Last year there was an OM about 6 miles from me who regularly ran 250W
on PSK. In QSO after QSO, he was told he had RF feedback in his signal,
he he pointedly ignored it all, saying he had a clean signal and wasn't
overdriving, and it was all just poor receiver front ends. It
wasn't...the RF was a big problem, and his signal covered over 1KHz.
73,
Leigh/WA5ZNU
On Wed, 30 May 2007 4:51 pm, Brian A wrote:
> "There is no need to run 1000 watts" is just plain wrong.
>
> It depends upon what your're trying to do.
>
> If you're trying to make a QSO with a station half a world away under
> tough propogation conditions, it may indeed be necessary. 1000 watts
> may be the minimum power required to make the contact.
>
> PSK and other digital contacts are good for DXCC digital credit. For
> example, some people did indeed work one of the VU4 dxpedition
> stations half a world away using PSK. It did take them a lot of power.
> It was legit to do so. Contests are also legit. Ragchewing isn't the
> only activity digital modes can be used for.
>
> I agree if you're intent on only working easy paths than 20-50 watts
> is mostly OK. That's not what everybody wants to do. The only reg
> requirements are min power necessary a clean transmitted signal and no
> intentional interference.
>
> Also there is no relationship between transmitted power and
> distortion. A KW can be clean and 2 watts can be dirty. You can't
> tell from a waterfall that somebody is running too much power for a
> given path. A clean 2 watts from across the street can look pretty
> dirty if your RX can't handle the signal without RX overload.
>
> The expectation that one is going to sit there day in and day out with
> a wide RX filter and not be bothered by other stations is unrealistic.
> This is a shared frequency hobby.
>
> Putting the blame on the other guy and trying to "reform him" isn't
> the answer. The answer is to make YOUR station as bullet proof to
> intefering signals as possible. That means narrow filters will often
> be necessary. It means knowing how to use passband tuning, notches,
> AGC, RF gain control and whatever other technology you can throw at it.
>
> QRM is part of the hobby. Digital modes are not immune or exempt.
>
> Quit crying and accept reality.
>
> de K3KO
>
> --- In digitalradio@yahoogroups.com, "Lew" <[EMAIL PROTECTED]> wrote:
>>
>> I have been running PSK for severial years, I run around 20 - 25
> watts, with
>> the ALC just starting to move
>> My IMD report is around -32. and the fan runs very little
>> I have tried running 50 Watts and after a few min. the fan is
> running at
>> full speed and the radio is hot.
>>
>> CW or voice are 50% duty cycle (not always xmitting at power set
>> point)
>> PSK and other digital modes on the other hand always has a tone being
>> xmitted. ie 100% duty cycle.
>>
>> I have talked to stations with sidebands and they were running around
>> 100Watts
>> had them cut the power to 20 - 30 watts, the side bands were gone,
> their IMD
>> got much better
>> and I could still copy them with no problems.
>>
>> I run a TS-2000 to a dipole and as a rule if I can hear them I can
> contact
>> them.
>>
>> so much for high power with PSK or other digital modes
>>
>> just my 2 cents
>>
>> Lew N4HRA
>>
>> ----- Original Message -----
>> From: "Roger J. Buffington" <[EMAIL PROTECTED]>
>> To: <digitalradio@yahoogroups.com>
>> Sent: Wednesday, May 30, 2007 10:56
>> Subject: Re: [digitalradio] Here's a silly thought.
>>
>>
>> > Danny Douglas wrote:
>> >>
>> >> Absolutely spot on Erick. That is one reason that we try to tell
>> new
>> >> people, on the digital bands, to start with as few watts as they
> can.
>> >> There is just no reason to run 100 watts ( and I expect some run
>> >> more) on the PSK, etc. digital modes. Everytime I say that though,
>> >> someone jumps in the middle and says that a well adjusted signal,
>> >> blah blah blah, wont cause problems. Ive been told to get a
> receiver:
>> >> get a rig: get a filter, etc. I have all three thank you - but
>> that
>> >> doesnt mean that the person transmitting such signals is not
>> >> responisble to the amateur code and should not run the "minimum
> power
>> >> needed to make contacts". One can almost always tell who is
> exceeding
>> >> necessary power, just from the view on the waterfalls. When one
>> >> signal out of 20 appears 4 time brighter, and has traces above and
>> >> below their main signal for half the width of the waterfall,
> they are
>> >> exceeding power badly. Especially with PSK, many of us use
>> broadband
>> >> copy software, so we can see and copy every signal on the band
> at the
>> >> same time. With one of those signals, I see the same station
>> readout
>> >> on a dozen or more channels of that window. Often, they just
> wipe out
>> >> everyone else.
>> >
>> > There is never an excuse for running an unclean signal on PSK or any
>> > other mode, i.e. with sidebands, etc. In fact, this is a violation
>> of
>> > Part 97 and analogous regulations in other countries that require a
>> > signal to conform (more or less) to the state-of-the-art as regards
>> > purity.
>> >
>> > On the other hand, it is a myth that PSK only requires 20 or 30
>> watts
>> > for effective communication. This is no more true of PSK than it
> is of
>> > the ultimate digital mode, CW. The laws of physics control all,
>> and a
>> > signal using more power will *sometimes* get through when a signal
> using
>> > 20 or 30 watts will not get through. This can be the difference
> between
>> > a solid QSO and no QSO. There is a reason why most CW operators
> run 100
>> > watts or more. Nevertheless, some ops are operating under the
>> > misconception that PSK is "digital" and therefore the power level
>> does
>> > not matter. This is no more true of PSK than any other mode, such
> as CW.
>> >
>> > The real problem on PSK is that many operators do not know how to
>> use
>> > their narrow filters and IF width and shift controls to filter out
>> > strong adjacent signals. They plop their VFO on 14070 or so, and
>> tune
>> > their rigs with the software (essentially by "tuning" the soundcard
>> > frequency) with their IF wide open. Every strong signal on the band
>> > then pumps their AGC and they wonder why all the traces but one or
>> two
>> > are faint and unreadable. Sure you can operate this way, so long
> as you
>> > don't mind not being able to read many signals that a little
>> filtering
>> > would render quite readable. I am often surprised by the number of
>> > operators who have no understanding as to how to filter out QRM on
> PSK.
>> > Instead, some take the position that no one should have a strong
> signal
>> > at all. (One wonders, do those who argue this also believe that
> no one
>> > should run a high-gain antenna? Is everyone on PSK supposed to
> run only
>> > verticals or dipoles?). This argument is, I submit, absurd on its
>> > face. Here at the bottom of the sunspot cycle signals are often
> darned
>> > weak, and some power will make otherwise infeasible qsos possible.
> Most
>> > rigs, if properly tuned, will permit a clean PSK signal at 100
>> watts.
>> >
>> > I happen to have several neighbor hams who are frequently S9 + 20
> on my
>> > s-meter. I nevertheless have no difficulty working on the same
> band as
>> > they do, because I use my filters and IF controls accordingly.
>> >
>> > de Roger W6VZV
>> >
>> >
>> >
>> >
>> >
>> > Announce your digital presence via our Interactive Sked Page at
>> > http://www.obriensweb.com/drsked/drsked.php
>> >
>> > Yahoo! Groups Links
>> >
>> >
>> >
>> >
>>
>
>
>
> Announce your digital presence via our Interactive Sked Page at
> http://www.obriensweb.com/drsked/drsked.php
>
> Yahoo! Groups Links
>
>
>
