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Author Topic: RM HLA 300 V Plus hf amplifier  (Read 49940 times)
K1ZJH
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Posts: 2911




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« Reply #30 on: March 22, 2012, 07:20:15 PM »

If they cared about IMD, it would be impossible to market FCC accepted Class C amplifiers.
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ZENKI
Member

Posts: 1249




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« Reply #31 on: March 23, 2012, 02:24:53 AM »

Poor CB bias circuits, wrong amplifier class and generally poor inherent  IMD performance also should be added to your list.

Lets face it CB amplifiers are the worst possible   solid designs available on the market and even suggesting that you can drive them cleanly is ludicrous. If all hams  were of your Caliber K6AER I would not be so worried, however when we have hams who dont even understand that using a class C amplifier is wrong on SSB we will soon have 10 meters sounding like the CB hand with 50khz  to 100khz of splatter as a norm.

Every  ham that i hear on the air that uses a RM italy amplifier splatters a lot, that anecdotal evidence suggests that its going to most hams problems.
.

The largest problem, “crudding the band”, are not reworked CB amplifiers. Half the hams on the air would not know where to start in connecting an amplifier.

Your on the air crud comes from;

•   To much mic. compression.

•   To high a mic. gain.

•   Over emphases low end audio response.

•   Excessive wide SSB transmissions.  (3KHz is plenty)

•   Overdriving the amplifier and expecting the ALC to remove the distortion.

•   Trying to get the last 5% out of the amplifier output.

•   Loading a 50 ohm amplifier output into ladder line.

•   RF into the audio because your G5RV is just above you in the attic.

•   Leaky coax connection (bad connectors) which were not a problem at 100 watts but now are at 1KW.

I will bet you dollars to donuts there are 10 more I forgot.

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ZENKI
Member

Posts: 1249




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« Reply #32 on: March 23, 2012, 02:32:09 AM »

Well Mike is wrong and using RM Italy CB amplifiers on the ham bands is recipe for disaster. The problem is that most hams and it seems some experience just  just dont get it.

Its amazing that we even have to have this debate, it clearly points to the poor technical understand of this issue. This is hardly a surprise, our hobby has lots most of its technical ability in RF science. It is then no surprise  that  we have CB'ers promoting crap CB equipment of poor technical standard on the ham bands.

Frankly there is no shortage of affordable decent amplifiers on the market, why go looking in the  technical garbage dumpster for CB products?

Hi,

1.  Mike is absolutely right on with his list.
2.  I am surprised it took ZENKI four days to post one of his name calling rants against RM Italy.

73,

John
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K6AER
Member

Posts: 3968




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« Reply #33 on: March 23, 2012, 06:02:30 PM »

You have 350,000 CBers who have passed ther ham license and now the ARRL sees gold. Only a small portion will buy an amplifier and even a smaller portion will take the time to understand the technical issues in using them.

I just wish they leave the CB lingo on 11 meters....roger that!

Quite franky RM Italy is the least of the band problems. It's Friday night and the WPX contest is in full swing. Not a single signal has better than 6 dB of dynamic range. Every one is distorted, over modulated except for 17 meters.

Looks like a good weekend for a motorcycle ride.
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KE3WD
Member

Posts: 5689




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« Reply #34 on: March 23, 2012, 08:39:17 PM »

Looks like a good weekend for a motorcycle ride.

Welcome to my world. 

When yer setup to go MotorcycleMobileCW, I'll be out there waitin' on ya. 


73
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KW6LA
Member

Posts: 106




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« Reply #35 on: March 23, 2012, 10:19:47 PM »

 <<  It's Friday night and the WPX contest is in full swing. Every one is distorted, over modulated except for 17 meters. >>

Mike-   Had to have a quick listen to WPX 20 meters and WOW can you screw up the quality of a SSB transceiver more ? Roll of at 500 on the low and 2K on the top.
Then compress it so you might as well be running AM. Under load the Amp with the Heil HC-4 mic and you have contest nirvana . Oh.. don’t forget to scream into the
microphone so they hear you better. Worry about CB amps killing the hobby?  Not any time soon and like you Mike, might be a good weekend to give it a rest.
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WB2WIK
Member

Posts: 21621




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« Reply #36 on: March 24, 2012, 05:28:11 PM »

Steve,

No IMD, its not on the FCC RADAR. They only care about out of band harmonics, case emissions and operation (positive gain) in the 26-28 MHz band.

Case emissions is strange. They must think we don't use antennas.

If that's the case, Andy Leimer at the FCC who wrote me the earlier correspondence must be all wet, as he stated they do measure IMD.  I wasn't sure about that, and now there's a disconnect.  I should probably ask somebody else at the FCC. Cheesy

Re the case emissions, that does seem weird but I think that wasn't intended to address in-band emissions.  Some amps do have microprocessors and stuff in them (in fact, any certificated amp to meet the 26-28 MHz lockout requirement would need to have a frequency counter in it, as I can't think of any other way to do that and still allow operation on 10m), and that stuff might have case emissions that are way out of band.

I don't like amp designs that are "too well" shielded, myself, they're just a PITA to service.  Even the SB-220 has way more internal shielding than makes sense.
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GM3SEK
Member

Posts: 80




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« Reply #37 on: March 25, 2012, 12:34:20 AM »


I don't like amp designs that are "too well" shielded, myself, they're just a PITA to service.  Even the SB-220 has way more internal shielding than makes sense.


To offer a contrary view, I hate 'open plan' amplifiers where everything - RF and non-RF components alike - is bathed in strong RF fields.

Yes, we all know it's amazing what you can get away with... but please don't call it good RF engineering.


73 from Ian GM3SEK



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OH7PS
Member

Posts: 22


WWW

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« Reply #38 on: April 14, 2012, 02:30:01 PM »

Hi

Nearly 10 years ago I had my first RM amp for 2m (2nd hand) - and at the same time the very last one.
It was oscillating and killed ft-897 finals.
Factory gave instructions how to fix it but I did not bother to do their job....

Maybe nowadays the quality is somewhat improved.

73 Ben

« Last Edit: April 14, 2012, 02:39:24 PM by OH7PS » Logged
G4KSG
Member

Posts: 9




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« Reply #39 on: August 19, 2016, 03:30:43 AM »

I've just bought a used 300V Plus and am very happy with it (except that it is too long). I drive it from a number of tcvrs through a 3 terminal solid state 6 db 100W attenuator. The 14.5V is from a cheap switched mode adjustable 50A supply.
So 50W from the tcvr (I don't like to push my tcvrs hence the decision to get an amp to help on 40m and 20m while the solar flux is depressed) is 12 W at the input to the amp and a whistle gets me 250W easy on my calibrated meter with a normal amount of ALC indication - just indicating. Haven't the faintest idea what PEP that would be but indications are that it must be around 350W ?? I use an old Lowe HF-150 rx with the antenna input shorted as a monitoring rx and my signal seems very good to me.
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JS6TMW
Member

Posts: 819




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« Reply #40 on: August 19, 2016, 06:03:25 AM »

Brave man for posting this here!

I use an RM too but CW only. Very happy with it.

Steve
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WY7CHY
Member

Posts: 340




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« Reply #41 on: August 19, 2016, 06:21:53 AM »

Contrary to what many may say, the HLA-300V is a pretty decent amp. If you treat it right, and feed it with about 20-25 watts, you'll get a good 300 watts out continuous. Using some pretty accurate PEP meters, I've measured peaks in SSB right at the 400 watt range. But you are correct, it's in the 350-400 range on actual ssb transmit. That's a good 6db gain of an amp.

And the amp has excellent protection built in. If it has too much power in or too high of an SWR it will alarm and stop output until you power cycle it. The fans do a great job of cooling it. I've got a number of amps, including another solid state, (AL-500); but I am very impressed with this amp. Of course, you'll have those that said they did all these super duper tests and they'll say it's bad IMD and other things. I've come to believe that some of the results are valid; some are biased to show results they want. Me personally, I think the amp is pretty decent. Especially for what it is and the cost. It's better than the newer FCC approved version HLA-305. And definitely cheaper.

The 305 is about $650-$700. If you know how to shop, you can find the 300V for around $450-$500. Many will say, for that kind of money, you can buy a better legitimate and proven amp. That's sort of true. You can buy a USED 500-800 watt amp for that kind of money. You won't find any new amp for this price, and if you want solid state, the closest in price would be an AL-500. And that's at the higher end. $650+. But the HLA-300v is also a lot smaller in many way. It's designed for mobile and can be mounted easily in a trunk. It's 100% automatic. It can also be used as a base amp.

Anyway; is it the greatest thing since sliced bread? Hell no. But it doesn't suck either. I picked one up new for $450. I saw one recently used, for about $350. For a reliable solid state, giving 300w continuous and 350-400w PEP SSB, that's a pretty decent deal for 6db.
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Born Wild - Raised Proud: 73
Cheyenne, Wyoming
G4KSG
Member

Posts: 9




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« Reply #42 on: August 21, 2016, 09:43:43 AM »

Yea brave that's me all over. Hams are humans so some suffer the same delusions of superiority. At my age I'm really a good at ignoring what I think are bad opinions. Any way 12W to 400W that's 15 dB isn't it?

Bob (66 years young licensed for 40 years)
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G4KSG
Member

Posts: 9




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« Reply #43 on: August 21, 2016, 09:46:27 AM »

By the way this forum has had over 56000 posts and over 49000 views - WOW
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ND6M
Member

Posts: 181




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« Reply #44 on: August 21, 2016, 10:39:04 AM »

By the way this forum has had over 56000 posts and over 49000 views - WOW

naw,.............  thats just "splatter" from adjacent posts Roll Eyes
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