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Author Topic: Flex 1500 Amplifier Recommendations ?  (Read 32821 times)
K5HTB
Member

Posts: 4




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« Reply #45 on: January 05, 2013, 09:09:30 AM »

I notice that ZENKI does not post his call sign.  Perhaps he is not even a ham.

Travis
K5HTB

Well Flex cant design a clean transmitter how would they know what clean is?

Whoever was talking on  behalf Flex had no idea what he was speaking about!

THE FCC does not have a mandated requirement for IMD specifications.
Filters in amplifiers dont filter out inband  IMD, they filter harmonics. Harmonics in transmitters is hardly the issue these days albeit an important issue.

More stupidity, you start with a ham transceiver that has average  to poor IMD. You feed it into  solid state amplifier with worst IMD  performance than your transceiver. You turn   a good ham transceiver into splatter generator
and then you feed the whole mess into a AL811. Not good thinking batman! You really just building a  transmitter chain is a recipe for disaster. Whats wrong with driving a 811 with standard ham transceiver?

There seems to be serious case of Technical Deficit Disorder when it comes to the issue of CB amps on the ham bands.... Hams who pursue these practices just dont get it. Its plain ignorance I am sorry to say.




I almost hate to say this, but, I was at the last Belton, Tx hamfest and
I asked one of the Flexradio reps there, what amp he would suggest to
use with my 1500. He said the HLA-300 amp from RMItaly. I asked why
and he said that it is filtered pretty well, and driving it with only 5 watts
from the 1500 would keep it within FCC required IMD specs. He said the
HLA-150 would be OK, but, the 300 better.
  Still haven't tried to pick up an amp for it yet. Might try to get one of those
fire-sale 3000 or 5000's from all the people frothing at the mouth to get
the new 6000 instead!
  Besides all that, even at 5 watts, I do pretty well with the 1500 as it is.
I might even try driving my Ameritron 811H with it!
james
WD5GWY
 
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W3KC
Member

Posts: 22




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« Reply #46 on: January 06, 2013, 08:07:56 PM »

TenTec 405.

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ZENKI
Member

Posts: 906




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« Reply #47 on: February 09, 2013, 02:27:42 AM »

I just noticed the IMD figures in the QST review for the TT405 was above  average. Its good seeing  that the  IMD numbers for this amplifier is better than most transceivers.
TT should be congratulated for  releasing a amplifier that has better than normal IMD performance. Its a  change from the  rather  typical CB type performance we get from most other manufactured amplifiers and kits.

It hardly matters in this case since the IMD performance from the Flex1500 is so poor anyway and it will probably be the same for the Flex6000 radios. Some manufacturers just dont get it!

TenTec 405.


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KE2TR
Member

Posts: 130




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« Reply #48 on: February 11, 2013, 02:49:22 PM »

A big tetrode with lots of gain like those russian tubes would be a great HB amp for the little Flex.
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W4HIJ
Member

Posts: 367




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« Reply #49 on: February 11, 2013, 03:13:37 PM »

A big tetrode with lots of gain like those russian tubes would be a great HB amp for the little Flex.
5 in / 500 out Cheesy  Actually I like my little 50 watt amp but would like to do something solid state that would give me about 300 or 400 watts.
Michael, W4HIJ
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K6AER
Member

Posts: 3484




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« Reply #50 on: February 11, 2013, 03:58:24 PM »

I have a RM Italy HLA-300V. With 5 watts in it produces 250 watts PEP at 14.4 VDC. The two tone IMD is about 34dB with two exciters on 20 meters. Did not check it on other bands for that is good enough. Harmonics are better than 43 dB of the log power. Push it to 300 watts and the harmonics start to rise. The fan noise is a bit high while transmitting. About 70 dBa at 12 inches with a A weighted meter.
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N0YXB
Member

Posts: 303




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« Reply #51 on: February 12, 2013, 10:21:24 AM »

The link below is worth reading so that one has a more balanced view of RM's amplifiers.

http://www.w8ji.com/rm_hla-150_test.htm

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Vince
W4HIJ
Member

Posts: 367




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« Reply #52 on: February 12, 2013, 03:02:53 PM »

As I said, I like my little 50 watt amp which is actually the forerunner of the Hardrock 50. I'd like to someday have the Hardrock because you get more bands, it adds 160 and 6 meters plus it's got some microprocessor control. If I want to go higher power than that, then I'd look into some of the Communications Concepts designs. They have  start up stuff. They are by no means complete kits, but give you a nice jumping off point. I do not understand peoples reluctance to home brew or build kits these days. Solid state amps are relatively simple to build when it's all said and done.
Michael, W4HIJ
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ZENKI
Member

Posts: 906




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« Reply #53 on: February 19, 2013, 12:44:39 AM »

Its still CB junk that does not deserve a place on the ham bands. The IMD performance is horrendous and any ham who buys this kind of amp will drive it to the limit. This will happen because of these products appeal
to people with poor technical sensibilities.  Why would you buy a 300 watt amp and run it 100 watts of output when you could just use any normal decent ham radio amplifier or radio?. Its just plain dumb and just plays into the hands of these  marketers whose only objective is too pollute the ham bands with crud.

Besides what kind of ham are you when you use such a poor performing piece of equipment when there is just so much good equipment available?

The link below is worth reading so that one has a more balanced view of RM's amplifiers.

http://www.w8ji.com/rm_hla-150_test.htm


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ZENKI
Member

Posts: 906




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« Reply #54 on: February 19, 2013, 12:50:37 AM »

Some hams discuss this CB equipment as if  the only thing that comes out of these CB amplifiers are harmonics. Just because a CB junk amplifier has filters in it and meets harmonic specifications does not mean automatically
that it becomes a "linear amplifier" It could have harmonic filters and still generate crud and IMD why aint we concerned about that.  This is typically the CB attitude if we dont know about it its not a problem. Promoting this CB junk for use
on the ham bands  is really the wrong thing too do,  If there was a decent CB linear amplifier that was cleaned and properly designed I would use it as well, the problem is that all of them are really poor designs. Again it does not help when you have a equally poor radio like the Flex1500 driving a CB amplifier, the end result is a disaster for other users of the HF bands. How can you morally and technically find this acceptable. Splatter is not acceptable and neither is using equipment that contributes to making the problem worst.

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N0YXB
Member

Posts: 303




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« Reply #55 on: February 19, 2013, 09:16:11 AM »

Well said, thank you Zenki.  Although what you've said won't be popular with the "it's all about me" crowd.  You know, those who rationalize polluting the bands with junk amplifiers because they "got a good deal on eBay".
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Vince
AB2YC
Member

Posts: 53




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« Reply #56 on: February 21, 2013, 12:12:16 PM »

Add me to the Tokyo Hy-Power HL-45B list

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W4HIJ
Member

Posts: 367




Ignore
« Reply #57 on: February 21, 2013, 12:52:03 PM »

Its still CB junk that does not deserve a place on the ham bands. The IMD performance is horrendous and any ham who buys this kind of amp will drive it to the limit. This will happen because of these products appeal
to people with poor technical sensibilities.  Why would you buy a 300 watt amp and run it 100 watts of output when you could just use any normal decent ham radio amplifier or radio?. Its just plain dumb and just plays into the hands of these  marketers whose only objective is too pollute the ham bands with crud.

Besides what kind of ham are you when you use such a poor performing piece of equipment when there is just so much good equipment available?

The link below is worth reading so that one has a more balanced view of RM's amplifiers.

http://www.w8ji.com/rm_hla-150_test.htm


Zenki, if you are so intent on cleaning up the ham bands why don't you start with all the rude inconsiderate operators out there? Or the ones  who have amps that are capable of two to three times legal limit and, "clean" or not, are driven so hard that they splatter up and down the band. A quality amp does you no good if you don't know how to use it properly and appropriately and most hams don't. My amplifier is not "junk". I've seen the spectral traces of it published on the web by the author. If you want to continue your constant raving about " CB amplifiers" why don't you write the manufacturers?
Michael, W4HIJ
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K3GM
Member

Posts: 1767




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« Reply #58 on: February 27, 2013, 04:32:06 AM »

The ARRL lab measured 3rd order IM products on TX of -22dB on 40m @ full output (5W).  If you take the output of the 1500 and boost it 20 dB by running it into an amplifier, any amplifier, you will end up with spurs of several watts inside the operating band.  That example is assuming the amplifier doesn't introduce any IMD of its own, and if you can show me one of those, I'll buy it.  The laws of physics are irrefutable: Even order IMD products typically fall outside the band and can/could be filtered out by a following PA.  Odd order IMD products typically fall inside the operating band and thus cannot be filtered out by any PA.  So for me, the Flex 1500 remains an interesting QRP setup.  I've operated my firend's and I love it.  I'd buy one in a second.  But I already have two QRP transceivers, and no responsible amateur who knows and understands the facts would place any amplifier downstream of the 1500's output.
« Last Edit: February 27, 2013, 05:24:01 AM by K3GM » Logged
KE5JPP
Member

Posts: 0




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« Reply #59 on: February 27, 2013, 04:53:51 AM »

... and no responsible amateur who knows and understands the facts would place any amplifier downstream of the 1500's output.

There are a lot of appliance operator Hams (glorified CBers) that have no technical understanding of this and will connect their splatter box amps to the dirty output of the Flex-1500.  Just look at the number of idiots on eHam who are using these crappy amps with their Flex-1500s.  All they care about is cheap, they don't care how it affects other users of the bands.

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