OTA signal for rx test in NW Lancs ?

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G4WIM
Posts: 125
Joined: Thu Jan 29, 2015 8:36 pm

OTA signal for rx test in NW Lancs ?

Post by G4WIM » Sun Jul 30, 2017 10:13 am

Hi,

I've just finished building a RBW rx for 146.5MHz using the V2 Minitiouner rx combined with a BF981 preamp, 3 pole helical filter and PGA103 amp.

This gives a measured NF of 1.5dB and 28dB of gain.

The tuned input and helical filter results in BW's of 4.5MHz @ -3dB , 9.5MHz @ -20dB and 16MHz @ -40dB

Hopefully this will be adequate to keep interference out of the rx, but may reduce the total gain slightly as I suspect 28dB maybe excessive ?

Interestingly when applied to the Minitiouner the MER shoots up to 22dB from my Portsdown, but due to signal leakage from the portsdown I can't measure the rx sensitivity.

So I was wondering if there's anybody who can give me a signal for test purposes ?

FYI this rx will eventually be installed on at GB3FT with a broad 4 ele yagi beaming SSE or thereabouts and I plan on streaming GB3FT to BATC such that it should be possible to see your signal even if you'can't rx the 23cm signal directly.

73 Tim

G4EWJ
Posts: 652
Joined: Wed Feb 17, 2010 10:11 am

Re: OTA signal for rx test in NW Lancs ?

Post by G4EWJ » Mon Jul 31, 2017 4:34 pm

Are you around on Tuesday evening? I'm thinking of popping out to Rhosesmor to have a play in the 2m contests.

Brian

G4WIM
Posts: 125
Joined: Thu Jan 29, 2015 8:36 pm

Re: OTA signal for rx test in NW Lancs ?

Post by G4WIM » Mon Jul 31, 2017 4:47 pm

Hi Brian,

can probably be available - what time ?

BTW Just bought three SL30/12 comags off ebay for £15 and set them up for 24cms DATV, I plan to loan them out once GB3FT is on site to help activity.

Hope the 146.5MHz rx proves useful as well.

73 Tim

G4EWJ
Posts: 652
Joined: Wed Feb 17, 2010 10:11 am

Re: OTA signal for rx test in NW Lancs ?

Post by G4EWJ » Mon Jul 31, 2017 5:25 pm

Say 7:45 to 8:00? I'll be swapping the beam to horizontal about then.

Brian

G4WIM
Posts: 125
Joined: Thu Jan 29, 2015 8:36 pm

Re: OTA signal for rx test in NW Lancs ?

Post by G4WIM » Mon Jul 31, 2017 5:29 pm

ok.

I'll be listening on 144.750 vertical and have the RBW rx set to 146.5MHz on a horiz beam ready, What symbol rate ?

G4EWJ
Posts: 652
Joined: Wed Feb 17, 2010 10:11 am

Re: OTA signal for rx test in NW Lancs ?

Post by G4EWJ » Mon Jul 31, 2017 6:13 pm

SR333, FEC 3/4. See you then.

Brian

g0mjw
Posts: 523
Joined: Sat Sep 20, 2014 9:15 am

Re: OTA signal for rx test in NW Lancs ?

Post by g0mjw » Mon Jul 31, 2017 6:29 pm

I might be around at the weekend on Winter Hill but no path to the North.

Mike

G4WIM
Posts: 125
Joined: Thu Jan 29, 2015 8:36 pm

Re: OTA signal for rx test in NW Lancs ?

Post by G4WIM » Mon Jul 31, 2017 6:51 pm

Great - with a bit of Mikes help I've got the rx running as required ready for tomorrow evening.

As for Winterhill - I've got a good view of it out of the shack window, but sounds as though Mike will be on the 'wrong side' for me.

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