Having received an offer from Ted VK1BL to help me find and fix the problem in my 13cm transverter, I spent an evening with him on 13th June. Moving through the various functional blocks in the transverter we found
The receiver was working quite ok, it was very close to the right frequency and was fairly sensitive, hearing -120 dbm from the HP sig gen pretty well
The output from the PLO was good and at a level of +7 dbm as recommended for the mixer
The output from the sequencer board, which includes attenuators and a level setting control for the IF signal, 144 MHz in this case, was working well and we calibrated that at -10 dbm for input to the mixer, with 0.5w drive on 144 mhz from the ft817
The output from the mixer and filter was at the expected level, about -13 dbm
The output from the tx IF amplifier/driver was +10 dbm, which was adequate for the power amplifier
The power amplifier had the correct negative bias and positive voltage on the correct terminals
But the power output to the antenna socket was zero.
The power output from the amplifier (before the relay) was about +35 dbm (approx 2.5 watts)
The relay board was examined and was found that the DC to the relay coil was intermittent. Resoldering the pins of the relay, a surface mount type, fixed that intermittent and made it a reliable connection. The output to the antenna socket was then +35dbm or 2.5w.
Transverter considered fixed.
With that result I discussed the possibility of an activation on Saturday morning to prove it in the field. Andrew VK1AD offered to activate Mt Stromlo and I decided to visit South Black Range. Coincidentally it was the day when bonus points commenced for VK2 summits above 1200m, so I half expected to find some snow on the higher parts of this summit, as it had recently snowed down to about 900m.
No snow, quite cold at about 3 or 4C when I got there, but it warmed up to about 8C by midday.
After initial contacts on 144 then 1296 we switched over to 2403 MHz and found we were able to make easy contact, my signal received a 5×8 report from VK1AD and I received his signal at an indicated strength 5.
Note: the distance of this contact was about 47.5 km, not bad for 2.5 watt transmitters. The locators of the two summits are QF44MQ (Stromlo) and QF44SN. The visual horizon is 35km so this is beyond “line of sight”. But how far over line of sight is it?
According to my iphone app DistBear the distance between centres of the two grid subsquares is 47.5km. So 2.4 GHz worked fine, well over the visual horizon. To get a more accurate distance I used the website https://sotamaps.org, using the “range mapping” option, we get a more accurate measure of the distance, at 48.7 km. I am sure there will be longer contacts made on this band using the same equipment.
The antenna in use for 2.4 GHz at my end is shown in the photo below attached directly to the 2.4 ghz transverter, was the SG-LAB PCB antenna, a 2 element HB9CV type on loan from Andrew VK1AD. The 2403 MHZ equipment was placed on a rock and turned so that the antenna pointed roughly towards Mt Stromlo, albeit through many trees nearby.
After completing the contact on 2.4 GHz I moved to HF and ran a few contacts on 7023 khz using the Pixie half watt morse transceiver (on a 50 x 50 mm PCB), then moved to the KX3 and ran contacts on 40m and 80m SSB and CW. I left the summit just after 12 noon, after spending 2 hours there. The temperature had risen to 8C by then.
I built up the Pixie kit, having bought it a year ago or more, just to see how it worked and intended to try it out on a SOTA activation.
Being invited to accompany Andrew VK1AD to Mt Marulan for a return visit, having done the same in December 2018, I decided to take the Pixie along to see if it could make even one contact with 40m conditions as dicey as they are at present.
I set up the station to use the Pixie, with the ZS6BKW doublet fed through an Elecraft T1 tuner and the choke balun recently built. (Did I write about that? Maybe not.)
I listened for a minute or two on the Pixie’s 7023 khz and could hear VK2ARZ calling CQ with a very high offset frequency, my guess was that he was on 7025 so would not hear me operating on 7023. The Pixie’s receiver is a direct conversion receiver without any inherent selectivity so if my ears had 10 khz frequency response I would have heard stations out to that offset in both directions, ie. higher and lower in actual frequency, eg. A signal on 7013 would produce a 10 khz frequency difference so the 10 khz would be coming through the receiver, as would a 7033 khz signal also produce a 10 khz audio frequency. My 69 year old ears don’t have that bandwidth any more, they have an inbuilt low pass filter. 🙂
So I spotted myself on Sotawatch using the vk port-a-log software on the android tablet, called CQ using the little blue hand key, listened, then called again. A big signal loomed in the earbuds and it sounded like a bug being used. Was it Steve VK7CW, yes, it certainly was, after the call letters marched across my ears and I logged the contact using the tablet. What strength was he? I didn’t know, sounded pretty good so I gave him 579. Received 559 in reply, not bad for half a watt. Steve said he was running an FT817 at 5 watts out. Monster power.
Three more contacts, regulars John VK4TJ in Toowoomba, Peter VK3PF in Churchill Victoria, and finally Paul VK3HN from Melbourne made it into the Pixie log and I’d qualified the summit in 11 minutes using a Pixie half watt, two transistor + one IC transceiver, that had cost me $9 for the kit.
In between the contacts I could hear some weak signals and I wondered how strong they were, perhaps they were others who I wasn’t hearing well enough to copy. So after completing the 4th contact and calling another CQ just to be sure I had worked all who were there, I transferred the antenna to the KX3 and had a better listen to the weak signals. They were weak on that radio too, and I think they were dx stations, probably US operators in a contest of some kind.
The rest of the activation was fairly straightforward using the KX3 and the same doublet antenna, some contacts on 80m, most on 40m, the Shires contest was running so I had to look up my shire, I quoted GM2 (Goulburn Mulwaree) so I hoped that was correct.
With benign early winter weather, cool mornings but calm clear days, it was clearly the right weather for activating summits.
The first was Mt Wee Jasper. It is on a famous walking track known as the Hume and Hovell walking trail. It can be accessed from the camping area south of the Wee Jasper village, but the walk is long and recent forestry work has apparently disrupted the trail. At 7+ km it would have taken too much time out of the day too. So my access route was to first head west on the Wee Jasper-Tumut road, then southwards on the Wee Jasper forest road by a few km. Turning off onto Pheasant Creek Rd, the mountain looms into view soon and the route to the parking area is fairly obvious though the road has been cleared of any gravel and may well be soft after heavy rain.
It is a pleasant and easy walk of about 15 minutes up the forest path to the summit, where there are two concrete-and-wood benches ideal as sitting and operating radios.
I deployed the zs6bkw doublet for hf with the kx3. For 1296 the ft 817 and the transverter were connected to the 4 el yagi mounted on the camera tripod. The icom v85 was used to make some contacts into Canberra on 2m fm. No available contacts for 1296 but the Canberra beacon from Mt Ginini was very strong. On hf it was easy enough to make contacts on 40 and 80m bands using ssb and cw. I aim to “qualify” each summit on both ssb and cw. It is also satisfying to make the required 4 contacts to “qualify” on each band, though this is a personal goal rather than any external requirement.
You may have read that wombats leave a rather uniquely shaped message on the ground. Here are a few I stepped over on my way up Mt Wee Jasper. Each “cube” is about a cubic inch. How they shape them like that is a matter others can deal with.
Despite the pleasant forest environment it was time to depart after an hour on summit, then pack away and head for the car. I had looked at the navigation options for reaching the next summit and concluded that the known roads were a more reliable option than trying to find shortcuts. So southwards on Wee Jasper forest road to Brindabella rd, east for a few km, then turning northeast along Nottingham Rd. About 15 km along this road is the parking point for Snowgum Mt. There is no public car access up to the summit so requires a steepish walk up a sealed road littered with leaves and twigs from the eucalyptus trees.
Icom V85 clipped onto the chain fence
The half wave vertical attached to the pole to get better signals over to Canberra
Setting up the gear again I heard signs that Andrew vk1ad was ready at Mt Stromlo for the planned s2s contacts including 1296 ssb. Hearing his voice weakly at first, I experimented with the position and direction of my antenna, peaking the signal in the expected direction. When his contact with a Canberra station ended, I called him and received a question as to who was calling. I moved to cw mode and sent a 20-30 second string of dots using that mode, to allow him to find the best antenna direction by setting it for the maximum signal. Dots are very good for this purpose as they have a constant average signal strength but are transmitted at maximum power, much stronger than voice signals with an average power of less than 30% of maximum. His reply came much stronger than the level I had previously heard. In fact over the next 5 minutes, signal strengths gradually increased to about 8 on the ft817 “blobometer”. (It isn’t a real meter, just blobs being lit up on the lcd display. )
Several additional contacts were then made on 2m fm, starting with Wade vk1mic, Matt VK1MA, then Dean VK1DW and I could hear Dermy VK1FDHA calling me but he was not hearing me on any of the antennas he tried. I also heard Peter vk1fphr calling but he also didn’t hear my replies.
At this point it was approaching 2pm and I knew that if I didn’t leave soon for my next summit, my departure from that summit would be in darkness. So I didn’t set up the hf antenna on this summit, failing to meet my goal of “qualifying” on several hf bands and also on cw. A return visit this year may be necessary.
I reached the next summit just on one hour after my planned activation time, sunset was at about 5 pm so I needed to get the contacts in the log. A few contacts were made with Wade and Matt over in Canberra on 2m fm but the rest of the activity was on 80m ssb and cw. I went to 40m but made only a couple of contacts on that band. Propagation conditions near sunset make distances below about 800 km quite difficult on that band. I was using my phone to log the contacts, as i could not find my logging tablet when I unpacked my gear on this summit. Had I left it in the car? Or had I packed up so quickly at Snowgum Mt that I had left the tablet there? It turned out that I hadn’t left it in the car at all, more of that to come.
UHF gear on the park bench
I would have to go to my backup logging technology, paper and pen. That posed a small problem because although I had a notebook there was no pen in my pack or in the accessories box. Then I remembered that I had been intending to test the logging functions in the ParksnPeaks ios app on my iPhone. So, logging on this site was done using the ParksnPeaks app on the iPhone and it did it very well. The test version I had was working well.
It was then coincidental and somewhat ironic that when I went to 40m I was called by Sue vk5ayl, the developer of the ParksnPeaks app. We had a good chat and I mentioned that i was using the app for logging.
But the light was fading and I had to get out of the forest before darkness made it difficult. So I called it quits at about 5pm, packed up and found my way back to the car.
Approaching the car, I was surprised but relieved to find my logging tablet on the ground behind it. Thinking back to when I had prepared for the activation, removing the ft817, 1296 transverter and tripod from the pack, I must have dislodged the tablet and failed to put it back into the pack. Another reminder of how important it is to look around before departing.
It was now almost dark and I did not want to drive back through the Wee Jasper forest, it is the time of day when kangaroos and wallabies move around in search of food. So I drove west to Tumut, stopped at the Oriental Hotel for dinner, then drove to Gundagai and back to Yass along the Hume highway. The highway is also named after the early explorer whose name was given to the walking track mentioned earlier.
On the way I crossed this bridge with a unique name, I couldn’t resist stopping to take a photo of the bridge sign. The bogs must shake a lot in that area.
Three summits, 18 activator points and some s2s points for the summit-to-summit contacts made. And a good meal at the Oriental.