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Ron Smith high gain FM aerials
Justin Aerial
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Can anyone explain this ?
Ron Smith make elaborate high gain FM aerials*. They claim an average gain of about 8dB (is that dBd or dBd ? ) for their Circular 5 aerial.
The next model up is the Diamond 12 which has a claimed gain of 13dB. But the only difference is in the number of elements in the reflector.
Now this is at odds with my research which only gave a difference of 0.8dB between an aerial with a full 6 element reflector and a partial 2 element one.
Has anyone got any ideas ?
* I have to say that in my experience hardly anyone actually needs a high gain multi element FM aerial. A half wave dipole is fine, even the round Halo type Omnis works reasonably for many people and they`re basically a bit crap ! They`ve got significantly lower gain than a half wave dipole.
Ron Smith make elaborate high gain FM aerials*. They claim an average gain of about 8dB (is that dBd or dBd ? ) for their Circular 5 aerial.
The next model up is the Diamond 12 which has a claimed gain of 13dB. But the only difference is in the number of elements in the reflector.
Now this is at odds with my research which only gave a difference of 0.8dB between an aerial with a full 6 element reflector and a partial 2 element one.
Has anyone got any ideas ?
* I have to say that in my experience hardly anyone actually needs a high gain multi element FM aerial. A half wave dipole is fine, even the round Halo type Omnis works reasonably for many people and they`re basically a bit crap ! They`ve got significantly lower gain than a half wave dipole.
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There may be some kind of non-standard gain measurement they are using or the circular dipole may affect the lobes/measurements weirdly but more likely, someone has added up all the elements including reflectors and looked it up in a yagi gain table as if all but two of them are directors! <rolleyes>.
I was really hoping that you'd get hold of some of these and do some of your testing on them Justin.
It's not the cost, it's that these seem to be on a par with gold-plated mains cables and air-spaced speaker wire holders
Perhaps something like this:
http://www.solidsignal.com/pview.asp?p=shd7082&d=Winegard-HD-7082P-High-Definition-VHFUHFFM-TV-Antenna%28HD7082P%29&sku=615798317478&mc=03&utm_campaign=PJ_AFF&utm_medium=AFF&utm_source=PJ
Welcome to the world of HiFi. Everything will be perfect so long as you believe but don't do anything stupid like going to a live concert with real musicians.
One was fitted on a rotator-pole as part of an installation on the BBC White City Building in the early 90s for monitoring transmissions... (specified by Projects who never asked the user-experts what they wanted) .
Someone probably still has a set of of measurements made off it pointed to different sources... It worked but performance wasn't outstanding if I recall correctly. However, it soon fell to pieces and was replaced by a Fuba yagi design - the one with twin reflectors.
Hmm, 180"", 4.5m long, I don't think you'd get away with a bodge job loft bracket screwed to the fascia with that...
It also gave me nightmares when one of those occasional storm force winter storms came along
Can you explain that a bit more please? I get the bit about the dynamics compression (introduced on "drive time" progs on Radio 3 in March 1989) but I'm unclear as to what the criticism of the 13 bit linear PCM system (first used in 1972 to Wrotham and then extended northwards) was/is.....
There was certainly amusement at the BBC in 1982 ish when CDs first appeared and some audiophiles who didn't like the idea of CDs held Radio 3 up as an example of how perfect an all-analogue system was, forgetting of course that the PCM distribution was digital, but you seem to be suggesting something else....?
Are you saying you`d expect a three element aerial (because that`s effectively what it is, one director, the dipole, then the reflector) to give nearly 6dBd / @8dBi) ? I have to say that seems rather high, I`d expect 3 or 4 dBd.
The gain seems to be quoted with respect to an isotropic radiator rather than a dipole, this adds 3db to the figures. It is not uncommon in aerial measurements, whether it is ethical or not is another matter.
You mean the infamous dBi ? I agree it`s a dubious marketing practice to quote dBi, but isn`t that +2.15dB ? Even adjusting for that still implies they`re quoting a gain of about 6dBd, for a three element aerial.....
3/2.15 seems to depend on who you ask, I'm sure it was 3 when I was at college (and god was a boy). Now about that special aerial cable you wanted, the one that adds a feeling of involvement to the sound, only £75/metre (+VAT). Perfect for Ron Smith Aerials!
Their "Gain" specs are obviously up the proverbial antenna mast, whether it be dB as quoted (dBd is implied), or dBi (which is not stated), at least the Galaxie 12 element versions and beyond. http://ronsmithaerials.com/catalogue/fmspecs.php
There is no way on this earth that a 44 inch long FM band antenna of that design can achieve a gain of 14.7dB (or dBi for that matter) as claimed for the G 14. That's the point some of us have been making.
14.7 dB seems close enough to me for the antenna you refer to !
Not when connected via our new graphene inspired ultra cable with gold plated plugs sheathed with an outer covering made from woven virgins hair, (very rare these days).
You must learn to love (HiFi) big brother Winston.
If you need lillel ole me to explain the tecky bits ,I will be pleased to .
But the price is you must write 50 lines on this forum that says
I don't know naff all about how a yagi works .
(only teasing )
I will give thee a clue .
The gain of a dipole is a miges dick over 2db ,add a reflector and it increases to >5db
X 3 = 9.5 dB plus some additional reflectors and directors that could add easily 5db .
The truth is designing antennas is complex ,but these days software makes it a tad easier and I do this for a living at other frequencies, amongst other things ,
such as moaning and winging .
But I am sure the manufacturers who designed this antenna know what they are doing and have done the measurements .
By the way I have no connection
It's equivilent to three