it is a matter of duty cycle,  on sub  it would be fine, but  on fm on both it would be too much., and my question is why would youw ant to transmit on both simultaneously. I have an astron 35 and it happily let me transmit  running 100w on fm on my ts2000 and 50 on my  2m mobile at the same time, but it got very arm after about 3 mins key down on both rigs. I of fuse transmitted into a dummy load on the 2000. I wouldn't recommend that for any length of time. Astron makes much larger supplies. Their 75 ao version has 4 pass transistors and two heat sinks if memory serves. It is a monster, but is a very nice supply.  That supply ran a ken wood ts 450, 50w packet rig, dual band mobile, 220 mobile and station accessories without breaking a sweat. transmissions not he packet station running a bbs and the hf or dual band mobile at the same time were common as you might imagine. while playing around in his shack I  keyed the mobile and the hf rig at the same time to mess with a cople friends, but  the supply was also a monster capable of 75 amps or more.  I do agree with the rule,  alway sbuy more than you think you will need. It is jus tike when i used to be int he freelance dj business. You can never have too much headroom.
On Aug 12, 2013, at 9:21 PM, Butch Bussen <[log in to unmask]> wrote:

> If both rigs are transmitting at the same time, a 20 amp wouldn't do it.
>  I tend to buy much larger than I need.  I don't know about switchers, 
> but standard supplies, such as the astron 35 although rated say 20 amps 
> continious gets very very warm.  I ran a kenwood commercial repeater at 
> 30 watts out, pulls around 12 ampss and that is of course key down as 
> long as the repeater is on, and the astron 35 ran warmer than I wanted, 
> so I put  a wrack mount supply I had out of a hundred watt commercial 
> machine.
> 73
> Butch
> WA0VJR
> Node 3148
> Wallace, ks.
> 
> 
> xOn Mon, 12 Aug 2013, Dr. Ronald E. Milliman wrote:
> 
>> Please double check my math...
>> 
>> If I am correct, a continuous 13.8 v. at 30 amp solid state, switching power
>> supply will handle both rigs, like a TS-590 and a TM V71A at the same time,
>> right? If I am correct, it looks like it could handle it with plenty left
>> over. Actually, a 20 amp supply could handle the load from my calculations.
>> 
>> Ron, K8HSY
>> 
>>