RCI-29 purchase update: Beware!!!

[Shadetree Mechanic]

The "Truck Stop Tunes" actually takes gain away from the radio, in exchange for watt's. The watts are useless without the gain.

Think of gain of watts the same as you would think of amps of AC volts.
What good is 120v AC with 0 (zero) amps?
What good is the voltage if no amps are present?

Stick two fingers in an 120v AC outlet that has 0 amps, you'll get a shock, but it won't kill you.
Now stick two fingers in that same 120v AC outlet and apply 3 amps to that 120v, it'll knock you across the room and could kill you.

Now, with that being stated, what good is 50w without the gain to back it up?

The gain is the goal when tuning a radio, we've learned a lot throughout the years. The gain comes from the sensitivity, the sensitivity comes from the alignment.

Yes, hacking, jacking, molesting these radios, and removing the limiters will result in higher watt meter readings, but at the cost of the gain.

The synthesizer oscillators, carrier oscillators, VCO voltage and buffer(s) all play a major role in the gain of a radio. No special "secret" tricks to it.

Just my 2 cents on the situation with truck stop tunes.

That is very interesting. I am fascinated by RF power and always thought that the gain produced the watts. But like you said, if there is no current, then nothing is happening. I am slowly getting equipment together to be able to do my own alignments, and learning as I go. I always enjoy your posts, and like to follow along to see what the fix is.
Thanks,
Chris

 

[loosecannon]

The "Truck Stop Tunes" actually takes gain away from the radio, in exchange for watt's. The watts are useless without the gain.

Think of gain of watts the same as you would think of amps of AC volts.
What good is 120v AC with 0 (zero) amps?
What good is the voltage if no amps are present?

Stick two fingers in an 120v AC outlet that has 0 amps, you'll get a shock, but it won't kill you.
Now stick two fingers in that same 120v AC outlet and apply 3 amps to that 120v, it'll knock you across the room and could kill you.

Now, with that being stated, what good is 50w without the gain to back it up?

The gain is the goal when tuning a radio, we've learned a lot throughout the years. The gain comes from the sensitivity, the sensitivity comes from the alignment.

Yes, hacking, jacking, molesting these radios, and removing the limiters will result in higher watt meter readings, but at the cost of the gain.

The synthesizer oscillators, carrier oscillators, VCO voltage and buffer(s) all play a major role in the gain of a radio. No special "secret" tricks to it.

Just my 2 cents on the situation with truck stop tunes.

boy Hawkeye you've got me here.
I can't figure out what you're trying to say.

especially the part about the AC outlet.

is there any way you can word that differently to help me understand?
you do understand that amps are pulled by the load and not pushed by the supply right?

and the "what good is 50 watts without the gain to back it up"?
im not sure what you're trying to state here.

i mean no offence, i just really don't understand.
LC

 

[FlatlandBusa]

The "Truck Stop Tunes" actually takes gain away from the radio, in exchange for watt's. The watts are useless without the gain.

Think of gain of watts the same as you would think of amps of AC volts.
What good is 120v AC with 0 (zero) amps?
What good is the voltage if no amps are present?

Stick two fingers in an 120v AC outlet that has 0 amps, you'll get a shock, but it won't kill you.
Now stick two fingers in that same 120v AC outlet and apply 3 amps to that 120v, it'll knock you across the room and could kill you.

Now, with that being stated, what good is 50w without the gain to back it up?

The gain is the goal when tuning a radio, we've learned a lot throughout the years. The gain comes from the sensitivity, the sensitivity comes from the alignment.

Yes, hacking, jacking, molesting these radios, and removing the limiters will result in higher watt meter readings, but at the cost of the gain.

The synthesizer oscillators, carrier oscillators, VCO voltage and buffer(s) all play a major role in the gain of a radio. No special "secret" tricks to it.

Just my 2 cents on the situation with truck stop tunes.

Watts= total energy. Volts = electrical pressure. Amps = electrical volume or flow. I'm not going to derail this thread so I won't reply from here forward to this thread. But, I will be happy to discuss this with you in another thread if you start one.

 

[nomadradio]

Watts= total energy

Nope. Power is measured in Watts. Power multiplied by seconds, or minutes or hours is "energy".

Think of the electric meter on your house. Watts is the snapshot of power just one moment. Watt-hours is energy over time.

73

 

[Shockwave]

The problem is the Ranger RT-5 finals. Biasing a switch mode MOSFET into the linear region for clean SSB use is somewhat tricky. They are instable enough to be very dependent on temperature compensation in the bias circuit. Sometimes the diode or thermistor used to sense the temperature, is not even properly mounted to the heat sink or transistor.

That eliminates the chances of ever getting one fixed bias level, to maintain the proper bias, when you're transmitting for different lengths of time. Bias in the first 10 seconds of transmission may be correct. 20 seconds later, it could be double and still rising, without effective thermal tracking.

I'd also be reluctant to give the same shop, 3 times to get it right. That's when you start demanding a refund. The short time it takes to burn up, strongly suggests thermal runaway on the RT-5 finals. What needs to be identified, is if drain / source current to the RT-5's is rising as the radio is keyed longer.

If it is, bias alignment is really just an unreliable Band-Aid cover-up. This places your technician in the awkward position of having to decide to keep the bias low enough so that it never creeps up into thermal runaway, sacrificing added distortion and reduced output. Setting it so the radio sounds clean, means long transmissions, especially with carrier, will enter a condition of destructive thermal runaway.

 

[Shockwave]

I've seen this problem before when I experimented with $1.27 TO-247 MOSFETS in a 170 volt line powered linear. The best thermal tracking could not respond fast enough to the temperature changes occurring inside the transistor die.

If thermal tracking is intact on the RT-5 finals for the RCI 69, this problem can still be corrected. When the electronic approach fails, try the hardware approach. By using as little as a 2 inch square, 1/4 inch thick copper spreader under the RT-5s, stubborn thermal runaway can be tamed.

 

[Hawkeye351]

Just me explaining more of what I was getting at.

Wattage is a unit of power, representing the rate at which energy is transferred or converted.

Gain is a measure of how much an amplifier or a device amplifies or boosts the input signal.

Many things in life have relationships to each other.

More examples:

What good is 700hp from an engine, if you don't have the torque to get that 700hp to the rear wheels? Would you get any use out of a 700hp engine without the torque?

What good is 13.8vdc on a CB radio without the amps to back up that 13.8vdc? Would a CB radio doing 150w work properly on a 13.8vdc source that has only 5 amps?

What good is 240vac if you don't have the amps to back it up? Would a central heat and air unit running off of 240vac work properly without the amps to back up that 240vac?

Same with CB radio, everything pertaining to HF/CB is related to gain. Again, what good is a truck stop 50w simple peak and tune without the gain to back up that 50w (ghost watts)?

Every radio I have went through, that had previously been to CB truck stop shops, now drive amps harder (some even getting more output than before on their amps) and reach farther. And that's with all the limiters intact with nothing more than a complete alignment, main focus being on the Buffer(s).

I had one guy call me a couple days after he got his 2547 back from me several months ago. He asked me "Hawkeye, how in the hell did you do this?". After he explained that the radio was doing 19w when he sent it to me, and now doing only 16w, he's getting 250w more out of his amp and the whole time when he is speaking, the power needle never drops like before, "How'd you do that Hawkeye with less output from the radio but more output from the amp?". I explained it exactly as I explained it above, what good is 19w without the gain to back it up. He's now a die hard Hawkeye client, lol... Bout every radio I go through ends up stronger than before, regardless of ending output results on a meter.

 

[loosecannon]

Just me explaining more of what I was getting at.

Wattage is a unit of power, representing the rate at which energy is transferred or converted.

Gain is a measure of how much an amplifier or a device amplifies or boosts the input signal.

Many things in life have relationships to each other.

More examples:

What good is 700hp from an engine, if you don't have the torque to get that 700hp to the rear wheels? Would you get any use out of a 700hp engine without the torque?

What good is 13.8vdc on a CB radio without the amps to back up that 13.8vdc? Would a CB radio doing 150w work properly on a 13.8vdc source that has only 5 amps?

What good is 240vac if you don't have the amps to back it up? Would a central heat and air unit running off of 240vac work properly without the amps to back up that 240vac?

Same with CB radio, everything pertaining to HF/CB is related to gain. Again, what good is a truck stop 50w simple peak and tune without the gain to back up that 50w (ghost watts)?

Every radio I have went through, that had previously been to CB truck stop shops, now drive amps harder (some even getting more output than before on their amps) and reach farther. And that's with all the limiters intact with nothing more than a complete alignment, main focus being on the Buffer(s).

I had one guy call me a couple days after he got his 2547 back from me several months ago. He asked me "Hawkeye, how in the hell did you do this?". After he explained that the radio was doing 19w when he sent it to me, and now doing only 16w, he's getting 250w more out of his amp and the whole time when he is speaking, the power needle never drops like before, "How'd you do that Hawkeye with less output from the radio but more output from the amp?". I explained it exactly as I explained it above, what good is 19w without the gain to back it up. He's now a die hard Hawkeye client, lol... Bout every radio I go through ends up stronger than before, regardless of ending output results on a meter.

Ok thank you i think i see what you mean now.

I would probably word it a bit differently, but the effect on performance is the same.

This is how i would explain it to that customer.

Your 2547 was showing 19 watts PEP on the wattmeter, but wattmeters are dumb and dont care what frequency those watts are on.
When the truckstop clipped that limiter, they did indeed make the radio do 19 watts, but not all of those watts were on the channel you meant to transmit on.

some of those watts were at 54mhz and above and were doing you no good as far as getting out further. all they are doing is heating up the radio and most likely causing an SWR mismatch with the input of any amplifier you connect.

when a real alignment was done on the radio and the limiter was replaced, the radio does 16 watts PEP but all of those watts are on the channel you are on so you're actually driving your amplifier correctly and getting the benefit of every last watt the radio can cleanly produce.

one great way to show those who disagree is to place a low pass filter between the radio and the wattmeter and watch the watts decrease.

thanks Hawkeye for taking the time to help me understand your point.
LC

 

[BC Coyote]

Your 2547 was showing 19 watts PEP on the wattmeter, but wattmeters are dumb and dont care what frequency those watts are on.
When the truckstop clipped that limiter, they did indeed make the radio do 19 watts, but not all of those watts were on the channel you meant to transmit on.

some of those watts were at 54mhz and above and were doing you no good as far as getting out further. all they are doing is heating up the radio and most likely causing an SWR mismatch with the input of any amplifier you connect.

when a real alignment was done on the radio and the limiter was replaced, the radio does 16 watts PEP but all of those watts are on the channel you are on so you're actually driving your amplifier correctly and getting the benefit of every last watt the radio can cleanly produce.

Well said loosecannon ! That is a very good explanation !