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I keep hearing about people puting in the "C" versions to get more power and they keep blowing them. The standards you can get away in most of the time just replacing the Toshibas but not with the C versions they are a totally different item.
You can get more power but they also take more drive
Only true at levels of S3 and above. Absolutely not true below...
Looks good on paper, but not in reality.
And if your friend is giving you S5, then he doesn't need to increase his output.
But,
If your friend is giving you S0~S1, then even doubling his output (+3dB) will increase his signal 1S unit or more.
Before you flame, test it on your own gear. Use your RF Gain or a SG to confirm.
Correct. The 2879C is totally different. It is NOT a drop in replacement. It has very different input and output impedances. Can't over volt and is rated at 150w out.
If any major amp builder would re-engineer their 2SC-2879 amps to use the HG 2879C with an AB bias (passive like Texas Star or active like Palomar), the radio world would beat a path to their door.
The HG 2879 D08 is the closest thing to a drop in replacement of the original Toshiba 2SC-2879.
I did extensive experiments on this with a friend about 15 miles away a few years back. The 1 S unit increase with 4X power was almost exact whether the original signal was S1, S5, or S9. Of course, above S9 everything is different because over that you are measuring dB instead of S units.......... This was all done using ham gear at both ends of the transmission circuit.
Not sure why it would be any different below S3 ? That certainly wasn't my experience, but as they say, your mileage may vary !
Anyways, I was more trying to make the point that double the power does not equal double the distance, which is a VERY common misconception, especially amongst newer CB'ers.
I remember one old timer. He'd key up and yell " 'Nother Watt, 'nother mile!"
73
73
(In the cleanest of ways) weather it's 100 watts and you would need 400 watts for another S Unit ................It would seem to me that more power is more power ? weather it's a quarter of a S unit or even 1/2 of a S unit more , might that little extra be helpful all the same ? You would think it would be . I heard someone say that 400 to 500 watts might be a sweet spot when it comes to power because then you would need 1600 to 2000 watts to get another S unit . (in the cleanest of ways) Like Nomads Kenwood 2 x Toshiba 2879s doing a nice smooth 100 watts peak for 30 years now ........that says a lot . Just cruising along . I need a Bird meter like I need a whole in my head ! Clean in and clean out , dirt in and dirt out ......waste not want not . Learning the truth can be a real kick in the ass at times but it all adds up to what works best and why. 40 years around this hobby and I'm damned lucky if I've even scratched the surface of it all. The needle and the damage done.
Shadetree Mechanic
Delaware Base Station 808
If your signal is in the mud, and flipping the switch only give you 1/2 S unit, but gets you out of the mud, then that's worth something. Right? To quote one of my locals, "If you got it, run it!".
But then people say that you should only run as much power as needed to make the contact. Ok, sure, I am trying to talk as far as I can.
But then people say that you should only run as much power as needed to make the contact. Ok, sure, I am trying to talk as far as I can.
You know what they say...One accurate measurement is worth a thousand expert opinions...
Here are accurate S meter measurements on 3 different radios that I had close at hand. I didn't have a long enough cable to get both the Sig Gen and the Radio S Meter in the same shot. Freq. = 27.205, AM mode, un-modulated carrier.
Cobra 200 GTL:
-98 dBm = S1 (S meter pic is fuzzy)
-95dBm = S2.5
3dBm = 1.5 S Unit
Cobra 148GTL:
-94.5 dBm = S2.9
-91.5 dBm = S4.8
3 dBm = 1.9 S Unit
Lincoln II+:
-112 dBm = S0
-111 dBm = S1
-110 dBm = S1
-109 dBm = S2
-108 dBm = S3
-111>-108 dBm = 3 dBm = 2 S units
I can do this all day...
For any S meter that has a single point calibration (S9), analog or digital, they will show these characteristics for low signal levels for two reasons.
1. The further you are from the calibration point, the more inaccurate the meter becomes.
2. The main reason for this behavior is the AGC. At low signal levels, it doesn't kick in. By S9 levels, the AGC is strongly clamped down.
For radios that have multiple calibration points for the S meter - some Qixiang built radios, maybe others - this isn't an issue.
Here are accurate S meter measurements on 3 different radios that I had close at hand. I didn't have a long enough cable to get both the Sig Gen and the Radio S Meter in the same shot. Freq. = 27.205, AM mode, un-modulated carrier.
Cobra 200 GTL:
-98 dBm = S1 (S meter pic is fuzzy)
-95dBm = S2.5
3dBm = 1.5 S Unit
Cobra 148GTL:
-94.5 dBm = S2.9
-91.5 dBm = S4.8
3 dBm = 1.9 S Unit
Lincoln II+:
-112 dBm = S0
-111 dBm = S1
-110 dBm = S1
-109 dBm = S2
-108 dBm = S3
-111>-108 dBm = 3 dBm = 2 S units
I can do this all day...
For any S meter that has a single point calibration (S9), analog or digital, they will show these characteristics for low signal levels for two reasons.
1. The further you are from the calibration point, the more inaccurate the meter becomes.
2. The main reason for this behavior is the AGC. At low signal levels, it doesn't kick in. By S9 levels, the AGC is strongly clamped down.
For radios that have multiple calibration points for the S meter - some Qixiang built radios, maybe others - this isn't an issue.
