Re: MD: RF Modulators
Kade Hansson wrote: Argh. PLL locked. ATM machine. PIN number. :-) Nope. PLL locked means locked by a PLL, ie. 'P'hase 'L'ocked 'L'oop locked. The two occurences of the word "locked" are referring to different things. The first "locked" refers to the phase of the synthesised frequency (a description of the operation of the circuit element), the second to the magnitude of the frequency. -cb -nitpicking... - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
PrinceGaz wrote: I think this "grabbing a strong signal" thing is rubbish, if a VHF tuner jumps onto a sig more than 0.2MHz away, it should be de-installed from the car and installed in a suitable bin for immediate disposal :-) It has to do with the characteristic of MF modulators and demodulators. They will capture the strongest signal if it is too close to the one you are trying to tune to. -- Jim Coon Not just another pretty mandolin picker mailto:[EMAIL PROTECTED] If Gibson made cars, would they sound so sweet? My first web page http://www.tir.com/~liteways/ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
RE: MD: RF Modulators
==BEGIN QUOTE=== I personally haven't tried any of them, but after hearing the stories I'm just gonna fork out the bucks for an in-dash MD player. ==END QUOTE I would assess the situation more carefully if you are considering MiniDisc in the car, especially on a permanent basis. This would mean assessing whether the factory head unit has a line-level input that can be opened up by any old device. Some AM/FM stereo car radios have a connection to feed in the signal from a separate cassette player which was available as standard or as a dealer-fit option. Here, you adjusted the volume for the tape sound by operating the controls on the radio. Also some car radio-cassettes made since the late 80s were equipped with connections for a separate CD player, available as a dealer-fit option in most cases. I had discussed the possibility of modifying a Sony add-on CD changer controller kit (which controls their MDX-65 MiniDisc changer), which uses the RF modulator setup to perform a direct feed into these car radios. The trick was to wire the controller to the vehicle power, then re-direct the RCA connectors that connect the changer to the controller, from the controller to the line inputs on the car radio, then use the "switched power output" on the lead to operate the line-level input trigger. If this is hard to do, look for an CD/MiniDisc stacker controller that installs in the output line and has its own volume and tone controls. Then you can use a speaker-line interface for those car stereos that only have speaker level outputs. These controllers then feed a powerful amplifier, thus modernising the sound in an older car stereo. Alpine and JVC make these kind of changer controllers and they are still worth investingating. They also come in handy if your car is a recently-made luxury one where external amplifiers are used for the sound system, such as the Bose, Harman-Kardon, JBL or Infinity sound systems. If you live in an area covered by a digital radio system such as the Eureka 147 system, keep an eye out for controllers that can control add-on digital radio tuners. With regards, Simon Mackay - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
Hi guys, What puzzles me about these VHF modulators is why they drift off frequency so much. I mean any half decent crystal-controlled oscillator's drift will be negligible. Why isn't a unit released where you can plug a crystal for say "107.9 MHz" or "101.7 MHz" or whatever. The unit will then produce that frequency from a harmonic of the crystal and it'll *STAY* that frequency, not wander all over the 76-108MHz VHF FM band! Should I now hide in a corner or get my coat, for over-looking something obvious that I have totally missed? Cheers, PrinceGaz - now downloading Red Hat Linux 6.1, as if Mandrake 6.1, and a succesfully burnt Caldera 2.3 weren't enought to choose from. I must be going mad-- 3x600+MB downloads on a 50kbps link... Email: [EMAIL PROTECTED] Website: http://website.lineone.net/~princegaz/ ICQ: 36892193 - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
PrinceGaz wrote: PrinceGaz - now downloading Red Hat Linux 6.1, as if Mandrake 6.1, and a succesfully burnt Caldera 2.3 weren't enought to choose from. I must be going mad-- 3x600+MB downloads on a 50kbps link... No, I'm mad -- Magic - Also downloading Red Hat Linux 6.1, but only on a 4kbytes/sec link and the calls aren't free. Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
PrinceGaz wrote: Hi guys, What puzzles me about these VHF modulators is why they drift off frequency so much. I mean any half decent crystal-controlled oscillator's drift will be negligible. The units need to be tunable so you can tune to an unused spot on the dial. They are also of low power, and as such as you drive near another radio station, interference casues the radio to drift to the stronger signal. (FM capture and intermodulation products probably) -- Jim Coon Not just another pretty mandolin picker mailto:[EMAIL PROTECTED] If Gibson made cars, would they sound so sweet? My first web page http://www.tir.com/~liteways/ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
Gaz asked, B What puzzles me about these VHF modulators is why they drift off frequency B so much. Jim answered, C The units need to be tunable so you can tune to an unused spot on the C dial. They are also of low power, and as such as you drive near C another radio station, interference casues the radio to drift to the C stronger signal. (FM capture and intermodulation products probably) On top of that, try *finding* an open frequency in a large metropolitan area. I tried two models and couldn't get either to work in my driveway, let alone throughout a short in-town commute. Even parked I had to keep retuning the receiver, so some of the drift has to be in the transmitter. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
From: David W. Tamkin [EMAIL PROTECTED] Gaz asked, B What puzzles me about these VHF modulators is why they drift off frequency B so much. Jim answered, C The units need to be tunable so you can tune to an unused spot on the C dial. They are also of low power, and as such as you drive near C another radio station, interference casues the radio to drift to the C stronger signal. (FM capture and intermodulation products probably) On top of that, try *finding* an open frequency in a large metropolitan area. I tried two models and couldn't get either to work in my driveway, let alone throughout a short in-town commute. Even parked I had to keep retuning the receiver, so some of the drift has to be in the transmitter. What I was thinking was, why not make a model where you plug a crystal in the back, or front or anywhere, and you choose the frequency crystal you want, eg. in Newcastle I would go for anything between 107-108MHz as it is unused. Since I don't have a car it's all hypothetical(?). Admittedly in London the VHF FM band is probably full of sigs across the whole 87.5-108MHz range, likewise in large US cities. So why not have the unit pump out a bit more juice. A 100mW ERP transmitter in your car, less than 4 metres from your receivers' antenna would probably drown out a 100KW Xmtr on a hill you're driving past. The only downside of this idea perhaps being that anyone on the road within a few hundred metres would also hear you. And perhaps 100mW could be excessive as it may overload your tuner's frontend. But you get the idea :-) I think this "grabbing a strong signal" thing is rubbish, if a VHF tuner jumps onto a sig more than 0.2MHz away, it should be de-installed from the car and installed in a suitable bin for immediate disposal :-) My point is that a *crystal* locked oscillator won't wander all over the VHF broadcast band, and when you get your for instance 107.5MHz crystal (obviously thats a harmonic but I won't go into that) and adjust your transmitters tuning of it's frequency multiplier and possibly power amp stage, it'll be as stable as any other pirate radio station. It may wander 10 or 20KHz but thats less than half any tuner's minimum tuning step. Cheers, PrinceGaz - prone to wandering all over the place, after too much beer - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
RE: MD: RF Modulators
I bought one of these (SoundFeeder SF100) with the same goal as you have. It turned out to be a complete waste of money. I ended up doing it right -- bought a MDX-C7900 car unit and LOVE it. The problem that I observed, in addition to the drift problem, was that the silly thing picked up interference from my MZ-R50 (as well as a portable CD player that I tried with it). The interference was in the form of an annoying buzz. I confirmed that this was definitely emanating from the MD unit, not the car's ignition system. It happened even when the car was off and only when the MD or CD disc was spinning. If you can't go for a deck with a built-in MD player, I would suggest getting a cassette adapter. These work reasonably well and are definitely much better than the SoundFeeder crap. Good luck, Paul -Original Message- From: Brian Andrews [mailto:[EMAIL PROTECTED]] Sent: Saturday, October 02, 1999 1:51 AM Subject: MD: RF Modulators I've been reading that you can purchase just an RF modulator that will allow a portable MD player to be used in a car. Do these just plug into the headphone jack like a cassette adapter would? Can anyone recommend one that would work with my Sharp 702? Thanks, Brian - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
"Jeffrey D. Scorsone" wrote: Yes, you can plug into either headphone or line out (if it's an option on your md player). However, there has been considerable talk on this list about bad experiences with these devices. Most of them seem to suffer from "drift". The digitaly tuned variety are a bit worse, as you can't "tweak" them back, and you have to either find a new frequency or just deal with it. I personally haven't tried any of them, but after hearing the stories I'm just gonna fork out the bucks for an in-dash MD player. Ive got a soundfeeder sf120 that bought so I could use my portable CD player in the car with only a semi-working am/fm tape deck. What I found was that if I used my walkman into it (playing a tape) I could get OK sound. If I used the CD player, it majorly distorted the treble - came right in mono mode, but whats the point of that?! Also, with it plugged into the headphone out of my 20es amp, it has a loud hiss constantly. If I change the digital filter thingie, when the outputs idle between modes for a second it goes quiet. I can only assume that the output has some signals on it about the audio range that are screwing with the modulator. In the end, I opened it up and removed the antenna, and fitted an RCA jack in its place, then I run a RCA- TV antenna cable to my 20db gain antenna amplifier, then to a pair or rabbits ears. This means that I can use my cheap AM/FM tape walkman to listen to MD/CD's while mowing the lawn or whatever around the house :) quite usefull in that situation. It was useless in the car, constanty needing retuning etc. I would much prefer it if it was PLL locked etc. If a $20 radio can do it for tuning then they should be able to do it for transmition. Ideally I will sort something out or else buy the adaptor thingie so that I can use the changer input on the back of the sony car cd player. Dont want to get a MD changer. -- Richard - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: RF Modulators
At 06:32 PM 10/3/99 +1300, RMS wrote: It was useless in the car, constanty needing retuning etc. I would much prefer it if it was PLL locked etc. If a $20 radio can do it for tuning then they should be able to do it for transmition. Argh. PLL locked. ATM machine. PIN number. :-) -- Archer http://www.geocities.com/SoHo/6413/ End. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
