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23cm antenna?


#48

Bargain!


#49

Matt (IAW),

I’ll be down from GM and active somewhere in G/NP on Sun March 19th and again in the G/NP,G/SP,G/LD part of the world for the Blackpool Rally on Sat 8th April. I’ll be returning to GM on Mon 10th. If you want to arrange some 23cms skeds then I will be happy to bring the 23cms gear with me and also to adjust my plans so I can be on summits which stand a greater chance of success with you.

If we can persuade a few people to be QRV too you may be able to get some QSOs that are long enough to let you claim a Microwave Award and also qualify an activation on 23cms alone.


#50

I too have gone for the 817 & SG labs xverter.
Just waiting for antenna to arrive from Wimo and could possibly be on air soon.
My plan is to try some of the local summits during the UKAC’s this summer.

Stuart. G1ZAR


#51

I could be persuaded to take 23cm out some where during Rally weekend.


#52

I couldn’t resist the SG Labs transverter, so I duly ordered one. It arrived within a week, complete with power plug to fit, 3.5 mm jack plug for control lead, and a 2 element PCB antenna.

Today being perfect for an outing, I took it up onto the Longmynd G/WB-005 to see if I could hear any beacons.

Just using the supplied antenna, I could hear:

GB3USK 1296.870 IO81VC (near Bristol)
G8MBU 1296.800 IO90IR (Isle of Wight)
And, of course, the Stoke repeater / beacon GB3SE 1297.075

Oh, yes, and the ziz from the big golf ball on Titterstone Clee :o)

Not a practical system yet, except for easy summits like this in nice weather, but very encouraging.
I’d like to find a lighter tripod, and perhaps mount the transverter in a weather resistant box - and make / acquire a better antenna. I also need to work out how best to handle talk back, given that the FT817 is connected to the transverter. (Though a 2m handie could be used as prime mover for 23cm FM)

I put up a spot for 1296.2 ssb. No takers on this occasion, but I had to try! I also called on 1297.5 with similar result.

Here are a couple of photos:

Looking forward to the first QSO :smile:

73
G4AZS


#53

Next band up…

How do you ensure you qualify the summit? Get your fellow GM SOTA ops to invest!


VHF/UHF is alive and well
#54

Most people stack antennas, but I suppose stacking rigs is another way of gaining contacts :wink:


#55

They only arrived the other day. 1 for me and 4 are going to SOTA ops and 2 to local microwavers. I need to do a bit of antenna brewing, probably a pair of double quads. That should give a theoretical 13db of gain whcih would give about 40W ERP. I have one for 23cms and a small PCB yagi similar to yours. The double quad is better than the PCB yagi and both knock spots off the rubber duck my 23cms handy came with.

There are microwave awards to claim. For S2S microwave contacts, the DB can work out the distance. For other contacts you enter the chaser’s locator or lat& long using the following formula in the comment field:

%QRA%IO87FB%

or

%QTH%53.1234,-3.654%

The DB will do the rest when it spots those in the comments you are were QRV on 23cms or higher.


#56

Yes Andy looking forward to our 13cms SOTA S2S’s and experiments Vertical & Horizontal.

As mentioned I have a design for tape/coaxial collinear and of course my 50mm pipe yagi - both horizontal/vertical design.

By the way was taking to David GM6BIG and he mentioned that the 13cms beacon is back on from the old CS site at the Tak-ma-Doon road, in preparation for our 13cm activity - horizontal - not sure the beamwidth - but certainly south. Maybe you’ll be able to hear it from your QTH? Not a problem for me - I look at it - hi!

73

Jack(;>J

PS: One of the down sides to vertical polarisation was in the use of a metal vertical support which could effect the beam pattern to varying degrees. Robin GM7PKT and myself will carrying out some experiments hopefully this year, going some way to answer the question if there is any significant difference between V/H on 2 metre - on distant summit paths.


#57

Hi Adrian,

I’m looking to fit 13cms SG Labs beastie in padded (waterproof?) laptop case. With a suitable clip this can hang on the rigid section of mast with a short coax feed to the aerial.

Nice pics :slight_smile:

73

Jack(;>J


#58

Yes! Certainly on distant paths.
For S2S then both ends should be able to arrange their polarisation to match but other stations may not be as flexible.
It is very unlikely that homebound Chasers will have a vertical with any gain/directivity on these higher bands and, as I have found when chasing Robin, his signal can go from “workable” when horizontal to “is he actually transmitting” when vertical and cross polarised.

I am sure there is an antenna guru out there who can explain the theory about “ground gain” and similar esoteric subjects which come into play with antenna polarisation.


#59

Hi Barry,

Exactly. And ideally if I could be bothered I would re-erect my 10 XY along with rotator on the tower and switch polarisation accordingly. But there are certain downsides nowadays to this so I have come up with a new set-up which I started building in 2015. But had to set-aside whilst I built new shack last year.

It consists of a high gain commercial collinear (used for paging at 140MHz I have moved it up to 145) which works without radials. I have introduced radials in the form of a homebrew heavy duty 6M (3 x 3/4 on 2M) horizontal dipole which I have ‘coupled’ into the collinear. Mounted below the collinear is a ABS box in which the 6M dipole is terminated along with a head amp and RF switching relays. When used in the Vertical mode the 6M is grounded. When used in the Horizontal mode the short is removed from the dipole which can be used on either 2 or 6M. The 6M dipole will be mounted E/W with the main lobes of course N/S (where the mountains are from this QTH).

So as you know, Activators prefer to ‘hunker down’ to get out the weather (certainly in GM land), rather than faffing about rotating a beam. And this is where vertical really scores. Put up your vertical hunker down and let the Chasers chase you vertically - FM,SSB, CW.

We will be trying this on 13cms and see how works out.

73

Jack(:>J


#60

One watt Alinco HT into 16 element Comet 23 cm Yagi, Entire package obtained for 246 USD. Sufficient for award certificate number one in the SOTA Microwave Award program…Elliott, K6EL

Mt Davidson, the only SOTA peak in San Francisco


#61

Hi Elliott,

Yep similar idea to my own thoughts for my 13 cms yagi.

Being 130mm (13cms) the standard 50mm water pipe will do the job nicely (as long as there is no metal compounds within the plastic make-up - a quick check in the microwave oven to see if it gets warm?). A 1/2 wave is about 65mm so unlike your own I will drill holes through centre of the pipe to take each ‘2mm solid rod’ element within itself. Likewise with the driven section - like yours a folded dipole with access holes on either side of the pipe to get access to terminate and mount a BNC or similar.

Now as the tube is 50mm there will only be about ( 65 - 50 = 15mm/2) about 7.5mm protruding - about a 1/3rd of an inch in old money - on either side of the tube. And ideal for clipping onto the outside of my SOTA rucksack without bending the elements.

Locating the yagi on my SOTA pole is determined by drilling two holes using a cone cutter on either side of the tube. The upper side of the pipe has a smaller hole than the lower. This is to accommodate the tapering nature of the telescoping pole. Another set of holes are drilled at 90 degrees. Either set of holes accommodate for vertical or horizontal polarisation operation. The yagi finds it’s own height on the pole (of course I have predetermined this from the hole diameters). I have used this trick from my telescoping 6M to 70cms SOTA dipole which I have used for many years.

Total price to produce the yagi I reckon a tenner £10 - if that. I have all the parts in my workshop bar the 50mm pipe.

Interesting times - on new band for me.

Es 73

Jack(;>J


#62

Love it, Jack. And can be scaled for other bands.

EL


#63

Of course Elliot,

13cms is ideal for this type of design and likewise 23cms, but as you progress down in frequency you introduce the ‘droop’ factor. Now this not a symptom of old age - just gravity playing with our designs & ‘desires’ :wink: .

Cheers

Jack(;>J


#64

I’m also using the SG Lab transverter for 23cm and 13cm and have enjoyed a few contacts on 23cm SOTA so far. The 13cm kit appears to be working but cannot test locally due to lack of stations on that band, hoping for a SOTA contact on my next trip in UK and Ireland.

I will be over in Ireland from 30/03 till 02/04 and EI/IE-003 Tonelagee in the Wicklow Mountains is on the agenda, WX permitting. From IE-003 (817m) there is a good chance to work Wales and the Lake District even with 1W.

I am using home built Yagis: a 10 el. (extension to 21 el.) for 23cm and a 27 el. for 13cm. All aluminium with folded dipole and 4:1 coax balun.

I’ve made an antenna support in polyethylene which clips onto a fiber mast. I would normally use horizontal polarisation for SSB but can easily arrange the clip for vertical polarisation.

Will be posting an alert nearer to the date.

73, Phil ON4TA


#65

Are you going to QRV on April 2nd? I am at the GMDX convention on April 1st so cannot get out to a summit then and I’ll be stuck at work the days before.


#66

Anybody using a Quaggi? I have one for 70cm that is very good. Easy to tune and match.
http://n6nb.com/quagi.htm


#67

Hi Phil,

Well done on your H/B yagi. Looks very impressive. Presume you used a beacon to determine it’s performance?

And. Interesting feed arrangement which I would possibly like to copy because the folded section could possibly fit within the diameter of the 50mm tube - the folded element through a 2mm hole near the top & bottom determined by the fold spacing - this would make for easy termination. And did you make the balun yourself?

73

Jack(;>J