An ice fishing box to house my ic-7000, an atu, a battery pack. Very crude but solid rack made of pine board I had laying around. This is cobbling of the best sort.
this post was submitted on 16 Sep 2023
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How much power does such a radio need? At what voltage (or just I and U)?
Ever since USB-C powerbanks with up to 20 V from PD are a thing, I use them for as much as possible.
Voltage is generally standardised to 13.8 V (don't ask me why).
I don't know what exact radio that is, but it looks like it can probably transmit at 50 W.
13.8v is the charging voltage of lead acid batteries. So it stuck.
That's a ic-7000 and it does 100w out on hf.
It looks like for FM it can go up to 100w.
https://www.dxengineering.com/parts/ico-ic-7000
Ah makes sense: alternator voltage of a car. I assume it works essentially just as well on 12 V, but USB PD, as of today, can not do 100 W or ~9 A at 12 V.
Amateur radios are generally spec'd at 13.8v plus or minus either 10% or 15% so that they work on a non-running car (12.something volts) or if an alternator is running a bit hot. A 100W radio like this is pretty much always going to require around 20amps at full power -but they have adjustable transmit power. They don't transmit as well at the lower voltage range, but most people don't worry about it.
How much RFI do those power banks spew out?
USB PD only goes up to 3A at 15V. That's not enough current to run a mobile radio.
A small LiFePO4 battery is a much better choice as it will supply a stable 12.8V without any switch mode supplies.
@AG7LR
@Eheran This is incorrect. USB PD does 20V 5A (100W) with the common 3.0 version. 3.1 increases that to 240W using higher voltages. https://www.usb.org/usb-charger-pd
Most radios won't run on 20V or higher. At 15V or lower, USB PD is limited to 3A.
If you wanted to get 100 watts, you would need a buck converter to step 20V down to 13.8V. Now you have two switch mode power supplies producing RFI.
I agree. Never measured the RFI since it usually replaces a cheap switchmode power supply from mains, so can only get better.