Subj : Re: QRP To : Angus Mcleod From : Spaceman Spiff Date : Sat Dec 11 2004 07:08 pm Re: Re: QRP By: Angus Mcleod to Spaceman Spiff on Sat Dec 11 2004 08:14 am > Re: Re: QRP > By: Spaceman Spiff to K0neo on Fri Dec 10 2004 21:04:00 > > > Ah an think if you can go with larger diameter coax and shorter feed line > > the antenna, if you could get that extra 3 dB back it would be like 1600 > > :) It really makes sense. > > Rig of the Future > ================= > > The next generation rig will be in two pieces, like a split-system air > conditioner. The first of these will be a control head. It will include > all the display and control hardware. Frequency readout, S-meter, > whatever else is needed, along with VFO dial, band-switches, filter on\off > controls, etc. It will also have jacks for inputs and outputs like mic., > key, TNC, and so forth. This unit will be small and lightweight. It will > communicate with the second part of the rig via a fibre-optic link-cable > which can be any length required. > > The second part of the rig will be a sealed, hardened, RF-proof, water- > proof unit. It will be designed for remote mounting, in the attic, or on > the tower itself. It will have connections for input power, the fibre- > optic link-cable, and coax output. It's shape and design will allow it to > fit to a standard rotor-mounting bracket. It will also be possible with > an adapter plate to be mounted on a tubular mast. The design will allow > units to be stacked and bolted together with optional hardware and other > accessories. > > Optional hardware and accessories will include > > * DC power supply to drive the rig and all other accessories > * Linear amplifiers of varying output power > * ATU or RTU (remote tuning unit controlled manually via the > fibre-optic link-cable) > * Rotor > > All of these units will 'stack' like lego bricks, and attach to the rotor > mounting plate on the tower. > > This design will eliminate lengthy coax runs and will allow antenna > placement to be made without feedline loss being a contributing factor to > placement. Moving the RF components to the masthead will reduce RF in the > home and eliminate any possible danger to excess exposure. Use of fibre- > optics for the link-cable will eliminate any path for home-generated EFI > to reach the RF sections and should help keep the RF out of the domestic > appliances, too. > > Oh yeah... it will probably be built by Icom..... ;-) > > > It would work. They even could send signals up the rood unit via an IF which then could be modulated. We pump IF all over the place at my work. We have IF coming in over Fiber Optics, dropped onto coax still as IF then running off to modulators to be modulated on respective channels for several Channel Line ups running out across several counties and states. Typical IF level runs to our equipment at 38 dBmV, digital stuff at 44 MHz, analog 41.250 audio carrier and 45.750 MHz video IF, if we are running that source across multiple modulators (i.e. Channel 34 on Line up A & Channel 27 on Line up B) we can just loop the IF in and out of the modulators. It can save us a ton of not having to deal with splitting Audio and video with Audio Distributin Amps (ADA) and Video Distribution Amps (VDA). Most of our Digital channels are runningout on 64 and 256 Qaudrature Amplitude Modulation (QAM) carriers though thios all will be phased out as everything is going IP based MPEG2/4 transmission but will end up on a RF QAM, the only IF would probably be internal in the modulation device. Our industry is changing so fast, within a year or so we will be doing very little anaolg channel stuff and in 10 years there won't be any new techs who will remember the days of 4.5 MHZ bandwidth IF and analog channels, just us old timers. :) Any way....your post brought all this to mind. It will be interesting to see how all this digital will carry over into HAM radio. I have not been impressed with the current SLOW digital modes on HAM radio. Yes ICOM has some cool looking stuff, GHz stuff, but you will need a repeater/node every 1/4 mile or so and who but the very wealthy will be able to afford it. :( APRS looks kind of neat, I am seeing some of the local hams doing it a lot. Still I think the best bang for the buck is a good old VHF FM rig and of course HF Phone and CW. Speaking of which, I saw Ten Tec has some nice QRP kits for about $159 QRP CW and pick your band. Back to your original post, I think the Optical link and seperation of the control head and the actual RF transitter is a great idea, I think there are already mobile rigs like this, control head in the front of the vehicle and the base of the unit in the trunk connected via a fiber optic line. All cool stuff. :) 73 Mark .