GB3EY OFF AIR

Locator: IO93WT
Location: Hull, East Yorkshire
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G3GJA
Posts: 122
Joined: Sun Nov 20, 2011 3:44 pm

GB3EY OFF AIR

Post by G3GJA » Mon Oct 21, 2019 9:06 am

We're sorry to report that GB3EY is off-air to allow investigation into the cause of low power output from the beacon transmitter. :(

After checking with some locals it appeared that EY's output was around 15dB down on what it should be.

A site yesterday and confirmed that the output was down. It should be 36.5dBm but was only 22.5dBm or around 300mW.

It's not possible to do much fault finding on-site so it was removed for workshop attention. We've no idea what might have failed at this time.

Updates will appear here first.

Clive G3GJA Engineering
Richard G4YTV Keeper
Last edited by G3GJA on Mon Oct 21, 2019 9:01 pm, edited 1 time in total.

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Wolfie G8VAT
Posts: 131
Joined: Sat Mar 26, 2016 11:56 am

Re: GB3EY OFF AIR

Post by Wolfie G8VAT » Mon Oct 21, 2019 5:28 pm

Thanks for keeping us up to speed Clive. Hope it's now't serious.
:
Dah-di-dah
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Graham G8VAT

G3GJA
Posts: 122
Joined: Sun Nov 20, 2011 3:44 pm

Re: GB3EY OFF AIR

Post by G3GJA » Mon Oct 21, 2019 9:08 pm

Driver is bust. The PD8504, which is part of the G4BAO 23cm driver kit, has an interesting blueing of the source tab and there's the usual phenolic smell of expired semiconductor. :(

Device is rated @ 4W out at 900MHz with 50mA bias but as per G4BAo's advice ran it at 250mA and about 250mW RMS of DATV out. I made some imrpovement to get the heat away but obviously not enough :lol:
IMG_20191021_214009.jpg
IMG_20191021_214009.jpg (316.72 KiB) Viewed 656 times
Clive G3GJA

radiogareth
Posts: 585
Joined: Wed Jan 06, 2016 9:46 am

Re: GB3EY OFF AIR

Post by radiogareth » Tue Oct 22, 2019 8:00 am

Looks like CCS got it... Hard to improve the heatsinking but I have had sucess by soldering on a decent copper tab and heatsinking that. Hope its an easy fix.
Gareth

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