Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: Prev 1 [2] 3 4 Next   Go Down
  Print  
Author Topic: RM Italy FCC Approved  (Read 24452 times)
KD8MJR
Member

Posts: 5532




Ignore
« Reply #15 on: March 20, 2016, 06:12:46 PM »

Oh for crying out loud people..

It is a good bang for the buck , and if you do not know how to use one , you should not be in the market for one.

Good Lord

Bill that may be true but every ham operator makes a mistake and when it happens with something like the FL-7000 or the THP amps, it's not a problem.  With most RM Italy amps the first thing that happens is that the finals go up in smoke!


73
Rob


Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
K6AER
Member

Posts: 5689




Ignore
« Reply #16 on: March 20, 2016, 07:15:03 PM »

No they don't go up in smoke with a oppsey. I have had my HLA-300V transmit into a broken and shorted whips on the mobile with not ill effects. The finals have fuses on the board output board just like every HF transceiver in existence. What prevents output transistor failure is running the device within device ratings with some margin for excessive phase VSWR. I will keep it simple...if the devices are rated for 320 watts total reduce the output 15%. I might add this also applies to mobile transceivers as well.
Logged
KD8MJR
Member

Posts: 5532




Ignore
« Reply #17 on: March 20, 2016, 07:50:14 PM »

No they don't go up in smoke with a oppsey. I have had my HLA-300V transmit into a broken and shorted whips on the mobile with not ill effects. The finals have fuses on the board output board just like every HF transceiver in existence. What prevents output transistor failure is running the device within device ratings with some margin for excessive phase VSWR. I will keep it simple...if the devices are rated for 320 watts total reduce the output 15%. I might add this also applies to mobile transceivers as well.

Fuses on the output of the finals  Huh
BTW I am looking for the FCC certification, does anyone know the number?

73s
Rob
« Last Edit: March 20, 2016, 07:59:40 PM by KD8MJR » Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
JS6TMW
Member

Posts: 1255




Ignore
« Reply #18 on: March 21, 2016, 03:30:39 AM »

Right on. Amps do not blow out their finals - their operators do.

I think K6AER means that the DC line is fused.

I've run mine into some bad SWRs and I can hear the switching supply fan running up so I back off.

Steve

« Last Edit: March 21, 2016, 03:38:00 AM by JS6TMW » Logged
W1BR
Member

Posts: 4179




Ignore
« Reply #19 on: March 21, 2016, 10:11:24 AM »

Ten Tec rigs either used current fold back or magnetic breakers to protect their PA's.  Apparently excessively low Z loads results in too high collector current.

Pete
Logged
KD8MJR
Member

Posts: 5532




Ignore
« Reply #20 on: March 21, 2016, 10:41:40 AM »

Right on. Amps do not blow out their finals - their operators do.

I think K6AER means that the DC line is fused.

I've run mine into some bad SWRs and I can hear the switching supply fan running up so I back off.

Steve

Steve the DC or AC fuses on the PS end are there mainly to make sure your house does not burn down!  They will never blow fast enough to protect the finals.  Operators do blow most amps but sometimes it's bad cables or various antenna problems that do the damage.  A good solid state amp is just about bullet proof and will shut down in micro seconds.  For instance the last version of the THP 2.5kfx with its new board and software was tested by jamming a screw driver across the output while transmitting past USA legal limit.  The design was so good that the amp just tripped and when reset worked perfectly afterwards.

73s
Rob
« Last Edit: March 21, 2016, 02:26:53 PM by KD8MJR » Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
KD6VXI
Member

Posts: 177




Ignore
« Reply #21 on: March 21, 2016, 04:09:03 PM »

You seriously just compared RM Italy to THP?   Really?

I mean,  besides it being apples to buicks,  THP priced themselves out of the ham market (err,  hams became so cheap that RM Italy became viable 'options'......)

Both Messenger and Texas Star CB amps contemplated 5 band switched output filters.....   Guess they where just a few years before their time.

--Shane
KD6VXI
Logged
K6AER
Member

Posts: 5689




Ignore
« Reply #22 on: March 21, 2016, 06:31:38 PM »

“A good solid state amp is just about bullet proof and will shut down in micro seconds.  For instance the last version of the THP 2.5kfx with its new board and software was tested by jamming a screw driver across the output while transmitting past USA legal limit.  The design was so good that the amp just tripped and when reset worked perfectly afterwards.”

I have worked for some of the largest amplifier companies in the world. Amplifiers built to withstand direct shorts, opens at all phase angles with up to 1000 volts being applied to the output. These amplifiers cost the government about $30-60 per watt. In each case with the best design money can buy, the service department was always busy. It is the nature of the beast. As Shane had just mentioned, hams are cheap. Look at the amplifier reviews.

56 manufactures are listed but only 9 still are in business. Of those 9 Manufactures, 2, Icom and Yeasu make an amplifier that is over 15 years old in design. You constantly see folks who are starting in a new amplifier business but then they just fade away. The business model never gets off the ground.

The quickest way to obtain a small fortune in ham radio manufacturing is to start with a large fortune. I applaud RM Italy for stepping up the game but they will abandon the market if hams don’t buy the product.

The Mic Gain knob is still the greatest IMD device in ham radio
« Last Edit: March 21, 2016, 07:10:37 PM by K6AER » Logged
KD8MJR
Member

Posts: 5532




Ignore
« Reply #23 on: March 21, 2016, 06:49:35 PM »

You seriously just compared RM Italy to THP?   Really?

I mean,  besides it being apples to buicks,  THP priced themselves out of the ham market (err,  hams became so cheap that RM Italy became viable 'options'......)

Both Messenger and Texas Star CB amps contemplated 5 band switched output filters.....   Guess they where just a few years before their time.

--Shane
KD6VXI

My comparison of the 2.5kfx was just to show you what is possible. Keep in mind that THP made a few low end models that had 400-500W output and were pretty much bullet proof.
What worries me is the bad rap that solid state amplifiers often get from hams because they burnt out the finals and then are told you should have gotten a tube amp.  I will agree that for the price the 300V is a good deal, but you are getting what you paid for.

As for THP going out of business that had nothing to do with the amplifier division, it was the medical division that sucked up all the cash during a Down turn in business and sunk the whole company.  Anyway I just hope that people run these amps in a very carefull manor or they will be out some money.

73
Rob
Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
HB9PJT
Member

Posts: 413


WWW

Ignore
« Reply #24 on: March 21, 2016, 11:28:14 PM »

Where is this information from? I guess THP went out of business because the Expert PA's are much better and THP did not sell well anymore because everybody vent with the Expert. Expert PA's do have a tuner, automatic 4-port antenna switch and two fine transceiver interfaces where the THP PA's only have a manual 2 port antenna switch. At the end THP tried with an external AT.

73, Peter - HB9PJT


As for THP going out of business that had nothing to do with the amplifier division, it was the medical division that sucked up all the cash during a Down turn in business and sunk the whole company.  Anyway I just hope that people run these amps in a very carefull manor or they will be out some money.
Logged
KD8MJR
Member

Posts: 5532




Ignore
« Reply #25 on: March 22, 2016, 11:18:19 AM »

Where is this information from? I guess THP went out of business because the Expert PA's are much better and THP did not sell well anymore because everybody vent with the Expert. Expert PA's do have a tuner, automatic 4-port antenna switch and two fine transceiver interfaces where the THP PA's only have a manual 2 port antenna switch. At the end THP tried with an external AT.

73, Peter - HB9PJT


As for THP going out of business that had nothing to do with the amplifier division, it was the medical division that sucked up all the cash during a Down turn in business and sunk the whole company.  Anyway I just hope that people run these amps in a very carefull manor or they will be out some money.

The people who worked at THP were mostly ham operators and they told us what happened to the company.  You can visit www.thpamplifiers.com for more info.

THP always had an external tuner for the 2.5kfx it was called the HC-1.5AT and had 3 automatic output ports and was cable connected to that amplifier so it followed the radio.  This tuner was out long before Expert Amplifiers came on the scene.  Personally I prefer an amplifier without a built in tuner.  Mainly because for people with mono banders or low SWR it saves them cash and second is that if something goes wrong with an external tuner I still have a working amp.

As for the Expert PA's being better, LOL  Grin

73s
Rob
« Last Edit: March 22, 2016, 01:45:02 PM by KD8MJR » Logged

“A lie can travel half way around the world while the truth is putting on its shoes.”  (Mark Twain)
KW6LA
Member

Posts: 128




Ignore
« Reply #26 on: March 22, 2016, 04:32:02 PM »

<<  RM Italy amps are that they blow out the finals too easily >>

Rob-   I would have to assume you own one of these amp?  But my experience and others with the HLA 300 amp is quite different. It has a red light/ shutdown to protect it and works very well.
If you have not used many transistor amps, you will  blow finals by long key downs and improper cooling fans. RM Italy, does sell amps without fans and that can be trouble. Good
heat sinks and fans are a must at full power out. You must be aware of the VSWR too.  A  1.8 to 1 VSWR can be trouble at high power and high duty cycles like RTTY or AM
I always have my amp where I can put my hand on it and feel the temperature. YOU need to know how the throttle a amp like this on long transmissions. Next we need to get over
the IMD’s and harmonics, cuz they are not all that bad!!  As Mike said ( does anybody read his posts ) mic gain will and does cause IMD’s problems and no one seems to care. Instead—
we continue to bash a FCC certified amp. How crazy is that ?  
« Last Edit: March 22, 2016, 08:30:31 PM by KW6LA » Logged
ZENKI
Member

Posts: 1621




Ignore
« Reply #27 on: March 23, 2016, 04:46:14 AM »

Harmonic output content of a transceiver is governed by FCC regulations.  I dont know what dumb hams dont want to get about these laws. Its really simple if you want a clean
amplifier  or radio they must meet these regulations. Its not optional period. If you want to be a brain dead CB'er and use equipment  that dont meet these laws dont pass this off as good engineering practice or not as important its dumb! Who buys a amplifier or radio without harmonic filters? Only CB'ers.

 RMItaly has certification because  it meets these harmonic output regulations. It does not however mean that the RM Italy amplifier are clean. The RM Italy amplifier will fail FCC standards for IMD if it was commercial amplifier  or radio, at 250 watts of output. Since the ARRL  or RMITALY has not published a full set of IMD figures that shows all IMD products and those above the 9th order you cant draw any conclusions about its real world IMD performance.

 Blaming hams with the  knobs to the right  mentality for a poorly designed piece of CB  crap is really unacceptable. Its the engineers job to design the amp so that it cant be over driven and secondly have very good IMD performance.  All we get  on the many  forums is  excuses for companies who have incompetent  engineers who cant even design a clean amplifier or radio PA stage, really they incompetent if they cant do this  today.

Now hams and amplifier experts can brag as much as they want about their expertise, but when they have not designed a clean solid state HF amplifier or cant do so they really should  stop offering opinions on what is clean. Its really simple design a PA with very good IMD performance or show us a amplifier that they designed that meets ITU standards.
Non of the RMItaly Amps would meet ITU standards for the suppression of the higher order IMD products. So in this context they filthy.

Hams  telling hams that these RMItaly amps are clean when they clearly so not especially when they have no information on the IMD products above  the 9th order is deceptive. The ARRL is being very irresponsible and amateurish only reporting IMD products upto the 9th order and they expect sensible people to take their word that any amplifier or radio is clean. Its unprofessional presenting engineering data in such a half baked manner.

When RM Italy designs a 250 watt Amp with the following IMD figures I might change my opinion about them.
- 36pep or better for the 3rd and 5th order.
-41db PEP or better for the 7th and 9th order products.
Anything above the 11th order should be suppressed by 64 db or more.
When the FCC did have high standards this  would have been the requirement and this is what the  gold standard should be for HAM radios and amplifiers with some variation for power level.

Sad that even today regardless of the price of the radio or amplifier we cant even get close to these numbers. I wonder why commercial engineers could easily achieve these standard for marine and other commercial HF equipment  20 years ago?  All we have from ham manufacturers is  lame excuses. Like Elecraft who keep  telling customers  that their radios have acceptable IMD at 50 watts of output but not at full power. Why cant the K3 be designed to have acceptable IMD performance at  100 watts of output power?   What they really saying is that that the amp is marginal and  should really only be a 50 watt output amplifier not a 100 watt amplifier.Do we blame hams for knobs to the right  when using a radio with a crap PA or  amplifier  with crap IMD. No, we should not, they and other manufacturers should design equipment with proper specifications. Its that simple. The ridiculous prices we pay for amps like the SPE  and radios like IC7851 you would think you would get a clean transmitter. Really hams are being fooled with lame excuses on why radios and amplifiers cant be clean from a splatter or IMD perspective.





<<  RM Italy amps are that they blow out the finals too easily >>

Rob-   I would have to assume you own one of these amp?  But my experience and others with the HLA 300 amp is quite different. It has a red light/ shutdown to protect it and works very well.
If you have not used many transistor amps, you will  blow finals by long key downs and improper cooling fans. RM Italy, does sell amps without fans and that can be trouble. Good
heat sinks and fans are a must at full power out. You must be aware of the VSWR too.  A  1.8 to 1 VSWR can be trouble at high power and high duty cycles like RTTY or AM
I always have my amp where I can put my hand on it and feel the temperature. YOU need to know how the throttle a amp like this on long transmissions. Next we need to get over
the IMD’s and harmonics, cuz they are not all that bad!!  As Mike said ( does anybody read his posts ) mic gain will and does cause IMD’s problems and no one seems to care. Instead—
we continue to bash a FCC certified amp. How crazy is that ?  

Logged
JS6TMW
Member

Posts: 1255




Ignore
« Reply #28 on: March 23, 2016, 05:13:27 AM »

I don't work much SSB at all, and when I do the bands out here are rather uncrowded. I realize the situation in Europe and the US is very different, but just how much is IMD/"splatter"/high order products/harmonics a problem for you active SSBers? Just as a point of reference, roughly what percentage of QSOs get messed up by poor amplifier performance, as opposed to near-frequency QRM, receiver overload, commercial stations, radars, spurious emissions from near or far, or whatever else can louse up the airwaves?

I don't even object to all the crud on 10 meters coming from fishing boats, because that band is like the wide open prairies must have seemed to the pioneers going West.

Steve in Okinawa
Logged
G3RZP
Member

Posts: 1224




Ignore
« Reply #29 on: March 23, 2016, 08:27:06 AM »

It could be argued that the high order IMD from the majority of transceivers makes good high order IMD from an amplifier somewhat immaterial. Why so many transceivers are so bad when they come from the same manufacturers (Icom and Yaesu at least) that also make the much cleaner HF marine radios is a bit unclear - unless the marine radios are rather more under run, which seems a bit unlikely.

The average tube PA transceivers in the years 1973 - 83 had IMD products better than the average SS PA since 2000 by about 6dB for 3rd order, 3dB for 5th order, 11dB for 7th order and more than 14 dB for 9th order. Average IMD values for the years 2000 - 2013 were 3rd order at -30dB, 5th at -41dB, 7th at -47dB and 9th at -52dB (all relative to PEP).

Numbers derived from an analysis of 123 QST product reviews....

I did a lecture on this at the 2013 RSGB Convention....

Logged
Pages: Prev 1 [2] 3 4 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!