>Subject: Re: [AMPS] SB-220 IMPROVEMENTS
>Sent: 4/03/1997 5:08 AM
>Received: 4/03/1997 7:59 AM
>From: Robert, w5robert@blkbox.COM
>To: Rich Measures, measures@vc.net
>
>>
>> >Subject: Re: [AMPS] SB-220 IMPROVEMENTS
>> >Sent: 4/02/1997 8:18 PM
>> >Received: 4/03/1997 1:32 AM
>> >From: Robert, w5robert@blkbox.COM
>> >To: Rich Measures, measures@vc.net
>> >
>> >1. 10db = 10db (don't matter if your on 28mhz)
>> What matters is how many db you are above the noise to start with. If
>> the noise is S-1 and your signal is S-8, you are 7*6db= 42db above the
>> noise floor. Adding 10db is a waste of energy. However, if your signal
>> is 1db above the noise to start with, adding 10db is worthwhile,
>> methinks.
>>
>> IMO, not running more power than is necessary to communicate makes
>> sense--except perhaps on CB Channel 6. .
>>
>> R. L. Measures, 805-386-3734, AG6K
>>
>
>
>10db = 10db , even on 28mhz.....
>IF you are 100 db above the noise and I'm 101 db above the noise,
>the DX will pick my call out first. It is important.
...snip...
Is being stronger really all that important?
During the early 1980's, I participated in daytime open-door discussions
on 7258KHz about virtually anything that was interesting to more than one
person. When 913 died at Jonestown, we talked about religious cults. On
January 1, 1984, we talked about Orwell's *1984*. We talked about
Judith Exner's visits to the JFK Whitehouse. No subject was off-limits.
The rule was high speed VOX. Lock to talk broadcaster-guys need not
apply. Sometimes there would be a couple of dozen participants.
According to my mail and telephone calls, there was a large listening
audience. Things would sometimes get pretty lively. Two QST staffers
told me that people were sending 7258 tapes to Newington. Eventually, a
number of jammers were attracted to these discussions.
It seemed as though I was getting more than a fair share of the
jamming. I decided that the solution was to build a higher-gain
amplifier than my SB-220. A gain antenna was out of the question because
the group was spread in every direction. Building a tetrode amplifier
looked like a solution. However, this took a bit of doing since the
Handbook did not have much about tetrode design, and still doesn't. I
talked about such an amplifier with lots of people on the air. It turned
out to be an interesting construction project. Grounded-grid was ho-hum.
This was fun.
Several of the recognized amplifier experts on 40m told me that I didn't
need to neutralize if I used a 450 ohm grid termination. One of them
even had the calculations to prove it. I left out neutralization. It
oscillated. I retrofitted a neutralization circuit and the beast was
tamed. I measured1200v peak into 50 ohms on 40m. This was
cool--although inside the shack it most certainly wasn't. When jammers
buried my signal, I switched on the tetrode. One second later, I was
being heard However, the guy I was talking to was buried by the
jamming. The only way to continue was via telephone---with the VOX on
and the receive audio turned down to zero. Thus, even with ten layers of
jamming, the conversation continued as if the jammers were not even
present.--an arrangement that seemed to best boggle the sociapathic
jammer-mindset
Did the extra suds do me any good? Not really. I used the amplifier
to work 75m ssb longpath into Europe--but then I find out that I can't
take the QSLs with me. The project was pretty much futile. The only
possible benefit was that the project gave me a handle on tetrodes with
handles. ............... If you are interested in tetrodes, you can read
about them in *Amplifiers* at:
http://www.vcnet.com/measures
*Amplfiiers* comes with an unconditional double-your-money back
guarantee---and, as an added bonus, if you think that the author left
something out or made a technoblunder, YOU can tell him tell him about
the problem. .... Is the Internet cool or what?...........
By comparison, it took years and years to get the wrong pi-L tank
formulas removed from the Handbook. The 1995, 1996 and 1997 Handbooks
have a formula error on page 13.13 (discovered by Phil Clements). It's
going to be interesting to see how long it takes to get that one removed,
Phil.
R. L. Measures, 805-386-3734, AG6K
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