GB3JT Site

Locator: JO00HV
Location: Hastings
Repeater is Work in Progress. Operational TX 24/7 Omni Slot.
TX Output Digital 1318 MHz DVB-S 4 Msymbols 1/2 FEC
RX Input Analogue 1249 MHz Analogue
RX Input Digital 1249 MHz DVB-S 4 Msymbols Auto FEC
RX Input Digital 437 MHz DVB-S 2 Msymbols Auto FEC (WIP)
Talkback: GB3HE or Echolink 71066

Website: http://www.rilges.org.uk
Stream: http://www.batc.tv/streams/gb3jt
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G8PUO
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Joined: Sat Nov 08, 2014 3:07 am

GB3JT Site

Post by G8PUO » Fri Nov 08, 2024 9:38 am

Following the long standing issues at the Hastings site (even though it was an excellent locations), and then temporary move to Eastbourne (which had coverage issues), I have now moved west of Maidstone in Kent.

An application has been submitted for site move and hopefully if accepted, I can get the DATV repeater back on air as soon as possible.

Dave G8PUO

G4HTZ
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Re: GB3JT Site

Post by G4HTZ » Tue Nov 19, 2024 10:11 pm

That’s good news ….i used to live in Southend on sea so that would have been a good location to me ….used to be quite a following on ATV in Kent and Essex when GB3KT was on from the isle of sheppy …….im in north Essex / Suffolk border now so probably out of range unless it’s top of bluebell hill !!

Good luck with the application
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

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G8PUO
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Re: GB3JT Site

Post by G8PUO » Wed Nov 20, 2024 4:43 am

Hi Steve, good to here from you.

Indeed, KT and the group, had a good following back in the day and would be nice to see if this interest can be rekindled and as a STEM Ambassador, get more involvement as part of this.

Not sure about Bluebell Hill options (although I may have one), but certainly looking at an alternative good site at Detling, so will see what pans over the next couple of months.

The prediction plots certainly offer encouraging coverage.

Updates to follow, once more is known.

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G8PUO
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Re: GB3JT Site

Post by G8PUO » Sat Nov 23, 2024 4:35 am

Hi Steve @g4htz,

Have done some example elevation plots using the below and included Sudbury Garden Centre as an example for you as I do not know the area or topology.

https://www.solwise.co.uk/wireless-elevationtool.html

This is based on ground level and although unsure of accuracy, is a good guide. Plan to go to site in the week and investigate options.

Looks promising and encouraging coverage. Although quite a distance to you, be interesting to know if you can access GB3RE which is on the same site, and/or GB3KN adjacent site. Unsure how well the repeaters are working but a guide.

Do have another site potential option on Bluebell Hill but Detling currently seems better for a number of reasons. See what pans out.

Should anyone else do an elevation plot, be interested on feedback.

KR
Dave
Attachments
GB3JT Elevation Examples Detling 241123.pdf
(657.97 KiB) Downloaded 61 times

G4HTZ
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Re: GB3JT Site

Post by G4HTZ » Sat Nov 23, 2024 7:04 am

Thanks for path plots Dave …I notice they don’t factor in the earth curvature ……
My location is JO02GB52 village of ashen …actually between Haverhill and Sudbury .
I will do a pathplot on heywhatsthat which factors in earth curvature.
Not sure on the FM repeaters as don’t currently have any vertical antennas up .
Interesting project anyway .
Regards
Steve
IMG_2435.png
IMG_2435.png (2.38 KiB) Viewed 1167 times
IMG_2436.png
IMG_2436.png (2.62 KiB) Viewed 1167 times
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

G4HTZ
Posts: 237
Joined: Sat Aug 02, 2014 4:21 pm

Re: GB3JT Site

Post by G4HTZ » Sat Nov 23, 2024 7:17 am

Sorry forget to add , these are from Detling to my QTH assuming mast heights of 30ft each end
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

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G8PUO
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Re: GB3JT Site

Post by G8PUO » Sat Nov 23, 2024 7:38 am

Thanks Steve, but I thought the earth was flat... Does this mean your Yagi will have a built in boom curve to compensate :)

Good to see your plots. Indeed antenna heights are ballpark. \

Will have a play with heywhatsthat.com

g0mjw
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Re: GB3JT Site

Post by g0mjw » Sat Nov 23, 2024 9:10 am

Assuming I have the right place?
Screenshot 2024-11-23 085351.png
Screenshot 2024-11-23 085351.png (716.8 KiB) Viewed 1146 times
How high is the antenna and what is the EIRP? If I assume 1kW which I suspect too much for the repeater itself but not unreasonable for someone trying to get into it and the repeater antenna at 20M above ground from the site shown I can get a rough idea of the coverage using path profile taking into account terrain and that the earth is not flat, but not and effect from trees etc that may be in the way
Screenshot 2024-11-23 085333.png
Screenshot 2024-11-23 085333.png (78.33 KiB) Viewed 1146 times
So not great for me, but that's to be expected. Coverage seems to favour the east and south-east as is usual from Kent. I have attached a very crude coverage plot inside the zip for google earth. What this means depends on power, antenna gain etc. but probably green, yellow, orange and red pixels have a shot.
GB3JT.zip
(46.19 KiB) Downloaded 52 times

Basil
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Re: GB3JT Site

Post by Basil » Sat Nov 23, 2024 11:10 am

I presume the curvature of the earth is grossly exaggerated, visually? Otherwise two points about 130kms apart occupy about one eighth of the world's circumference!
Best regards,

Chris, 2E0ILY in rural Shropshire.

It was a lot more fun being 20 in the 70's than being 70 in the 20's

g0mjw
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Re: GB3JT Site

Post by g0mjw » Sat Nov 23, 2024 11:15 am

Yes, otherwise you would see noting but a flat line. The curvature is accurate in relation to the terrain height. A path that long has over 200m of earth to get over, even on a plain with no hills. This is why in open flat terrain or on the sea, the horizon is a few km away at head height.

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