And it’s gone!

Posted by on December 14, 2010 No comments

D’oh!

Was just having a fairly decent chat with VK4ALO (fantastic reception!), and up came the noise! currently sitting here listening to the noise sweep up and down the band.. sigh!

Though proved that the vertical was my problem! Interestingly, Paul (VK4ALO) is using a squid pole – so says something for our area, since I tried my squid pole with a wire cut for 40m, and didn’t get any better performance than the TEV-1 (though MUCH better SWR!)..

Wow, 11pm, might be time to head in and get some sleep 🙂

–edit– Ahh, noise dissappeared, and was able to finish my QSO with Paul!

Was a good night!

Woohoo, a contact

Posted by on December 14, 2010 No comments

WOW!

Just WOW!

Turned on the 897 tonight, and WOW, 8 simultaneous stations on 7.03515!! That’s just incredible – says a LOT about just how insanely bad the TEV-1 was on 40m! AND I managed a contact! Well, kind of.. – I couldn’t get a lot of what JA2GSD said, but he was hearing me, and I was hearing him 🙂
VK2TDG VK2TDG de JA2GSD JA2GSD

GA ur RSQ 599 599

eiame : Kiichi Ki chi ichi

QTH ShizuoØa Shizuopa

Loc :PM94dv [348.4° 7,704.0km] PM94dv

BTU VK2TDG de JA2GSD KN

.g. VK2TDG VK2TDpée JA2GSD J
2GSD

NtQ 599 599

Ntme : Kiichi Kiichi Kiii

QT= whi, e eka Shizuoka

Loc :PM94dv PM94dv

BTU VK2TDG JA2GSD KN

Yep, not a very good decode.. but he could hear me! That’s the first time EVER I’ve been heard – not bad for the first minute of firing up on the dipole.. Well, not really a dipole when you look at it – even using the MD gal pipe, both end pipes have a decent bow in them – and the dipole centre is a good 2 metres below where it *should* be.. so I guess it’s an inverted inverted-V? does that make it a V? lol!

Close, but not quite

Posted by on December 14, 2010 No comments

Well the 40m dipole (top dipole only, haven’t done the rest) is up! Although it is 1:1 swr on 6.625MHz, not 7.10MHz as calculated..

Thankfully I left a fair bit of overlap (3%, 30ish cm) incase I needed to lengthen it.. with 35cm per side (70cm total) added to the length, it is now 1:1 at 6.480MHz. Ahh of course, it needs to be shorter! Now, 35cm lengthening (per side) made it 0.145MHz lower. I want it 0.475MHz higher than the starting point.. which would make it 3.28*35cm which I want to shorten each end by? That is 1.14 metres per end?!?! That seems a little short?! And MMANA-GAL says it should be horrid! But we’ll give it a try 😉

Ok, it gets down 1.05:1 at 7.290MHz.. Hrrrm! Let’s add 40cm to the length and see if we can get it closer to 7.1 😉

Ok! measured it to 75cm longer than original (so 10.91m per side), and it’s now 1:1 at 7.05MHz. Woo!

Seems to work quite nicely on 15m as well.. we’ll see how we go on PSK31 on 40m and 15m tonight 🙂

The first test ;)

Posted by on December 12, 2010 No comments

First test is to simply build a 40m dipole. Aka, ensure that the centre is built correctly..

Dipole center+Balun is completed, and ready to go:
117601176511770

Multi-band dipole

Posted by on December 4, 2010 No comments

With the two 8m tall masts erected on each side of our yard, it’s time to build the dipole!

Because I don’t like doing things by halves, I’m building a ‘multi-band fan dipole’.  This is comprised of three dipoles, in a ‘fan’ layout.  As explained here, I have so far built the centre insulator.

Center Insulator:

The 'center insulator' for my tri-band fan dipole

Now to run two lengths of copper wire up the sides (1.0mm mains cable should do nicely? 🙂 ), build an ugly-balun on the bottom, and measure out the cable lengths for the dipole..  The top run (40m band) will be 3mm stainless steel 7×7, as it’ll be carrying the weight.  The lower two (or maybe three?! 😉 ) runs will be simple speaker wire.

Wire lengths should be:

Band Centre Freq Wire Length Notes
40m (+15m) 7.100Mhz + 21.3Mhz 20.28m (4% short) (I’m not interested in the upper 200khz of the band, as I don’t do CW)
20m 14.15Mhz 10.61m
10m 28.5Mhz 5.263m (note, using 28.5 rather than 29, as I am more interested in digital modes than anything else. And 2Mhz bandwidth is probably hoping for too much 😉 )

Note: this *was* originally calculated with a 30m dipole as well, but after modelling it, that was quite horrid.. (swr of 38 on 30m)