New Base Station Setup

[WRXU861]

My new base radio arrived earlier this week, and I set it up with a home-made copper pipe J pole and RG 213 coax.  I'm able to hear my local repeaters very clearly and have carried on a few conversations across a repeater that's about 30 miles away.  Unfortunately, most other operators can't seem to hear me very well.  Sometimes, they can, but not always.  I've already set my antenna up where it has clear line of sight according to https://www.scadacore.com/tools/rf-path/rf-line-of-sight/, but it could always be higher.  I've also made sure I'm using wide band, but my voice seems to be hit and miss over the repeater.  If anyone has suggestions about how to make things better, please let me know. 

-Steve

WRXU861

[Hoppyjr]

-Move the antenna higher

- Use a better antenna

- More power

- Accept the fact that you get what you get and be happy with that

[OffRoaderX]

3 minutes ago, Hoppyjr said:

Accept the fact that you get what you get and be happy with that

THIS ^  

[BoxCar]

I would check the antenna. Use a Nano VNA if possible and check the frequency the antenna resonates at along with the bandwidth. As you stated it's a home brew, its possible it is off frequency.

[WRUU653]

7 hours ago, WRXU861 said:

.  If anyone has suggestions about how to make things better, please let me know.

Try higher and better antenna. Go to doughnut shop, get maple bars. Works for me but I’m only five miles from repeater and the doughnut shop is even closer. Pro tip make sure to get what kind the spouse likes if you have one. I may be distracted this morning. Sorry. Doughnuts… 

[Socalgmrs]

You didn’t say what radio/watts your base is but if everything else is working correctly and you really do have line of sight then it’s the junk pole antenna.  Line of sight with a 5w hand held at 30miles should come in very clear so with a base and a good antenna like a comet 712efc and even a 15w base station with lmr400 cable 30mile should be a drop in the bucket.  

[nokones]

Get an antenna analyzer and check and see what the center resonance is then check the VSWRs with the radio in-line with the antenna transmission system. Check your station output power with a Load Terminator that measures at 50 ohms.  Also, make sure that repeater you're trying to access is either a wideband operation or a narrowband operation and set your station accordingly.

[GrouserPad]

 

5 hours ago, Socalgmrs said:

You didn’t say what radio/watts your base is but if everything else is working correctly and you really do have line of sight then it’s the junk pole antenna.  Line of sight with a 5w hand held at 30miles should come in very clear so with a base and a good antenna like a comet 712efc and even a 15w base station with lmr400 cable 30mile should be a drop in the bucket.  

What is the output power of a 5 watt ht when it gets to the antenna after traveling 100ft up some rg213? About 1 watt. I’m calling shenanigans lol

[WRYZ926]

3 hours ago, GrouserPad said:

 

What is the output power of a 5 watt ht when it gets to the antenna after traveling 100ft up some rg213? About 1 watt. I’m calling shenanigans lol

A lot will depend on the gain of the antenna. According to the https://kv5r.com/ham-radio/coax-loss-calculator/; you will get an ERP of 1.9 watts when using a radio with 5 watts output, 100 ft of RG-213, and an antenna with 1 dBd of gain. As you can see the calculated ERP is 1.9 watts

Now the ERP will go up as the antenna gain goes up.

So if the antenna gain is 2 dBd then the ERP will be 2.4 watts. And if you jump up to a gain of 5 dBd then the ERP will be 4.7 watts

One thing to keep in mind is that most antenna manufacturers list the gain in dBi while most loss calculators use dBd. Subtract 2.14 from the dBi value to get the dBd value. 

The kv5r coax loss calculator is not exact but it is close enough to see what the loss difference is between different types of coax and at different lengths.

[WRUE951]

14 hours ago, WRXU861 said:

My new base radio arrived earlier this week, and I set it up with a home-made copper pipe J pole and RG 213 coax.  I'm able to hear my local repeaters very clearly and have carried on a few conversations across a repeater that's about 30 miles away.  Unfortunately, most other operators can't seem to hear me very well.  Sometimes, they can, but not always.  I've already set my antenna up where it has clear line of sight according to https://www.scadacore.com/tools/rf-path/rf-line-of-sight/, but it could always be higher.  I've also made sure I'm using wide band, but my voice seems to be hit and miss over the repeater.  If anyone has suggestions about how to make things better, please let me know. 

-Steve

WRXU861

Copper J-Poles are pretty hard to  build for UHF, you must get the precise measurements to a T for the frequencies  and they extremely hard to tune SWR's.   As others suggested the best way to tune them is via a NANO VNA.  I came up with a sliding adjustment gimmick for tuning SWR that works well.  Made with cooper compression splices you can get at home depot.  

[WRXU861]

That's innovative.  I went a different way with the tuning, though and got my right around 1.05.  Today, I raised my antenna by about six feet, which greatly improved the situation.  Turns out, the line of sight tool shows a green line of sight even if there's some topography in the way.  The extra six feet cleared things up.  Sometime over the next few weeks, I'm going to move it up another 10 or 15 feet.

-Steve

[WRXU861]

11 hours ago, WRUU653 said:

Try higher and better antenna. Go to doughnut shop, get maple bars. Works for me but I’m only five miles from repeater and the doughnut shop is even closer. Pro tip make sure to get what kind the spouse likes if you have one. I may be distracted this morning. Sorry. Doughnuts… 

The problem was the antenna height.  My SWR is really good and I'm using 50 ft of RG213.  I moved the antenna up from around 9 feet to around 15 feet.  Now, I'm reliably getting through the repeater around 30 miles away.  There's a little static, but just enough to remind me that I'm on a radio.

[WRUE951]

52 minutes ago, WRXU861 said:

The problem was the antenna height.  My SWR is really good and I'm using 50 ft of RG213.  I moved the antenna up from around 9 feet to around 15 feet.  Now, I'm reliably getting through the repeater around 30 miles away.  There's a little static, but just enough to remind me that I'm on a radio.

J-Poles don't like any type of obstruction around them..  I have talked 90 miles + with my portable setup when mounted out in a wide open area.. But when i get around something like a single treee, it goes to hell like what you are describing.  Overall i get pretty good performance from it, defiantly better than a fire stick.   I also built a Ladder Lead J-pole, like the Ed Fong version, the copper version seems to work much better.   

[WRUU653]

1 hour ago, WRXU861 said:

The problem was the antenna height.  My SWR is really good and I'm using 50 ft of RG213.  I moved the antenna up from around 9 feet to around 15 feet.  Now, I'm reliably getting through the repeater around 30 miles away.  There's a little static, but just enough to remind me that I'm on a radio.

Outstanding that worked out for you.

[WRXU861]

6 hours ago, WRYZ926 said:

A lot will depend on the gain of the antenna. According to the https://kv5r.com/ham-radio/coax-loss-calculator/; you will get an ERP of 1.9 watts when using a radio with 5 watts output, 100 ft of RG-213, and an antenna with 1 dBd of gain. As you can see the calculated ERP is 1.9 watts

Now the ERP will go up as the antenna gain goes up.

So if the antenna gain is 2 dBd then the ERP will be 2.4 watts. And if you jump up to a gain of 5 dBd then the ERP will be 4.7 watts

One thing to keep in mind is that most antenna manufacturers list the gain in dBi while most loss calculators use dBd. Subtract 2.14 from the dBi value to get the dBd value. 

The kv5r coax loss calculator is not exact but it is close enough to see what the loss difference is between different types of coax and at different lengths.

I'm using a 40 watt radio with 50 ft of RG 213.  Moving my antenna high enough to get a clear line of sight made all the difference.  Turns out, I was misreading the line of sight graph.   Now, I can carry on clear conversations with all the repeaters within my local area.

[WRYZ926]

59 minutes ago, WRXU861 said:

I'm using a 40 watt radio with 50 ft of RG 213.  Moving my antenna high enough to get a clear line of sight made all the difference.  Turns out, I was misreading the line of sight graph.   Now, I can carry on clear conversations with all the repeaters within my local area.

Line of sight does make more of a difference when using VHF and UHF. I'm glad to hear that you are getting into all of the repeaters now.

A j pole antenna has zero gain when measured in dBd, which is the same as a dipole antenna. Using the kv5r loss calculator and your specs, you will have an ERP of 21.8 watts. As you see that will still work even though you are losing about half your power output.

Switching to 50 feet of LMR400 will only gain you 6.9 more watts on ERP. I would not bother switching out the RG-213 to LMR400 for that little power gain.  What will make a difference is going with an antenna with higher gain.

But no need to change anything if it is working well for your needs.

Edited 14 hours ago by WRYZ926