April 2013

Cedar Lakes mid-lake

I was QRV for the first time from this spot at Cedar Lakes at 12:00local. It took me 5 minutes to set up my station plus the usual EFHW. After tuneup on 7020Khz om Monk ZS4SF came back to me and gave me a 599+10db report. I gave him the same. The repair I completed yesterday on the ATU was now working fb. The problem was a broken wire on the smallest toroidal inductor. Looked like the wire had been damaged on installation. This being the beauty of the K2. Any faults can be corrected by the operator. I also repaired my Palm Paddle, however a more permanent fix is needed. The design for the cable could be better since all strain is taken on the screen.

Ialso copied ZS0BOT/B on 7027Khz, 509 and ZS2VJ on 7052Khz also 509. The band was in reasonable shape and very quiet. ZS4SF also reported some QSB.

17 April 2013

Rietvlei Dam and Game Reserve

Last weekend Sunday April 14th Berry and I took a drive to the Rietvlei Dam and Game Reserve in Irene. This is about a 45 minute drive from our QTH. I reckon it is further to drive than to Krugersdorp Game Reserve. After a drive around and viewing a group of 4 Rhinos with their horns cut off (see pics below) we settled near a waterhole and bird watching area on the east side of the park. This is also a pleasant braai area. Not great from a field radio perspective since the area is quite small and crowded with picknickers. Would be great during the week I think. The entrance fee to the park is R40 each.

I deployed my efhw into a tree about 5 meters high and strung the wire along below a partial canopy of trees. I was QRV at a picnic bench after about 10 minutes at approx 12 noon. Again I noticed total stability in SWR when I touched the coax and rig. It is clear to me that as long as the tuner is a few feet max from the ground that the configuration is stable. When I was at Leopard Creek I had the tuner suspended in the air and up about 6 feet agl. This was when it was not stable. I immediately was in QSO with om Monk ZS4SF who was monitoring the frequency and for which I am truly appreciative. We had a nice ragchew for about 40 minutes. he gave me a 579 report. I felt like propagation conditions were good but that my QTH and deployment were not great.

I also copied 2 beacons ZS2VJ and ZS0BOT on 7027Khz and 7052Khz. Neither moved the needle but both were easily readable.

In conclusion. Rietvlei will be a good place to deploy during the week but crowded at the weekend. We did not get a chance to explore the lake areas which may be better. There are also cottages for hire. These need to be explored also.

Ragchewing with ZS4SF. Thanks Berry for the pic
Weird  guineafowl protecting chicks. Willowfeather farm Irene. Nice lunch spot

07 April 2013

Leopard Creek Country Club, Malelane 

Berry and I were invited for the weekend to this exclusive golf club and associated residential resort. Apart from a beautiful golf course this resort is also build unobtrusively into the lowveld bush alongside the crododile river and Kruger game park. So nature certainly surrounds you. http://www.leopardcreek.co.za

I did not have much time for radio but I did set up my EFHW and K2 in order to check in to the ZS0AWA net on Saturday afternoon. I got the wire into a bush tree at the now familiar height of 5meters. I had the tuner dangling in the air at a height of about 2 meters. The K2 was on a large teak table. Interestingly I had a bit of a challenge getting the SWR down. I was only able to obtain about a 1.7:1 SWR. Also when I touched the tuner or the K2 there was definitely a variation in the SWR.

Having said that I checked into the net and received 579 report from om Andy ZS6ADY. Also on the net were ZS6AJY (Joburg), ZS5DM (Durban area) and ZS6JBJ (Witbank). All stations were able to copy my signal FB. I was unable to stay long on the net due to a need to attend to a discussion with other guests. I dismantled the station in 5 minutes after the net. The distance to Joburg being approximately 420Kms. Conditions on 40m were definitely better than the week before,


  1. Perform some tests on variations of SWR with tuner height above ground. This deployment experienced the same SWR variations that I remember seeing in the USA during similar deployments.
  2. Find a way to easily describe to curious onlookers what I am up to. The idea of using morse code  appears to provide great opportunities for leg pulling...hi hi. The contest on Larry King live where 2 old timers beat a couple of high speed kids in sending CW/Text always gets attention. 

02 April 2013

DVB-T dongle 2m/70cm antenna deployment

Having successfully managed to get the RTL dongle working I was now on a mission to explore further what I could hear with a better antenna/s. I could clearly hear the commercial FM stations on the broadcast band with a 2 foot piece of wire. I also copied the weather forecast on AM from Lanseria airport just above the noise. What could I hear with a decent antenna system?
After some searching around on the SARL VHF/UHF forum I read about the J Poles manufactured by ZS6PVW om Pieter van Wyk in Pretoria. I contacted Pieter and he kindly send me some pictures of his antennas for review. Please see the pics below.
I travelled to Pieter's QTH in Pretoria on Good Friday March 30th and spent a very pleasant time. He showed me around his extensive VHF/UHF antenna farm. His being a ham family meant that it is necessary to deploy enough antennas for everyone! I could see that the installation quality and quality of the home brewed antennas are excellent. It was clear Pieter's profession as an expert welder certainly provide him with the tools and capability to build a truly wonderful radio antenna farm. He has an antenna for every polarization for 6m/2m/70cm. Pieter told me about a lightening surge that destroyed much of the electronics in his home. However none of his antenna installations were affected. Perhaps a testament to the extensive ground system installed. Each mast has a separate ground system installed.
I purchased a ZS6PVW 2m/70cm Dual Band J-Pole. Here are the details as provided by Pieter.
Serial Number: 046
Manufactured: October 2012 by ZS6PVW
SWR 2m.  144.350-1.45, 145.000-1.2, 145,575-1.0.
SWR 70cm 430.500-1.2, 431.500-1.35, 433.500-1.6, 435.500-1.4, 437.500-1.6, 439.500-1.95
I was not able to measure the SWR since I dont have an antenna analyzer that works at these frequencies.
I purchased a 3 meter pole and bracket from Builders Warehouse. I installed the bracket on the side of the wall and to the right of the door entrance to my radio operating position.
I was able to copy the Sandton Radio club bulletin on 2 meters although it was not full quieting. I also can see a strong signal on 145.800Mhz. I believe this is likely an APRS signal. I have found that by increasing the RF gain on the SDR that I can slightly improve the S/N ratio. The dongle itself seems to show about a -60db noise floor with most received signals about 15db above this noise floor. There is good opportunity to adjust the controls on SDR# and so I am still learning about the optimum settings.
I am also able to hear a number of Airband stations quite well and many other NFM signals that sound like taxi or security firms.
Even though the antenna is designed primarily for the 2m/2cm bands it seems to be able to function reasonably across the VHF/UHF bands. I have yet to hear a repeater on 70cm, however I suspect is a lack of activity on this band.
The antenna is up about 2.5 meters above the apartment roof top, however there are surrounding building structures and roofs which mean that this is not an ideal location.
From the point of view of having something to play with in order to gain experience with SDR this is a great and inexpensive set up. I believe the ZS6PVW antenna will withstand any weather that we are likely to experience at this QTH.

The dual band J pole for 2m/70cm on the right of the pic to the right is the one I purchased.

ZS6PVW homebrewed tower and antenna arrays for 6m, 2m and 70cm. Also an HF fan dipole.

Installation at ZS6RSH QTH

Matching element on left, 70cm center, 2m on right

Cedar Lakes upper park bench site

On Easter Sunday March 31st at 12 noon I had half an hour to spare so gathered my gear and walked up to the park bench in the upper east corner of the Cedar Lakes property and right under the electric fence. I was QRV by 12:10 pm with no problems. The end of the efhw was up 25 feet with the mid point being about 10feet up.. This is a good location since it is quite high up the slope behind cedar lakes. I could hear at leas two electric fences. My noise blanker on setting 2 was able to eliminate some of the fence noise spikes but not totally. It is better at eliminating a single fence since I imagine that it settles on a specific cadence. When there is more than one fence it is unable to resolve fully.
 I called for about 10 minutes and was answered by om Derek ZS5DM in Kloof near Durban. He reported a perfect day weather wise and gave me a 599 signal report. He was unable to QSO for long. By 12:30 I was back at the house and ready to head to a braai at my sister's place. I was again truly amazed at the ability to effectively communicate over a long distance with such a simple and fast deployment. This time of day seems to be optimum for SA wide operations on 7020Khz at this time of year. It will be interesting to see how propagation changes as the season progresses.

Bird crap is an occupational hazard :)

Cedar Lakes picnic bench upper lake

Today, Easter Saturday March 30th, I took a walk and set up my field station from a nice picnic bench with a lapa for shade. A lovely view from here looking NW across towards the Lion Park. There is a tree about 50 feet away which I was able to get my yoghurt bottle over in one shot. I reckon practice makes perfect. I find it quite easy to get the end of the EHHW up at 20 feet with the center up about 10-12 feet. I still find that the launch rope is too sticky for this application. It is often more effort to get the weight to fall to the ground than it is to launch to 20 feet. I also need to think about getting the middle of the wire up at 20 feet in a kind of inverted Vee config. Max radiation takes place from the center of this antenna according to what I have read since it is basically a dipole (albeit NVIS config). This is an interesting area to explore further.
I quickly fed the other end of the efhw wire through a convenient spar atop the grass lapa shading and down to the picnic table. I was QRV after about 15 minutes set up time at 14:15hrs local. I started calling on 7020KHz and was answered by ZS4SF om Monk in Welkom, We had an good chat although Monk was having some trouble copying me from time to time due to heavy QSB. I would receive a 599 report and then next over, the signal would drop to a zero on his scale. He even tried swapping radios to see if an improvement could be obtained. I had no trouble copying his QRP and QRO signal fb. The propagation conditions definitely were down since I only copied the ZS6LP antenna test signal at 549. Grid square KG33xu.
At 14:00 hrs local I checked into the ZS0AWA net run this week by ZS6AJY om Barrie. Also on the net was ZS6AZP Dave from Irene. I copied Dave's QRP signal FB and I look forward to working Dave and his QRP signal in the future.

Lessons learnt this trip:

  1. Take a cloth to clean the picnic table
  2. Take some timing measurements for set-up time as a measure of improvements in technique
  3. Write in detail what the steps are for a fast and smooth field deployment