August 2010

Gentoo/MIPS Stages: Coming Soon

Well, after a long hiatus and a few battles more recently, I now have the Qube2 building O32 stages for the little-endian port of Gentoo.

N32 will probably come soon with Matt Turner throwing some Broadcom BCM91250 heavyweights at the task. I intend to keep O32 going as there’s a lot of hardware out there that cannot use N32 that people use Gentoo on, and there are also a lot of systems which still run Gentoo O32. To provide a continued operating system for these systems, I’ll continue to maintain an O32 port.

At this point… I have produced a seed stage 3 based on modern sources, and have the Qube2 busily working through the final stage 1 for MIPS1 now (at package 55 of 60). I have the occasional hiccup such as baselayout trying to install a .keep file in a mounted /proc and dying… I’ve also had the man ebuild try to call groupadd before shadow was installed.

Other than that, things are moving forward, and I hope to have new stages to you shortly.

VK4MSL/BM: First true bicycle-mobile contact: ZL3SV

Well… it seems my tinkering has paid off. This weekend was the weekend of the International Lighthouse Lightship Weekend… and also a federal election.

On Tuesday, I bought a trailer for the bicycle … this is primarily so that I can transport groceries, etc… to home since I’ve got the place to myself for a few weeks and need to be independent. Being so low to the ground, the trailer is hard to see, so I made the decision to move the CB whip over to the trailer, not only does it now radiate a signal, but it also alerts drivers to the trailer’s presence.

I was up to 3AM figuring out how to mount this antenna on the trailer… but eventually I cobbled together a mounting, moved the homebrew autotransformer over, and hey presto… I had nailed the propagation and visibility problems all at once. SWR is still horrid with the CB whip on the trailer, but the autotransformer brings it down to a manageable <15:1 SWR, which the AT-897 can deal with easily.

On the way to the event, I had the station on 14.200MHz… I heard a Chinese station… a BT call, and also later, a New Zealand station. Didn’t make any contacts until I got to the Bulwer Island lighthouse (AU0003) where I made contact with VK5SR, Cape Jaffer Lighthouse (AU0007), registering a weak 53 signal.

On the way home this evening, I first started hunting for a 40m tap on the autotransformer… found one that gave me a 10:1 SWR on 7.080MHz… Okay, not great, but better than the >25 I’d get otherwise.

Around Bardon, I was hearing some VK7 stations, tried to make contact, but I was in amongst their noise floor. As I got to Ashgrove, I tuned around and heard VK3ARK, Cape Liptrap Lighthouse (AU0037). Managed to make contact, and initially registered a 56 signal, but quickly dropped off as I rolled down the hill towards St. John’s Wood… by the time I hit Royal Parade I had dropped off completely. They got that I was mobile, not sure about the bicycle bit… but never mind. 🙂

I travel to the end of the road, trying to put out a few calls, then when I join the bike path I pause, and have a tune around… a very loud signal on 7.145MHz just about blew me away. I listened for a bit as I cycled… it was Gary ZL3SV, in the South Island of New Zealand.

He was in contact with a US station in New Jersey at the time. I could just make out the US station, however Gary just about blew me off the bike… so I waited for a break and called in. 2 others also jumped in… VK4FMVC and VK3BOT. I was barely able to hear VK3BOT, couldn’t hear VK4FMVC (40m can be like that). Gary could hear me though… he was getting me a strong 58 signal. When I checked the S meter briefly, he was registering 59+. This was around 7:00PM (UTC+10).

I was doing 100W at the time… running off a 9Ah SLA battery. I suspect I’d be lucky if even half of that was being radiated by the CB whip… Gary mentioned he was using 200W into a 1500′ centre-fed sloper… undoubtedly an excellent system. I’ll have to see about sending a QSL card over to NZ. As I continued home, there was also a VK6 station that joined us on the frequency, however I didn’t get to make a contact there… and I was nearly home.

I don’t think I’ll make HF a regular habit on the bike, but I’ll consider doing it again sometime. I’ll also see if I can document the setup a bit more… as it’s showing a good deal of promise. This was one contact I really didn’t think I’d be able to make.

VK4MSL/BM HF: Second stationary test contact

Well… after borrowing an antenna analyser and tweaking a few things… I made my second stationary contact using the bicycle mobile station on 20m.  This time, using 20W transmit power.  I now know where to place at least one of the taps on this autotransformer for 20m use. 😉  The station borrows heavily on the “Wonder Whip” style concept, where an autotransformer provides a means of matching the wild variances in impedance of the antenna, to something reasonable for the radio to cope with.

Shown here, is the station, exactly as it was during this contact.  The fibreglass 6′ CB whip has been spray painted yellow to make it more obvious, I plan to put a flag on there so that it resembles a bicycle safety flag (a big one) so it arouses less suspicion.  Click on any of the photos for a closer view.

VK4MSL/BM HF: as set up during the contact

VK4MSL/BM HF: as set up during the contact

This weekend was the day of the Remembrance Day contest, which is one of the major contests ran by the WIA.  Tuning around on 20m, I heard Kirby VK7KC booming in a S8 from the apple isle.  At first I tried contact with 5W, no dice… then 10W, then 20W… no luck.

I tuned off, and tried a different tap on the autotransformer… bingo, that sounded a bit noisier… I hit the button on the autotuner to clean up any last issues with the SWR, then tuned back and had another go.  Eventually after some perseverance, contact was made.

Below is a shot of the FT897D showing the frequency and S-meter reading shortly after the contact was made…. I was weak into Tassie, but that didn’t matter to me… as far as I was concerned, if I got outside metropolitan Brisbane, I was happy.

FT-897D frequency and S-meter during contact with VK7KC

FT-897D frequency and S-meter during contact with VK7KC

I haven’t yet tried other bands, although I’ve figured out some tap points for 6m, 10m and 15m… and some possible maybe points for 40m although I think the antenna will be very deaf down there.

On 80m it’ll probably be a mostly receive-only antenna, with maybe a Tx range of under 10km… if it’s enough for me to know what’s going on with the AWNOI net before I get home … and to maybe get a message relayed to VK4SD so I don’t get hassled about a late note, it’ll be great. 😉

The transformer still uses a map pin pushed though to select the tap… I’m not sure how well this will go long-term, and I think moving towards using banana plugs (or at the very least, alligator clips) will be a better solution.  Switches are another possibility.  Something that will be a more reliable connection than a pin pushed through a wire.  Shown here, is a close-up of the rear basket, the autotransformer is shown underneath the antenna bracket… which helps provide a bit of capacitance.  I find having it close up against the bracket helps, although I made provisions to be able to hang it vertically too (thereby reducing the coupling).

Rear basket showing homebrew autotransformer

Rear basket showing homebrew autotransformer

For now I’ll probably solder the centre conductor of the coax in place of the map pin, so that it’ll stay put until I can find a more convenient solution.  At least I have something on HF that works to a moderate degree.  I’ll probably give it a try next weekend on my way to the Queensland Maritime Museum, where I’ll be operating the Bulwer Island lighthouse as VK4MM in the International Lighthouse Lightship Weekend.  Hopefully I can stir up 20m sufficiently so that there’ll be some activity when 00:00 UTC rolls around.

Gentoo/MIPS: Netbooting from Windows

Hi all…

I’ll put this in the handbook when I get around to updating that… but in short, those who need to be able to netboot SGI systems from a Windows host, might wish to give tftpd32 a try.  I’ve been tinkering with this TFTP server in order to load some ARM-based devices (Ka-Ro TX27s using RedBoot).  I find this server daemon is inconsistent with its loading speed when transferring files to a TX27 (sometimes speed is good; around 1MB/sec, other times it crawls at 3KB/sec), however experimenting with it in a VirtualBox VM running Windows 2000, it works flawlessly for netbooting the SGI O2 I have here.

Below is a screenshot of the settings used.  A Linux or Unix-based TFTP server would be better if that can be organised, but for those who have no option, this may be a viable alternative.

TFTPD32 Configuration, tested with an SGI O2

TFTPD32 Configuration, tested with an SGI O2

VK4MSL/BM HF: The autotransformer

Well, I did some experiments this weekend regarding the bicycle mobile station using an autotransformer to match the shortened end-fed whip (6′ 27MHz helically-wound) to the 50ohm impedance my set demands.

I haven’t tried this on the bike itself… these were done in my bedro^W(ahhem) “radio shack”… with the antenna and its bracket sitting on a wooden chair connected to a longer bit of coax than I’ll probably use on the bike.  I will have to try this on the bicycle (ideally with an antenna analyser) to get a better idea of performance, and the up-coming Remembrance Day contest may provide a good opportunity to gauge performance, as the bands will be sufficiently “busy”.

The autotransformer is a simple design… about 50 turns of cheap speaker wire (~1.5mm diameter; ~0.2mm insulation thickness) on a 42mm OD PVC pipe section about 160mm long.  The pipe has small holes down its length, drilled at a spacing approximately identical to the wire centre-to-centre spacing (2mm).  The two extremes of the coil connect to the antenna and the metal antenna bracket respectively, the latter also connecting to the braid on the coax going back to the radio (about 30cm RG58C/U coax).  The centre conductor of the coax connects to a short piece of wire which is soldered to a small map pin, which is simply pushed through the wire’s insulation, piercing it and poking through the hole in the PVC pipe… I can select any turns ratio from 1:1 to 1:50, achieving a very wide matching ratio.  (On paper, able to match >10kOhm impedances to 50ohm.)

Early testing seems to indicate the ability to obtain good SWR figures on 6m, 10m, 20m and 40m.  80m (the holy grail for me) eludes me… and I suspect the actual radiated signal will be very low down to most stations… but if I can cover parts of metropolitan Brisbane with it, I guess I’m doing okay.  The fact that this antenna got down to VK5 with 100W up it, is a promising sign… perhaps with the autotransformer, it may do better.  Then again, it may do a lot worse… We’ll see.  Plan is to try and get it up and running before the ILLW… so that I can stir up some activity on the bands on my way to the Bulwer Island lighthouse (AU0003) before becoming VK4MM and operating a station there.

Gentoo/MIPS: New mipsel stages coming soon

qube ~ # catalyst -f /home/catalyst/configs/stage1.spec 
Catalyst, version
Copyright 2003-2008 Gentoo Foundation
Copyright 2008-2009 various authors
Distributed under the GNU General Public License version 2.1

Using default Catalyst configuration file, /etc/catalyst/catalyst.conf
Setting sharedir to config file value "/usr/lib/catalyst"
Setting snapshot_cache to config file value "/home/catalyst/snapshot_cache"
Setting hash_function to config file value "crc32"
Setting storedir to config file value "/home/catalyst"
Setting portdir to config file value "/usr/portage"
Setting distdir to config file value "/hd/0/gentoo/distfiles"
Setting options to config file value "autoresume kerncache metadata_overlay pkgcache seedcache snapcache"
Autoresuming support enabled.
Kernel cache support enabled.
Package cache support enabled.
Seed cache support enabled.
Snapshot cache support enabled.
Use of metadata_overlay module for portage enabled.
Envscript support enabled.

        WARNING: No value set for key cxxflags...deleting

        WARNING: No value set for key distcc_hosts...deleting

        WARNING: No value set for key pkgcache_path...deleting

        WARNING: No value set for key portage_overlay...deleting

        WARNING: No value set for key ldflags...deleting

        WARNING: No value set for key portage_confdir...deleting
Using target: stage1
Building natively for mips
stage1 root path is /tmp/stage1root
Source path set to /home/catalyst/builds/seeds/seed-20100806.tar.bz2
Caching snapshot to /home/catalyst/snapshot_cache/20100806/
The autoresume path is /home/catalyst/tmp/default/.autoresume-stage1-mipsel1-20100806/
stage1 stage path is /home/catalyst/tmp/default/stage1-mipsel1-20100806/tmp/stage1root
Resume point detected, skipping target path setup operation...
Location of the package cache is /home/catalyst/packages/default/stage1-mipsel1-20100806/
Location of the kerncache is /home/catalyst/kerncache/default/stage1-mipsel1-20100806/
Checking for processes running in chroot and killing them.
--- Running action sequence: unpack
Referenced SEEDCACHE does not appear to be a directory, trying to untar...
No Valid Resume point detected, cleaning up...
Removing AutoResume Points: ...
Emptying directory /home/catalyst/tmp/default/.autoresume-stage1-mipsel1-20100806/
Emptying directory /home/catalyst/tmp/default/stage1-mipsel1-20100806/

Starting tar extract from /home/catalyst/builds/seeds/seed-20100806.tar.bz2
to /home/catalyst/tmp/default/stage1-mipsel1-20100806/ (This may take some time) ...

And with that… a new round of stagebuilds begins… I’ll do the initial stage builds on the Qube2 for now, so things will take some time, but I want to iron out all the issues I’ve been having and get something together that builds smoothly. I may even run it through Catalyst a second time just to make sure everything is clean. These should also include the newer tools, such as baselayout-2 and eselect.

This seed stage was mostly cross-compiled on my now dead Duron. I now have a 6-core AMD Phenom II which I also plan to set up QEMU on, for stage-building purposes… and soon will get distcc going on a few of the hosts here… so hopefully I’ll have stagebuilds going much more regularly.