Jim Thomson wrote:
> Date: Thu, 25 Mar 2010 07:30:45 -0700
> From: James Colville <jimw7ry@gmail.com>
> Subject: Re: [Amps] 'Good engineering'
>
>
> I'm sure glad I have a delete key. And a spam box.
>
> Oh... And by the way Jim (VE7RF).... The legal, moral, fair, and gentlemanly
> allowable power output here in the US is 1500 watts.
>
I'd agree with the legal aspect here in the US, BUT... when it comes to
the pileups, which is more fair, moral?, and gentlemanly? One quick
call with a strong clean signal followed by a 15 to 20 second exchange,
or stations trying to get the most out of lesser signals by turning up
the audio gain, compression, and running all the drive they have
available and calling repeatedly. Then when they finally do connect with
the DX, giving him their and their station's life history. Then there
are hundreds of 100 watt stations calling 4 or 5 times and often far
more than that.
So which is more far and gentlemanly, one quick call, or call, after
call, after call... OTOH it's at least 75% skill/timing.
Now I did mention the one station on 6-meters from the South West US
that is not only *loud* but broad as well. I don't know what he's
running and from his attitude I'm sure he thinks it's clean, but when
stations a mile or two from me running the legal limit are normal band
width, I don't think it's my receiver.
With my voice characteristics my signal does benefit from moderate
compression and actually sounds better than without BUT most of the time
I operate from my shop (toy house) which is quiet at times. OTOH when
the humidifier is running which is most of the time in cold weather and
the circulating fans, plus ceiling fans the compressor makes it sound
like I'm running one of those super amps with cooling running just short
of hurricane force. Then when the heater fires up it really gets loud.
The heater is one of those used in aircraft hangars. It's a 30' long
IR/tube heater. Then in the warmer weather it's the air conditioner. So
I have to remember to change the audio settings appropriate to conditions.
Me? I'm far more concerned with the band width and sound of the stations
than the power. My own station at present is just a barefoot 756 Pro
with some reasonably good antennas.
73
Roger (K8RI)
> 73
> Jim W7RY
>
> ## That's funny. The fellow at AES tells me the big slugs
> for the BIRD/CD line sections were literally flying off the
> shelves that week I ordered 5 x of em. [ mine were small to big]
> There was a big contest coming up apparently.
>
> ## legal limit here is 2250 w pep on ssb.... measured across a Z
> matched load. The load is the ANT. Allow for just .5db line loss
> [11%].. and now I gotta generate 2.5 kw... just to get 2250 w
> at the top of the tower ! Now if feedline loss is 1 db [21%],
> now I have to generate 2848 w pep... to get 2250 w pep to top
> of tower.
>
> ## Kinda tough for me to generate 2.5 kw.. much less 2848w
> from a 8877, without putting the IMD into garbage land.
> 2 x 8877's is just not cost effective..even Chinese 8877's.
>
> ## legal limit on AM is 800 W cxr. That's 3.2 kw pep.. with 100%
> pos modulation.. and 4 kw pep.. with 125% pos modulation....
> and 4.8 kw pep.. with 150% modulation.
>
> ## To get 4.8 kw pep to the top of the tower with just 1 db of
> feedline loss [21%] requires the amp to put out 4800/.79=6075 w pep.
>
> ## typ tank eff on the high bands is 50-60%, on a linear amp. That
> requires a lot of anode diss. Now if you want to dabble with quasi
> class A modes.. and superb imd... u need even more anode diss.
>
> ## What tube do you suggest I use ?? BTW... CTR surplus is selling
> YC-156's for $125.00 .. but you better hurry, he doesn't have many left.
> www.ctrsurplus.com [419] 683-3535. Arnold Howell, of Howell tube sales,
> has abt 26 x YC-156's left. [ youngstown, ohio] CTR is also in Ohio.
>
> ## what's moral, ethical, or gentlemanly to run 1.5 kw into 6 x yagi's on
> a big tower.. with an ERP of 8-15 kw ??? And then scream into the mic
> for 48 hrs straight, making thousands of useless qso's ??
>
> ## meanwhile, 2 kw into an inverted vee on a noisy 160/75m band,
> during summer months... is a... 'no-no' !
>
> Jim VE7RF
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