How much power on psk31 - Digital Forum at eHam.net

$\'\'$

$\'\'$

$\'\'$

eHam.net Forum : Digital : How much power on psk31

Forum Help

11-20 of 26 messages

Previous Page 2 of 3 Next

RE: How much power on psk31	Reply
by AA4PB on November 6, 2008	Mail this to a friend!
Providing that you have a clean signal (regardless of power) the only other issue is how strong your signal is at some receive location. Signal strength is related to propagation more than power or the antenna in most cases. If some guy up the band from you is receiving you at 20dB/S9 and is using a SSB filter to display the whole waterfall then you are likely to push his AGC up, decreasing his receiver sensitivity and perhaps causing him to loose copy of a much weaker station. This can happen when running only 5W if the propagation is right. The only solution is for him to be able to select a narrower IF filter in order to reduce your signal strength without reducing the strength of the signal he is trying to receive. You've got to remember that receiving a 31Hz wide signal with a 3KHz wide filter is like trying to receive a normal SSB voice signal with a filter that lets in the whole 20M band!

RE: How much power on psk31	Reply
by K5MBV on November 6, 2008	Mail this to a friend!
The previous post brings up an interesting question: Would it be worthwhile to either raise the frequency of the LPF and lower the frequency of the HPF or to use the CW filter when overloaded AGC is causing a problem? Ken

RE: How much power on psk31	Reply
by LB4VE on November 7, 2008	Mail this to a friend!
Yes, a narrow filter will attenuate strong stations affecting the AGC and hence sensitivity of your receiver. I regulary find myself supplementing with the IF-passband shift in order to get even better results. 73, Gary

RE: How much power on psk31	Reply
by AA4PB on November 7, 2008	Mail this to a friend!
Would it be worthwhile to either raise the frequency of the LPF and lower the frequency of the HPF or to use the CW filter when overloaded AGC is causing a problem? ------------------------------------------------------ Absolutly. Even a tunable notch filter placed over the offending signal will help. Anything you can do to reduce the strength of the offending signal without reducing the strength of the weak signal you are trying to receive. I use MixW and have a macro that can automatically center the signal I am listening to in the waterfall by tuning the radio via CI-V control and then select a 50Hz IF DSP filter. Suddenly everything on the band disappears from the receiver and the waterfall except the signal I am listening to.

RE: How much power on psk31	Reply
by G0GQK on November 10, 2008	Mail this to a friend!
Quite a number of replies. Originally it was suggested that 10 watts was quite sufficient but that was when the bands were in a better condition. I would suggest between 25 and 30 watts. Make certain that there is NO ALC showing, not any ! Also check that the processor, or compressor is off, the RIT is in neutral, in fact everything should be off and this will ensure you have a clean transmission. Kind regards, Mel G0GQK

RE: How much power on psk31	Reply
by WB8ROL on November 19, 2008	Mail this to a friend!
To have decent QSO's on PSK31 most of the time (ragchews) I would recomment 500w or higher OR a high gain antenna up 50ft or higher. Either that or use a mode that actually decodes better. If all you want to do is have quick QSO's and exchange barest info then 30w will do though you may have to repeat often.

RE: How much power on psk31	Reply
by G0GQK on November 25, 2008	Mail this to a friend!
Last week I read a moan on one of the ham group pages where this fella was using 200 watts of PSK 31 and still didn't get any response to his CQ's. Just imagine 200 watts, and when it was sent originally they used 10 watts ! G0GQK

RE: How much power on psk31	Reply
by N5YPJ on November 26, 2008	Mail this to a friend!
Mine still is sent with 10 - 25 watts, gee I can't imagine 200 watts. It is pretty amazing how well this mode works under poor band conditions. If conditions are too bad switch over to Olivia or Domino instead of QROing, those modes work very well even in poor conditions.

RE: How much power on psk31	Reply
by 5R8GQ on April 26, 2009	Mail this to a friend!
How much power to use on PSK-31? Like every other mode in ham radio, as little as needed to get the job done! I worked California to Australia using 3 watts on my end into a Butternut HF6V. That's 7,000 miles.Oh, and my transceiver was built from a $100 kit, SWL PSK-20.

RE: How much power on psk31	Reply
by G0GQK on April 27, 2009	Mail this to a friend!
When the mode was developed over ten years ago it was suggested that all that was required was about ten watts. It was the ultimate narrow band low power communication medium. Since then, as expected, people feel the need to use more power. Some months ago I saw that a US station was transmitting 200 watts of PSK. Unbelieveable ! Then two weeks ago I saw that a station in Portugal was using 500 watts. Outrageous ! Its all very well people answering questions with comments like 30% of maximum power and no ALC for a clean transmission, what people are completely forgetting is that excessive power, even with a good IMD wipes out the frequency. The screen goes black and stations are unable to continue with their contacts because contacts cannot be seen, they are wiped out ! There are lots of contacts in very close proximity so that using excessive power could, and will demolish dozens of PSK contacts. When QRP stations using CW can make contacts around the world using from 1-5 watts, and worldwide contacts using PSK can be made in good conditions using 20 watts those who are using excessive power are demonstrating their uncaring attitude towards fellow radio amateurs. G0GQK

Previous Page 2 of 3 Next

Next Topic: FT-847 on PSK-31?
Previous Topic: How to get digital audio out of IBM laptop t41

Email Subscription
You are not subscribed to this topic.

Check our help page for help using Forum, or send questions, comments, or suggestions to the Forum Manager.

$\'\'$