From mboxrd@z Thu Jan 1 00:00:00 1970 From: Harry Popov Subject: Re: struggling with gMFSK setup Date: Fri, 03 Nov 2006 20:48:48 +0200 Message-ID: <1162579729.4376.18.camel@ham> References: <20061103140739.06C951173@teufel.hartford-hwp.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20061103140739.06C951173@teufel.hartford-hwp.com> Sender: linux-hams-owner@vger.kernel.org List-Id: Content-Type: text/plain; charset="us-ascii" To: "H.Haines Brown" Cc: dplatt@radagast.org, linux-hams@vger.kernel.org Haines, > The FT-817 manual says nothing about limiting power for digital > modes. So apparently it's safe to run a full 5-watts, but based on > what you say about IMD, 2.5 would be a good idea. All said befor is corect in principe. Particularly for FT817 do not wory so much for IMD and thermal problems. Just have in mind the radio is prepared for FM chatters on VHF. If it is engeniered to survive 5W FM carier it should do on PSK too. I use FT817 for several years on digi modes HF and WSJT VHF. I worked DXCC on all bands except 80m with 5W and 20m LW just about 5 meters above ground. Here is how I adjust PSK31 level. I turn down audio from sound card. Go on TX and encrease gradually until I have full 5W. There is a point where more encrease of audio do not produce more power. That is so called "point of compression". You should always be just on it or strace down. IMD is good due to good ALC of transmit unit of FT817. Later if I need QRP down I just use FT817's own power levels without touching any more the audio level from sound card. At least I tune in this way. I never had splatter complains. And I have several neighbours just about 200 to 800m away from me. According mith that PSK31 does not need power. The explanation is only one. Majority of stations use between 10 and 30W and our 5W QRP is compeating very well with other stations. It should be the same on CW and almost the same on SSB if all used the minimum necessary power. You know reality is much different. Every one and his brother use QRO and that is only problem for QRP stations to compeat during pile ups. But not impossible!!! While using QRP one gain knoledge and one day take the pleasure when overshout all the QRO gung. That is real pleasure. Beleave me I had it many many times. Excuse my spare English. I think you got the point. 73, Harry LZ1BB