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I hate them The ones iv'e had have been unreliable, And then theres the noise from them, Weird whistling sound that sweeps through the HF Bands Gimme a BIG fat transformer any day of the week, Size of a couch ..oh yes
Anyhoo just having a wee super rant, Sure somebody will reply saying iv'e had mine for 20 yrs and not had a problem, Well mine are el - crapo, And those watson things are only good for propping the shack door open in warm weather
ch25 wrote: ↑20 Mar 2022, 12:48
I wouldn't trade my SPS to transformer type.
Do you have 3 or 2 wire electrical installation in house?
Three, Its got an adjustment to alter the frequency of the noise, But that just moves the noise up or down the band.
The one i have at the minute is a ''mydel'' Sometimes when you switch it on you get about 2 volts from it, You have to turn it off and back on to get the full 13.8v
Real 3 wire or neutral connected to earth in wall wart?
On the other hand, if SPS have noise offset knob it's crap.
Major HF radios manufacturers are manufacturing SPS and selling them with their radios, no noise issues.
Maybe just get quality SPS?
WE ARE MOTÖRHEAD, AND WE PLAY ROCK N' ROLL
You can't have too many antennas...
ch25 wrote: ↑20 Mar 2022, 12:56
Real 3 wire or neutral connected to earth in wall wart?
On the other hand, if SPS have noise offset knob it's crap.
Major HF radios manufacturers are manufacturing SPS and selling them with their radios, no noise issues.
Maybe just get quality SPS?
Real three wire earth system, I have a server PSU, I might dig that out one day and give it a try, Think it's 80 amps.
ch25 wrote: ↑20 Mar 2022, 12:56
Real 3 wire or neutral connected to earth in wall wart?
On the other hand, if SPS have noise offset knob it's crap.
Major HF radios manufacturers are manufacturing SPS and selling them with their radios, no noise issues.
Maybe just get quality SPS?
Real three wire earth system, I have a server PSU, I might dig that out one day and give it a try, Think it's 80 amps.
Definitely dig out your server supply Jason. Mine is excellent with respect to noise, so you shouldn't have any issues.
Auldgeek - Drew
Winner of IBTL Autumn 23 Edition I've changed radios so many times, I've forgotten what I have
It's on the to do list, I have a couple of those digital V/A Meters with shunts, But the last time i messed with it i could get a voltage reading but no current reading, And as far as i'm aware the PSU only puts out 12v and isn't adjustable,
Got the voltage up to 12.5 volts, There's no internal pot to adjust the voltage, Although there is a near identical model which does have a voltage adjustment pot,
Problem is the fan sounds like a harrier jump jet, The mod to lower the fan speed doesn't seem to work.
Fan Speed Control: A 5K to 10K ohm Fan Speed Control: A 5K to 10K ohm potentiometer connected across the 12V output with the
center wiper connected to pin B3 will allow control of the fan speed. .
It's difficult to evaluate users comments based on no model numbers nor his set up and configuration of smp.
But here's some rules about using smp with with radios that are tried and tested.
1. Smp do not like to be dc negative ground linked to earth a big no no
They are balanced outputs just like rf
You ground it it will go noisy dc rfi etc !!
That's been tested in controlled tests.
Ensure no ground loops via your mast or antenna.
I recommend using a pvc sleave to isolate mast earth to antenna
Mounting brackets.
Only use antennas once isolated from mast with proper ground radials to ensure antenna has a ground plane to work against.
Limiting common mode issues.
Ensure mast if metal earthed via a strap/copper stake for electrical safety always!!
Note masts are not to be used as ground planes or counterpoises a common mistake made and misplaced info in books!!!
Why common mode can happen too.
2.Use an high quality shield emi ac powerline filter ! Inline with the ac input to smp psu is a must.
3.Check your smps ac voltage on dc rails with a dvm,you should see less than 1V AC on both pos and neg dc terminals.
If you see 1-100V ac leakage ,your smp has poor capacitors filtering on it.
One resolve is use 680nF 1Kv 310AC capacitors on dc pos to frames earth ground ,and another capacitor from dc neg to earth frame ground,that should fix it.
Also use higher quality branded smp psu for radios ,if you don't its lucky dip time.
If you stick to those rules you should be fine.
Another problem I have seen is poor antenna installations
Mast height at 24-32mhz to low min I've found is 65ft from ground and use ground radials isolated from mast so least common mode affect.
Another is poor coaxial cables on base installations
I would only now recommend using double shielded coax with foil .
I've come across cases of induce rfi actually getting into the coax feeder externally from electronic sources close to Walsall of buildings.
Good luck in smp quests ,as original user posted
I now don't get these problems by following these guide lines rules with smp psu.
Part of the issues is lack of of updated information on subject and many books and Internet posts don't quite get it right by applying older knowledge bases on equipment and older linear technologies where you could get away with a lit of things unoticed.
The ones iv'e had have been unreliable, And then theres the noise from them, Weird whistling sound that sweeps through the HF Bands 
