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Author Topic: 10 meter mobile amp  (Read 25843 times)

Posts: 5688

« Reply #15 on: November 18, 2012, 06:30:55 AM »

Wait a minute,

10 meters? 

Difference between 25 watts and 100 watts or 300 watts? 

I know some 10 meter hams, older fellows that got their license back when the 5WPM Technician Class was the thing and they never upgraded, mostly for reasons of CW speed, that have worked the world with 5 watts. 

When the band is open, it is open. 

When the band is not open, it is not open.

But there is also this meme going around these days that a compromised antenna somehow can be made to work better by simply throwing more RF power at it. 

Lots of hams don't seem to understand the "log 10" of the dB scale and what it is really trying to tell them. 

This OP would be better off, IMO, spending whatever amount of money that would be needed to obtain the "shoes" (amp) on two things:  A better 10 meter radio, for starters, as the one mentioned is not all that great really, -- and a better ANTENNA. 

I'd start with the antenna situation, which would likely improve use of the HR2600, but then would be looking to replace that "almost CB" with a good rig that not only would have the higher power level (100W?) but also would have a better receiver, much better selectivity, sensitivity, passband filtering, etc. 

A used Alinco DX70 or DX70TH, a used Icom 706 mkII, Yaesu makes an equivalent, etc. 

On top of being able to really work the 10 meter band, the other bands would be available at such time as you upgrade antennas to suit, or take the thing out of the mobile and also utilize it at fixed antenna sites with affordable wire antennas, etc. -- which don't always have to be at the home qth, could be temporary wire stringups at campsites, parks, etc. 

Used to know an old Elmer who worked the world with his beloved Collins KWM-2. 

The KWM-2 was a 70 watt radio. 


Posts: 1648

« Reply #16 on: November 21, 2012, 01:56:47 AM »

Yeah we all understand the reasoning. The problem is the idiots who dont understand what they are using. To them its just a  cheap amplifier.

The bottom line is that we need enforced commercial ITU mandated IMD standard forced onto the ham radio market because of the lack of technical ability of new hams.  You or I could fix the bias problem on a CB amp. The problem is that you have hams who dont know how to solder on a PL259 or even solder a simple audio patch cable. How can you expect them to even come to understand what IMD is or how to fix it. When you  dont have the brains to  know that your  illegal CB radio  sold for ham purposes  has a crap receiver and a equally poor transmitter, how can  you even expect these types of hams to be considerate to other users of the ham bands?

We just have to face the fact that many new hams are no smarter than the dumb blonde who uses a cell phone and will never ever have any technical understanding of the technology that they using. With this level of expertise  we need rules that govern what equipment they use and how they use it. Having mandated technical standards like the HF marine  and other radio services is the way to fix the problem of dumb hams. I never thought I would use the the words dumb and ham in the same sentence, but here we are today. If you need your evidence listen to the PT0S pileups, the IMD and crud is bordering on obscene and many of those signals come from CB amplifiers.

It does not matter how logical your arguments are,  these CB amps dont belong on the ham bands and new hams need to get this message. You cant negotiate your way through problem this with sensible arguments, you dealing with idiot end users who treats the ham radio hobby as his or her personal property to do as they see fit. Its just unfortunate that these dummies choose CB amplifiers and have no appreciation
 for the technical reasons  why doing what they doing is wrong and inconsiderate. Its wrong and inconsiderate, end of argument. No different to the ESSB users who are inconsiderate and selfish users of the ham bands for no real improvement  in science, its all about looking good and having a ego. If that  includes  taking out 15 khz of the band thats OK for these types of people. We live in a society  where individuals deem that their personal freedom is  more important than the greater community and if you dont like the smell tough luck, ham radio is no different.  CB amp users on the ham bands are IDIOTS, end of story.

quote author=ZENKI link=topic=86252.msg633814#msg633814 date=1353054675]
All really poor CB rubbish that does not belong on the ham bands.

Why any ham would want to use this CB garbage on the ham bands in the form of   splattering CB amplifiers and freeband CB radios with poor IMD suppression is beyond belief. There  are so many affordable genuine ham radios
available that perform much better and cost less. A second point is that the economics of buying a freeband radio and  crap CB amplifier dont add up when you can buy a proper 100 watt transceiver like the IC718 for much less money.
The operating ergonomics  is certainly superior. I guess you cant take the CB'er out of some hams. It seems many CB'ers who become hams dont want to give up their ignorant  ways and poor equipment.

Leave the CB junk up on the CB bands not on the ham bands.

 Hams who use this type equipment stand out like sore thumb on the ham bands because of the interference that they cause.  It seems many hams who use this equipment suffer from technical deficit disorder, it seems that there is no cure for this malaise.

You need to understand the purpose of each equipment first, then start calling it "junk" or otherwise. A transmitter made to run on mobile, on a monoband resonant antenna and with 10KHz spacing between channels won't be as clean in IMD and harmonics as a transmitter made for the ham bands, of course; that doesn't mean it's junk, just that it was made for another purpose, where it may do it's job very well. Also, the CB mobile amplifiers are running in class-C because they're made for FM, and certain designs can meet ERP harmonics requirements even without amplifier output filters; the equipment is not necessarily junk, it's designed for another purpose.

The person that uses such equipment in another way that it was intended to, well, that is the real problem. A "500W" CB amplifier usually uses a pair of transistors that can actually put out less than 300W in total, and to be SSB IMD compliant you need to modify it to class AB and run it at below 200W out. It's specs will stand up to any decent ham amplifier this way, but it makes no sense in getting such a thing as long as you already have reasonably priced ham transcievers out there that put out 100W.

@ Mark W8GU: from 25W to 100W you have a 6dB increase, that is a single S-unit at the recieving station. In my opinion it's not worth it to go trough the trouble for only that much; you would first need to go for the best antenna you can use, than start thinking about more power - and when you do, go for something around 300W, otherwise you won't even notice the improvement. Plus there is the problem of not overdriving the amplifier, usually amps have around 10-13dB gain (5-10W input > 100W output), if you want to drive a 100W amplifier with 25W you'll have to either add an attenuator (one that can handle 25W will get hot, needs a radiator, box and RX/TX switch of it's own, adds to the price) or turn down the transciever output power, wich may kill the amplifier by overdriving if you accidentally forget to turn it down everytime you switch the amp on, or the transciever may spike on TX (ouputs max power for a very short time even if power it's turned down).

Posts: 960

« Reply #17 on: November 21, 2012, 05:13:50 AM »

The Amateur license is a much easier license to obtain now. The numbers were dropping off from us older guys becoming SKs.....hi
It's really on the enforcement end of all this that makes those horrible splatter generators available on the market. The CBers have a field day building 5KW amplifiers and no one is there to stop the foolishness.
And the economy is a little tough and who, especially a new Ham, could resist buying some inexpensive CB stuff that will operate on the Ham bands? Same goes for the CB folks. They get Ham gear and use it on their bands. Modifying and 'opening up a radio' is not hard to do these days.
So it cannot really be a bunch of idiots out here. The dumbing down of the Amateur testing takes away all of the technical stuff that was required to EARN a license. It's time to be patient and educate our new Hams and let them see the light.

Posts: 5688

« Reply #18 on: November 21, 2012, 06:30:51 AM »

I'm not into "forced" ZENKI. 

Civil Liberties are being shoved down the drain at an alarming rate. 

The Ham Bands have survived despite 11 meters shenanigans, freebanders, pirates, bootleggers, even licensed Amateurs who suffer from various psychological issues and are bent on sharing them with the rest of the radio world. 

I believe that the better path is one of education, mentoring, elmering, etc. such that we have a situation where a free people can participate in a free society as intended by The Founders. 

There is a responsibility built into that kind of freedom. 

But being an American, I can also appreciate a certain amount of healthy rebellion as well. 

My joy doesn't depend upon whether or not there are spurious radiations being generated on a band. 


Posts: 1826

« Reply #19 on: November 21, 2012, 07:30:00 AM »

ZENKI:  ..transmitter made for the ham bands, of course; that doesn't mean it's junk, just that it was made for another purpose, where it may do it's job very well. Also, the CB mobile amplifiers are running in class-C because they're made for FM, and certain designs can meet ERP harmonics requirements even without amplifier output filters; the equipment is not necessarily junk, it's designed for another purpose.<<<

Maybe where you are CB is FM but here in the USA CB can be AM or SSB. neither of them will get through
a class C amp without significant distortion.  Enough distortion to annoy CBers!  Not slamming them
but ALL of the linear amps that are sold to CBers here in USA are illegal and are made/imported  to
black market so there are no possible controls on quality.

What I expect you meant is class B which can be higher IMD but still linear.   

However having played with a few 100W class "CB linears" what I've found are the older ones were class AB1 sweep tube grounded grid and even hams used them.  They were ok for IMD if not driven to saturation.  Examples of those were the BL/ML-100 and a few others.  There were also a few tube
amps made that carried the idea to extremes one having a pair of 6JS6 driving 8 more 6JS6s for
a KW DC input and dirty to the max along with horrific construction.  At the other side I did see one
that used a single 4CX250 (really!) with well regulated screen likely home brew nicely made 250W.

The later solid state amps were single ended and tended to be poor in both power and distortion
reflecting the devices used.  It was often a transistor designed for class C and run at minimal bias
(class B) for DC stability.  Generally they were poor or unstable. 

The later push-pull designs were straight out of amateur practice (or Granberg) and generally if
executed well were decent to good.  There were junkers out there though.  There are some I've
encountered that were the peak of stupidity and flat out insanely bad and had no purpose existing.
I've looked at a few I've seen at fleas and some were worth picking up and some were clearly
garage hacks of dubious value if even functional.  A few had such inadequate heat sinks for the
claimed power there was no possible salvage value in them.

I find it hard to use the large tar brush of "CB amps" and most I see in the last 10 years were
actually 80-10M ham amps with tuning changes.

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