Texas Star Linears on the amateur bands?

If it was 3.810...I wouldn't follow tech advice learned there unless you did a lot of work on your own to find out why it was bad advice before following it ;-).

Those guys frequently run trash setups with CB amps and many have some of the dirtiest signals I've seen on the band.

I can see them there all the time as they are within my panadapter viewing width most of the time and it is really amusing/sad just how dirty their signals are.

No technically knowledgeable ham would ever tell you that it was o.k. to run those amps without extensive/expensive filtering modifications to them. I've looked into this quite a lot and there's a reason that proper mobile HF amps are so expensive.

I even started asking similar questions right here when I first got started so I'm no hypocrite, I just know better now.

 

Some of those guys making/selling Ham amps are robbing people without using a gun.
Tokyo HiPower, etc, etc..$4,000 for an amp?!?
Oh - puhleeeze!

The problem with these Palomar amps is - that they are usually getting too many volts to drive them - for one. The 2SC2879's are designed to run at 12v; but most go well beyound that. I'd like to see an experiment where the voltage sent to this amp was set to 12v, put a tuneable filter between the rig and the amp - and then another tuneable filter AFTER the amp. Because, one will NEED to find a way to get around the high cost of amplifiers - when one knows that the prcie of transistors are cheap!

Even Ameritrons are pricey - when one considers what their dollar is buying!

 

So you totally misunderstand all the controller circuitry they have in them and the cost of all the filter networks. Many people do.

Start adding up all the components to do that properly and you'll understand the cost too.

They are needed and that is why they are expensive.

If Ameritron isn't doing it cheaply, there is a reason.

 

Ive dialed back the power on my icom 706mk2g to 20 watts on ssb and ran it into my texas star dx500v and a vintage palomar magnum. worked pretty good. this was on a base setup. these are not ham amps by no means,but im not a ham and i dont go on the ham bands. this was done on 38lsb and surrounding areas. maybe one of these days when i grow up ill buy a ameritron. 4000$ tokyo high power mobile amp.??? no thanks.

 

OK; no pee contest...
Adding a multiple band adjustable filters to the Palomar A N D turning down the voltage feed - is both a bet and an experiment that I would like to see played out - honestly.

Since much of the harmonics and distortion are primarily a product of the output transistors being used beyond the voltage parameters of their design construction - running the RIGHT voltage would be a first step in the right direction. That alone should have a more desirably clean output - at least within reason. To ensure that any harmonics aren't going to be amplified, one needs to place a multi-band adjustable filter between the rig and the amp. Then - to ensure that any residual harmonics aren't going to exit the antenna, another multi-band adjustable filter is placed after the amp. With a o-scope and a harmonics analyzer, I would be most interested in seeing what happens to the output signal - once the filters on both sides of the amp are adjusted for effect.

The $400 price of the amp in question plus the price of two adjustable filters (~$250) is well below the price of a HiPower and still much cheaper than the Ameritron. It's just too bad that I don't have the money to spend to see what would happen. If it worked out as I imagine, one could conceivably sell more amps to Hams - and more people could find them affordable.
That is a bet - and a possible business plan...

 

AND....the filtering has to be done right. A lot of folks think just adding a Low Pass filter to the output is all that needs to be done. Wrong.

The filtering networkS -- one per band or band segment -- have to be of the bandPASS variety. Pass from 14.0 to 14.35 MHz and roll off sharply at the top AND bottom ends. And that's just for 20M.

I don't think I'd have much problem operating a TS on CW, although I'd use my spectrum analyzer very thoroughly to make sure all the power was where I wanted it to be.

 

you show me a $4000 low pass filter, Id like to see it.

 

yes. people dont understand that the tokyo amp is a base station amp. Its only fair to compare it with other ham base amps. But the solid state amp from them is no-tune, meaning its just key up and talk.

Also, about the texas star amps. People need to understand those amps are RF keyed, with a delay required for SSB. The ham amps are keyed by the radio, which is actually a much better way because as so as you unkey you are receiving. The ham amps also provide an output voltage to prevent the radio from over-driving the amplifier: it only kicks in when the radio puts out too much.

I vaguely recall a discussion with the designer of the ameritron solid state amps. It might have been W8JI, i cant remember. But he said the texas star bias circuit was unregulated. This means that as you drive the amp harder, the bias current reduces so eventually when you drive it hard enough, it would become class C, although at low power levels it would be class AB which is what you need for lower power levels at SSB. The texas star bias circuit doesnt even have a bypass capacitor to maintain the bias on audio peaks.

If you operate a texas star on 75 meters, you gotta consider the 3rd harmonic on the 12MHz area which is not in the ham bands. Because the amp would have as much gain on 12MHz as it does on 75meters.