1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice

Texas Star Linears on the amateur bands?

Discussion in 'General Ham Radio Discussion' started by TonyV225, Jul 22, 2009.

  1. TonyV225

    TonyV225 W9WDX Amateur Radio Club Member

    Joined:
    Apr 18, 2005
    Messages:
    5,824
    Likes Received:
    290
    Ok I have a good question here I was talking to a few guys on 75 meters that claim they had used Texas Stars on 75-80 meters and they said that they worked great. It was a long conversation and there were 2 guys that said they have indeed ran Texas star 500 and 667 on the band.

    I ask others about it and Im told its impossible but yet these other 2 fellas 1 with a 500 the other with a 667 had no issues and said again that it worked great mobile they just ran a tuner and all was good. Has anyone else heard of this?



    I researched both transistor types used in each the 500 and 667 and both show the frequency range would work but I was thinking that everything else was a bit off. Now I see these new amplifiers being made and sold on Ebay they take a high watt drive instead of the driver transistors being added the radio hf rig or high power radio does the work and I emailed the seller and he said they work a wide band spectrum heres what he replied (3.5 to 29 mhz) so now Im wondering and thinking maybe its possible.


    When we were talking about it there were a few other old timers that also jumped in and said they have done the same with the Texas Stars years ago anyone else ever tried this or tested it? These guys had no reason to lie about it but I look at it as some people may just be luckier than others and its a luck of the draw type thing.

    Without the band selector filtering Im sure it would be a splatter box but if this would work a person could a external filter selector type setup. Ill have to get on tonight again and get more info from these guys that have done it. Heres a link to these new amplifiers sold

    Palomar Elite 900HD Linear Amplifier RF Amp 900+ Watts - eBay (item 130320034454 end time Jul-23-09 18:49:36 PDT)
     

  2. SR385

    SR385 Active Member

    Joined:
    Mar 9, 2007
    Messages:
    794
    Likes Received:
    13
    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.
     
  3. Robb

    Robb Yup

    Joined:
    Dec 18, 2008
    Messages:
    10,821
    Likes Received:
    2,479
    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!
     
    #3 Robb, Jul 22, 2009
    Last edited: Jul 22, 2009
  4. TonyV225

    TonyV225 W9WDX Amateur Radio Club Member

    Joined:
    Apr 18, 2005
    Messages:
    5,824
    Likes Received:
    290
    I think it was RM Italy that makes a digital swr power frequency meter with the selectable filtering and thats what I was thinking when talking of an external filter system I didnt ask these guys on the radio about filtering I know they would be splatter boxes but with filtering it would make the difference.

    I have a few HF amplifiers but was messing around today and seen that this guy had emailed me a reply to the frequency range question I had and then I thought about the Texas Star conversation we had a few months back it wasnt the frequency that was listed above to clear that up aswell.

    I think someone else had also said that there was a guy years ago who was redoing the Texas Star amplifiers and adding the filtering and switch to get them on the other bands aswell.
     
  5. SR385

    SR385 Active Member

    Joined:
    Mar 9, 2007
    Messages:
    794
    Likes Received:
    13
    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.
     
    n8fgb and Captain Kilowatt like this.
  6. TonyV225

    TonyV225 W9WDX Amateur Radio Club Member

    Joined:
    Apr 18, 2005
    Messages:
    5,824
    Likes Received:
    290
    Thats the way I look at it aswell IT HAS TO BE DONE THAT WAY and I know its exspensive and more work but thats the price we pay for quality work or quality over the easily obtainable cheaper amplifiers for free band.

    We can all learn something from this topic and I dont want it to be a pi$$ing match ;)
     
  7. 190

    190 Active Member

    Joined:
    Jun 22, 2008
    Messages:
    181
    Likes Received:
    1
    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.
     
  8. Robb

    Robb Yup

    Joined:
    Dec 18, 2008
    Messages:
    10,821
    Likes Received:
    2,479
    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...
     
    #8 Robb, Jul 22, 2009
    Last edited: Jul 22, 2009
  9. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    856
    But the Ameritron also has remote band switching, SWR/fault protection, an input swamping circuit to help protect from over driving it, among other things. You have to add ALL the functions up to compare prices accurately.
     
    Captain Kilowatt likes this.
  10. Beetle

    Beetle Sr. Member

    Joined:
    Dec 7, 2005
    Messages:
    2,874
    Likes Received:
    730
    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.
     
    Bearcat and Captain Kilowatt like this.
  11. Captain Kilowatt

    Captain Kilowatt Professional Amateur
    Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    15,011
    Likes Received:
    6,598
    All I'm going to say about this is that a reading on a wattmeter and a signal report is not all it takes to make the statement "works good with no problems".
     
    Road Squawker likes this.
  12. TonyV225

    TonyV225 W9WDX Amateur Radio Club Member

    Joined:
    Apr 18, 2005
    Messages:
    5,824
    Likes Received:
    290
    I agree Q thats why I was asking out here if anyone else has experimented with this so I can get a little more detail. I think that sure it will key but whats actually happening as your keying? how good is it really doing what is the audio and signal width how much of the band is it chewing up? Interesting to say the least I am going to try and catch the guys that were talking about this out on the air and ask more questions.

    If I had the equipment Ide do the testing myself and show the results of whats happening with this type of amplifier on 75-80 meters. Sure anything will work but how efficiant is it working and for how long will it work is the question. I still would love to find someone thats ran a Palomar TX 5200 like mine with the filtering / band selector on the amateur bands aswell I know these along with the palomar 350Z tube type base amplifiers with the band selecting are also illegal or not FCC type accepted but do they actually work on the bands or is it just for show?
     
  13. linearone

    linearone King of NY

    Joined:
    Apr 2, 2005
    Messages:
    614
    Likes Received:
    5
    you show me a $4000 low pass filter, Id like to see it.
     
  14. Moleculo

    Moleculo Administrator
    Staff Member

    Joined:
    Apr 14, 2002
    Messages:
    8,831
    Likes Received:
    856

    You're kidding us, right? If not, you obviously haven't even looked at the specs of that Tokyo Hi-Power amp. This model is $3300:

    HF Linear Amplifier :: HL-1.5Kfx - 160m~6m

    People keep getting hung up on the cost of putting in selectable band-pass filtering (a simple 30MHz low pass filter is useless if you're going to use this on bands other than 10 meters) and aren't looking at what else is driving the cost of these units:

    It has:
    -1.5KW SSB output on 1.8Mhz - 28Mhz
    -650W SSB output on 50mhz
    -Built in power supply that works between 100v-250v, variable by the end user
    -Automatic band switching by sensing the RF voltage
    -Built in interface for most HF Mfgs.
    -Two antenna outputs that auto switch if the user defines which band to use for each outpu
    -Internal protection for everything possible: Over supply voltage, over drive, over heat, high SWR, wrong band selection, fuse blown, etc.
    -If you use the Tokyo Hi-Power tuner, it will also auto control that.

    In addition to the standard amplifier functions, how much do you think it will cost you to build all of that?
     
  15. dudmuck

    dudmuck Active Member

    Joined:
    May 21, 2007
    Messages:
    483
    Likes Received:
    4
    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.
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!