Power supply requirements

VK4BXI
Posts: 62
Joined: Sat May 22, 2021 11:44 am
Location: Brisbane

Power supply requirements

Postby VK4BXI » Sat May 22, 2021 9:07 pm

Hi I’m new user waiting for his radio. In preparation I want to have a battery powered ( big li-ion) supply ready for use. User spec gives 13.8 volts +-5%. But please for receiving what is the drop out / over voltage range ? Reason is that I want to use a 4S battery pack that will float at 16.8 volts with forward biased power diodes to drop the voltage to 13.8 volts on transmit but will float the volts up a bit higher on receive. Using Li-ion batteries doesn’t match up well with 13.8 volt supplies, but it’s what I have handy.

Regards Bob
VK4BXI
Posts: 62
Joined: Sat May 22, 2021 11:44 am
Location: Brisbane

Re: Power supply requirements

Postby VK4BXI » Wed Aug 04, 2021 10:05 am

Hi all,
I’ve managed to get a PSU sorted for my 7000 II to be. However it has its negative supply tied to the case and also to the earth of the supply cord. I have no problems with “floating” the earth and was intending to use the station ground to earth the case to……..but I’m not sure how the negative of the 13.8 volts supply is connected internally inside the rig ? is it solidly connected to the RF ground ? or via an RF choke or something like that. I don’t want bypass something important in this fashion. I’ve just had a burnt firewire cable ground core from my flex 5000A when the negative lead of the rig connector became less than perfect and the transmit current returned via the firewire connection to the grounded chassis of the computer. Is there any information to make this sort of issue clear ?

Regards Bob
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w-u-2-o
Posts: 5525
Joined: Fri Mar 10, 2017 1:47 pm

Re: Power supply requirements

Postby w-u-2-o » Thu Aug 05, 2021 3:44 pm

The grounds are connected internally.

There is no safe way to "float" the ground to prevent the sort of damage a bad negative lead to the power supply can achieve.

Instead you want to have a proper station grounding and bonding system in order to help prevent such occurrences. Make sure that all equipment, including computers, has a separate, dedicated ground lead attached and connected to a singe point in the station.

These work great: https://www.amazon.com/Siemens-EC2GB152 ... B007ZZGSQI

6AWG bare or insulated copper stranded cable works well for ground wires. I like to use 6AWG welding cable because it is very flexible.

Mechanical lugs work great at the equipment end: https://www.amazon.com/14-4-Aluminum-Me ... B00NVDE0Z4

Finally, applying 16.8VDC to your ANAN will likely damage it. Strongly not recommended.
VK4BXI
Posts: 62
Joined: Sat May 22, 2021 11:44 am
Location: Brisbane

Re: Power supply requirements

Postby VK4BXI » Fri Aug 06, 2021 12:09 am

Thanks very much for the reply.
for the record I am a semi retired electrical engineer and have been an active radio amateur for almost 40 years. I do subscribe to the bond everything together philosophy and use 2 inch wide copper foil for the purpose. I am still waiting on the factory for my radio (The state of Victoria at this point has just gone back into lock down) , but I think perhaps the best thing to do at this point is to privately request a set of drawings from them and do my puzzling from there.

Regards Bob

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