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

CV /forums/images/graemlins/grin.gif

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 /forums/images/graemlins/grin.gif 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! /forums/images/graemlins/frown.gif

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
 
[ 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 /forums/images/graemlins/grin.gif
 
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 /forums/images/graemlins/grin.gif.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. /forums/images/graemlins/frown.gif
 
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.
 
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?
 
It would be nice if this were the case and the RTTE regulations were adhered to, but I dont know of any type approval testing that goes on before a Marine Radio is put on to the market...does Ofcom test each model before they allow it to be sold in the UK??
It not like the Old PMR type approval regime in the home office days.
My guess is that it is sufficient for a company to say it complies...sort of self assessment.
Radios can vary wildly both on power output and receiver sensitivity, there have been many instances of 25 watt radios only achieving 15 watts or so.
It's to do with poor coupling into the final output module, which is an alignment issue.
Conversely my own DSC radio measures at 28 watts into a dummy load, which would be out of spec...but I'm not complaining.
As I have said on other replies I am most worried about Receiver sensitivity issues, because it is here where performance can really be affected.
Transmit power has much less effect on communication distance than receiver sensitivity.
No Transmit power in the world will help you if you have a deaf receiver.
The tests that the magazines carry out just are not detailed enough.
They only concentrate on ergonomic issues and ignore how well the actual radio bit of it performs..or rates up to other similar equipments.
It would be nice for instance to see the technical comparison of a Simrad up against a Cobra...and why the Simrad is worth over 200 pounds more.
It may be even more interesting for an engineer to open up the radio and discover that maybe some of the more expensive radios originate from the same production lines as the cheaper offerings.

Steve.
 
C'mon Woofy, we all know Tornado nose cones are filled with concrete to compensate for the fact that the radar is still in the lab 'under development'.
 
Steve
I am one that accepts the thrust of your points.

I also think that expensive radios such as the raymarine 240E are basically badged radios which I think are made in the Cobra factory.

However when i choose a radio I tend yo go on features. When I chose the 240E it was the only one that offered muti station with full DSC functions at each station - I was surprised at that but it was the only one of the major brands that did it.


I would be fascinated by a real technical bench test on radios - it may throw up a few surprises :-)
 
Does not really matter which factory - does not matter if is the same factory as a much cheaper radio - nor does it matter if radios are made by father Xmas's elves at the North Pole - nor does badging a product concern me. All that matters is what you get for your money. To establish what you get for your money you need to compare the features and as you rightly state you should be able to compare the technical specs hence the mags should include a set of standard bench tests.

When I went to look for a handheld I wanted a fully waterproof one and that feature alone cut down the alternatives drastically. Wjen I went to look for a new static radio I wanted full DSC functionality at each station and that reduced my choice down to one. However if the bench mark tests on that choice showed it did not conform to spec that would have stopped me in my tracks.

Even though the bench tests may be highly technical, the mag test results do not need to be expressed in highly technical terms - it can express the results in plain english - this radio at 25 watts and full battery only outs out 19 watts is clear and simple.
 
From recollection,you tell the bloke in China what you want to spend and what bit of the band you intend using it on.He cobbles up half a dozen units from scratch or more likely by copying a competitors unit you have sent to him and want to rip off,but slightly altered a bit praaps different case/metal box dimensions etc/forums/images/graemlins/grin.gif.He sends you some samples which you then send of to independant UK lab to see if it meets current gov approved specs.If OK they give you cert of type approval or if not,you phone China and they mod it a bit and send new radio for recheck.You give 2-3K for test work to lab and send to your manufacturor the text you want silk screened on to front of radio and packaging art work.Total time from start to finish 3 to six months.Approx cost of unit wild guess 20 quid ish.
Each boxed unit will contain either rubbish photocopy of certificate (cheapo end )or posh shiney printed copy if top end gizmo with signature or importer promising that stuff is OK to use in UK.
 
aha, blue circle or F3 nose radar (AI24). A fabulous unit modified and got working down the corridor. Just as they had most of the fleet up and running the Govn sounded the death nail for the aircraft and announced the introduction of the Typhoon. Now, normal people, knowing military radar and how good the F3 radar was (and it is a brilliant bit of kit), would suggest fitting it in the new Typhoon, oh no, we need a new all singing all dancing radar.

So now another 10 years getting the radar working, keeps em in work I guess!

I worked on the GR1/4 radar, far more interesting with the terrain following stuff! Lakesailor will have been cooked by my gear on many an occasion!
 
Whist your points are valid from your point of view and maybe that of a number of people I think the vast majority of the 66,000 licenced marine radio users here in the UK would rather the tests are as they are.

To most what is important is:-

Is it waterproof?
How long will it last on a charge?
Does it sound good?
How far can i talk on it?

I do feel that some of the recent tests made statements that were not correct.
This will lead to end users getting the wrong impression of a certain bit of kit.
Particularly in the recent fixed DSC test.

Am also aware of a very recent hand held test that did not test all of the main radio currently on the market.
So again giving the end user a false veiw of the market and the best radio to buy.

IMHO the tests work well as they are if, the units are correctly and tested.
All the units on the market are tested.

Regards
 
You are right that it is the features that count.

I chose an Icom Euro for my handheld because of the features starting off with waterproof - so that it could be taken into a liferaft and survive.

I chose a Raymarine fixed for my new boat because no other fixed set offered me the full DSC functions at all stations.

In both cases my choice was feature led but I still expect the radio to perform as to spec and that is always best checked in an independant fashion.

As regards missing out radios on mag tests - to me it invalidates the test. Say sub £150 h/h sets are being tested and they miss out some models.makes - it leaves the question open as to how they would have performed. Nor do the reviews make the real differences between sets at various prices very clear.

The tests should be harder hitting and with the chance of the supplier to comment before publication - this is because often a review gets a product totally wrong - for example stating it does not have a certain feature when it does etc.
 
What makes it worse was that one of the radio's on the MBY test is, as far as I know, no longer available!

IMHO they should re run the tests with the full UK line tested fully.

Regards
 
You must log in or register to reply here.

Share this page

Top