Grid pack versus yagi

[VK4WDM]

Hi everyone

I need a compact 23cm antenna, initially for home station use until I get something bigger organized, and then for portable use.

I am unable to carry out much in the way of home building atm so I contacted Radio Specialists in Adelaide who advertise a 18 element 15dBi yagi and a 18dBi grid-pack. When I contacted them they said that they no longer stock the yagi and that the grid pack out-performs the yagi anyway.

I have very little experience on the 23cm band and know absolutely nothing about grid-packs. Obviously the proposed grid-pack has more gain than the yagi in this instance but are there more factors to consider when comparing the two?

Would this grid-pack be a good buy or should I try to source a small yagi? (I believe Comet make one).

Power output will be 10w, 40w when I get my amp running, and terrestrial work only, at least at this stage.

73

Wayne VK4WDM

[ZL2WHO]

Guday Wayne.
Im in much the same boat as you when it comes to 23cm. I have no 23cm gear here as yet but its on the to-do list.
I can however report that I have had good success with panel ants for the Waipuna 23cm beacon. This type of panel antenna is fairly easy to make and i can offer you dimensions for the 1296.xxx part of the band.
I took a guess at the dimensions and found it to be slightly high in freq, so another was made and so on until 1:1 match was seen.
The 23cm beacon at Waipuna has 1x South panel and 1x North panel and good signal reports have come from both ends of the North island.

http://techdoc.kvindesland.no/radio/vhf ... 102181.pdf
Waipuna panels are 6 loop panels and have been tested by Wayne ZL2BKC at about 10-13 dBd. They must be ok as Wayne has asked me to build a pair for the Wellington beacon.

Give me a shout and ill supply you with my build spec if this is what you are after.

Mark
2WHO

[VK4WDM]

Hi Mark

Thank you for the offer but I unable to do any home building for a while and need something that is plug and play.

73

Wayne VK4WDM

[VK4KHZ]

Wayne
I have one of the Radio Specialists 18 element yagi's gathering dust. It is unlikely I will use it again so if you want it give me your details I will see what I can do to get it too you.

Regards

Shane VK4KHZ

[VK4WDM]

Hi Shane

That would be wonderful! I will send you an email later.

73

Wayne VK4WDM

[VK4CLG]

Just adding my bit here to the post and letting you know that I also own an 18el Radio specialists 23cm yagi and it works real well. I use it for everything from portable vhf/uhf field days to the 23 on 23 and have had great results from it. It worked so well I built a replica of to use on the home station. I have heard some people call them little more than a 50 Ohm dummy load but mine works brilliantly. I would how ever like to know if anyone has got a grid pack on 23 cm and how it performs against a yagi as I was thinking of getting one just for the experimentation.

Cheers
Robert
VK4LHD

[VK4APN]

Hi everyone
Would this grid-pack be a good buy or should I try to source a small yagi? (I believe Comet make one).
Wayne VK4WDM

I have the grid pack antenna from this company. It works very well with my meager 1 watt. It is physically well made with the grid made from cast aluminium together with stainless hardware. It has been through several cyclones with out any damage.

[VK4REX]

Have one of these coming to test against my 23 element loop yagi. It's currently passing thru Heathrow and due here next Wednesday. Will post on this thread how it compares.

http://www.antennas-amplifiers.com/23cm ... 296-36-3UT

Rex

[VK2BLS]

Hi Wayne,

I got a Directive Systems 24 element Loop Yagi to get my feet wet on 23 without too much cost or structural problems to erect a dish.
Very happy with it, so got another and phasing harness to eventually stack.
You can buy fully assembled or the kit is a bit cheaper, but goes together easy like a Meccano set, has excellent instructions, all parts & screws are bagged with step by step details. Very light weight and a small footprint.
Aiming for a Grid Pak one day, meanwhile not bad dB gain for the price with the Loop Yagi.
Price & postage cost was quite good and very quick delivery.

http://directivesystems.com/1200-mhz/23 ... -dec-2013/

Cheers,

Darrell vk2bls

[VK4WDM]

Hi Darrell

I brought one of those kits a number of years ago but sold it before I could use it. Not a solution now though because I have intermittent bad arthritis and/or numbnes in my hands and putting fine stuff together can be very difficult. Have to go the ready-made option this time Comes with this I suppose

73

Wayne VK4WDM

[VK5BI]

Hi Wayne,

I use the comet CYA-1216E yagi, bought from DX engineering in the states. Far cheaper than in Aus.
Great for base use and small enough to go portable with.

Wayne VK5BI

[VK4WDM]

Hi Wayne

I have been kindly given a yagi by Shane VK4KHZ, but I am going to US later in the year so I could grab one of the Comets and I would have a stack of two.

73

Wayne VK4WDM

[ZL2WHO]

https://www.youtube.com/watch?v=QwwH5yMD0fk

Video on CYA 1216e yagi.

[VK3ZAZ]

Hi everyone

I need a compact 23cm antenna, initially for home station use until I get something bigger organized, and then for portable use.

I am unable to carry out much in the way of home building atm so I contacted Radio Specialists in Adelaide who advertise a 18 element 15dBi yagi and a 18dBi grid-pack. When I contacted them they said that they no longer stock the yagi and that the grid pack out-performs the yagi anyway.

I have very little experience on the 23cm band and know absolutely nothing about grid-packs. Obviously the proposed grid-pack has more gain than the yagi in this instance but are there more factors to consider when comparing the two?

Would this grid-pack be a good buy or should I try to source a small yagi? (I believe Comet make one).

Power output will be 10w, 40w when I get my amp running, and terrestrial work only, at least at this stage.

73

Wayne VK4WDM

FWIW
We (in BA) use Grid Packs for RBR (Re Broadcasting receivers) on UHF over short spans like Portland to Warrnambool due to moderate gains and good side lobe rejection.
We don't use them on links over 100KM.
However I noticed on way down A5 from Rockhampton to Goondoowindi last month big grid packs feeding an exchange out near Carbide or somewhere and it was a BIG GRID PACK.

Looking at a spare dipole feed I have here acting at prime focal point, lots of hardware and matching stub.

In a phrase too hard yagis [provide better over path gain and to that end we use two diversity yagis at many sites between 50 and 150 km away on VHF and UHF

2 cents

68 YOBAE

[VK2ZIW]

Bandwidth, bandwidth, bandwidth

Long yagis are by their nature narrow bandwidth, so home brewing one is thwart with danger. Tolerances less than 1mm, hard.

I use a 12 el phased array. From here, Emu Plains, I hear the Dural beacon quite well and by rotating it, work the Dural or Chatswood
repeaters (just). I got it from Dural T&T, never used.
I've taken it on Field Days, where it worked well.

>The 23cm beacon at Waipuna has 1x South panel and 1x North panel and good signal reports have come from both ends of the North island.
>http://techdoc.kvindesland.no/radio/vhf ... 02181.pdf
> Waipuna panels are 6 loop panels and have been tested by Wayne ZL2BKC at about 10-13 dBd. They must be ok as Wayne has asked me to build a pair for the Wellington beacon.

Questions:
Can we surround this with a square horn and increase the gain?

How sparse can we have the driven elements before we loose gain?

My setup:
http://www.unixservice.com.au/hamradio/ ... /23cm.html

80
Alan VK2ZIW

[VK4CZ]

I'm a gluten for punishment... for the sake of the experiment and challenge of building a long boom yagi I'm more than 50% of the way to completing a 74 el DL6WU on 23cm.... a boom length of nearly 6.5m. All elements measured and filed to achieve the nearest 1mm accuracy... but not the 0.1mm the design called for!

Best case it works.... worst case.... I cut it down and have gained a lot from the experience

Boom bracing still to be made and TIG'ed.

[VK3AUU]

Good luck Scott. You should have about 21 dbd which is the equivalent of a 1.5 metre gridpak. You might do better with a split dipole for the feed, but that is only a guess.
Contrary to popular opinion, suitably designed long yagis can have -3db gain bandwidths of around 10 percent. The DL6WU doesn't do too badly either. It is only those which are designed for maximum gain that are more restricted in bandwidth and even then the loss of gain is generally less than 1 db at the design frequency.

David

[ZL1TPH]

Should work well Scott,
Same antenna design used here. Slightly different in that I stacked four 30 element Yagi's. Works well and the front lobe is sharp. My QTH is at sea level and I can hear the ZL2WHO/b on 1296.271 S1 at 317 km 24/7.

120 elements 23 cm

Cheers, Steve