RaDAR – AO91 Cubesat RaDAR ready

Let’s face it, on a satellite pass all operators should show discipline and able to receive the down link perfectly. Transmissions must be kept to the minimum passing only relevant traffic.

This afternoon was one of those disciplined nets and the throughput was excellent.

As AO-91 flies in range of Kinshasa / Brazzaville in north Africa it encounters a signal which keeps the satellite active and blocks out all possibility of good communications.

Andre, ZS2BK determined the QRM area by monitoring the footprints of numerous passes. Not much that can be done about it though which is a pity.

But, before the satellite comes in contact with the QRM the tiny cubesat is perfectly usable for fast communications!

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RaDAR – Equipment and purpose

For me at least, the amateur radio equipment I have on hand should fit a purpose.

Anything in excess should go to a good home …….

So, I thought I’d make a list each with it’s purpose. Still, maybe too much from a RaDAR perspective.

My higher power RaDAR setup

FT-897d (Built in 13.8 v d.c. 20A PSU) + LDG AT897 ATU + Mic + Bencher paddle + QRO end fed tuner + Mofified MFJ tuner / HF SWR Meter / 160m end fed tune + Dual 7 A / Hr SLABs+ (New design) ZS6BKW open wire fed HF antenna + Coax.

Parks On The Air (POTA) (Medium power – carried permanently, stored in the car (Not installed) )

B25 ex military radio + Handset + 7 A / Hr SLAB + HF Link dipole and coax.

On foot RaDAR

FT-817ND + LDG z817 ATU + Mic + Vidi Paddle + Lensatic compass + Rossi battery supply / torch + Headlamp + 9:1 UNUN fed long wire (Multiband) + Garmin legend GPS + Smartphone (Camera) + Backpack.

Digital modesΒ 

HP 210 Netbook + Elementary OS Linux + FL-Digi / WSJT-X + Signalink USB + Wireless mouse.

RaDAR SatComms

FM Satellites / Cubesats : Full duplex TH-D7A(g) + Mic + Mono headphones + MP3 Recorder + Dual band Arrow Yagi incl diplexer + Tripod+ Rossi battery supply / torch + Headlamp.

Linear transponders (SSB) : Half duplex On foot RaDAR kit (FT-817ND) + coax flylead and adapter.

The rest is really only CW “fun stuff”

HB1A + Hand keyΒ + Rossi battery supply / torch

QCX 40m CW Only (Rechareable penlight batteries) /Β 49er CW Fixed frequency (7.023) (Penlight batteries) + Miniature hand key + 40m end fed tuner + 40m EFHW long wire.

 

 

RaDAR – AO-91 ideal for RaDAR Ops

I’d heard that a simple dual band handheld could be used to work this newly launched cubesat so I decided to give it a go with the absolute minimum. At 12:43 local time I called from the roof of my saltmine here in Lichtenburg, Northwest province, South Africa using my TH-D7A and a slighly larger dual band whip I’d bought for it many, many years ago.

I heard NOTHING!!!

I called on the uplink 435.250 MHz FM sometimes adjusting 5 kHz down then up initially to account for 70cm doppler but still heard nothing on the downlink.

The down link is supposed to be 145.960 MHz FM and there should be no need there to adjust for doppler.

BUT, when I got back to the Office a recording was posted on our WhatsApp HamSat group ….. the guys heard ME!!!

Half way there πŸ™‚

Update 2017-11-28

Had two QSO’s at lunch time, one with ZS2BK and the other with ZS40VDK, special event station πŸ™‚

I used the TH-D7A on full duplex and Arrow yagi. Downlink was 59+++++

 

73 de Eddie ZS6BNE

 

RaDAR – Meet TUD the QCX

My QCX 40m CW only transciever built from a kit, nickname “TUD” – The Ugly Duckling.

I had a few challenges building this rig and it almost became a …. beacon, but hey, it can still be, quite handy if I want it to be!

T1 – everyone’s nightmare but mines working now …. I think. Not such a big issue peaking the band pass filter. The biggest problem was the audio that gradually got worse but this was the cause ……… an intermittent short circuit on the earphone socket. The socket was a mission to fit I recall but at first all was OK!

So I moved C51 and soldered a new socket to the 49er “daughter board” introduced as a audio output work around a while back. Now I have TWO audio outputs, the HiFi QCX output and the LM386 output. The one can be used to feed a MP3 recorder for recording CW QSO’s!!!

I have now completed my journey and can get on with my ….. ham ….. life!!! πŸ™‚

Hoping for a QSO or two later today ……… πŸ™‚

73 de Eddie ZS6BNE

 

 

RaDAR – 49er vs QCX vs HB1A

I had all three rigs at my disposal this weekend and it was a good test. I made a few QSO’s and here is an extract from the log.

It tells a story. I had just repaired T1 on the QCX the night before, or at least found a workaround for it. It worked as expected and although I must still peak the band pass filter by removing a few turns from T1 again, it worked well.

The QCX Pro’s

It has a good CW receiver with 200 Hz audio filtering and a good Class E transmitter. It has an automatic facility for sending pre-programmed messages although it needs a firmware upgrade because mine only sends the first of sixteen choices – not serious though. The on board micro switch can be used as a hand key. The rig is VFO controlled adjustable to a resolution of 10Hz. Power consumption appears to be acceptable.

It has a built in keyer.

Advanced technology design. Low cost (Kit) in the region of R950.00

The QCX Con’s

It’s very difficult to make changes once built. If you’re lucky enough to have everything working perfectly and you don’t need to touch it then it’s fine. I wanted to rewind T1 and caused slight damage to a track or two on the PCB and had to find a workaround so mine no longer looks so pretty but fortunately still works! If you can build it, you can repair it!

I had audio problems and built in an external LM386 audio amp. It alleviates the only problems I ever had. The possibility of further PCB damage trying to fix the audio is just too great. My “Ugly duckling” will stay an ugly duckling for the time being, at least my duck is still kicking!!!

There is a CW decoder which is quite nice but if you’re going to rely on it you’re going to lose one QSO after another as it sometimes decides to go deaf when you most need it …. that missed comment! Your brain is still the best morse coder reader there is πŸ™‚

The biggest con ……. The QCX is a CW ONLY rig. It cannot be used to listen to SSB transmissions without some innovative intervention like I did with the audio amp.

No AGC.

No container.

40m Only.

The 49er is a fun rig but certainly stands it’s ground against the competition! It’s a straightforward no nonsense radio.

49er Pro’s

Very good power consumption for it’s odd 1.3 Watts output. Very easy to repair if you must and uses standard components. Simple analogue design using easy to get components. It has a good receiver with sufficient CRYSTAL filtering.

Low cost, in the region of R130.00 An IDEAL entry level radio.

49er Con’s

Single frequency, 7.023 MHz for receiving and transmitting. This frequency is not a “watering hole” either and skeds are usually made to meet at appropriate times. The audio side tone is great but there is “thumping” at times, exaggerated by using cell phone earphones. It can be unpleasant sometimes while sending.

No AGC and no volume control πŸ™‚ You need to adjust the distance of your earphones from your ears, more than enough audio though!

No container.

40m Only.

The HB1A. I had to repair this one but it’s also a reasonably straightforward design but does have some firmware much like the QCX. A lot of the components are surface mounted.

HB1A Pro’s

Well it has a sturdy container. An overkill really πŸ™‚ Power consumption is acceptable. Very good audio and side tone with volume control. It has four levels of filtering for CW and SSB. Yes it can receive SSB transmissions and is also capable of cross mode (CW / SSB)Β  QSO’s. It also receives AM stations with reasonable audio quality.

It has a built in keyer.

This particular model can operate on 40m, 30m and 20m

Price unknown as I swopped it for my immaculate 50W 2m FM Alinco DR135 with optional built in APRS / Packet TNC but like I said it needed a simple repair on the LCD display.

HB1A Con’s

I can’t think of any? It is a CW only transmitter but all three under discussion are. Power output the same as the QCX at around 3W.

Overall comments.

Obviously all options are lightweight if one needed to take a radio with you on the trail. Certainly you don’t want to limit your contact base to CW only. There may be a SSB station in range and the operator able to send and receive morse code. VFO control is a must when doing some serious amateur radio communications.

This brings the HB1A to the top of the list, the QCX second and the 49er third. The QCX even with it’s modern design has only an advantage over the 49er with a little more power out (Typically 3W) and is VFO controlled. If they were to be used only on 7.023 MHz then the filtering may be an advantage with the QCX but the 49er’s receiver is surprisingly good!

So, my CW only trail friendly radio I’d take with me on serious hikes would definitely be the YouKits HB1A.

About a year ago, I bought a Rossi battery and it has proved to be an absolute gem as far as a power supply is concerned! It serves as a decent torch too and if you really needed to, a cell phone charger although I’d steer away from that option from past experiences!!!

I have an end fed antenna which is adjustable to a certain extent for working on 40m, 30m and 20m (Pushing it). I have a tuning indicator which has proved invaluable for peaking the capacitor setting once deployed and the deployment of an end fed is usually the fastest and easiest of all antennas. Use a tree branch and if there are no trees then certainly the RaDAR Painters pole mast is the optimum solution. This one has a one meter length “counterpoise” but simply used to tie down the rig end of the antenna.

 

73 de Eddie ZS6BNE

 

RaDAR – QCX Recovery

The QCX is an awesome kit using modern technologies to achieve it’s excellent results. Mine was successfully built but had an audio problem and comments on the QRP Lab forum led me to believe the problems may lie around the receive transformer T1.

The QCX’s PC Board is very finely designed and doesn’t easily stand up to anything more than the initial soldering of components. Removing T1 for a rewind was a recipe for disaster which became reality. My rig was reduced to that of an intelligent QRP beacon … the transmitter still worked.

I built up the courage over a week or two to make a plan to wire in an alternative transformer. I used a T80-2 and even then winding the four coils was a mission. I used veroboard and soldered the coil’s four start’s and finishes in a sequence I could implement within the remaining PCB contact points …. those that weren’t damaged through removal of T1.

I had to connect directly to a Surface Mounted IC, pin 7, in one case. I actually used the wire itself as an extension to my soldering iron bit by strippinng the wire, soldering leaving a little excess solder, touching the IC pin with the wire and heating the wire till the blob of solder at the end melted and flowed between the wire and the IC pin.

Success …………

Peaking of the Band Pass Filter – C1. Also presently fully un-meshed at the peak which requires removal of a few turns on T1 but easier to do now ….. next week’s task but peaked sufficiently I think to use this weekend!

I simply tucked the receive coil under the chopping board and fixed it in place with double sided tape. The QCX was saved.

I still have a bug in the QCX’s audio section but I at this stage don’t want to try desoldering again causing inevitable damage to the PC board so I’m still using my workaround by connecting a 49er board’s audio section to the QCX’s volume control. It works well enough.

Looking forward to making some new contacts with the QCX again this weekend!!!

73 de Eddie ZS6BNE

RaDAR – The reality

That’s one thing about these RaDAR challenges. They are not easy. There are many things to contend with, logistics, propagation, weather, participation. If you try the movements that adds a whole new set of challenges, fitness, working against time, and each deployment is a new puzzle especially if you’re in a place you haven’t been to before.

Then it’s grid determination, good voice procedures to get the info sent and received without errors. Safety in unknown environments against man and beast. Food, hydration and protection against the cold and rain.

Then try to make 5 QSO’s from each position. In South Africa we don’t have extreme weather but certainly a challenge to get sufficient QSO’s. RaDAR even makes provision for participants to sit in their shacks listening for the RaDAR stations out there but sadly that doesn’t often happen.

RaDAR also puts the operator into a real world scenario where all these things are a daily reality. If you’re out there alone and you need to communicate with someone quickly using what you have (Hopefully regularly practised) then you will come up against these obstacles too but RaDAR operators will know how to handle it … through experience

73 de Eddie ZS6BNE

Over forty two years ago …..