20190511 UHF up satellites and full duplex

This post has been a long time coming – Around July/August 2017 is when I got my Yaesu FT-857D – this was for 100w portable but more importantly to be able to work satellites full duplex – I cant remember when the Alaskan Arrow arrived from the USA but it would have been around then or just a month or so later too… apart from trying FO-29 full duplex once with a poor result of one bumbled QSO I have never used the duplex combination… until Monday last week (Easter Monday).

I looked for an FO-29 pass as I was familiar how that worked and thought it best to ease myself in gently so I stripped out the VHF in the shack by removing the FT-817nd to pair up with the FT-857D for full duplex and got all the rest of the kit together.. it’s a real faff and my set up is quite messy but that’s probably down to never using it in anger so it hasn’t been refined – actually no probably about it! ha ha

I met up with my friend 2U0UUO as I wanted to show him a linear satellite pass and what better way to do that than to try something new for myself at the same time, what could possibly go wrong ha ha ha – I get to the site I wanted to work from and it was really busy, a sunny bank holiday meant that the car park I had planned for the eastern pass was mobbed… so we went elsewhere – got there late.. got set up – all four 2m elements and ten 70cm elements, now I’m wielding the Alaskan in anger…. here we go – it was crap – I needed 3 hands to tune, key up and point the pointy thing, plus I could just about hear myself… what a poor ‘show and tell’ that was – however I heard myself (even if I was weak) so that was a plus… At least it highlighted that the Alaskan isn’t practical for a normal pass (yeah I knew that really)… I think I’ll keep that 14 element set up for the low passes… when I get to them 🙂

A week passes by and on Saturday morning (yesterday) I decided that I would try to build an afternoon of linear satellite passes but this time UHF up and VHF down (FO-29 is the opposite and easier in my opinion).
After fannying around with SatPC32 and AmsatDroid FREE I built a list of passes using 5 satellites from 10:00 – 17:00 UTC – I wrote out notes so that I don’t loose my way with the basics, frequencies, max elevation and direction of the pass etc – I find it useful as a crib sheet to save me second guessing myself when I get caught up in the moment.

AO-7XW-2A – XW-2C – XW-2F & FO-29 (just to make my life more difficult)

crib sheet
planned passes – times detailed are UTC+1 (BST)

I’m still at home for the first three and so my horizons are greatly compromised because of houses and close hills all around me but I’ll try them, why not eh…

11:10 – XW-2A – I missed this – still planning stuff.

12:26 – AO-7 – first time ever trying a UV linear satellite and I just couldn’t find myself… up and down the band I went… not a sausage… gutted – I must be doing something wrong – then I checked twitter and Peter (2M0SQL) had posted that the satellite had been flipped out of Mode B – amazingly it wasn’t my inability! 😉

Flipping AO-7 – This means that the mode the satellite receives and transmits on is different – Mode A means it becomes VHF (2m) up and HF (10m) down, or something like that – basically it screws it up for everyone as RX on 10m is quite specific and rarely used as far as I know, but I may be wrong (?) – most satellite operators use just 2m and 70cm (& 23cm).

The previous links above (for each satellite) take you to some more specific details on them but briefly – AO-7 was launched in November 1974 – 45 years old, wow!!!! – it went quiet in 1981 – It was then found again mid 2001 but with issues and is very sensitive to the power of signal’s sent to it – high power CW (50w CW will do it) causes the ‘flipping’ due to the satellites instability.

14:14 – AO-7 – I tried again – I still cant get it however good ole Twitter / 2M0SQL comes to the rescue again… its been ‘flipped’ AGAIN – such a faff to get set up and quite demoralising but to know it isn’t me now makes a huge difference in my confidence…

Moving not so swiftly on..

16:06 – AO-7 – This time I’ve left home and gone to high ground with a view over the sea and good horizons all around… let’s give this AO-7 one more try… boom.. I hear voices… It’s best (I think) to make recordings direct from the receive radio (more of the faff) to ensure you can re-listen to call signs and grid locations, it saves writing them down, anything for an easy life 🙂

I worked IZ1DBY who took my UV cherry.. the satellite seems noisy and crackly but I assume that’s because it’s not really in good shape so it’s tough going… I kept calling CQ and up popped G0IIQ, David (twitter @G0IIQ) thankfully he was gentle and although hard going for me (and him no doubt with my noob abilities) the QSO was completed.

16:17 – FO-29 – I threw this one in just for shits and giggles.. because the other satellites I had planned to work were UV thus moving to FO-29 (a VU sat) means that I have to change everything around – TX on 2m, listening on 70cm, change the diplexer over too – I find it good to force a situation, it helps you think on your feet and learn stuff so it all becomes second nature and that’s what I think you need when working satellites.. if you second guess yourself that’s when you loose where you are and what you should be doing, well that’s what happens to me… Anyway, I didn’t manage to hear myself very well until past half way through the pass.. I kept calling CQ and very near the end HB9TSW called me… bish bash bosh, in the log 🙂

17:13 – XW-2F – back to UV satellites.. I hadn’t managed the XW sat in the morning so this was going to be something different – they are fast and crikey, really loud… the pass band is small too so it was obvious when I hear my first voices there wasn’t much space… I had mentioned on Twitter I would be on this one and David, G0IIQ popped in to say hi.. the audio is so much better and clearer than AO-7 – Peter, 2M0SQL came to say hi too (thanks Pete, I know you weren’t feeling too good at the time either).

It wasn’t a hard satellite to work, the only thing I would say is that because it’s a small pass band it could get busy.. it seemed to be to me because I’m not confident where I’m going or what I’m doing and I didn’t want to stamp all over someone. I was very conscious of my fumbling when I heard others around me. I’m not sure I would recommend a weekend XW pass to a noob like me…

17:41 – XW-2C – in for a penny, in for a pound eh! This was actually a little easier – wondering if that was just because of my baptism of fire and thus getting used to it a little more… however it was really nice to hear Jerome, F4DXV come back to my CQ and then near the end of the pass G0VHS respond to me too – he told me he could hear me on the input frequency of the satellite as strong or stronger than coming from the output of the satellite itself, however Terry is in Weymouth and the satellite was getting low to the horizon, a little bit of tropo too… guess that’s why..(?) After completing our QSO I kept calling CQ to past 0° elevation and could just about hear myself and Terry let me know he could still hear me at 55 through the sat so that was really interesting information duly digested… I must be getting out OK, possible de-sense has been mooted.. worthy of further investigation..

18:00 (ish) – AO-7 & FO-29 – AO-7 was low to the west so I had hoped that there may be some US stations I could have worked… however I really struggled with this… I could barely hear myself… I gave up after about half way through the pass and moved on to the last part of the FO-29 pass but this was disappointing too… when I posted on Twitter about my weak audio (at times) some of the comments brought up this de-sense issue so this really does need looking at…

It’s been a cracking Saturday (weekend actually) – a day spent playing radio, planning, learning stuff and a few QSO’s to boot… Today (Sunday) has been a day of housekeeping, confirming call signs from the recordings, grids too, updating LoTW etc and writing this post – if I don’t do it straight away it all passes and I forget..

What have I learnt? UV linear sats are bloody hard at first and you need three hands, but only doing it the way I did. My set up needs to be made slicker and not so much of a chore to deploy and get out… I’ve put the following list together (in no particular order) of what I need to do (& not do) to sharpen up the operation 🙂

  • Longer tails to / from the radios
  • Low loss coax – I must get rid of the RG58
  • Headset & mic arrangement to free a hand up, by using VOX I guess
  • Program the radios for easier sat / frequency changes
  • Low / high pass filters
  • Batteries – I used 2x 7Ah SLA’s – LiFePo’s would be nice 🙂

Thanks to Claudio, IZ1DBY – David, G0IIQ – Gabriele, HB9TSW – Peter, 2M0SQL – Jerome, F4DXV – Terry, G0VHS for their patience with my ineptitude and poor workmanship, your tolerance is appreciated 🙂

The drive for getting back on sats was because of a sked that VA3NNA requested – to read more about that please see the next post

Hopefully you will hear me on some more satellites very soon -73! 🙂


  1. Brilliant write up Ad – loved it! Just goes to show with grit and determination that you can do what you set your mind to do!

    I know I looked at “the birds” briefly at the back end of 2017 but other radio related things took over – Im sure I’ll get around to it at some point – your post is definitely inspiring!!!

    73 bud

    Kev G4XLO

    • Hi Kev

      Thanks for your kind words as always – if I’ve inspired just one to have a go that’s huge plus. I write the posts for me really, a diary if you like, as an aide memoir – I find myself referring back to my site a few times to remind me how I did things…

      Getting peer approval and even better post/comments on my posts is a added bonus – it would be lovely to see more but the instant gratification of social media has taken away a lot of that I guess.

      I would highly recommend you make this https://www.george-smart.co.uk/antennas/dual_band_satellite_yagi/ – it cost sod all as I made mine from coat hangers and an old bit of roofing batten… some of its exploits are posted in the early days of this blog… do it and we will see you on SO-50 in a jiffy 🙂

      Thanks for taking the time to write and post comment… it’s really appreciated!

      73 mucker
      Adam – MU0WLV 🙂

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