| Saturday, August 23, 2008
| Portable QRP Satellite Operation
|I have recently received the US Imported Arrow LEO 145/435 hand held Satellite antenna which I purchased from The Antenna Warehouse in The US.
I decided I would like to try work a few Satellites with my hand held radios after watching fellow Ham and Youtuber K7AGE Randy, in one of his many excellent Youtube videos.
I particularly enjoyed Randy's video which showed him making a QSO via AO51 with the Arrow Antenna mounted on a tripod using a simple hand held radio.
I also found other Hams on youtube with similar videos, one video with EA1GHW using two hand held radios which made the job of listening to your own transmission via the down link much easier.
So with the inspiration and ideas both taken on board as well as some ideas of my own, I began to set up my own Portable QRP Satellite Station.
The first job was constructing the extension boom which would incorporate two radio mounts as well as providing somewhere to site a compass and my HP Ipaq which runs windows mobile software and sat track.
I used some aluminium sheet which was 3mm in thickness. I cut the sheet using a guillotine and then placed the aluminium in to a bench folder which allowed me to fold the ally into a L shape, similar to angle iron.
Once the extension boom was drilled to fit the pre-drilled and tapped back part of the antenna boom, I assembled the ext boom. Then I began to plan the best way to mount the two hand held rigs I was to use which are Yaseu FT-470, and Kenwood TH-7e.
The next stage was where I fabricated two alloy carry case type radio supports, these were tailor made for each transceiver. I made them from 1.5mm high grade aluminium and mounted them to the L shape boom with 4.8mm diameter rivets.
I fitted the radios to the antenna and used the built in duplexer with a maximum input of 10 watts to practice receiving signals from the LEO(low Earth Orbiting) Satellites.
Both rigs are capable of working VHF & UHF and both have Dual watch(Two VFOs on screen).
After testing during the initial setup, I found the Kenwood worked excellent on VHF and could even be used to receive(RX only) VO52 operating on USB.
However, the Kenwoods performance was so not as good on Receiving AO51, AO27, and SO50 which are all FM UHF down links, the TH7e seemed to be deaf on 435 and 436 MHz.
This was not a great surprise as I have compared the little transceiver/multi mode scanner many times before with my almost antique out performing Yaesu ft-470.
The FT-470 can also be used as a one rig set up as I found out with successful QSOs being made from Germany and the Ukraine on AO51 and SO50.
The FT-470 has a fader that allows for example: AO51 up link 145.920 to TX whilst the down link can still be heard with the balance of the fader set to UHF at the same time as your transmission.
I found the old radios receive capability was outstanding and the only weak spot now was pressing the band select button to RX VFO whilst adjusting the Doppler frequency, then back to the up link band to TX.
So the final stage was to remove the boom fitted duplexer supplied with antenna, and to feed the dual bands directly to the two Hand helds.
I hadn't been to my local Ham radio shop for a while so it was time to visit Steve( M5LAR) at LAR(Leeds Amateur Radio)Centre.
Steve has a good selection of Equipment new and second hand, as well as the other bits and pieces related to radio you may need. Local for myself and the best place to get some quality feeder, fittings and new rechargeable battery's for the old Yaesu.
Me outside LAR.
Once I returned from LAR, I fitted the feeder and began to play.
It was not long before AO-27 became in range, and with the two radios working I was easily able to operate the QRP satellite operational portable station out in the garden and made a successful QSO via the satellite.
The FT-470 was in RX mode whilst the kenwood was used to TX.
Here you can see both rigs and mounts fixed to the EXT L boom.
A close up of the FT-470 and home brew mount.
The Radio's, Ipaq, and Compass.
HP Ipaq running windows mobile software and Sat Track to know when and where to point the antenna when the Satellite is in range.
Technology is great but a trusty compass makes life easier when finding the correct direction.
The Completed project.
Easily becomes Vertical polarisation and works well on 2m Fm and SSB, good for SOTA work.
I've been running in and out quite a lot the past couple of days working nearly every pass that each satellite provides with the new QRP set up, I am really surprised on how well it is performing.
I am enjoying this interesting way to make radio contacts and hope to hear you all calling CQ Satellite soon. It makes a change to be working the satellites making QSOs from the usual WX monitoring. Which lately the constant rain has told its own story. I would just like to say this type of activity is an exciting, fast paced way to make QSOs that seems very addictive and time consuming as I have worked two satellites since beginning this post and am constantly watching the Satellite Radar waiting anxiously, what good fun I'm having, I love it!
p.s tnx to Louise (M3TLL my YL) for putting up with it all. h.i
|posted by Simon Davison @ 6:38 pm
Hi Simon! Nice extension L boom modification, great work.
I wonder if compass show accurate data, if antenna has an elevation? I used similiar compass when I ran orienteering long time ago and I remember,it worked good only in horizontal position.
GL,GD DX,73 de Tomas
Tnx for the comment, I agree 100%about the Compass. It only works accurately in the horizontal position, but I can plan the pass start and end points before the pass.
Good DX, GL, and best 73 hope to hear you on agn soon! de 2e0hts, Simon.