Category Archives: satellites

Eggbeater anntennas for Satellite communications

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Having an IC-9700 offers the benefits of full fuplex communication on the 2m/70cm bands used by satellites. I previously used two yagis and a rotator with some sucsses in contacting satelltites. The IC9700 with HRD performs excellently in doing the ‘doppler’ tracking, but still found that manually rotating the antennas a distraction when attempting to have QSO’s as the ‘birds’ flew over.

With that early this year I ordered the M2 Satellite Package but due to work and study commitments its been sat in my hallway for several months, waiting to be setup. Well today was that day, with fine weather forecast in the shortening winter months, it was now time to take this on, taking a nice break from my academic and technological pursits also got me outside, albeit just to the front garden !

removing the yagis

My first tasks was to remove the Yagis from the existing beam (I was later to learn this wasnt strictly necessary), so I took the 70cm and 2m yagis and put them in them in storage. They can probably be well used on the bike stand for /P operation in the future, although I do have the handheld arrrow antenna for that as well.

70cm loop eyelets
70cm copper in place
a study loop antenna

I unpacked the antennas, which had been done very well by M2 in the US, you’ll see more of that on the video once I edit it all together ! I started on the 70cm antenna as it was smaller and easier to handle, and would give me some experience ready for the larger 2m antenna.

I found that getting the copper into the loop configurations was easy enough, by feeding thru gently into the eyelets and placing into the holders at the base, the small screws were manageable even with my large fingers. I had tightened and then finished with the allen key.

radial bolt holders
they are small

I then started on the base of the radial holder, whilst the antennas can be used without these, for satellitle communicaton they proivde a reflective plan providing gain at the horizon and a null directly overhead, this is exactly what is needed as the time a ‘bird’ is spent overhead is very short, with the tracking previously done via the TV rotator taking the time to get across the sky.

radials attached
attention required
a solid fit

For the 70cm radials one hand holding the radial and another screwing in the bolt was not an issue due to the size of/lightness of the radials. These went in really well thanks to the precision engineering.

mountin on the provided beam
a sturdy antenna

Having completed the main 70cm antenna, it was time to attach it to the supplied beam. I always seem to struggle with getting these U-Clamps on, and it was still no exception in this case, still after a bit of fettling, I had the 70cm nicely installed on the beam, ready for the 2M antenna to go on next. I had a break and a nice cup of tea first tho.

2m antenna completed
before tidying up

Having had a nice cup of tea and a bit of a break, i then went on to the 2m antenna. This is much larger in size than the 70cm antenna and features a extender bolt. All of the components looked good quality and should provide years of good serivce. I had no problem with the copper wire to form the egg beater. Having taken my knowledge from the 70cm construction, i put the small radial trap-bolts in 90% of the way, then locked in the radials one a time, this really made sure that I wouldnt lose the bolts and the radials had a good girp.

After tidying up, I moved the antenna to where I will try it out first and know I have enough feed line to reach it, it should just about get the roof line of the bunglow in this part of the garden.

Forecast for weather tomorrow is not looking to bad, but not quite as nice as today, hopefully there is a few hours to at least get the feed line and the antenna up. I do have a mast head amplifier as well, but I’m taking it one stage at a time !

Hopefully i’ll provide another update soon !

Satellite Antenna build – 70cm antenna

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So during a break from studies and the fact this 70cm antenna had been sat in the shack since mid July, I decided this morning to at least make some progress with it.

The warm weather continues here in England/IO90BS – neighbouring Hampshire is now on a hosepipe ban, I’m hoping with the plentiful rivers and springs that Bournemouth will not be subjugated to such things, but with another 30c week forecast next week, who knows. I’m having to do any outside work very early in the morning else its just too hot to work.

wx in IO90BS

I enjoyed my attempts at satellite communcation with the Kenwood THD7 and Arrow antenna, this is great for portable operation. In the shack I have the ICOM 9700, which is built for satellite operation, as yet I’ve only used the 9700 on simplex and repeaters per-band, so probably 50% less than what the radio can actually do ! The Satellite feature allows split channel and (2m&70cm), so I wanted a solution to use the 9700 at the QTH.

I didnt want to spend a fortune on antennas, so I hunted out a reasoniibly priced 2m and 70cm antenna. For today will talk about the 70c antenna, the DUAL PA432-8-1.2RA. I got mine from Nevada Radio, other places sell them, but I’ve never had any problems with Nevada radio in terms of getting products to me and after sales care.

The specifications for the antenna are very good for the price, and with satellite communications you don’t want an antenna that is very focused (i.e. with alot of elements on it) else it makes tracking the passes a very precise movement across the sky. As I’m using an old TV rotator at 30 degrees fixed tinflation, this should be a good antenna for me.

Assembly was easy enough, the instructions and labelling of the elements are very good to ensure they are put in the right way first time. I have yet to threadlock my screws until the antenna goes up, but will do when I know it is working correctly and raised. There is a choke on there, its important *not* to unclips/cut these, if you’ve not seen a 70cm antenna before you might be tempte dto cut them thinking its packaged this way, and its not, just leave as is 🙂

Once completed I erected the antenna on the bike stand. Initial results were disappointing with the SWR very out of the 70cm band. Rembembering how volitle and sensitive equipment is at this frequency I swopped out the coax, which resulted in much better results.

70cm band and the PA432

I was very happy for about an hours work to get an antenna with high gain and good SWR reports.

As I want to mount the antenna on a horizontal beam, I will need to work out how to attach it (probably another 90 degree holder), but for now I’m glad the antenna is out its box and ready to use.

measurement tools and longer coax
antenna on bike stand

Next week I’ll hopefully get the 2m Yagi built (Diamond A144S5R2) and then can see how to tie it all together.

2E0FWE – AO91

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Today (19/6/22) was my first attempt of using satellites put in place for amateur radio. Having read up and joined Amsat (a very modest fee for quality content!) I targeted AO-91 as my first satellite.

AO-91 – GoSatWatch

I could see there was at least a possible chance of making a contact at 09:14 BST, so I set out with the Arrow II 146/437-10WBP 2m/70cm antenna and my TH-D7 hand-held.

antenna packing
in parts
constructed

Having got the antenna built and radio ready (I pre-programmed the optimal tuning in the shack) I setup a comfortable postion to operate from.

I made sure i was ‘aligned’ to the sky with a real magnetic north compass to ensure that I would stand the best chance of being able to hear the satellite as it came over on its relatively low and short pass.

I was astounded that with pointing the antenna on frequency I was soon hearing QSOs from Italy and the Netherlands via the satellitle on 2m and 70cms. As I was about to try calling my THD7 stopped working ! In a rush I got the THD7 plugged into the Bongo power and could continue to receive, but was unable to complete a QSO this time.

Whilst the battery had got the better of me making a QSO, I was really happy that the antenna and receiver worked and even on a ‘low’ short pass I was able to hear QSO’s. I was amazed at how quickly people gave callsigns and grid locations – there was little time more for anything more – I can see why people recommend recording contacts on satellitle and make the log book after.

I headed back to the shack and tried the AA battery pack that came with the THD7, this also failed to power the radio, so I had to engineer a solution ! I found a ‘spare’ connector from an adaptor set and ‘butchered’ that to make a DC power supply from the batteries I usually use on the IC705, these would be more than enough power for the THD7, even with the squelch fully open, to operate receive and transmit for the times the satellites came over.

Conclusion

Whilst my first attempt at satellites didnt result in a QSO I gained valuable experience and could confirm my antenna and transceiver worked correctly. Whilst the in-built battery was bad, and replacements unreliable/dangerous, I was able to manufacture a replacement. I’ve since ordered a ‘cheap’ Digital voice recorder and headset for QSO’s – I think I have a splittler cable, but will find out when the digital recorder arrives how to drive both headphones and recorder.

In all I was very happy to go from 0 experience, to at least listening, which is pretty much what I done on all the bands in the past anyway, so was very happy to make my first steps in amateur radio satellite communication.