Brian needs more power... any suggestions ?

[BriansBrain]

Brian - I think you've answered your own question. If energy costs are the driving factor, you can't/won't put up a higher gain aerial, and you don't think you can beat the Elenos on efficiency with a DIY rig, then buy the Elenos and be done with it.

I know...
I personally just think it's sad that...
''Normally'' custom built means ''better than what you can buy off the shelf'' and cheaper

But as I have found out in terms of FM Transmitters Equipment this is not the case.

[BriansBrain]

That said I think the main reason for your low efficiency numbers is that youre looking at a cheap shit no-name PSU from ebay.

Wrong.......
Originally I was looking at a 1000W pallet to run at 600W and a Power supply from the Dutchrfshop
Using the ELTEK POWER SUPPLY 52 VOLT 60 AMPERE with an efficiency of > 95.5%

Capture.JPG

However....
According to Freescale MRFE6VP61K25HR6 pdf
@ 660W output = 50V x 19.3A = consuption 965W
@ Estimated RF out put of 600W after Low Pass Filter and other losses
Power supply Efficiency = 95.5% so Pallet would consume = 1010W
+ 2 x 220V 80x80mm fans 14w each = 28W
+ Tugicom TX180 1W exciter = 20W
Total estimated consumption = 1058W = 57% Efficiency

At the end of the day all Elenos are doing to get such good efficiency numbers is pairing an efficient PSU with an efficient amp. There's no magic here, and if they can do it there's no reason why you can't do it too. Or maybe you decide it's not worth the effort and you'd rather just pay the premium to let Elenos do it for you. Either option makes sense, it just comes down to your priorities.

It's not a matter of the effort, as I have explained before, my head still thinks it could do all the things I used to do when I was young.
But...
I am now 71 years old, with very very bad (close up) eyesight and a cataract in my right eye.
Plus rheumatoid arthritis in both hands, I can hardly hold a soldering ion any more let alone use one effectively.

Unless you are offering to come and help

[BriansBrain]

I am often sceptical of large manufacturers inflating expectations!

I have seen a 1000W running cool'ish @ 1014W
BTW: a Bird Meter also showed 1000W
It was consuming on a proper V/A Din Rail Meter
223V @ 6.2A so consuming a total of 1398W = to 72.5%

I did research the ETG1000 specifications, They mentioned the use of "ICEFETS" A new revolution!
Sadly, i did not find any useful data on these devices?? (Maybe highly classified info)

Correct, I don't think they don't use standard devices

[BriansBrain]

You really do need to look at antennas with gain!

I will set up a meeting with all the big wigs in my little community that have the say in what goes on and what does not in the area

Then you could come over and convince them that I need a bigger antenna array.

I'm sure they will listen to you.

By the way, you do speak Fluent Spanish...... don't you ?

.

[radiocomm]

Elenos were always a bit "economical" with their quoted figures. Their 500W box was meant to have second harmonic of -60dBc. I've measured one into a dummy load, and they achieve -42dBc at best. Their in-band noise is horrible, and their "efficiency" figures should win a Booker Prize for Fiction. They're desperate to sell their rubbish.

For just €85 more, you can get a Siel 500W box that has a real second harmonic content of -71 dBc, no measurable other harmonic products, and the first adjacent noise floor (ie: +/- 200 kHz from the nominal carrier frequency) is about -98dBc (very close to the limit of my analyser noise floor, so +/- 1dBc). The Siel effort has a measured overall efficiency of 57% - typical for gear of its type.

The Bext offering in that class manages just 52% efficiency (for a circuit very similar to the Siel box). A couple of other manufacturers offer overall efficiencies of around 50%, and this is considered pretty good in the industry.

You really do need to look at antennas with gain!

I don't like when people write nonsense and unverified information. I would like to see the measurement procedure and equipment used to measure the II-harmonic at -42 dBc. Where are the results of those measurements? There can be two reasons, one is that it is a faulty transmitter and the other is that the measuring equipment is not working. In addition, the price of Siel FM transmitters is 25% lower than Elenos, so I don't see the point of this story!

[BriansBrain]

Elenos were always a bit "economical" with their quoted figures. Their 500W box was meant to have second harmonic of -60dBc. I've measured one into a dummy load, and they achieve -42dBc at best. Their in-band noise is horrible, and their "efficiency" figures should win a Booker Prize for Fiction. They're desperate to sell their rubbish.

For just €85 more, you can get a Siel 500W box that has a real second harmonic content of -71 dBc, no measurable other harmonic products, and the first adjacent noise floor (ie: +/- 200 kHz from the nominal carrier frequency) is about -98dBc (very close to the limit of my analyser noise floor, so +/- 1dBc). The Siel effort has a measured overall efficiency of 57% - typical for gear of its type.

The Bext offering in that class manages just 52% efficiency (for a circuit very similar to the Siel box). A couple of other manufacturers offer overall efficiencies of around 50%, and this is considered pretty good in the industry.

You really do need to look at antennas with gain!

I don't like when people write nonsense and unverified information. I would like to see the measurement procedure and equipment used to measure the II-harmonic at -42 dBc. Where are the results of those measurements? There can be two reasons, one is that it is a faulty transmitter and the other is that the measuring equipment is not working. In addition, the price of Siel FM transmitters is 25% lower than Elenos, so I don't see the point of this story!

Well said

[sinus trouble]

Elenos were always a bit "economical" with their quoted figures. Their 500W box was meant to have second harmonic of -60dBc. I've measured one into a dummy load, and they achieve -42dBc at best. Their in-band noise is horrible, and their "efficiency" figures should win a Booker Prize for Fiction. They're desperate to sell their rubbish.

For just €85 more, you can get a Siel 500W box that has a real second harmonic content of -71 dBc, no measurable other harmonic products, and the first adjacent noise floor (ie: +/- 200 kHz from the nominal carrier frequency) is about -98dBc (very close to the limit of my analyser noise floor, so +/- 1dBc). The Siel effort has a measured overall efficiency of 57% - typical for gear of its type.

The Bext offering in that class manages just 52% efficiency (for a circuit very similar to the Siel box). A couple of other manufacturers offer overall efficiencies of around 50%, and this is considered pretty good in the industry.

You really do need to look at antennas with gain!

I don't like when people write nonsense and unverified information. I would like to see the measurement procedure and equipment used to measure the II-harmonic at -42 dBc. Where are the results of those measurements? There can be two reasons, one is that it is a faulty transmitter and the other is that the measuring equipment is not working. In addition, the price of Siel FM transmitters is 25% lower than Elenos, so I don't see the point of this story!

Just an observation? So correct me if i am wrong?

Radiocomm! Do you work for Elenos?

As Albert's perfectly legitimate opinion seems to have triggered you??

[jvok]

Unless you are offering to come and help

Lol if you're paying 7 grand I'll build you anything you want

[Albert H]

It's NOT an "opinion". We measured several branded transmitters in the range of 400 W to 1 kW for a client who wanted to purchase a whole pile of such rigs for export to countries south of the Equator. The original idea was to identify a product with a good performance to price ratio, and would (ideally) have short lead times. We were dismayed to discover that many of the manufacturers were somewhat Economique avec l'acualité and that some of the ostensibly "commercial" transmitters had significantly worse performance than some "pirate" rigs we've seen!

We rapidly discovered that brand names really didn't mean much - differing products from the same manufacturer could have quite wildly differing performance. One company produced a 500 Watt box that had possibly the cleanest output we'd ever seen, but their 1 kW box would probably get you arrested!

Exciter and amplifier topologies tended to follow one of four basic designs. Most of the European products used "at-frequency" generation, whereas the American ones frequently used either frequency multiplication or a mixing approach. Most used switched-mode power supplies, but two of the very best products we found used good old-fashioned transformer, bridge rectifier, smoothing and regulation. These exhibited significantly lower overall efficiency, and were very much heavier items, but the quality of the output more than made up for the other shortcomings.

There were a couple of "all-in-one" units, that included audio processing and stereo encoding in the same box. Though these might have been seen as convenient, their performance was compromised by cramming everything into the same case....

"Radiocomm" - we have test facilities similar to those found in companies like R F I in Surrey, and our instrumentation is kept accurately calibrated and maintained. We do this stuff for a living! (At least I used to until I retired).

[BlackBeard]

Aha!! The gain of "5.15 dBi" is actually fractionally less than 3dB over a dipole. The "dBi" figure is the theoretical "gain" over a non-existent "isotropic radiator". Aerial charlatans always use the "dBi" theoretical figure in an effort to make their aerial appear to have more gain that it actually has. Your measured average 3db over a dipole is probably about right.

An "H" (2-element Yagi - radiator and reflector) will give you almost 3dB more than a dipole, and has semi-circular radiation. You can then "stack" these aerials, adding to the radiated power in the direction you want to go. You're going to have to make phasing harnesses (not difficult) and possibly some Pawsey Stubs (unless you go for Gamma Matches).

Sorry to dig this thread out again. So, Albert, if I'm not mistaken the gain of the H-antenna and the J-pole is roughly the same - about 3 dBd - but the J-pole is omnidirectional and the H-antenna is bi-directional? Or are you explicitly talking about the slim jim?

I read a little bit about the J-pole and a lot of hams said it doesn't have any significant gain over a dipole.

I'm a little confused because the J-pole is omnidorectional with 3 dBd gain and the H-antenna is bi-directional with 3 dBd gain - or did I understand something wrong?

[yellowbeard]

You're getting dBi and dBd mixed up there, the j-pole does not give the 3 dBd of the Yagi, it gives a theoretical 3dBi and has been measured at about 2.5 dBi after losses. This is measured, not theory, not advertising or hype but settled measured numbers. The Yagi is directional and it's gain stated in dBi would be more like 6 dBi in the dominant direction. Have a look here for the dirt on j-poles:
http://on5au.be/content/vhfuhf.html
The 3 part "Some j-pole I have known" and "What is a slim-jim" are good reading, it's by Laurence Cebik who was an authority on antennas. The other part of his site with the non VHF antennas and theory section are mirrored here:
http://on5au.be/content/radio.html

[BlackBeard]

Thanks yellowbeard! Which antenna would you recommend if the area I want to cover is in the north of my tx location? I basically have an "angle" of 180° and want to cover everything that's in front of me (in the north). Behind me are only fields. I'm on top of a hill. I was either thinking about the H-antenna or a 3-element-yagi.

[yellowbeard]

Probably I'd use a vertically mounted Moxon antenna for that, a Yagi would have more gain but even a 2 element one would have too narrow a beam to cover 180 degrees. A Moxon has a cardiod shaped radiation pattern when you mount it vertically. There are details on that UHF/VHF page I posted earlier (Building a 2 Metre Moxon) and this guy has a calculator that works...
http://w4.vp9kf.com/moxon_design.htm

[Albert H]

I'll second that - the Moxon is a good choice (but can be a little finicky to align). I've used "staggered "H"s" and "Staggered 3-element Yagis" to get a slightly wider coverage spread. The ideal "H" provides close to hemispherical radiation, and you can tweak the beam width (a bit) by altering the radiator to reflector spacing a little, but the impedance changes and the match changes too.....

As ever, electronics is about compromise!

[BlackBeard]

I'll second that - the Moxon is a good choice (but can be a little finicky to align). I've used "staggered "H"s" and "Staggered 3-element Yagis" to get a slightly wider coverage spread. The ideal "H" provides close to hemispherical radiation, and you can tweak the beam width (a bit) by altering the radiator to reflector spacing a little, but the impedance changes and the match changes too.....

As ever, electronics is about compromise!

Thanks to you both! Then I guess, I'll stick to the Moxon . Sadly, I don't have enough space for stacked aerials - I'd love to have some stacked/staggered yagis haha.

The Moxon seems to be a good compromise - also regarding it's relatively small size. I need to get the antenna out of a roof hatch. It's a hip roof (slanted/sloped). Alternatively (for a bigger antenna), I could use the lower roof window - which is much bigger - put the antenna out and pull it up with a rope (my mast will be up where the roof hatch is).

Oh, one last question: Is the heigth over ground of an antenna measured from the feedpoint or from the point of the lowest element? Same for stacked antennas, where the antennas need to be a certain wavelength apart, if I'm not mistaken.

[Albert H]

With stacked antennas, it's usually easiest to calculate from the feedpoint. However, there are all sorts of ways of measuring aerials - the Amateur 144MHz aerials (for repeaters) are usually easily scaled to Band II and can give omnidirectional coverage.