pinny Posted August 30, 2011 Share Posted August 30, 2011 hi all im currently running a 300tdi discovery on a n plate but im looking to upgrade to a td5 discovery this year my question is ill soon be sitting my last 2 parts of my amateur radio licence which will allow me to transmit 400w of radio power on frequencys between 1mhz upto approx 440mhz oviously there is breaks inbetween but this is a rough guide has anybody got a mobile set up in anything newer than a 300tdi as ive been told the td5 wont like the rf power many thanks chris Quote Link to comment Share on other sites More sharing options...
simonr Posted August 31, 2011 Share Posted August 31, 2011 I've not run 400w - but I'm not sure in practice you will want/need to either. The antenna you use will make a bigger difference to your DX capability than your ERP - and unfortunately there is just not the space, even on a Land Rover for a worthwhile DX antenna. I would be inclined to stick to about 25w and you'll be able to talk to most people you want to, particularly on HF. A bigger issue is going to be the amount of noise generated by the ECU. Decoupling & ferrite core chokes will kill most of it but I've still found the Td5 noisy. Unless you are only planning to talk to other stations putting out 400w, if you have sufficient gain to receive lower power stations at a distance, they will be swamped by RFI from the vehicle. For high power DXing, I would build a decent base station at home with a decent tuned antenna and you'll be able to talk to people all over the world. Si (G7DMQ) Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 31, 2011 Share Posted August 31, 2011 I have 50w VHF 2m band sets in all my vehicles and neither of the V8s I have owned have any issues with TX interference with the ECU nor RX interference from the ECU. The police here use Td5 Discoverys and again no issues. I have received stations out to around 90 miles from the top of a mountain I think HF is more susceptible but have no direct experience - if I want to communicate with somebody on the other side of the world I send them an e-mail I agree with Si that putting 400w in a vehicle is really just throwing s*** against a wall without a good aerial - and you'll be drawing 40 or 50 amps out of the electrical system. Stephen VP8CIX Quote Link to comment Share on other sites More sharing options...
ThreeSheds Posted August 31, 2011 Share Posted August 31, 2011 I have read on radio forums, of RF affecting various (usually anciliary - like window opening) ECU functions on various cars but I must admit I didn't take too much notice. I believe that the best solution was to use a separate leisure battery for the radio and isolate it from the car when using the radio. Personally I have a direct connection (live and earth) to the main vehicle battery (fused on both sides as advised for all mobile installations) and have noticed no problems. However my ECU is so old and crude I doubt that it knows what RFI is! As mentioned above you can work the world on 25w and a leisure battery will last a long time driving that! Also it is unlikely that once you have, as my mother would say, 'had your fussy out', you will want to work HF mobile - more likely park up at some high point and see what you can manage with 5w and a long wire fence or somesutch Personally I have only once worked HF mobile as an experiment - a Dutch station on 20m, but I decided it's way too difficult tuning in while driving. Having said that I am about to enhance my mobile setup with an ATU and a mobile HF antenna but as I said - this is mainly for use parked up. The other thing to consider is that you really are rather limited on antenna options on a car and are usually stuck with vertical polarisation which, with the rest of the world using horizontal, will sometimes loose you 10dB or so both in and out... I hope that the above is of some help, but really your question would probably be better put on a radio amateur forum rather than here - still, nice to know that you are out there and hope to work you one day! 73 de m0xpt Roger Quote Link to comment Share on other sites More sharing options...
G4FUJ Posted August 31, 2011 Share Posted August 31, 2011 I do a fair bit of hf mobile, mainly from the 90 (and from the FourTrak - a temporary motor while the 90 was rebuilt). I wouldn't bother with more than 100W (and usually run the radio at reduced power, 50-75W) - remember your /M antennas are so short compared to wavelength they are highly inefficient unless working on 12m & 10M. Plus, as others have said, you're going to need some pretty big power generation to run that linear - your 100W radio is going to take at least 22A on transmit peaks, so you'll be looking to supply over 100A on peaks... Do you really expect to run 400W on vhf/uhf? Should be interesting to see how many people can't open their cars if you do it on 70cm As far as emergency services vehicles goes, they are modified to reduce emc issues (both on Tx and Rx) with additional filtering etc. Both my 200Tdis (first in Disco and now in the 90) generate interference to non FM modes, particularly at hf. I run a second battery, vehicle charged, so that most hf operating can be done engine off, without worrying about a restart afterwards. The interference appears to be from alternator/charge controller... Haven't got to the bottom of it yet and fitting Rover's own additional capacitor made no difference. Hopefully, I will soon run hf from the Clubman Cooper D too. Presently just 2m/70cm. Oh yeah - good luck with the final exams! 73 Graham G4FUJ Quote Link to comment Share on other sites More sharing options...
pinny Posted August 31, 2011 Author Share Posted August 31, 2011 thanks for the replies guys im just looking into options at the moment and yes 400w is extreme havent got a newer vehicle yet and havent passed the final exams so still limited to me 10w but on 2and70cm its not a prob as there is many repeaters around but thanks for the different reports, chris. Quote Link to comment Share on other sites More sharing options...
western Posted August 31, 2011 Share Posted August 31, 2011 my ham licence issame as yours [M3] 10watts at the feed in to the antenna, you'll be surprised just how far you can reach with small power output. Quote Link to comment Share on other sites More sharing options...
pinny Posted August 31, 2011 Author Share Posted August 31, 2011 western totally agree with you ive got a ft897 at home with a trapped vertical on a 40ft clark pneumatic mast and like you said when the skip is running its brilliant thanks mate chris Quote Link to comment Share on other sites More sharing options...
simonr Posted August 31, 2011 Share Posted August 31, 2011 I actually find it a bit disappointing how few devices are affected by RF - even running AM. Years ago, we were being a radio vehicle for the Lombard RAC and besides the Rally radio, I had an all mode 2m rig which would spit out 25w. We went in a convoy with three or four Amateurs in the group. We stopped to fill up once and from well outside the forecourt I could hear buzzing from the forecourt PA system when I keyed up on FM. Sudden inspiration, switch to AM - and now my voice was coming out of their PA quite loud! Much amusement followed "please would the owner of the car at pump 3 ........" Sadly, it never happened anywhere else Si Quote Link to comment Share on other sites More sharing options...
BogMonster Posted August 31, 2011 Share Posted August 31, 2011 Sudden inspiration, switch to AM - and now my voice was coming out of their PA quite loud!Much amusement followed "please would the owner of the car at pump 3 ........" Brilliant Quote Link to comment Share on other sites More sharing options...
discomikey Posted August 31, 2011 Share Posted August 31, 2011 Si (G7DMQ) Stephen VP8CIX 73 de m0xpt Roger 73 Graham G4FUJ confused?? are these your handles? Quote Link to comment Share on other sites More sharing options...
western Posted August 31, 2011 Share Posted August 31, 2011 confused?? are these your handles? they are official amatuer calls allocated by OFCOM, they are not just random & do have a meaning. G & M - UK the first number refers to the level of licence held & the last 3 are either a random allocation or can be reserved if not previously allocated. Quote Link to comment Share on other sites More sharing options...
steve_d Posted August 31, 2011 Share Posted August 31, 2011 Good luck with the exam. Steve M3BBH RAYNET Quote Link to comment Share on other sites More sharing options...
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