VK Logger Ham Radio Forum Archive

Phil, I can't help with sourcing the bits you need, but just a little heads-up about those rigs. You mention your IC251E has a tuning issue (unspecified). I once had an IC-551 (the 6m version of the 251) whose tuning started behaving very strangely. Sometimes it would even tune all by itself, either...

Thanks Adam, a very interesting read. I've often remarked, in connection with noise figure, that if you can measure it, it's probably too high!

Chas
VK3PY

I found this today: https://spaceaustralia.com/news/communi ... -telescope

All very self-explanatory. Great to see young people getting into science in a practical way, especially where it involves microwaves.

Chas
VK3PY

Had some fun in the 8-hour/multi-op section today. After a hiatus of a couple of years, VK3UHF is getting back into it. Operators were David VK3QM, Bert VK3TU and me, Chas VK3PY. Being a little under-staffed, we only took gear for the bands 50 MHz to 10 GHz inclusive. We still had heaps of fun. Than...

Lou, A reasonable explanation for the distorted 23cm loop. The phase centre is band-dependent on this kind of feed. The accuracy of placement relative to the dish focus is most critical for the highest frequency, so that's what you aim for. The wiggle room is greater at longer wavelengths. Loop shap...

Yikes, Lou! How on earth was the placement of the 23cm loop chosen, I wonder? Also, that reflector "disc" looks like it was cut very approximately. Not the latter would make any significant difference to the feed's performance, but hardly what you'd expect for a pretty pricey item. Owners ...

Damien & Ralph, I will try to get my creaky bones into the field for some of the time. Which day depends on WX and enthusiasm. I will provide some uwave contacts to you guys and anyone else within earshot. I will take 2m and 70cm too. Not sure about 23cm. Failing that, I can operate 6m to 23cm f...

Another exceptional outing on 3.4GHz today courtesy of the Geelong Amateur Radio Club's initiative. While the total number of operators was slightly down on last time, the good news was finding two new operators on the band, being Dennis VK3BQZ from Lara and David VK3KQT from Ballarat. My total cont...

Good summary Lou. My second reply was directed at establishing that Mal had a "minimal" system hooked up, i.e. Rig, power supply, dummy load and nothing else. I'm still wondering about the voltage drop - 2V @ 15A and who knows what at 25A (if it's a purely resistive issue, it would be abou...

In that case Mal, I'd be checking for RF feedback into the microphone circuitry next. Ken ZL3OZ is spot-on with his advice. Most "faults" are usually not all that complicated. Try this for starters: Disconnect the antenna, tuners and any other stuff. Hook up a suitable dummy load to the ri...

C'mon, guys.....are you serious with your diagnoses? Wood....forest....trees.... VK3TV wrote: Watching the the ALC the needle does seem to jump and peak going out of range. Solution: Turn down your mike gain like the user's manual tells you. Also when talking normally the forward power also seems to...

VK2ZIW asked Isn't this MUCH easier? Maybe. Incremental improvements in antenna performance become ever more challenging. But there are other considerations. In my case, I have a whole shipload of stuff to carry inside my car (2m through to 3cm, plus the little luxuries of life demanded by a veteran...

I am very much looking forward to operating in the next 3.4GHz QSO party on ANZAC Day. My QTH will be the same as last time, QF21CU, 15km west of Geelong at about 210m ASL. This time I might just take my 600mm dish rather than the 1.2m one as the smaller dish is a little easier to handle on my own. ...

VK3LL wrote: VK3KQ/p will be out at usual location QF12VG, around 25km south of Ballarat in the Ross Creek State Forest. My self-preservation instincts tell me that I should acquiesce to my XYL's wishes on the FD weekend. However, I may be able to sneak out Saturday with some gear. Failing that, I c...

Rex, That is a neat solution. I contemplated the same approach, especially as my "soup can" already had a hole diametrically opposite the probe for a tuning screw (unnecessary as it turned out) which would have allowed "in situ" adjustment. However, I hit the sweet spot for the p...

How did you remove the inner Dilectric and conductor from the UT-085 coax. Very easily. Take a piece of UT-085 and a sharp Stanley knife. Roll the blade over the copper outer jacket on the workbench, about 3-4mm in from one end. You only need to score it. Then use a pair of pliers to break off the ...

Thanks for your kind remarks, Robert. Regarding the effects of the coax running back into the dish centre, it surely must have some effect, as would the support structure for the can. It is an inevitable consequence of this type of feed. I expect the main effect would be to introduce some uncontroll...

......And supermarkets for trying to modify your buying behaviour with the microwaves beamed at you as you approach their doors! Then what about those GPS satellites forcing you to follow pre-determined routes to your destination!

Chas
VK3PY

VK4WDM wrote:

How would you respond when somebody knocked at the door and said that your signals were altering their mind state or that of their children?

I'd reply, "Yes - I never thought of that. Please turn off your home wifi and mobile phones forthwith!".

Chas
VK3PY

This is my just-completed 3.4GHz "soup can" feed for a 600mm dish. It is modelled on the design described by W5ZN in his article "Horns for the Holidays" which can be found at http://www.w5zn.org/files/Horns%20for%20the%20Holidays.pdf I can't recall what product my can originally...