There is no marking to identify which one is 978 and which one 1090.
As there was no way to find out, I tried these, first both at 1090 and again both at 978. Both proved hopeless at both frequencies. Inferior than the mag-mount stock antenna of generic dvbt placed over cookie-can lid.
I am not using these as these are hopeless. I break-open one of these. Here is the photo:
Have you tried running them without the plastic cover?
Seen a video of someone testing one of these antennas and the producers tuned them without the plastic shroud which makes quite a difference apparently.
I’m certainly noticing an improvement with the FlightAware stick and NooElec antenna laid completely flat I’m getting quite a good range considering it’s just 8ft high in a garage
Both of mine opened nicely, no cuts required, and therefore re-usable.
I cut the wire antenna and trimmed the PCB to a size where it becomes just a solder pad. I’ll solder a wire with the proper length, and place the cover back on.
The SMA side of one of the jumpers, being a bulkhead type, will be installed on a food can with the proper dimension. I can then use this setup with a no-name generic dongle, which I have too may laying around.
For future reference. RG-58 is very lossy at 1GHz. 21.5 dB per 100 feet. So even if your feedline is only 10 feet long, you’re losing 2.15 dB of signal and if there’s no amplifier at your antenna, then the S/N ratio is degraded by the same amount.
has finally arrived and it seems to be a little better than my cantenna.
Not by much though, not that i was expecting much.
Better than the FA antenna is something i seriously doubt, maybe the OP has bought a fake FA antenna?
Note i don’t have an FA antenna and don’t really plan on buying one they are kinda expensive in the EU.
Anyway the advantage over a cantenna is it looks a bit nicer, so i might go from the attic under the roof to on the roof. Also i don’t need to weatherproof my cantenna
The noise figure for a passive device is equal to its attenuation.
Here’s an explanation from a professor at Kansas State University who teaches an RF design course.
The main point I was trying to make is that RG-58 has really lousy performance at 1 GHz.
It’s OK up to the top end of the HF part of the spectrum (30 MHz). Above that, performance drops off quickly. For a very short run, e.g. less than a meter, it would be OK.
That is a theoretical noise figure that discounts actual noise that is received by the antenna. Practical S/N ratios depend on actual noise present, don’t they?
But you are of course correct the cable is less than optimal.
It does indeed sound “only theoretical” but it’s actually a spec that RF engineers need to take into account when designing a receiver.
He mentions:
However, for passive two-port devices (e.g., an attenuator), we find that attenuation A and noise figure F are not only completely dependent—they are in fact equal!
A transmission line can be equated to an attenuator in that respect, since both devices exhibit signal loss.
But say you have 2 signals, 1 being specified as noise and 1 being the interesting signal.
Both are now attenuated by the cable by the same amount. Now if you don’t have any noise coming from the antenna or the noise that’s a different story but it’s not necessarily realistic.
Maybe i’m missing something but i don’t think as quoting the pdf you linked:
On the other hand, as A gets very large, the input noise is
completely absorbed by the device. The noise at the device
output is entirely generated internally, with a noise
temperature Tout = 290KD
equal to its physical temperature.
So yes you get more noise with higher attenuation but if the input noise is a significant factor it probably is the more significant part after the cable.
Not sure what you’re saying here. Did a word get left out?
It sounds that way, but one of the things that can affect antenna noise contribution is where its pointing.
e.g. if it’s pointed skyward, the noise temperature can be as low as 10° K.
An antenna with a flattened pattern, like a colinear, “looks” more toward the horizon vice the sky like a ground plane antenna does, hence is likely to affected by terrestrial noise sources to a greater degree than the ground plane.
IOW, if the noise contributed by the antenna is several decibels greater (at the receiver input) than the receiver noise floor, the antenna-contributed noise will be the predominant noise, and the receiver noise can be ignored for practical purposes. So in essence, we’re both correct. If the transmission line loss is high, then changing to a low-loss line might improve the SNR, but not if the ambient site noise is high.
Ambient noise being white noise, vice RFI.
On the other hand, if the site noise is not high, then a low-loss feedline will improve SNR.
