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10 Meter Transverter Band limited for transmit:Please someone Help

Michael Boudreaux
 









I use my 2 Elad Duo SDR transceivers to drive my new 2 meter/ 70cm Transverter which operates on 28 through 31MHZ.  When I go beyond 29.99 I get Out of Band Message and Radio does not Transmit. I am in Australia and use these on Stand alone basis but would like it to work with software as well! how can I get my Radio to work with my Dual Band 2m 70cm Transverter and 28-31Mhz 10 Meters.  I am very disappointed my Elad Duo does not allow me to use my new equipment fully. Please Help! Mike VK3XZ VK4SY

Mark Stewart <spooter12@...>
 

You would need to wideband the radio

Neil Smith G4DBN
 

Hi Mark, the DUO already covers the necessary transmit frequencies using the 0dBm port, but some transverters have a weird setup where they need several watts dumped into an attenuator, and only take a few hundred microwatts into the mixer, wasting the rest as heat.  I guess this is a hangover from the 1980s when people had IC202s, and that carried on to the FT817, which also lacked a transverter output port.

Older trransverters which used to have a low level input to suit 1970s rigs then dropped out of production and we were left with this silly design, generating power and IMDs, then attenuatiung it and dumping several watts of heat into the case of a transverter. Crazy.

We are stuck with this pretty dreadful state of affairs with a lot of transverters.  I've modified all of my VHF/UHF/SHF transverters to work with a low level input, wither 0dBm from my DUOs or up to 10dBm from a G4DDK Anglian transverter fed at 28MHz from trhe 0dBm port.  My Kuhne 144 (14-17MHz IF) and 1296 (28-32MHz IF) transverters both have a low level input as standard.

It did feel a bit mad to invalidate the warranty on my brand new Kuhne 13cm G4 transverter by modifying the attenuator, but it was totally worth it.

Neil G4DBN

On 23/02/2020 03:10, Mark Stewart wrote:
You would need to wideband the radio
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>

Mark Stewart <spooter12@...>
 

To get entire 2 meter band, the rig needs transmit above 30 MHz. The ELAD needs widebanded to accomplish this 


On Sun, Feb 23, 2020, 12:15 PM Neil Smith G4DBN <neil@...> wrote:

Hi Mark, the DUO already covers the necessary transmit frequencies using the 0dBm port, but some transverters have a weird setup where they need several watts dumped into an attenuator, and only take a few hundred microwatts into the mixer, wasting the rest as heat.  I guess this is a hangover from the 1980s when people had IC202s, and that carried on to the FT817, which also lacked a transverter output port.

Older trransverters which used to have a low level input to suit 1970s rigs then dropped out of production and we were left with this silly design, generating power and IMDs, then attenuatiung it and dumping several watts of heat into the case of a transverter. Crazy.

We are stuck with this pretty dreadful state of affairs with a lot of transverters.  I've modified all of my VHF/UHF/SHF transverters to work with a low level input, wither 0dBm from my DUOs or up to 10dBm from a G4DDK Anglian transverter fed at 28MHz from trhe 0dBm port.  My Kuhne 144 (14-17MHz IF) and 1296 (28-32MHz IF) transverters both have a low level input as standard.

It did feel a bit mad to invalidate the warranty on my brand new Kuhne 13cm G4 transverter by modifying the attenuator, but it was totally worth it.

Neil G4DBN

On 23/02/2020 03:10, Mark Stewart wrote:
You would need to wideband the radio
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>

Neil Smith G4DBN
 

The rig will transmit anywhere from 1kHz up to about 50MHz out of the box.  The 0dBm port is already widebanded.  As I mentioned, I use up to 32MHz to feed my 23cm transverter, and 14 to 17MHz for my 2m transverter.  You just can't use the inefficient scheme of generating several watts then attenuating it.

Neil G4DBN

On 23/02/2020 17:17, Mark Stewart wrote:
To get entire 2 meter band, the rig needs transmit above 30 MHz. The ELAD needs widebanded to accomplish this 

On Sun, Feb 23, 2020, 12:15 PM Neil Smith G4DBN <neil@...> wrote:

Hi Mark, the DUO already covers the necessary transmit frequencies using the 0dBm port, but some transverters have a weird setup where they need several watts dumped into an attenuator, and only take a few hundred microwatts into the mixer, wasting the rest as heat.  I guess this is a hangover from the 1980s when people had IC202s, and that carried on to the FT817, which also lacked a transverter output port.

Older trransverters which used to have a low level input to suit 1970s rigs then dropped out of production and we were left with this silly design, generating power and IMDs, then attenuatiung it and dumping several watts of heat into the case of a transverter. Crazy.

We are stuck with this pretty dreadful state of affairs with a lot of transverters.  I've modified all of my VHF/UHF/SHF transverters to work with a low level input, wither 0dBm from my DUOs or up to 10dBm from a G4DDK Anglian transverter fed at 28MHz from trhe 0dBm port.  My Kuhne 144 (14-17MHz IF) and 1296 (28-32MHz IF) transverters both have a low level input as standard.

It did feel a bit mad to invalidate the warranty on my brand new Kuhne 13cm G4 transverter by modifying the attenuator, but it was totally worth it.

Neil G4DBN

On 23/02/2020 03:10, Mark Stewart wrote:
You would need to wideband the radio
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>

Mark EI3KD
 

Hi Neil,

 

In a scenario where the transverter drive power needs to be adjustable, say remotely – is there any way of doing that using the 0dbm output? Using the (up to) 5W output allows remote power control but is not ideal, as you infer.

 

Regards, Mark EI3KD

 

From: EladSDR@groups.io <EladSDR@groups.io> On Behalf Of Neil Smith G4DBN
Sent: 23 February 2020 18:49
To: EladSDR@groups.io
Subject: Re: [EladSDR] 10 Meter Transverter Band limited for transmit:Please someone Help

 

The rig will transmit anywhere from 1kHz up to about 50MHz out of the box.  The 0dBm port is already widebanded.  As I mentioned, I use up to 32MHz to feed my 23cm transverter, and 14 to 17MHz for my 2m transverter.  You just can't use the inefficient scheme of generating several watts then attenuating it.

Neil G4DBN

On 23/02/2020 17:17, Mark Stewart wrote:

To get entire 2 meter band, the rig needs transmit above 30 MHz. The ELAD needs widebanded to accomplish this 

 

On Sun, Feb 23, 2020, 12:15 PM Neil Smith G4DBN <neil@...> wrote:

Hi Mark, the DUO already covers the necessary transmit frequencies using the 0dBm port, but some transverters have a weird setup where they need several watts dumped into an attenuator, and only take a few hundred microwatts into the mixer, wasting the rest as heat.  I guess this is a hangover from the 1980s when people had IC202s, and that carried on to the FT817, which also lacked a transverter output port.

Older trransverters which used to have a low level input to suit 1970s rigs then dropped out of production and we were left with this silly design, generating power and IMDs, then attenuatiung it and dumping several watts of heat into the case of a transverter. Crazy.

We are stuck with this pretty dreadful state of affairs with a lot of transverters.  I've modified all of my VHF/UHF/SHF transverters to work with a low level input, wither 0dBm from my DUOs or up to 10dBm from a G4DDK Anglian transverter fed at 28MHz from trhe 0dBm port.  My Kuhne 144 (14-17MHz IF) and 1296 (28-32MHz IF) transverters both have a low level input as standard.

It did feel a bit mad to invalidate the warranty on my brand new Kuhne 13cm G4 transverter by modifying the attenuator, but it was totally worth it.

Neil G4DBN

On 23/02/2020 03:10, Mark Stewart wrote:

You would need to wideband the radio

-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>
-- 
Neil
<a href="http://g4dbn.uk/"><small>g4dbn.uk</small></a>

Chris Bartram
 
































Hello Mark


Although, between house refurbishment duties, I'm still working on my new system, one aspect of it which is pretty well defined is the RF interface between the DUO and my transverters. The transverters, and the interfaces for 70 and 144MHz - largely of my own design - are designed to work with a standard drive level of 0.5mW, and to be operated remotely from my desk.

The 0dBm output of the DUO is then enough drive a longish coax link to the either the outdoor boxes or across to the shelving on the other side of the room where most of my gear sits. The DUO output is then switched to the individual transverters by a switch matrix made using solid state RF switches. To control TX power, I then have a switched 1dB/step attenuator, also made using S/S switches.

The receiver path is pretty well the inverse of the TX path.

I hope that's some sort of help!

73

Chris G4DGU
















hello Mark

On 24/02/2020 09:07, Mark EI3KD wrote:

 

In a scenario where the transverter drive power needs to be adjustable, say remotely – is there any way of doing that using the 0dbm output? Using the (up to) 5W output allows remote power control but is not ideal, as you infer.



--
Chris Bartram G4DGU