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Approx 2 Metres, maybe 2.5
Flicking between 1 & 2 bars this morning.
Flicking between 1 & 2 bars this morning.
Right by the yagi, smartphone on same network, 3 bars out of 4 
So, should I try to get some of the LMR-400 you speak of?
Would that fit into the same SMA connectors as I bought for the RG58?
What makes LMR-400 a good choice?
Was wondering.. the yagi has a short length of the RG58 coax which is soldered to the driven element inside the connector box, with the other end (4 or 5 inches away) terminated with a female SMA connector.
If I used a different cable for the main run, e.g. this LMR-400, would that cause some kind of impedance related problem where it meets the RG58
I was thinking of taking the LMR-400 straight to the connector box and soldering it direct to the ends of the driven element to avoid that. Would that be a good idea, and should I include some kind of balun arrangement if I do that?
Sorry for sooo many questions
edit.. ahhhhhh I found a label on my cable: "LMR-195 50 ohm coaxial cable" "KINGSIGNAL"
http://www.timesmicrowave.com/downloads/products/LMR-195.pdf
hmm.. LMR-400 specs
http://www.timesmicrowave.com/downloads/products/LMR-400.pdf
the attenuation figures seem a heck of a lot better for the LMR-400
Would that fit into the same SMA connectors as I bought for the RG58?
What makes LMR-400 a good choice?
Was wondering.. the yagi has a short length of the RG58 coax which is soldered to the driven element inside the connector box, with the other end (4 or 5 inches away) terminated with a female SMA connector.
If I used a different cable for the main run, e.g. this LMR-400, would that cause some kind of impedance related problem where it meets the RG58
I was thinking of taking the LMR-400 straight to the connector box and soldering it direct to the ends of the driven element to avoid that. Would that be a good idea, and should I include some kind of balun arrangement if I do that?
Sorry for sooo many questions
edit.. ahhhhhh I found a label on my cable: "LMR-195 50 ohm coaxial cable" "KINGSIGNAL"
http://www.timesmicrowave.com/downloads/products/LMR-195.pdf
hmm.. LMR-400 specs
http://www.timesmicrowave.com/downloads/products/LMR-400.pdf
the attenuation figures seem a heck of a lot better for the LMR-400
Last edited:
davenn
Moderator
LMR-400 is excellent low loss cable for use above 1GHz, but you are not going to get SMA connectors for it
2.5 metres of RG58 isn't great at 2400MHz its a bit lossy but shouldn't give you the poor reception you are getting. I would be more worried that you have done a bad coax connection or that that yagi is just a crap design
Dave
2.5 metres of RG58 isn't great at 2400MHz its a bit lossy but shouldn't give you the poor reception you are getting. I would be more worried that you have done a bad coax connection or that that yagi is just a crap design
Dave
LMR400 has the same impedance as RG58. The difference is that it has *far* lower losses.
Yes, I would replace the entire cable from the dipole to the phone with a single run of LMR400.
Looking at your datasheets, I have pulled the wrong part number out of my head. LMR400 is a replacement for RG8 which is a much thicker coax.
Yeah, the LMR195 is probably the right thing to use. (But as Dave says, 2.5m is not going to make a heck of a difference -- and you are the ruler of heck)
Does the SMA connector on it plug into your phone? What happens if you plug the antenna directly into your phone and move toward the place where you want to mount the antenna? Do you see improvement that is strongly influenced by the orientation of the antenna?
It's probably better to determine where the fault is. Replacing the cable is pointless if (for a few examples):
1) the antenna element is at fault
2) the balun is at fault
3) the antenna termination is at fault
4) one of your terminations is at fault.
Whilst not a guarantee, measure the resistance between the two conductors in your cable while it is not attached to the antenna. It should be open circuit.
Yes, I would replace the entire cable from the dipole to the phone with a single run of LMR400.
Looking at your datasheets, I have pulled the wrong part number out of my head. LMR400 is a replacement for RG8 which is a much thicker coax.
Yeah, the LMR195 is probably the right thing to use. (But as Dave says, 2.5m is not going to make a heck of a difference -- and you are the ruler of heck)
Does the SMA connector on it plug into your phone? What happens if you plug the antenna directly into your phone and move toward the place where you want to mount the antenna? Do you see improvement that is strongly influenced by the orientation of the antenna?
It's probably better to determine where the fault is. Replacing the cable is pointless if (for a few examples):
1) the antenna element is at fault
2) the balun is at fault
3) the antenna termination is at fault
4) one of your terminations is at fault.
Whilst not a guarantee, measure the resistance between the two conductors in your cable while it is not attached to the antenna. It should be open circuit.
the 2.5M LMR195 cable from the yagi is terminated with two identical male SMA connectors. pin to pin shows very low DC resistance as does connector body to connector body. Haven't done a megger test across the dielectric but a basic continuity test shows open circuit between pin and connector body.
The thing that's doing the receiving is not a phone, it's a huawei router unit with two female SMA external antenna connectors. The router is automatically recognising the yagi when connected to antenna port #1. I haven't tried antenna port #2 yet as the directions for 3G is to just use port #1
Two ports are available because it's a 4G-ready device & provision is available for 2-antenna MIMO. The local tower / network plans to introduce 4G in the near future, probably on 800MHz frequency but maybe 1800MHz. Currently it's just 3G on 2100MHz.
Next attempt will probably be to dispense with the SMA female-to-male junction near the yagi, by soldering the LMR195 direct to the ends of the driven element.
If I can muster the time & energy I might do a homebrew yagi, I have plans for a 16 dB design by someone called "audionut" which uses a dipole type driven element
The thing that's doing the receiving is not a phone, it's a huawei router unit with two female SMA external antenna connectors. The router is automatically recognising the yagi when connected to antenna port #1. I haven't tried antenna port #2 yet as the directions for 3G is to just use port #1
Two ports are available because it's a 4G-ready device & provision is available for 2-antenna MIMO. The local tower / network plans to introduce 4G in the near future, probably on 800MHz frequency but maybe 1800MHz. Currently it's just 3G on 2100MHz.
Next attempt will probably be to dispense with the SMA female-to-male junction near the yagi, by soldering the LMR195 direct to the ends of the driven element.
If I can muster the time & energy I might do a homebrew yagi, I have plans for a 16 dB design by someone called "audionut" which uses a dipole type driven element
