VK Logger Ham Radio Forum Archive

An on air contact with my 2.4 gigahertz transverter and FT817. Earlier in the day we had confirmed that Richard VK7ZBX's system was also working. The path is not line of sight and is over 1200m (4000 feet) mountains. Amazing signal considering the path and the location of my grid pack.

Hayden, I am about to order a 23cm transverter from SG Labs and am wondering if a mesh antenna like the one you used in this video would be the way to go. If so, where did you get yours?
Regards
Grant VK4JAZ

Hi Grant,
The mesh antenna in the video is for 2.4 GHz. There isn't really a lot to be gained from trying to use such an antenna on 23cm too.

There are plenty of 23cm antenna designs around -

https://vk1nam.wordpress.com/2017/12/27 ... d-antenna/
https://vk1nam.wordpress.com/2017/06/29 ... i-antenna/

Alternatively you can purchase yagis. I have purchased from Antennas and Amplifiers (Europe) in the past. His antennas are great, but an expensive way to get on the air quickly.

https://www.antennas-amplifiers.com/23cm-antenna

Hi Grant

There is a great repository of information here that has been posted in the past.

2.4 GHz grid pack discussed here before.
Try reading: http://vklogger.com/forum/viewtopic.php?f=40&t=9617

It's such a shame so many prefer the ease of posting on Foolbook these days - but try finding things on FB after nine years, like the above topic. Impossible.

Be careful of the wire mesh type grid packs - they are flimsy.
The cast alloy are better suited to the rigors of being "chucked" in the car boot and going portable.
As always, you get what you pay for.

And if you haven't seen it already, the 23cm SG transverter was discussed here: http://vklogger.com/forum/viewtopic.php?f=40&t=12105

Thanks guys for all the information; great stuff. I am in communication with Andrew about his home brew plans for antenna. I don't think it'll be too long now before I join you guys on the band.

Here is a follow up video on a rainy day in VK7.

More testing on 3.4 GHz using a WA5VJB PCB antenna as a grid feed

Hayden,

There are few tests you can do.

(1) rotate the antenna in the horizontal and see what the beam width is

(2) see if there are any lobes - these will be evident if the feed is not quite in the correct position

(3) move the LP in and out to try and minimise any lobes - anything better than -20dB is good!

(4) rotate the antenna in the vertical and check what the vertical beamwidth is.

(5) given the symmetry of the feed, there is nothing you can do about any lobes in the vertical.

(6) Check what the conduit is doing RF wise - it might be affecting the return loss on some bands.


Perhaps your VK7 friend can put a constant carrier up on FM at low power for you to work with.


Cheers

Peter VK3QI

Thanks Peter for the suggestions.

The next test I probably will do is with my small signal generator at home setup to use as a reference and try the adjustments you mentioned.

I might pop the conduit into the microwave and see how warm it gets. Its just solar conduit that I found lying around.

I'll also do some further testing on the bench to see how warm the LP antenna gets at a lower power level.

Hayden