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  1. #21
    steverow's Avatar
    steverow is offline Registered User
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    Default Re: Magazine Radio/Electronic tests..waste of time??


    Woof,

    I'm impressed.
    You might not have liked it, but many would not realise just what a high level skill tuning waveguide, horns and arrays is. Being PMR for most of the time I always had a healthy respect for the guys who did the very short wavelength stuff the p to p links etc. Me I lop bits of element off with a hacksaw check it on a VSWR meter whilst you guys tap away for hours with a little hammer checking and tuning...etc etc.
    Antenna work often cannot be learnt from books, probably because there aren't that many good books dedicated to it. (with the notable exception of Butterworth's excellent tome). OK there is the theory side, but mostly as I'm sure you know, it's a black art, and relies heavily on practice, skill, hunches and intuition.
    Are you still in comms??

    Steve.

  2. #22
    steverow's Avatar
    steverow is offline Registered User
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    Yes Fred, but if it was one kHz off and only two watts, that would equal at least a 50% degradation in performance getting exponentially worse the further away from the other station that you are. Surely you wouldnt want to buy a radio that only worked half as well as it should?? And what would happen if the radio you were communicating with was 1kHz off the other way??
    We take too much for granted these days. A radio is only as good as it's design and alignment.

    Steve.

  3. #23
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    Arrrrgggg stop talking about waveguide i come on here to relax...............

    My company designs and manufactures Microwave Filters a lot of them in waveguide (more often machined aluminium though). These days we have design software that mainly does away with the need for hammers, punches and dints, although it is still the last resort sometimes.

    Don't start the "black art" bit, it drives me mad when the engineers keep telling me that and I'm chasing the month end numbers! My Technical Director compares tuning filters to piano tuning...........his engineers are certainly as precious as any keyboard maestro

  4. #24
    steverow's Avatar
    steverow is offline Registered User
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    Things to do Monday....

    Listen to my technical director more,

    Give him and his engineers at least a 5000 pa pay rise,

    Organise Advert in technical press for two more antenna engineers, (to ease the workload of current overburdened chaps)...

    Are you still standing??

    What stuff do you make? circulators and isolators etc for multiple occupancy sites for mobile phone industry as an educated guess??



    Steve.

  5. #25
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    I had forgotten about gain horns, thank you for bringing that up!

    CV [img]/forums/images/graemlins/grin.gif[/img]

    No, no longer doing it, medically retired now. I was talking to SWMBO the other night and as I have now been out of work 18 months, my only electrical work being 12v stuff on the boat, I am shocked how much I am forgetting.

    Simple basic theory has just disappeared, often find myself googling when I read stuff on here to recall the methods. I guess it is not too bad when a quick scan read brings it back, but I am sure it will soon completely go. A big problem for me, I never actually had any passion for electronics not like some of the people I worked with, some ate and slept it. Not my bag.

    I was mainly RADAR though did the odd comms stuff and IFF which generally comes under comms. The last 5 years before I left I was was working on the Harrier and Tornado Radar warning and ecm systems, the stuff that sends bells to the pilots head set when another radar paints his aircraft. How twee that the UK use a bell sound [img]/forums/images/graemlins/grin.gif[/img] It was quite interesting kit and unlike the Tornado nose RADAR which I specialised previously, the RWR kit gave me a better idea for repairing marine kit should I ever need to, if I can remember anything!!


    If I had not finished, I had put in to move on to the seaking and lynx helicopter gear with the idea of getting a transfer down to Fleetlands or Yeovilton. But judging by what has happened to dara probably would not have been the best move!

    I always wanted to go to sea, in fact I was setting to buy a trawler, but ended up 'getting a trade' first to appease my mum. Well without that I would be in trouble now as I hear the fishing sick pension is pretty poor! [img]/forums/images/graemlins/frown.gif[/img]

    Sorry about acronyms

    rwr - radar warning receiver
    dara - Defence Aviation Repair Agency
    IFF - Identification Friend or Foe (a bit like AIS)
    ecm - electronic counter measures

  6. #26
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    [ QUOTE ]
    Antenna work often cannot be learnt from books, probably because there aren't that many good books dedicated to it.

    [/ QUOTE ]

    The first day on the Tornado nose radar floor I was given a book to read to get an overview or systems and the radar.

    A WHSmith aircraft in action type 'The Tornado'. There was nothing available from the MoD. oh we had technical books, but nothing gave a better overview, even though some of the information in the book was a bit close to the confidential stuff and I think the particular publication might have been pulled!

    It made me laugh anyway, here I was expected to fix the kit, referring to a book many school boys would get for Christmas [img]/forums/images/graemlins/grin.gif[/img]

  7. #27
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    Trying to remember the last time we had something that did not function straight out of the box and would cause us to check with test kit.At the budget end of the market we may have the odd CB returned but normally this has more to do with it being force fed 24V [img]/forums/images/graemlins/grin.gif[/img].On the PMR and marine side if anything has got through not up to spec,then it certainly has worked well enough for not a single item to have been returned over last year or two.Main grief we have is erm certain nameless people who are incapable of pushing the correct keys where the programming software is concerned. [img]/forums/images/graemlins/frown.gif[/img]

  8. #28
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    Yes partly right but broader based than that

    http://www.bscfilters.com

  9. #29
    steverow's Avatar
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    I'm not saying that they are going to be faulty, just that some may not perform as well as others.
    This could be for a variety of reasons, design or more probably alignment.
    The magazine tests seem to assume that all radios are the same and will perform the same and that it is just a case of listing the features and feeling the goods.
    How would they know...for instance..that transceiver A had got a much better RF front end than the others, and performed well down to say 0.1 microvolt for 10db
    whereas B and C performed to spec at 0.5uV and D was deaf at 0.9uV.
    This sort of difference, although not noticable on the coast will severely limit usefulness at 15 or 20 miles out.
    It is also being unfair to the distributors of radio A, who obviously have a superb RX design, but it is not being noticed.
    This is my point how can you pit one radio against another without really knowing what is going on with the Whole Radio not just the buttons and the screen.
    I dont expect full type approval testing, bit half a dozen simple RX/TX tests should be well within the capabilty of the magazine.

    It should also highlight (or lowlight probably) what the differences are between a Raymarine or Simrad radio at 350, and much the same thing from NASA Cobra and others at less than 150. Why is there this difference... are the radios that much better.....these are the things the mags should be investigating and that can only be done by objective technical testing.

    Steve.

  10. #30
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    Default Re: Magazine Radio/Electronic tests..waste of time??

    You are absoutely right.

    I am wrong then in thinking the eu regulations are so tight that all equipement has near the same tolerance and it is just down to how it looksand continues to function then.


    how do you test for longevity then ? eg a sailor vhf against one of the cheapest offerings?
    David

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