This year i spent quite some time in preparation of the 10m contest. Already a year ago i bought some fishing rods with the plan to make a Moxon antenna. This antenna was realized now. The transceiver was my HiQSDR again driving a R155 PA. In order to improve sensitvity i connected a wideband LNA from Funkamateur. The LNA was switched on and bypass by one of my sequencer PCBs. Quisk SDR forwarded 192kHz IQ samples to skimmer and from there the decodes went to the bandmap of tlf log. I started in CW and worked quite some multies. After one hour i changed to SSB which was a likely a fault because the activity in phone was low. The last 30 minutes were spent in CW again.
The map below shows the locations of the stations worked. They were taken from internet and might be incorrect. The map shows that i mainly had the moxon to north and west direction.
stations worked in 10m contest 2021 – maps by openstreetmap and opentopo contributors via DL4MFM edi analyzer
The most heavy part of the moxon is the mounting plate. The fishing rods are snapped to the plate and then fixed with U brackets. There are 16 wing nuts to fix.
10m moxon antenna under test indoor
Getting the antenna outside is not that easy. It needs to be mounted outside and there was little space because of a chimney nearby.
Moxon antenna mounted outside the roof window
It you do not take care everything will end up in a big mess.
Gordons knot – wires of the moxon
The software did cosist of Quisk, skimmer and tlf log.
SDR software just before the contest
The R155 PA can generate 100W with 5W input. Unfortunately it seems not very robust against some RF nearby. The linear power supply i tried to use before went unstable in SSB. Therefore i had to swap the supplies.
PA and power supply
HiQSDR is quite unsensitive on 10m. I used a LNA from Funkamateur which has bypass relais for TX. I had to replace the transistors because both where faulty.
The last DUR activity of the year was out of competition due to the new restrictions with respect to Covid-19. Therefore the portable activity was low.
23cm ended with 12QSO and ODX DL1SUZ about 300km. I several times tried with HA8V without any success. Also other signal appeared quite weak. I heard Uwe on 13cm as well. Since i do not use a PA yet (only 1W) i was not able to make a QSO there. 13cm finally had 6 QSO, everything local. On 9cm i was able to reach DL6ABC and DC7QH in Berlin + DL4DTU locally.
Due to partial lockdown no multi-op activity. Other weekend activities cancelled as well, so found some time to participate the MMC from home.
The setup was my usual HiQSDR + ME2HT + 200W Transistor PA + 4 ele.
About 11h operating time resulted in 134 QSO with ODX 730km..
It was pretty obvious that almost all the big multi-op teams where missing. Still some good DX oportunities even for my tiny station.
IQ3AZ was super loud. The attempts with SM6VTZ and YO5LD failed although we heard each other for short moments.
TOP 10 DX QSOs:
9A8D JN95LM 731 km by DH5YM
9A4M JN85EI 669 km by DH5YM
IQ3AZ JN65QQ 602 km by DH5YM
S51S JN75ES 595 km by DH5YM
HA6W KN08FB 592 km by DH5YM
HG1A JN86MM 564 km by DH5YM
9A5RJ JN86EL 550 km by DH5YM
PA0O JO33HG 539 km by DH5YM
HB9FAP JN47PH 529 km by DH5YM
S59P JN86AO 528 km by DH5YM
Marconi Memorial Contest 2020 // Image created by DL4MFM log analyzer. Kartendaten: OpenStreetMap-Mitwirkende, SRTM | Kartendarstellung: OpenTopoMap (CC-BY-SA)
Recently my new 23cm LNA showed up here. For the DUR activity contest today i integrated it into my transverter system. 9cm got double points this month. Therefore i also tried to be active there. Not that much activity and only 2 QSO. The 23cm result was quite good due to some nice DX with SM6VTZ, HA5UA, HA5YA and OM5CM.
23cm result October DUR // Image created by DL4MFM log analyzer. Kartendaten: OpenStreetMap-Mitwirkende, SRTM | Kartendarstellung: OpenTopoMap (CC-BY-SA)
Originally planned some more QSO but in the end there where more time constraints than expected. Therefore only 21 QSO on 23cm sunday morning. I skipped all other bands. 70cm was not ready anyway. ODX HA5KDQ with >500km.
I planned to make some QSO from home. In the end i had about 10h of participation mainly during the night and sunday morning. The setup was 4ele and 200W with my HiQSDR and ME2HT transverter. The raw result shows 95QSO with highlights YT4B in CW random and IQ5NN even in SSB via aircraft scatter. 7S7V and 5P5T had pretty strong signals here.
This weekend i did some new trials with QO-100. In the picture you can see parts of setup i used. This time the TX setup was purely classic. You can see it in the grey box in the foto below. FT-817 on 2m as IF followed by an upconverter made from some old UMTS measurement equipment block (silver box in the middle). It does dual upconversion with high-side LO. The LO consist of an ADF4351 each (the two smaller boards above the converter). The reference is a 96MHz OCXO of G8ACE design (left of the PLL boards). The converter block generates up to 200mW on 2.4GHz. I drive a WLAN PA (black box) that probably generates 1W. And the final PA is a MRF21030 PA (on the big heat sink on the right). It provides about 10W in SSB. The antenna is my 60cm offset dish with the DJ7GP patch (the one that has the round patch element). Left to the grey TX dish you can see a black 40cm camping dish with Octagon LNB and TCXO modification. But instead i used the BATC websdr this time. The reason is the amount of cable i currently have. I use 3 power supplies (28V, 13.8V, 5V). Reducing the number of required cables is one of the next steps. However i was pleased to do some nice QSO.
Since quite some while there are 5.7GHz PAs intended for video transmission from drones to ground. Those PA are made with 5GHz WLAN IC and very cheap (below 30Euro including shippment). These PA can be used for 6cm amateur radion but need some modification upfront to generate a usable amplifier.
The PA comes with heatsink, small fan and a short power cable.
The PCB side has a metal cover that has a sticker with some technical data. The PA is supplied with 12-16V. It is intended for 5.7GHz operation. The sticker also mentions 2.4GHz but the PA will not work there. The specified output power is 2.5..3W although the vendors usually state 5W. You will not reach 5W.
Removing the metal cover shows that the PA PCB contains two Sige 5004L WLAN amplifier IC, some splitter/combiner, an input attenuator and a power supply circuit. The connectors are Reverse SMA (RSMA) and they are mounted really poor. I would not even try to use the PA with those connectors and the air gaps to the PCB.
Now the silly RSMA connectors are removed. The pads need to be cleaned. Also clean the ground ring to prepare re-assembly of the shield later on.
Solder some new SMA connectors. The grounds of the SMA connectors shall touch the top side of the PCB. You need to shorten the ground connectors a little bit. Likely you do not have connectors intended for the PCB thickness. You may solder the other side for mechanical reason. Solder the inner pin of the SMA last in order to prevent breaking the RF trace.
Some attention needs to be put on the thermal conductivity between PCB and heat sink. Removing the PCB from the heat sink shows that cost optimizations safed the thermal compount which makes the heat sink almost useless. So add some thermal paste to the marked areas below the amplifier IC. Probably the switcher IC needs some cooling as well.
The PA PCB contains a input attenuator. The default attenuation is around 18 to 20dB. If you have less input power you might want to change it. For my measurements i removed the 3 resistors and soldered a 0-Ohm upside down to the middle resistor position. After everything is modified and tested you will likely want to re-assemble the metal shield.
The PA has about 27-28dB gain and my sample achieves 3W output at 7dBm (5mW) input and a current of 1.3A at 12V. Saturation might be somewhere at 4W with 10mW of drive and 1.5A current.
I was working the contest from home and part time. The 23cm transverter with 10m IF and the HiQSDR work pretty well. I used the Quados4 antenna since the 36ele ordered was still stuck in customs. ODX was HA5KDQ and in total 41QSO and 6900 points raw score. I also made some QSO on the higher bands on request. 3x 9cm, 1x 6 and 3cm each.