Know I’ve linked this before, but it’s inline with this thread as a few of the antenna brought up here were included in the test.
I’ll be doing a new round with Airspys and more antenna. Will also be adding VNA shots for kicks.
If anyone has recommendations to make the test methodology better, I’m all eyes. I think the Airspys will help since they aren’t as anal about gain as the RTL based radios due to their increased sensitivity and dynamic range. I won’t be doing a full 24 hour test on each this time either… won’t be needed when testing true side by side. Plus I don’t want to sit there and test for a month straight. I need to grab a few more antenna and find the time first.
Add: if anyone has an extra DPD or Jetvision laying around that they want to sell, please hit me up. I’d rather not pay full retail if I can help it… chances are I won’t even be using them after testing unless one of them blows the rest out of the water for my location.
I’ve been preaching this on here for a long time, but the general opinion is that if you have a mast head pre-amp (or even a pre amp at the bottom of the coax) then the quality of the cable doesn’t really matter because the gain of the amplifier compensates for the loss of the cable. Signal to noise ratio and noise in the cable doesn’t seem to come into the equation.
Neither does impedance with people happy to use 75 ohm satellite cable (it’s cheap) and accept the small additional loss by the mismatched impedance.
Personally I want to squeeze every bit of performance out of a system so I always buy the best and highest spec cable I can afford and use the shortest run possible to minimise loss.
I understand RF engieeering, but still I dont like to spend too much money for the last bit of improvement (say last 15%). I would prefer to give this money in charity rathar than to excessively invest it in a hobby.
keithma I agree. at some frequencies the line loss is not a big factor, but when u get in the Ghz range it is critical. Connectors are also a big deal. Use the best and adapt as little as possible.
Yes, one of the things that particularly concerns me is the number of impedance transitions some people have in their system. Mismatch loss on a single transition may appear minimal but the effects of phase distortions caused by multiple reflections, I think, could lead to serious degradation in performance. My view is pick an impedance and stick to it. My choice is 50 ohm throughout, as that is what all the combiners, directional couplers, antennas, receivers etc. I have are designed for.
