Hi All,
I have taken the plunge and have decided to give the microwaves a try. Will just have to improve my soldering ability and ask some questions which may have already been asked and answered. If that is the case then I apologise for the double up.
Was looking on ebay for antennas and came across this one and was wondering if anyone may have some ideas on its useability.
http://www.ebay.com/itm/32-Round-Grid-A ... 3f14b5996f
The sellers page has various antennas of different sizes for different bands.
Thank you in advance for the assistance I receive.
Eddie - VK4EDD
Microwaves - Starting Out
-
VK3BJM
Re: Microwaves - Starting Out
G'day Eddie.
The basic idea is fine - grid-packs like that one are used for 13 cm and some of us use them for 23 cm, 9 cm and even 6 cm (with some modification). They are light and easy to handle - I've used them both for portable work and I use one as my home station 13 cm antenna.
That seller may not ship to VK, though. I'm not sure what the shipping costs would be like if they did. There are several sources of similar grid-pack dish antennas in Australia; RF Shop in Brisbane leaps immediately to mind: http://www.rfshop.com.au/Store/tabid/63 ... id+Antenna
They also turn up secondhand a fair bit as well, at much reduced prices.
Enjoy!
Regards,
Barry
VK3BJM
The basic idea is fine - grid-packs like that one are used for 13 cm and some of us use them for 23 cm, 9 cm and even 6 cm (with some modification). They are light and easy to handle - I've used them both for portable work and I use one as my home station 13 cm antenna.
That seller may not ship to VK, though. I'm not sure what the shipping costs would be like if they did. There are several sources of similar grid-pack dish antennas in Australia; RF Shop in Brisbane leaps immediately to mind: http://www.rfshop.com.au/Store/tabid/63 ... id+Antenna
They also turn up secondhand a fair bit as well, at much reduced prices.
Enjoy!
Regards,
Barry
VK3BJM
Re: Microwaves - Starting Out
Hi Eddie
As Barry mentions, I would first ask about freight.
This may help prevent the onset of a heart attack after the Buy it now button has been clicked.
Grid packs come in two varieties.
The cast alloy type and the wire type.
The cast alloy is much stronger and the reflector will maintain it's shape, despite being knocked about.
I have a few of the RF Shop wire type reflectors (they were throwing them out at one stage), and they are no where near as robust, which can be a consideration if it's being hauled around from activity day to activity day.
There are quite a few Aussie eBayers selling the cast type.
http://www.ebay.com.au/sch/i.html?_odkw ... +&_sacat=0
These "just work".
My own 2.4 GHZ project (my first dabble in microwaves) was documented with plenty of pictures of this forum, which may offer some ideas as well ;
viewtopic.php?f=40&t=9731
The next most popular band is 10 GHz, but 5.7 GHz is also becoming popular now.
As Barry mentions, I would first ask about freight.
This may help prevent the onset of a heart attack after the Buy it now button has been clicked.
Grid packs come in two varieties.
The cast alloy type and the wire type.
The cast alloy is much stronger and the reflector will maintain it's shape, despite being knocked about.
I have a few of the RF Shop wire type reflectors (they were throwing them out at one stage), and they are no where near as robust, which can be a consideration if it's being hauled around from activity day to activity day.
There are quite a few Aussie eBayers selling the cast type.
http://www.ebay.com.au/sch/i.html?_odkw ... +&_sacat=0
These "just work".
My own 2.4 GHZ project (my first dabble in microwaves) was documented with plenty of pictures of this forum, which may offer some ideas as well ;
viewtopic.php?f=40&t=9731
The next most popular band is 10 GHz, but 5.7 GHz is also becoming popular now.
Adam, Brisbane
vk4ghz.com
VK4GHZ on Youtube
VK4GHZ on Odysee
10 things that happen when you stop checking Facebook constantly: http://tiny.cc/t5h7cz
How to quit Facebook: https://www.consumerreports.org/social- ... -facebook/
vk4ghz.com
VK4GHZ on Youtube
VK4GHZ on Odysee
10 things that happen when you stop checking Facebook constantly: http://tiny.cc/t5h7cz
How to quit Facebook: https://www.consumerreports.org/social- ... -facebook/
Re: Microwaves - Starting Out
Hi Eddie.
Don't even think about going through that guy in the USA on eBay. I tried 3 times to make contact with him to see if I could get one of his antennas. The simple answer (when I got it) was no he will not post to VK as he has no interest in selling outside the USA. I'm only a new comer myself to Microwave and got bitten by the bug early this year. I was able to get a nice 5.7 ghz grid pack from the RF shop and my 2.4Ghz grid pack came from the the Radio Specialist in VK5. I was also lucky enough to score a 3.4Ghz grid pack second hand on eBay from Sydney. It pays to just keep looking on eBay (in VK) and vk classifieds as they come up from time to time.
Don't even think about going through that guy in the USA on eBay. I tried 3 times to make contact with him to see if I could get one of his antennas. The simple answer (when I got it) was no he will not post to VK as he has no interest in selling outside the USA. I'm only a new comer myself to Microwave and got bitten by the bug early this year. I was able to get a nice 5.7 ghz grid pack from the RF shop and my 2.4Ghz grid pack came from the the Radio Specialist in VK5. I was also lucky enough to score a 3.4Ghz grid pack second hand on eBay from Sydney. It pays to just keep looking on eBay (in VK) and vk classifieds as they come up from time to time.
Re: Microwaves - Starting Out
Barry, Adam & VK4LHD,
Thank you all for the replies. Will keep my eyes out on the Australian sites and start getting the antennas locally. In the mean time it will be saving up and collecting the components to look at building my first transverter.
Adam found your 2.4Ghz project very interesting and informative. I should be able to source components from your detailed description of ebay
Again thanks for your replies and you never now one I will get there.
Eddie
Thank you all for the replies. Will keep my eyes out on the Australian sites and start getting the antennas locally. In the mean time it will be saving up and collecting the components to look at building my first transverter.
Adam found your 2.4Ghz project very interesting and informative. I should be able to source components from your detailed description of ebay
Again thanks for your replies and you never now one I will get there.
Eddie
Re: Microwaves - Starting Out
Try art-in-part on eBay. He has flat panel antennas for around $40 shipped.
Ben
Ben
-
VK4KHZ
Re: Microwaves - Starting Out
Another good overseas supplier of microwave goodies is http://www.rfhamdesign.com
I recently purchased a 2.4G helix feed from them and it arrived very quickly and it seems to work well.
I have just ordered one of their 1.2m prime focus mesh dish kits so we will see how that one goes...
It is hard to go past the 2.4G cast iron grid packs previously mentioned - they are good value for money are durable and just seem to work well.
Good luck
Regards
Shane VK4KHZ
I recently purchased a 2.4G helix feed from them and it arrived very quickly and it seems to work well.
I have just ordered one of their 1.2m prime focus mesh dish kits so we will see how that one goes...
It is hard to go past the 2.4G cast iron grid packs previously mentioned - they are good value for money are durable and just seem to work well.
Good luck
Regards
Shane VK4KHZ
Re: Microwaves - Starting Out
Eddie,
Don't be so hasty to part with your $$$. First of all, start building or otherwise acquiring the RF gear for the band in question. Then make contact with microwavers in the wider microwave community. Go to hamfests and look under the trestle tables. Let it be known what you're working towards, and the bits you need. Show some progress and commitment. A strange thing will happen. "Stuff" will appear out of nowhere. Down here in VK3 we call it "shaking the trees". You never know what will fall out.
Good luck with your enterprise.
73,
Chas
VK3PY
Don't be so hasty to part with your $$$. First of all, start building or otherwise acquiring the RF gear for the band in question. Then make contact with microwavers in the wider microwave community. Go to hamfests and look under the trestle tables. Let it be known what you're working towards, and the bits you need. Show some progress and commitment. A strange thing will happen. "Stuff" will appear out of nowhere. Down here in VK3 we call it "shaking the trees". You never know what will fall out.
Good luck with your enterprise.
73,
Chas
VK3PY
Re: Microwaves - Starting Out
If you're playing on 10GHz (or 5.7GHz) you can usually find a surplus satellite TV dish for nix which can be pressed into service.
73
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
Re: Microwaves - Starting Out
Hi Shane,VK4KHZ wrote:Another good overseas supplier of microwave goodies is http://www.rfhamdesign.com
I recently purchased a 2.4G helix feed from them and it arrived very quickly and it seems to work well.
I have just ordered one of their 1.2m prime focus mesh dish kits so we will see how that one goes...
It is hard to go past the 2.4G cast iron grid packs previously mentioned - they are good value for money are durable and just seem to work well.
Was just wondering if your 1.2m dish turned up and what you thought of the quality of the product.
Looking at their site it seems to be quite good. A question for the more learned people. I noticed that they do multiband feeds and was wondering how big a compromise would I be making have a 4 or 5 band feed on a 1m or 1.2m dish. Do like the idea of the single setup just not certain. Would it be better having 2 separate setups one for 23, 13, & 9 and one for 6 & 3.
As for the grid packs for 2.4G found this for 5.7G http://www.ebay.com.au/itm/181169516552 ... 1423.l2649
Regards,
Eddie
-
VK4WDM
Re: Microwaves - Starting Out
Grid packs are quite often found at our local metal recyclers. Don't know about other places.
73
Wayne VK4WDM
73
Wayne VK4WDM
Re: Microwaves - Starting Out
As for the grid packs for 2.4G found this for 5.7G http://www.ebay.com.au/itm/181169516552 ... 1423.l2649
This is the grid pack I'm using on 5.7Ghz and I got it locally at the RF Shop. It works very well as I found out at the Microwave Activity Day back in July. I got a 180 km distance on 250mW and was very happy with that. It was also my first ever microwave contact.
The antenna is bit big in size for a grid pack but no bigger than some of the 2.4Ghz grid packs being used by others. I recommend this antenna for 5.7Ghz.
Robert
VK4LHD
This is the grid pack I'm using on 5.7Ghz and I got it locally at the RF Shop. It works very well as I found out at the Microwave Activity Day back in July. I got a 180 km distance on 250mW and was very happy with that. It was also my first ever microwave contact.
The antenna is bit big in size for a grid pack but no bigger than some of the 2.4Ghz grid packs being used by others. I recommend this antenna for 5.7Ghz.
Robert
VK4LHD
Re: Microwaves - Starting Out
Eddie VK4EDD,
I saw your question about RFHamdesign multi-band feeds.
I have a number of these feeds and they work extremely well. Well constructed, waterproof, good return-loss figures and best of all, a concentric focus point, which when set for best focus at the highest frequency, will also be at best position for the lower frequencies.
You question the issue of more than 3 bands on the one feed. You are correct - trying to run 5 bands from 1.2 through to 10GHz on the one dish means either the higher frequencies are too sharp to point on a large dish or on a smaller dish, the gain on the lower frequencies is too low.
In my case, (1) I use a triband 3,5 and 10 Ghz feed on an offset feed 900mm dish which is a good match all round. (2) a dual band 1.2 and 2.4 feed on a 1200 mm offset dish, which still gives useful gain on 1.2Ghz and (3) a dual band 1.2 and 2.4 feed on a 2400mm prime focus dish which really kicks "a***".
In the case of the higher bands, coax losses become an issue, so give consideration to at least mounting your transverters as close to the feed (back of dish) as possible.
The other thing to watch for is that these multi-band feeds are optimised for an F/d of 0.45 to 0.5.
So if possible, try to avoid dishes with an F/d of less than 0.4 or more than 0.55 or some compromise in directivity will occur.
Typical C band mesh dishes are 0.4 and many of the offset TVRO dishes are greater than 0.6. However there are still plenty of dishes within the 0.45 to 0.5 range out there.
Cheers
Peter VK3QI and VK3ER/p
I saw your question about RFHamdesign multi-band feeds.
I have a number of these feeds and they work extremely well. Well constructed, waterproof, good return-loss figures and best of all, a concentric focus point, which when set for best focus at the highest frequency, will also be at best position for the lower frequencies.
You question the issue of more than 3 bands on the one feed. You are correct - trying to run 5 bands from 1.2 through to 10GHz on the one dish means either the higher frequencies are too sharp to point on a large dish or on a smaller dish, the gain on the lower frequencies is too low.
In my case, (1) I use a triband 3,5 and 10 Ghz feed on an offset feed 900mm dish which is a good match all round. (2) a dual band 1.2 and 2.4 feed on a 1200 mm offset dish, which still gives useful gain on 1.2Ghz and (3) a dual band 1.2 and 2.4 feed on a 2400mm prime focus dish which really kicks "a***".
In the case of the higher bands, coax losses become an issue, so give consideration to at least mounting your transverters as close to the feed (back of dish) as possible.
The other thing to watch for is that these multi-band feeds are optimised for an F/d of 0.45 to 0.5.
So if possible, try to avoid dishes with an F/d of less than 0.4 or more than 0.55 or some compromise in directivity will occur.
Typical C band mesh dishes are 0.4 and many of the offset TVRO dishes are greater than 0.6. However there are still plenty of dishes within the 0.45 to 0.5 range out there.
Cheers
Peter VK3QI and VK3ER/p