10Ghz Demi question....


Tony Gallagher <tony_g_ireland@...>
 

This weekend we were setting up the other two 10Ghz kits and getting them ready for air.
However we encountered a very odd problem.
The units are Demi 10Ghz units to be used with FT290s using the DC voltage from the rig over the IF to key it.
The transverter will work and TX correctly when used with my FT817 which is modded to send 5VDC over the IF on TX, but it wont work with the FT290s!!!
The 5VDC on the IF is present from the FT290 radio when the radio transmits but when its connected to the Demi, the IF voltage drops from 5VDC to 1.2Volts, I assume this drop is causing the Demi to not switch to TX mode. Why is this happening?

Thanks in advance everyone.

Tony
EI4GHB


Tony Gallagher <tony_g_ireland@...>
 

Sorry, I should have mentioned, we tried two different FT290s, MK1 and a MK2 and also with two brand new transverters!!!! Makes things even more confusing! :)


Tony

--- In ukmicrowaves@..., "Tony Gallagher" <tony_g_ireland@...> wrote:

This weekend we were setting up the other two 10Ghz kits and getting them ready for air.
However we encountered a very odd problem.
The units are Demi 10Ghz units to be used with FT290s using the DC voltage from the rig over the IF to key it.
The transverter will work and TX correctly when used with my FT817 which is modded to send 5VDC over the IF on TX, but it wont work with the FT290s!!!
The 5VDC on the IF is present from the FT290 radio when the radio transmits but when its connected to the Demi, the IF voltage drops from 5VDC to 1.2Volts, I assume this drop is causing the Demi to not switch to TX mode. Why is this happening?

Thanks in advance everyone.

Tony
EI4GHB


Andy Talbot <andy.g4jnt@...>
 

Output resistance of the FT290 DC feed (what's the betting someone arbitrarily decided on a 10k R because its a nice value)   vs.  input resistance of the Demi ....................?

Andy  G4JNT
wobbleU cubed .g4jnt.kom


2009/6/7 Tony Gallagher <tony_g_ireland@...>



Sorry, I should have mentioned, we tried two different FT290s, MK1 and a MK2 and also with two brand new transverters!!!! Makes things even more confusing! :)

Tony

--- In ukmicrowaves@..., "Tony Gallagher" wrote:
>
> This weekend we were setting up the other two 10Ghz kits and getting them ready for air.
> However we encountered a very odd problem.
> The units are Demi 10Ghz units to be used with FT290s using the DC voltage from the rig over the IF to key it.
> The transverter will work and TX correctly when used with my FT817 which is modded to send 5VDC over the IF on TX, but it wont work with the FT290s!!!
> The 5VDC on the IF is present from the FT290 radio when the radio transmits but when its connected to the Demi, the IF voltage drops from 5VDC to 1.2Volts, I assume this drop is causing the Demi to not switch to TX mode. Why is this happening?
>
> Thanks in advance everyone.
>
> Tony
> EI4GHB
>



Geoff Blake <geoff@...>
 

On Sun, 7 Jun 2009, Tony Gallagher wrote:

Sorry, I should have mentioned, we tried two different FT290s, MK1 and a
MK2 and also with two brand new transverters!!!! Makes things even more
confusing! :)
To the best of my knowledge, the FT290RII does not have the +ve feed on TX
as standard - mine didn't. Sam G4DDK has the mod to add the +ve feed on
his web site.

That aside, it seems that the series resistor is to high, if it is
dropping the voltage to 1.2V. I used 8K2 to switch a DB6NT transverter
successfully.

Geoff


--
Geoff Blake G8GNZ located near Chelmsford, Essex, U.K.
Please reply to: geoff(at)palaemon(dot)demon(dot)co(dot)uk
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See <http://www.gnu.org/philosophy/no-word-attachments.html>
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