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Author Topic: Nice Amplifier  (Read 24190 times)
WD5GWY
Member

Posts: 393




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« Reply #15 on: May 26, 2013, 07:25:02 PM »

Just for curiosity , why would you be mindset it"spatters" with out looking at it or trying it? Is it just because someone said it was a "cb" amp? Its actually NOT a CB amp for sure with the BPF in it. I looked at it pretty close at work on the bench , its very clean compaired to my other amp.

They have a very well designed BPF in them , here is the schematic , VERY well designed

http://www.rmitaly.com/download/instructions/HLA300-instruction_rel_100.pdf
  I know that it's not sold as a CB Amp.  I was quoting another member,,,,who hasn't posted
here...........yet. But, that same person has provided proof that the HLA-300 from RM Italy
has a lot of problems with 3rd order and higher, IMD products, which produce splatter.
There have been a ton of posts regarding this amp and it's little brother, the HLA-150.
There are plenty on them in this forum. (Amplifiers)  On W8JI's website there is some test
data for the HLA-150. And, as long as the drive level is kept low,(for about 90 watts output) then IMD products are not too bad. The same for the HLA-300.......keep the drive level low, and IMD will not be so bad. But, as that other poster pointed out, not many hams will keep drive levels low
in order to reduce splatter. (IMD) And at 450Watts on the HLA-300, you are proving his point.
Look at the output from the amp on a spectrum scope and you'll see what I'm talking about.
Anyone listening to you "on frequency" will not notice any problems. But, those up and down the
band from your signal may very well do so. I have heard people using the HLA-300 on the air. On frequency, they seemed good. But, I could tune up and down from them and hear the splatter.
And when I have asked about output and drive levels, it's been the same. Full bore.......
   I agree that for the money, you get an amp that produces a lot of output, but, it is not a clean
amp by any stretch of the imagination.
  As another poster here mentioned, the Band Pass Filters are fine for out of band IMD products. But,they are next to useless for in band IMD products. Do some reading on IMD and what causes it and I think you will understand what I'm talking about.
In my first post, it was simply a bit of jest as the previous two posters were doing, because we all were pretty sure that Zenki would be along shortly with his opinion of the RM Italy HLA amps.
He hasn't posted as of now, but, don't be surprised when he does. And it will probably be pretty caustic too, as he is very strong in his opinions of the RM Italy amps.
james
WD5GWY
   
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G3RZP
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Posts: 4526




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« Reply #16 on: May 27, 2013, 04:52:36 AM »

Firstly, there are NO IMD or harmonic specs given. Being bipolar, it will have high order IMD products, especially when pushed to full output - the logarithmic transfer characteristic pretty well guarantees that, especially with the limited amount of NFB provided by the resistors from base to collector. As M0CHN says, the bias regulator doesn't look up to being man enough.

>They have a very well designed BPF in them , here is the schematic , VERY well designed<

No, they don't! Those are Low Pass Filters! Look at the filter responses. The attenuation of 2nd harmonic from the 160 and 80m filters isn't too good, either. OK for mobile with a resonant whip, I expect. All harmonics need to be -50dB for Europe, and they are most unlikely to meet that on 160 and 80 with those filters.

I see they are CE marked. So what standard did they use? The standard for commercially available amateur radio equipment is EN301 786 parts 1 and 2 and the corresponding EMC Standards EN 301 489-1 and -15. They do not cover equipment with a power over 160 watts, because there is no ISO standard for power measurement over that level. So to get CE marking, they will have needed to go to a Notified Body for an opinion. It would be interesting to see the opinion and the Technical Construction File. My suspicion is that most manufacturers in Europe don't bother, because the enforcement level on what is really a minor market is apparently non-existent. I know, on the other hand, that Alpha have gone to some trouble to make sure their amplifiers do fully meet the requirements.

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N4ATS
Member

Posts: 810




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« Reply #17 on: May 27, 2013, 05:24:24 AM »

"No, they don't! Those are Low Pass Filters!"

I stand corrected , you are right "low pass filters"

Either way , its nice to see other manufacturers of low cost amps try to come on board, they my not be up to the expert specifications and opinions but maybe that will drive them to change.

Cheers

 
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TANAKASAN
Member

Posts: 933




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« Reply #18 on: May 27, 2013, 05:35:34 AM »

Today I have decided to be diplomatic.

This unit would not be my first choice should I purchase a power amplifier for my shack. The case and heatsink may however be of use should I wish to construct something more suitable for the task.

Tanakasan
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N4ATS
Member

Posts: 810




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« Reply #19 on: May 27, 2013, 07:38:28 AM »

I agree , for the shack , low choice , but for a mobile application as it was designed for? I would take it over the high current sucking ALS-600M and day of the week.
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KE3WD
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Posts: 5689




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« Reply #20 on: May 27, 2013, 08:08:41 AM »

I think Ron White has something pertinent to say at this point: 

https://www.youtube.com/watch?v=fL6wbsGx9qw

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N4ATS
Member

Posts: 810




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« Reply #21 on: May 27, 2013, 09:04:59 AM »

Yes , he very funny for sure , got to love it...
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WD5GWY
Member

Posts: 393




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« Reply #22 on: May 27, 2013, 10:13:18 AM »

I agree , for the shack , low choice , but for a mobile application as it was designed for? I would take it over the high current sucking ALS-600M and day of the week.
I don't think the ALS-600 was designed for mobile use. Maybe, you are talking about
the 500M. That one is intended for mobile use. I have not used one, but, know a couple
of guys that do, and for the money, they are decent amplifiers. And the IMD specs are good
on them too. And, on the used market, they can be picked up in the $400-$500 range. And
a lot of times that includes the remote control head too.
  I have seen the HLA-300 at a couple of hamfests, (used) and have been tempted to buy one.
One even sold for under $300 at one hamfest. But, I have held off. I had been wanting an amp
for my Flex 1500, QRP rig. But, that radio has IMD issues (on 40 meters) that, at low output,
(5 Watts or less) do not create problems. But, using a higher powered amp with it, and one that
has known IMD problems, would only add to the problems and not correct them. So, instead of
buying an amp to go with the 1500, I have been saving for an SDR radio that runs 100 watts out
of the box.
   Good luck on your amp. If you keep the drive level low, you will still have reasonable output and
hopefully, not have issues with IMD.  I wish companies like RM Italy, would use better RF devices
and designs in their amps and have the guts to have them tested properly and post the results.
Of course, that would drive the cost of the amps up, putting them in the same price range as
the Ameritron ALS-500M and even the Tokyo High Power amps.
  james
WD5GWY
 
 
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WX7G
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Posts: 6024




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« Reply #23 on: May 27, 2013, 11:00:03 AM »

The amp should be able to run 300 watts PEP but not the advertised 550 watts PEP. I could use one for my KX3.

N4ATS, how much power do you run your amp at?
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N4ATS
Member

Posts: 810




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« Reply #24 on: May 27, 2013, 11:14:22 AM »

Sorry , I mean 500M... I am running this RM amp at 300 watts , seems to work really well , stays cool. As for the 500M , I had one but it was very power hungry so I took it out.

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WD5GWY
Member

Posts: 393




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« Reply #25 on: May 27, 2013, 12:01:56 PM »

Sorry , I mean 500M... I am running this RM amp at 300 watts , seems to work really well , stays cool. As for the 500M , I had one but it was very power hungry so I took it out.


What radio are you using it with mobile? Also, I have read that the HLA-300 is, (like the 500M)
very sensitive to SWR issues and will go into bypass mode easily. Do you find that to be true?
How much drive does it take for you to get 300 watts out on the HLA-300? Like WX7G stated,
it won't do the 550 Watts output on SSB, without driving pretty hard. But, then again, if driven
that hard, it too would be power hungry!
james
WD5GWY
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N4ATS
Member

Posts: 810




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« Reply #26 on: May 27, 2013, 12:26:06 PM »

I run an IC-7000 into a HQ (Comet) antenna. My setup is not permanent , its kind of a kluge if you will. I have a 2013 Camaro and do not want to hard mount anything right now but am playing with the concept of hard mounting soon. The power input to the RM is about 20 to 30 watts on SSB to give 300 to 350 out (10 dB) on an  Array Solutions power meter. The SWR on the comet HQ is darn near 1.1 to 1.5 as I had these antennas custom ordered from Mick at Comet.  Each band has its own antenna. If I want to switch bands , I change the antenna.

I just gave the amp to a friend of mine to see what he thinks , I doubt I am going to keep it , it was just a "want to try" period that I am going thru. I really love HF in the car , if you google me and look at "Images" you can see several of my cars with HF installed but this car I have now rejects the idea of a drill entering her body.


Cheers
« Last Edit: May 27, 2013, 12:34:59 PM by N4ATS » Logged
K6AER
Member

Posts: 3512




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« Reply #27 on: May 27, 2013, 12:44:49 PM »

I might as well wade into this mess.

The HLA-300V amplifier uses 4 ea.  SD 1446 transistors. They are good for 80 watts out at 12.5 VDC.  With higher Vcc voltage around 14.4 volts DC you can see as much as 345 watts out.  I use the amplifier in conjunction with my IC-7000. The transceiver runs a bit hot so reducing the power out to 20 watts makes the radio run cooler and the amplifier puts out a very clean 270 watts into 50 ohms. The amplifier is auto band switching and runs very well off of a 55 amp DPS power supply.

Over the weekend I connected the transceiver up to the 4 element SteppIR at 100 feet and played on 20 and 17 meters. All the while I was looking at the signal bandwidth on my Agilent 4402B spectrum analyzer. The signal was very clean. If I turned the drive up to 30 watts the power output went to almost 400 watts but the signal got wide and the second harmonic grew rapidly. Turning the power output back down to under 300 watts produced a very clean signal.

In each case I ask the ham on the other end to tune up and down the band to see if my signal was out of order.  I came up clean every time. Any amplifier can be overdriven. I have had Alphas, QRO’s, Palstar’s, ACOM’S and many others and in each case they, with improper drive, could be made to splatter.

It is not the amp but the operator who in the quest for the last watt overdrives the amplifier.  I might add that the transceivers can be overdriven as well and that is where most of the band splatter comes from.
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WD5GWY
Member

Posts: 393




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« Reply #28 on: May 27, 2013, 01:52:38 PM »

^^^^^ Well stated ! And using good test equipment helps a lot.
And I agree that ANY transceiver or amplifier can be over driven to
the point of causing splatter. A lot of problems on the bands can be
attributed to "pilot error". Wringing the last watt out of a radio or amp
does cause problems. For some reason, BIG Numbers on the S meter
seem to be more important than having a clean, intelligible, signal.
Pure power alone does not guarantee a good signal on the other end
of a QSO. Taking the time to do things right, seems to be lost on a lot
of people. It's not that hard and makes using the frequencies we have
available to us much nicer for everyone.
james
WD5GWY
 
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WX7G
Member

Posts: 6024




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« Reply #29 on: May 28, 2013, 04:25:19 AM »

Looking at the W8JI testing of the HLA-150 and it's seems it needs to be run at no more than 90 watts. And being that the HLA-300 is essentially two HLA-150 amps it seems it should be run at no more more than 180 watts. The 3rd order IMD renders it not the 550 watt amp it is claimed to be, and not even the 300 watt amp implied by it's name, it is a 180 watt amp for $340 (Amazon.com). That's $1.89 a watt. The Ameritron ALS-500 can be bought for $800 at DX Engineering. That's $1.60 a watt at 500 watts and $2.00 a watt at a more realistic 400 watts.

But having a KX3 I could use the gain of the HLA-300 while keeping the power down. How about on CW? I wonder if it can be run at 300 watts without producing objectionable key clicks?

http://www.w8ji.com/rm_hla-150_test.htm
« Last Edit: May 28, 2013, 04:49:16 AM by WX7G » Logged
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