Help with splicing RG58A/U Coax

[ArloG]

It's more like you have 4x4 and you put on the best low profile road tyres you can get but you only drive on gravel and in the terrain. You pay too much for something that are not neccesary. Scanner antennas and scanners are not expensive 2-way radios and antennas that have a perfect 50 ohm impedance at the frequency they are used for. If RG6 coax and connectors are good enough to be used with sat dish signals at 3GHz then it's probably good enough for scanner use.

Spend your money on a low-noise amplifier, it will isolate the impedance from the antenna to the coax and with a lower noise level it will increase the scanners sensitivity and also make the coax a non attenuating device, a win-win situation. Always use a variable attenuator to adjust for best possible signal quality in the scanner as little too much signal will instead make the scanner loose it's sensitivity.

/Ubbe

Oops. 950-1450MHz at the lnb port. Not like the old LNA/Downconverter days.
And yeah. I'm using a nooelec LANA for my sdr radio and even on my IC-R8600. Not even at the antenna.
And fyi. Before I bought my F compression crimp tool I just used 2 pairs of small Channel Locks to do the deed. Cable companies have all gone to compression crimp from hex crimp to assure a weather resistant seal.
There just aren't that many walk-in electronics stores anymore and so we all know the drill. Order and wait.
I'm not going to even go into Tires here. Amateur casual users jury rig too much and end up spending way more chasing bugs when they could have just done it right.
We can discuss the CB trucker who plumbed his Freightliner with a nice antenna, connectors, and radio and just happened to have a spool of good 75 ohm coax. Assumptions had me chasing terrible SWR (which DOES matter on any system rx and tx). I assumed too well and saw what he used. Lets talk about that later. There went several feet of my 9913 off the spool and some spare PL connectors from the box-o-connectors.
So, good luck and I hope you do it the right way.

 

[KO4IPV]

It's more like you have 4x4 and you put on the best low profile road tyres you can get but you only drive on gravel and in the terrain. You pay too much for something that are not neccesary. Scanner antennas and scanners are not expensive 2-way radios and antennas that have a perfect 50 ohm impedance at the frequency they are used for. If RG6 coax and connectors are good enough to be used with sat dish signals at 3GHz then it's probably good enough for scanner use.

Spend your money on a low-noise amplifier, it will isolate the impedance from the antenna to the coax and with a lower noise level it will increase the scanners sensitivity and also make the coax a non attenuating device, a win-win situation. Always use a variable attenuator to adjust for best possible signal quality in the scanner as little too much signal will instead make the scanner loose it's sensitivity.

/Ubbe

Please explain a variable attenuators: should this be something I need to do to receive best and more ? Using the SDS100 new

 

[Ubbe]

Please explain a variable attenuators: should this be something I need to do to receive best and more ? Using the SDS100 new

Attenuators do not help enough with a SDS100 as it has problems even at lower signal levels.

But electronic amplifiers have internal noise, the noise figure NF in decibels. The higher the dB the worse sensitivity it will have. There's also a maximum level of signal they can receive until the NF will rise. It's often a relationsship between low NF and low level where it starts to increase NF.

When the signal reaches that ctitical level it will desense the receiver, it gets worse and are not as sensitive any more. If the signal increases even more it begins to act like a mixer and mix different input frequencies with each other and creates a third one that only exists in the receiver, intermodulation. But long before that happens the receiver have lost some of its sensitivty and usually without you knowing about it.

If you have a varible attenuator you connect that to the receivers antenna jack and set it to 0dB, no attenuation. Then listen in analog mode to a weak signal and adjust the attenuator to get the best noise free signal. Some receivers like portables that are designed to work with a small inneficient antenna might need attenuation when connected to bigger antennas but base/mobile receiver are often designed to cope with big signals. If you use an amplifier you will need to attenuate the signal to not get inte desense levels or even into intermod.

A receiver like Icoms R2 and R10 that have a sensitivity of 0,15uV gets into trouble almost immediatly when encounter a stronger signal but a receiver like Pro 2006 with a 0,5uV sensitivy can handle almost any kind of strong signal without any problem or sign of desense. That's why some people say it's their most sensitive scanner, when in fact it is their most unsensitive one but are the best at handling strong signals without loosing its sensitivity.

/Ubbe

 

[KO4IPV]

Attenuators do not help enough with a SDS100 as it has problems even at lower signal levels.

But electronic amplifiers have internal noise, the noise figure NF in decibels. The higher the dB the worse sensitivity it will have. There's also a maximum level of signal they can receive until the NF will rise. It's often a relationsship between low NF and low level where it starts to increase NF.

When the signal reaches that ctitical level it will desense the receiver, it gets worse and are not as sensitive any more. If the signal increases even more it begins to act like a mixer and mix different input frequencies with each other and creates a third one that only exists in the receiver, intermodulation. But long before that happens the receiver have lost some of its sensitivty and usually without you knowing about it.

If you have a varible attenuator you connect that to the receivers antenna jack and set it to 0dB, no attenuation. Then listen in analog mode to a weak signal and adjust the attenuator to get the best noise free signal. Some receivers like portables that are designed to work with a small inneficient antenna might need attenuation when connected to bigger antennas but base/mobile receiver are often designed to cope with big signals. If you use an amplifier you will need to attenuate the signal to not get inte desense levels or even into intermod.

A receiver like Icoms R2 and R10 that have a sensitivity of 0,15uV gets into trouble almost immediatly when encounter a stronger signal but a receiver like Pro 2006 with a 0,5uV sensitivy can handle almost any kind of strong signal without any problem or sign of desense. That's why some people say it's their most sensitive scanner, when in fact it is their most unsensitive one but are the best at handling strong signals without loosing its sensitivity.

/Ubbe

Ok then !!!!! Wow I think as you mentioned my scanner, won’t be much help , thanks for your thorough explanation.

 

[Ricardojv0811]

Buy a lightning protector for your antenna and ground the device. It worked for me.

MFJ-272MF Lightning Arrester DC-1GHz UHF-M/F 1.5kW

Hope it helps.