habamp use as amp for a DTX1 ??

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

habamp use as amp for a DTX1 ??

Post by G4HTZ » Fri Oct 10, 2014 2:52 pm

just getting the bits together for 70cms DATV
bought a DG0VE converter and have a tetra amp on its way

on the TX side am considering the DTX1

I have a HABAMP which i was going to use as a preamp before I bought the DG0VE converter

would the HABAMP be suitable to use as a amplifier for the DTX1...it produces about 27dbm at 70cms followed by a filter...if so I could use this as a low level drive for the tetra amp
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

M0DTS
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Re: habamp use as amp for a DTX1 ??

Post by M0DTS » Sat Oct 11, 2014 7:13 pm

Hi Steve,

The HABAMP will give about 30mW from DTX1 if the gain figures are correct.
But the problem looks like the filter, it rolls off by about 5dB from 437-438MHz where we normally operate.

Rob

G4HTZ
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Re: habamp use as amp for a DTX1 ??

Post by G4HTZ » Sat Oct 11, 2014 8:11 pm

Ok rob
Thanks for info
Steve
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

2E0DTX
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Re: habamp use as amp for a DTX1 ??

Post by 2E0DTX » Sun Oct 12, 2014 10:33 am

Hi -

Why not take a look at the filter here http://www.dtx1.info/NewProducts.html

The DTXF-70 would be the one to look at.

73's

Laurence 2E0DTX

G4HTZ
Posts: 254
Joined: Sat Aug 02, 2014 4:21 pm

Re: habamp use as amp for a DTX1 ??

Post by G4HTZ » Sun Oct 12, 2014 6:02 pm

Need to get power up from the -5dbm to a few watts ...will need a amp of some kind to take the low level
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

g4wvu
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Joined: Sat Jun 22, 2013 10:42 am

Re: habamp use as amp for a DTX1 ??

Post by g4wvu » Mon Oct 13, 2014 7:35 am

IIRC the Nokia Tetra amplifier lumps can be driven from as low as -15dBm if you include all the drive stages - don't have details to hand but will look out shortly.

g4wvu
Posts: 52
Joined: Sat Jun 22, 2013 10:42 am

Re: habamp use as amp for a DTX1 ??

Post by g4wvu » Mon Oct 13, 2014 9:09 am

On Robs site some details specifically low level drive

http://www.m0dts.co.uk/?tag=432MHz&item=68

G4HTZ
Posts: 254
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Re: habamp use as amp for a DTX1 ??

Post by G4HTZ » Mon Oct 13, 2014 1:42 pm

Yes will have to investigate that mod further
Cheers
Steve
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

g4wvu
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Joined: Sat Jun 22, 2013 10:42 am

Re: habamp use as amp for a DTX1 ??

Post by g4wvu » Tue Oct 14, 2014 7:32 am

Good luck - I will be doing similar when I get around to modifying the Nokia lump I have here. I will look to about 0dBm level as I have a MMIC drive amp in my DTX1 to raise it to a comparable level as an SR Systems TX (max about +6)
I will leave high bias level on the amp as original I think (linearity)

73s

Mark

G4HTZ
Posts: 254
Joined: Sat Aug 02, 2014 4:21 pm

Re: habamp use as amp for a DTX1 ??

Post by G4HTZ » Tue Oct 14, 2014 4:11 pm

Ok mark
May be possible to work you on 70cms atv some time
Often get gb3lo and TN down here on 24cms with a slight lift
Good luck with tha amp ...still waiting for mine to arrive
Regards
Steve
Steve G4HTZ

ASHEN nr Sudbury JO02GB52 90m ASL

PORTSDOWN and a RYDE …

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