SDS200 range question. Is the telescopic have good range if mounted 25ft compared to a dipole?

[xkingxkaosx]

Hello everyone!

General question: Is the telescopic antenna that came with the SDS200 radio have good range compared to a dipole?

Backstory: My SDS200 is connected to a 50ft low-loss 50ohm cable connected to a dipole. I live in Eastern Kentucky ( Letcher County ) and range and reception is very important. I set my SDS200 for 50 miles but because of the hills and trees, I may get maybe 30 miles. I was going to engineer something to use the telescopic antenna that came with the SDS200 and mount it at least 30ft. The question that worries me is; would I get better range or worse range?

My dipoles are also telescopic. I tried to attach the pictures but they was too big for the server. I have uploaded the picture on my website if anyone needs a visual for better determination > https://ki4kao.net/wp-content/uploads/2024/11/20241123_165547-768x1024.jpg .

I know when it comes to radios, experimenting and testing different antennas and elements usually is needed but in order to save some time, I thought I ask around and see if anybody has this setup.

 

[dave3825]

Usually an antenna mounted up high does better than one low to the ground. What do you listen to with a horizontal dipole?

 

[xkingxkaosx]

Currently listening to law, ems, fire and state police for the county - Letcher County, Kentucky (KY) Scanner Frequencies and Radio Frequency Reference

I feed this into Broadcastify and if I can improve on the range, i definitely will.

 

[doctordialtone]

Currently listening to law, ems, fire and state police for the county

You may want to read up on Antenna Polarization.

Understanding Antenna Polarization - everything RF

What are the different types of polarizations?

www.everythingrf.com

 

[xkingxkaosx]

You may want to read up on Antenna Polarization

Thank you! I am reading up on this now.

 

[mmckenna]

Hello everyone!

General question: Is the telescopic antenna that came with the SDS200 radio have good range compared to a dipole?

Backstory: My SDS200 is connected to a 50ft low-loss 50ohm cable connected to a dipole.

What cable, exactly? Brand/model is important.

I live in Eastern Kentucky ( Letcher County ) and range and reception is very important. I set my SDS200 for 50 miles but because of the hills and trees, I may get maybe 30 miles. I was going to engineer something to use the telescopic antenna that came with the SDS200 and mount it at least 30ft. The question that worries me is; would I get better range or worse range?

My dipoles are also telescopic. I tried to attach the pictures but they was too big for the server. I have uploaded the picture on my website if anyone needs a visual for better determination > https://ki4kao.net/wp-content/uploads/2024/11/20241123_165547-768x1024.jpg .

Most LMR is vertically polarized. Your antenna is horizontal. That 90º mismatch is probably losing 30dB. Each 3dB is half the signal. So that's not doing you any favors. Rotate it so it's vertical, and it should help performance. But a random length of element won't work well on all frequencies.

I know when it comes to radios, experimenting and testing different antennas and elements usually is needed but in order to save some time, I thought I ask around and see if anybody has this setup.

Fix antenna polarization would be step 1. See if that helps.

Correct coaxial cable would be something to consider. Since we don't know what you have, we don't know if that's an issue or not.

Tuned antennas will work better, but if you listen to a wide slice of the RF spectrum, that gets to be a challenge.

 

[xkingxkaosx]

What cable, exactly? Brand/model is important.



Most LMR is vertically polarized. Your antenna is horizontal. That 90º mismatch is probably losing 30dB. Each 3dB is half the signal. So that's not doing you any favors. Rotate it so it's vertical, and it should help performance. But a random length of element won't work well on all frequencies.



Fix antenna polarization would be step 1. See if that helps.

Correct coaxial cable would be something to consider. Since we don't know what you have, we don't know if that's an issue or not.

Tuned antennas will work better, but if you listen to a wide slice of the RF spectrum, that gets to be a challenge.

RG58 BNC Male to BNC Female Coaxial Cable 50 ohm Low Loss​

I went ahead and took down the dipole and switched it out with the telescopic antenna that came with the SDS200. Its been up for about 15 minutes now and currently testing and currently vertical. Funny thing about vertical is my dipole was vertical but last week made them horizontal while fixing up my pole, switched out the feed lines to the new RG58 low loss and made it more higher.

I will remember next time about the polarization.

 

[mmckenna]

50 feet of RG-58 is going to have quite a bit of loss. The manufacturer stating "low loss" doesn't really mean anything. It's just marketing.

At 850MHz, 80% of the received signal will never make it to your radio due to coax loss.
At 450MHz, almost 70% of the signal is lost
At 150MHz, almost 50% of the signal is lost before it gets to your radio.

Losing 50% if all you listen to is VHF may not be a big deal. If you are listening to UHF or 800MHz, the losses are probably impacting what you can hear.

If you really need 50 feet of cable to get from where your radio is to the antenna, then you may want to upgrade your coax. If you don't need 50 feet, shorten it.

 

[xkingxkaosx]

50 feet of RG-58 is going to have quite a bit of loss. The manufacturer stating "low loss" doesn't really mean anything. It's just marketing.

At 850MHz, 80% of the received signal will never make it to your radio due to coax loss.
At 450MHz, almost 70% of the signal is lost
At 150MHz, almost 50% of the signal is lost before it gets to your radio.

Losing 50% if all you listen to is VHF may not be a big deal. If you are listening to UHF or 800MHz, the losses are probably impacting what you can hear.

If you really need 50 feet of cable to get from where your radio is to the antenna, then you may want to upgrade your coax. If you don't need 50 feet, shorten it.

RG58 will be replaced during tax time. I did have a 25ft foot cable I replaced it with after increasing pole size. I do have another shorter spare I can replace it with. Thanks for this info!

 

[buddrousa]

I was in the London area 1st Week of November with a Tri Band MNO antenna on the Vehicle I was Driving and as long as I was not next to a Big Hill you have in the area I was able to receive the TACN System from Tn Laurel County and all Counties that are around it as well as KSP for the area.

 

[mmckenna]

I was in the London area 1st Week of November with a Tri Band MNO antenna on the Vehicle I was Driving and as long as I was not next to a Big Hill you have in the area I was able to receive the TACN System from Tn Laurel County and all Counties that are around it as well as KSP for the area.

Yeah, I think a good multiband vertical with a ground plane kit would outperform a dipole. If it's in the OP's budget, it might be a good upgrade in the future.