Latest Threads |
New / Would-be forum user...
Forum: SYSTEM NOTICES
Last Post: VK4ADC
Yesterday, 07:35 AM
» Replies: 0
» Views: 66
|
3 - 30 MHz Choke
Forum: Homebrew
Last Post: VK4ADC
16-07-2024, 08:56 PM
» Replies: 6
» Views: 580
|
2m amplifier using BLF 27...
Forum: General Discussion
Last Post: VK5AYD
14-07-2024, 05:22 PM
» Replies: 2
» Views: 345
|
visualising my logbook da...
Forum: Computer related
Last Post: VK2CSW
11-07-2024, 05:52 PM
» Replies: 6
» Views: 740
|
FTDX101D or IC7610 ?
Forum: Transceivers, Transmitters & Receivers
Last Post: VK4SMJ
10-07-2024, 12:02 AM
» Replies: 2
» Views: 478
|
Wire Antennas and Foliage
Forum: Towers, Masts & Transmission Lines, Antennas
Last Post: VK2CSW
09-07-2024, 05:42 PM
» Replies: 4
» Views: 622
|
LOTW back on air official...
Forum: General Discussion
Last Post: VK2CSW
04-07-2024, 06:14 PM
» Replies: 1
» Views: 473
|
Release Candidate WSJT-X ...
Forum: General Discussion
Last Post: VK2XAX
03-07-2024, 10:50 AM
» Replies: 0
» Views: 395
|
Multiple instances of WSJ...
Forum: Computer related
Last Post: VK2XAX
30-06-2024, 10:03 AM
» Replies: 2
» Views: 722
|
has anyone had any luck u...
Forum: General Discussion
Last Post: VK5PJ
28-06-2024, 11:14 AM
» Replies: 3
» Views: 1,084
|
|
|
Possible biconical antenna build |
Posted by: VK3UVW - 24-05-2024, 12:23 AM - Forum: Homebrew
- No Replies
|
![](https://www.ahrdf.net/forum/images/default_avatar.png) |
Hi there,
I'm slowly building up some DIY test gear - if I build a thing for use at work, I try to build a spare for myself at the same time.
Next on my list is a biconical antenna. We want to do some EMC testing on some gear, and although we could buy or hire one the idea of just making the thing is pretty appealing. I've now got a couple of LISNs via github->kicad->china for the same reason. They've already been handy in finding conducted EMI, which was nice.
I found the original drawings in MIL-STD-461A (from 1968, when they included useful detail in standards!), and it seems fairly straightforward - particularly in this brave new world of just sending a .stp file away and getting back cnc'd aluminium for the bases and caps.
The only part I'm slightly less confident about is the balun, though it looks like passing coax through a few toroids might do the trick, or perhaps wrapping it about a ferrite core. I base this on a commercially available biconical referring to using a 'modified guanella' balun.
Has anyone built one and had a bad time? Anything to avoid or things to know?
Cheers,
Scott
|
|
|
Repairs & improvements at VK3RBA in recent times |
Posted by: VK3BA - 18-05-2024, 07:51 PM - Forum: FM, Repeaters, D-STAR
- No Replies
|
![](https://www.ahrdf.net/forum/images/default_avatar.png) |
G'day All, there's been a fair bit of work go on at Mt Buninyong in recent times...
On Friday, Tim VK3TIM and Shaun VK3KK spent the day fault finding & diagnosing the ongoing issues with the RBA 2m repeater. It was eventually tracked down to a radio that was in standby mode from another agency, that mainly operates during summer. It has since been isolated and Tim has developed a solution for this to suppress the intermod issues in future.
On Saturday, Tim VK3TIM with the assistance of Shaun VK3KK, Tony VK3UBO and Nik VK3BA spent most of the day up there again, replacing a waterlogged feeder, removed any redundant steelwork, rusty bolts, etc, replaced an antenna, removed a faulty antenna, re-arranged part of the filtering chain, installed some new internal feedlines between racks, replaced the 23cm repeater with a new Kenwood based 23cm repeater and fixed a fault with the 10m simplex repeater. There is a slight new noise getting into the 23cm repeater, but it’s not dominant and set for further investigation. These things can often work well on the test bench, but put them up on a prominent site and new issues can arise.
Tim and Shaun have spent a fair bit of time up there in recent weekends, giving the whole site a makeover. There is still plenty to do, but the 2m, 70cm & 23cm repeaters and link radios are now working very well. Tonight we had a report from Chris VK3AML in East Burwood that he was hearing the 2m repeater at 5x9 +20 and the best he’s ever heard this repeater. Steve VK3ZH in Ringwood has reported tonight that the RBA 2m repeater is a vast improvement to his location. That’s an excellent report and validation of the work carried out over recent times.
Our next main project is to convert the 10m repeater into a duplex device, with large church-organ-pipe like cavity filters and crystal filters from California to make this all work and has been an ongoing work in progress by Tim VK3TIM.
I’d also like to acknowledge Andy VK3AS for his generous contribution around many of the improvement costs around the VK3RBA site as well. Thanks must also go to Amateur Radio Victoria for their assistance with this site.
In the interim for a while, the 2m & 23cm repeaters will often be linked together via an IP connection for testing & observation purposes.
We’d like to think that the improved 2m repeater will be a much better experience for everyone in the Ballarat and surrounding area.
Cheers,
|
|
|
7285kHz AM? |
Posted by: VK3RX - 25-04-2024, 01:16 PM - Forum: Off Topic!
- No Replies
|
![](https://www.ahrdf.net/forum/uploads/avatars/avatar_8.jpeg?dateline=1535533973) |
Anyone know what’s going on there?
Continuous AM transmission, loud in VK3, quite broad. Heard afternoons the last couple of weekends, and now today.
Runs for hours on end, no break in transmission.
Initially I thought it was an open mike, hearing a bunch of people talking and rambling on not radio related, and then at times there seems to be playing of tape recordings of same.
Doesn’t seem to be live conversations, because occasionally a local time is mentioned which is around midnight or early morning.
|
|
|
VK3XPD 23cm 65W modules |
Posted by: VK3BA - 22-04-2024, 09:06 PM - Forum: 1296MHz, Microwave & Opto
- Replies (1)
|
![](https://www.ahrdf.net/forum/images/default_avatar.png) |
G'day all,
Years ago at Gippstech, Alan VK3XPD sold a quantity of 23cm 65W modules. They may have been Lucent cellular modules. I bought one for an intended use, it sat idle, then I moved it one to someone else with a more immediate use. Sellers remorse since set in. Sound familiar? Now that I’m after one for ATV or D-ATV use, I’m after one again and have since been offered one tonight. I’m pretty sure when I bought mine years ago, there were one or two pages of application notes to go with it. If there was such a thing, would anyone here still have a copy of these notes who would be kind enough to send me a copy please?
I’m assuming that for 65W out on SSB will equal about 15W out for DVB-T TX at saturation at short duration. My main two questions were, was it about 26vDC or 28vDC input and what was the input power to drive to saturation? I’d obviously have to back it off to run DVB-T for 10mins at a time without letting the smoke out.
Thanks in advance.
Cheers,
|
|
|
23-on-23: Tuesday April 23, 2024 |
Posted by: VK4CZ - 19-04-2024, 01:22 PM - Forum: 1296MHz, Microwave & Opto
- No Replies
|
![](https://www.ahrdf.net/forum/uploads/avatars/avatar_13.jpg?dateline=1496620142) |
Welcome to the April 23-on-23.
Tuesday April 23, 2024 is the next scheduled 23-on-23!
Another great opportunity to activate your 1,296MHz and other uWave home station capabilities.
Operations are typically conducted as follows:
Phone/CW
Start time: 10:00z / 8:00pm AEST
QRG: 1,296.100MHz
Digital, 2,400/2,403 and 3.398MHz
Start time: 11:00z / 9:00pm AEST
23cm QRG: 1,296.225MHz (Mode JT65)
13cm QRG: 2,400.100MHz or 2,403.100MHz USB
9cm QRG: 3,398.100MHz
These events are designed to develop the level of activity on 23cm and above amateur bands.
Everyone is very welcome to participate. Please do not hesitate to share with others who you know have capability and see if we can continue to grow the numbers of participating stations, by promoting with your local club, on other forums and FB pages.
Activity is not limited to stations within SE VK4, and the growing contingent from VK2 and even VK5 in the last couple of 23-on-23 activation events.
As is often proven, if the participating stations are unaware of your operation, there is a high likelihood that you won’t be worked. [Quite simple and very logical really!]
Please take a moment to share advice of your participation here, and on the night log into VKSpotter [https://vkspotter.com/] ‘2m and above’ page and chat, so that attention to 'exploiting' the path can be achieved.
Good luck to everyone.
de VK4CZ
|
|
|
|