What meter is Mr Hollings using?

Banus_radio · Post by **Banus_radio** » Sun Feb 19, 2017 2:34 am

Take a look at this:
https://www.linkedin.com/pulse/fm-anten ... ms-limited

Can anyone tell me what type of meter this is that Alberts best friend is using? he is holding a dipole connected to a meter to see where this super duper 5/8 is radiating.. Looks just like a power meter to me. Im guessing it has a 5ohm resistor in and set to return power? But further down page he says they are only transmitting few miliwatts so im pretty sure a power meter would not pick this up???

Analyser · Post by **Analyser** » Sun Feb 19, 2017 10:14 am

Link didn't work for me.

nrgkits.nz · Post by **nrgkits.nz** » Sun Feb 19, 2017 10:45 am

Analyser wrote: ↑Sun Feb 19, 2017 10:14 am Link didn't work for me.

Need to copy paste url and replace the a***f with obvious. Unfortunately Hollings is willing to sue anyone these days. I saved a lot of the info about him from the old forums and it's on my NZ hosted website out of his reach.

Banus_radio · Post by **Banus_radio** » Sun Feb 19, 2017 11:19 am

https://www.linkedin.com/pulse/fm-anten ... ms-limited

Replace the ***** with the name thats blocked

MiXiN · Post by **MiXiN** » Sun Feb 19, 2017 2:36 pm

Albert's best friend. Hahahahaha

Albert H · Post by **Albert H** » Sun Feb 19, 2017 9:15 pm

1. How can he claim a gain figure for that thing?

2. Why does he "measure" against a theoretical isotropic radiator? That's just a crude way to inflate his already bogus gain figure.

3. The gain he's claiming isn't going to give anything close to 5X ERP as he claims.

4. Why can't he get some real test gear and put the thing on a proper tower and measure real field strength against a properly matched vertical dipole in the same tower?

5. Why is he putting this BS up on LinkedIn?

6. Why can't he get real, useful gain out of such a big aerial? I'd get much more out of four stacked dipoles or even a super-J, and either would be smaller than that abomination. He really doesn't have a clue.

nrgkits.nz · Post by **nrgkits.nz** » Mon Feb 20, 2017 2:17 am

Even I'm still learning and gaining knowledge, many thanks to Albert for this.

I have an example of a recent Hollings PLL board here someone gave to me and I can spot the major stuff ups on it straight away that Paul seems oblivious to. One such example is the non balancing of the oscillator.

Banus_radio · Post by **Banus_radio** » Mon Feb 20, 2017 7:03 am

So do we know what type of meter he is using in his hand?

Albert H · Post by **Albert H** » Mon Feb 20, 2017 8:13 am

It looks like a CB SWR meter. That'll be as much use as a motorbike ashtray. His claims for low SWR cannot be taken seriously .

The correct way to test an aerial is to put it up a tower - at least one wavelength above all the metalwork (unless it's designed to use the tower as a reflector). You also put up a properly matched dipole or ¼-wave vertical with ¼-wave groundplanes (ie: zero gain) aerial with a good match at the same which will allow proper (basic) comparison. You then plot curves of equal field strength - a bit like weather isobars - for both aerials, using the same transmitter. The field strengths along these lines of equality are then averaged, to give a real measure of gain.

If the actual gain is disappointing, you add 2.15dB to your gain figure and call the rating dBi - the gain over an "isotropic" radiator (a wholly artificial construct that cannot physically exist).

A pair of properly matched and fed stacked dipoles will give (roughly) +3dBd so is doubling the ERP. The other benefit is that the radiation pattern is flattened, putting the energy where you want it. A single slot colinear can give around +5dBd (Harry Lythall claims 6dBd, but I think he's being a bit optimistic).

You also have to consider where the energy is going - if it's going straight upwards, you're wasting your time! Stephen Moss's ½-wave vertical has a very advantageous radiation pattern, but the feedpoint impedance is incredibly high, so there's loss in the matching circuit. I does give useful gain over a dipole when properly matched and can perform really well.

⅜-wave, ⅝-wave and ⅞-wave verticals all show gain over a dipole, but need matching coils and groundplanes. The bigger the aerial, the bigger the gain over a dipole. These are all useful aerials and are frequently used for mobiles.

Holling's full-wave monster aerial won't actually ever match properly (unless he adds a gamma, lambda, or other impedance converting match). The "half-wave stub" will actually terminate the lower radiator, so the upper part won't do much at all except add to the weight and turning moment of the aerial! He really doesn't have any clue at all. According to him, a Pawsey stub "can't work" and is just a waste of expensive coax.

Santiago · Post by **Santiago** » Wed Feb 22, 2017 11:32 pm

As useful as an ashtray on a motorbike is one of my personal favs

Sent from my iPhone using Tapatalk

Albert H · Post by **Albert H** » Wed Feb 22, 2017 11:56 pm

thewisepranker · Post by **thewisepranker** » Thu Feb 23, 2017 9:17 am

Albert H wrote: ↑Sun Feb 19, 2017 9:15 pm 6. Why can't he get real, useful gain out of such a big aerial? I'd get much more out of four stacked dipoles or even a super-J, and either would be smaller than that abomination.

I see your point but four stacked dipoles somewhere in Band II would be around six metres in total length, including a bit at the bottom for mounting to something. Did you mean "two"?

Albert H · Post by **Albert H** » Thu Feb 23, 2017 11:32 pm

A single properly matched dipole will probably outperform that silly effort!

A Twin stack can work very well - and isn't too big - but a Quad is MUCH better!

An end-fed ⅞ wave with groundplanes will match 50Ω easily and has an unbalanced feed point, so doesn't need a balun. If properly built and calibrated, it'll outperform the Twin Stacked Dipoles and is much less obvious from the ground! Mine were always made out of H-section aluminium rods, and were usually painted dull grey so they didn't stand out as shiny!

I haven't put one of those up a London block since the late 80s, and was amazed to discover one for 101.9 MHz still up a block in North London just a few weeks ago! The coax (RG213) was still there too, and ran down the inside of the supporting pole, through the roof of the lift room and ended with an N-type plug under the water tank - where I'd left it all those years ago! A quick check with the antenna analyser, and it was bang on 50Ω resistive on 101.9 MHz. It's still there if anyone wants to use it!

Maximus · Post by **Maximus** » Fri Feb 24, 2017 1:03 am

I've been told that the Sirio gamma matched dipoles are meant to be good. Especially when stacked. Although you need to spend more time to tune them correctly.

Also these Moonraker 5/8 GP verticals look alright for £70 delivered:
https://www.ebay.co.uk/itm/182367067713

Sent from my iPhone using Tapatalk

Banus_radio · Post by **Banus_radio** » Fri Feb 24, 2017 6:28 am

Albert H wrote: ↑Thu Feb 23, 2017 11:32 pm I haven't put one of those up a London block since the late 80s, and was amazed to discover one for 101.9 MHz still up a block in North London just a few weeks ago! The coax (RG213) was still there too, and ran down the inside of the supporting pole, through the roof of the lift room and ended with an N-type plug under the water tank - where I'd left it all those years ago! A quick check with the antenna analyser, and it was bang on 50Ω resistive on 101.9 MHz. It's still there if anyone wants to use it!

Well funny enough I'm good friends with beat fm, if you would be so kind to let me know Albert I'll take a sneaky peek. Of course there will be some beer money left in return.

Is this the same aerial u found last year? There was mention of a block last year that you went up and an antenna was still there from the 80's.

Thankyou in advance

thewisepranker · Post by **thewisepranker** » Fri Feb 24, 2017 8:35 am

Maximus wrote: ↑Fri Feb 24, 2017 1:03 am I've been told that the Sirio gamma matched dipoles are meant to be good. Especially when stacked. Although you need to spend more time to tune them correctly.

Correct. You need more than just a SWR meter to tune one. You could do it with just a SWR meter but you would never want to do a second one.

Analyser · Post by **Analyser** » Fri Feb 24, 2017 12:15 pm

thewisepranker wrote: ↑Fri Feb 24, 2017 8:35 am
You could do it with just a SWR meter but you would never want to do a second one.

You f**kin' got that right!

thewisepranker · Post by **thewisepranker** » Fri Feb 24, 2017 7:51 pm

radio-berlin · Post by **radio-berlin** » Fri Feb 24, 2017 10:59 pm

I read that aareeeeff thing twice..
Correct me if I'm wrong and I've only got very basic limited knowledge of antennas but if you make a half wave collinear you would use a half wave matching stub ( e.g. Half wave length long folded forming a u shaped stub 1/4wave long)
So for 5/8 wave vertical stacked in collinear type form is the stub not suppose to be wavelength wavelength divided by 4 forming half of the 8th, if that makes sense ! So once it's folded it will be 300/freq x 8, a fair bit shorter than half wave length.

His matching stub looks like it's 1/2wave length (1/4 length sticking out once folded) on a 5/8 wave vertical. Would that work or would it just terminate the signal there?

Or am I going wrong here and barking up the wrong tree? Of course it's hard to tell from the photos

Albert H · Post by **Albert H** » Sat Feb 25, 2017 3:00 am

His "stub" will prevent the upper part of the aerial doing anything useful - you're right. He's also trying to base-feed it, which won't work at all. Trying to assess the dimensions from those photographs, it really doesn't look like it's going to work in Band II