Reception Question

[WRZP701]

Greetings all.  I'm still pretty new to this so any suggestions would be greatly appreciated.  I seem to be having issues with reception.  At-least, I think I am.  I've got a UAYESOK Fiberglass GMRS Base Antenna (https://www.amazon.com/UAYESOK-Fiberglass-Antenna-Repeater-Motorola/dp/B0CF9DV3ZM), about 30' up off the ground (a good 10' above the house ridge line).  It's going into a Wouxun KG-1000G-Plus from a 50' RG213 coax, into an arrester (that's ground out to an 8' grounding rod buried at point of entry to the house), followed by a 10' RG213 coax entering the house, down into the radio.  SWR shows around 1.0 at full 50watts.  (Maybe fluxuate a littlle every once in a while but never over 1.5:1).

Nearest I can tell, this is about as optimal as I can make it.

I can hear NOAA, local Air Traffic Control, local HAM (2m/70cm repeaters) all with this antenna (and it's only a UHF tuned for GMRS).  I have been trying to make contact with folks on a repeater (WMTG600) that's a fair distance away (about 30 miles give or take).  I know my transmits are getting through as I can almost make out folks coming back if I turn off the squelch and just monitor closely.  But I'd have expected to be able to hear much better than this.  

Any thoughts or suggestions on improving reception?  Or, is it just "quite" out there with this repeater and those trying to respond back are really just that far away?

Appreciate the feedback.

[WRYZ926]

The wrong type of coax or bad coax will cause even the best antenna to not perform well. RG-213 is good for HF frequencies but not so good for VHF or UHF frequencies.

I suggest getting some good LRM400 or equivalent coax first. And if that doesn't help, look into a better antenna. The Comet CA-712EFC is an excellent antenna and is not much more than that no name antenna from Amazon.

[SteveShannon]

32 minutes ago, WRXP381 said:

Haha this would only matter on transmit.  Not receive so the op was asking about receiving. 

Resistive losses in coax cable work in both directions. 

[WRWE456]

Hello and welcome!

What is the terrain like between your antenna and the repeater? GMRS is UHF and is mostly line of sight. It can penetrate some amount of vegetation and homes etc but not hills or mountains.

Use this Line of Sight mapping tool to check your path:   https://www.scadacore.com/tools/rf-path/rf-line-of-sight/

In the pop up graph you can input the height of the antennas for more accuracy.

Start there.

[SteveShannon]

25 minutes ago, WRZP701 said:

Greetings all.  I'm still pretty new to this so any suggestions would be greatly appreciated.  I seem to be having issues with reception.  At-least, I think I am.  I've got a UAYESOK Fiberglass GMRS Base Antenna (https://www.amazon.com/UAYESOK-Fiberglass-Antenna-Repeater-Motorola/dp/B0CF9DV3ZM), about 30' up off the ground (a good 10' above the house ridge line).  It's going into a Wouxun KG-1000G-Plus from a 50' RG213 coax, into an arrester (that's ground out to an 8' grounding rod buried at point of entry to the house), followed by a 10' RG213 coax entering the house, down into the radio.  SWR shows around 1.0 at full 50watts.  (Maybe fluxuate a littlle every once in a while but never over 1.5:1).

Nearest I can tell, this is about as optimal as I can make it.

I can hear NOAA, local Air Traffic Control, local HAM (2m/70cm repeaters) all with this antenna (and it's only a UHF tuned for GMRS).  I have been trying to make contact with folks on a repeater (WMTG600) that's a fair distance away (about 30 miles give or take).  I know my transmits are getting through as I can almost make out folks coming back if I turn off the squelch and just monitor closely.  But I'd have expected to be able to hear much better than this.  

Any thoughts or suggestions on improving reception?  Or, is it just "quite" out there with this repeater and those trying to respond back are really just that far away?

Appreciate the feedback.

So at 450 MHz RG213 loses 5.2 dB in 100 feet, so in 60 feet you’re losing a little more than 3.12 dB. That’s half of your power. 
That also affects your measurement of SWR if you’re measuring right at the radio because you truly are not measuring the power that reaches the antenna and the reflected power measurement is much lower than it truly is. 
Try temporarily shortening your cable and measure the SWR right at the antenna. 

[WRZP701]

1 hour ago, WRWE456 said:

Hello and welcome!

What is the terrain like between your antenna and the repeater? GMRS is UHF and is mostly line of sight. It can penetrate some amount of vegetation and homes etc but not hills or mountains.

Use this Line of Sight mapping tool to check your path:   https://www.scadacore.com/tools/rf-path/rf-line-of-sight/

In the pop up graph you can input the height of the antennas for more accuracy.

Start there.

What a fantastic website!  Mostly trees/woods/typical rural houses.  Elevation may be at issue  I'll also check Steve's suggestion on measuring at the roof/antenna end of the coax as well.

 

[gortex2]

TX power has nothing to do with reception. If you are on the edge of the repeaters coverage then have 3db of loss in cable that's most likely your issue. A 50 watt radio will not receive any better than a 5 watt radio. Depending on the repeater this may be your issue.

[Socalgmrs]

Do you have any other radios to test this out. 30 miles may just be on the edge of the repeater.  Do you have a mobile or hand held you can start at your home and drive closer and closer untill you hit it?   We’re I’m at we have very nice repeaters that are all 50w with great antennas that have well over 100mile radius but some just don’t.   And honestly the antenna you linked to may not be very good. Kind of a no name antenna.   Id send it back and spend a little more and order a comet 712efc it’s 10’ tall and 9db gain. Id also dump the co-ax and get real Lmr400.   You spent all kinds of money on the radio and very little on the important antenna and coax.  Unfortunately you did things backwards.  

[WRXR255]

3 hours ago, WRWE456 said:

Hello and welcome!

What is the terrain like between your antenna and the repeater? GMRS is UHF and is mostly line of sight. It can penetrate some amount of vegetation and homes etc but not hills or mountains.

Use this Line of Sight mapping tool to check your path:   https://www.scadacore.com/tools/rf-path/rf-line-of-sight/

In the pop up graph you can input the height of the antennas for more accuracy.

Start there.

That is an important and helpful tool, but the Hat Trick is how do you find the lat/long and antenna height of say, the repeater your looking at?

[WRWE456]

1 hour ago, WRZP701 said:

What a fantastic website!  Mostly trees/woods/typical rural houses.  Elevation may be at issue  I'll also check Steve's suggestion on measuring at the roof/antenna end of the coax as well.

Out of curiosity what distance did the map indicate? Is the repeater on the left side of the graph? The higher one? You do have some terrain in between. The line will turn green when the path is in the clear. It may still work somewhat but that is likely part or most of the problem.

And yes better cable is very important as well.

 

[WRZP701]

54 minutes ago, WRWE456 said:

Out of curiosity what distance did the map indicate? Is the repeater on the left side of the graph? The higher one? You do have some terrain in between. The line will turn green when the path is in the clear. It may still work somewhat but that is likely part or most of the problem.

And yes better cable is very important as well.

 

Repeater on right side in the graph. I’m on the left.  30mile distance.

Appreciate everyone’s feedback.  I’m good with replacing the cable. I’m still pretty new to this. For some reason I had it in my head 213 was better for GMRS than LRM when under 100’. And the antenna I had gotten as a gift before I knew to even ask. 
y’all gave me some good things to dig into. Much appreciated. I’ll get to work.

thanks.

[WRWE456]

This forum is a great resource. Use the search function as this is a common topic.

[SteveShannon]

2 hours ago, WRZP701 said:

Repeater on right side in the graph. I’m on the left.  30mile distance.

Appreciate everyone’s feedback.  I’m good with replacing the cable. I’m still pretty new to this. For some reason I had it in my head 213 was better for GMRS than LRM when under 100’. And the antenna I had gotten as a gift before I knew to even ask. 
y’all gave me some good things to dig into. Much appreciated. I’ll get to work.

thanks.

There are lots of different types of LMR cables and RG cables. Generally speaking larger diameter cables have less attenuation. Times Microwave makes the genuine LMR cables and for distances like yours LMR-400 is typically considered the minimum.

There are several companies that manufacture cables that are very similar in quality to LMR-400 as well. Messi &Paloni is one I like.

You probably want to steer clear of the knockoff brands from China, such as the KMR400.  I haven’t tried it myself so I can’t definitively say it’s bad, but I also haven’t heard anyone brag about it.

RG213 is good cable for the right application (lower frequencies and/or shorter distances). If you only had to go 20 feet the difference would not matter as much. But hang onto it. You always need a few jumpers. 

[WRZP701]

5 minutes ago, Sshannon said:

There are lots of different types of LMR cables and RG cables. Generally speaking larger diameter cables have less attenuation. Times Microwave makes the genuine LMR cables and for distances like yours LMR-400 is typically considered the minimum.

There are several companies that manufacture cables that are very similar in quality to LMR-400 as well. Messi &Paloni is one I like.

You probably want to steer clear of the knockoff brands from China, such as the KMR400.  I haven’t tried it myself so I can’t definitively say it’s bad, but I also haven’t heard anyone brag about it.

RG213 is good cable for the right application (lower frequencies and/or shorter distances). If you only had to go 20 feet the difference would not matter as much. But hang onto it. You always need a few jumpers. 

Good feedback.  I was just starting to look into the differences between LMR & KMR.  I kinda miss the old RadioShack days where you could just walk in and talk to the local retired Navy guy and he'd give you all the answers.  I'm noticing a lot of LMR400 generally come with Type N connectors.  The Comet CA-712EFC is also an N-Type; however, the radio is a UHF/PL259.  What's the mindset here?  Is it appropriate to use an adapter at one end?  I generally thought you could lose ~3db with each adapter you put in-line.  Or is it more appropriate to get the raw cable and put the correct connectors on each yourself with appropriate crimping/soldering?

[SteveShannon]

13 minutes ago, WRZP701 said:

Good feedback.  I was just starting to look into the differences between LMR & KMR.  I kinda miss the old RadioShack days where you could just walk in and talk to the local retired Navy guy and he'd give you all the answers.  I'm noticing a lot of LMR400 generally come with Type N connectors.  The Comet CA-712EFC is also an N-Type; however, the radio is a UHF/PL259.  What's the mindset here?  Is it appropriate to use an adapter at one end?  I generally thought you could lose ~3db with each adapter you put in-line.  Or is it more appropriate to get the raw cable and put the correct connectors on each yourself with appropriate crimping/soldering?

When the PL-259 and SO-239 connectors were first introduced, they were called UHF connectors, but now UHF runs from 300 MHz to 3000 MHz and the PL259 and SO-239 are not very good connectors for that high of frequency.  The losses for almost everything in radio increase at higher frequencies.  Some PL259 and SO239 connectors have a lot of insertion loss above 300 MHz.  N connectors solve that problem.  Unfortunately, almost every manufacturer sold in the US puts SO-239 connectors on their radios.  Most manufacturers of UHF antennas make antennas with N connectors as well as SO239.

It's a little confusing, but PL259 is the PLug and SO239 is the SOcket.  The numbers came from the military.

In an ideal world, GMRS radios would have N female connectors on their backplanes.

Fortunately, Messi & Paloni (M&P) and probably Times Microwave (as Amphenol) have developed higher frequency SO239 and PL259 connectors that are supposed to be good for frequencies in excess of GMRS.

I buy cables with connectors, but I have cut them to custom lengths. But to me this is a hobby and doiing things like this are enjoyable.

DXEngineering will make up cables with whatever connectors you want to any length you want.  The tools required for the Times Microwave are pretty pricey but you can get by with just a decent crimper and utility knife if you're very careful.  M&P can be done with just a soldering iron and wrenches. 

[BoxCar]

20 minutes ago, WRZP701 said:

I'm noticing a lot of LMR400 generally come with Type N connectors.  The Comet CA-712EFC is also an N-Type; however, the radio is a UHF/PL259.  What's the mindset here?  Is it appropriate to use an adapter at one end?  I generally thought you could lose ~3db with each adapter you put in-line.  Or is it more appropriate to get the raw cable and put the correct connectors on each yourself with appropriate crimping/soldering?

I only know of one radio that comes with an N connector as its output. Using adapters is common and they don't really add to any loss figures so an N female to PL259 or N male to SO239 adapters are fairly common. They are a little on the pricey side compared to the normal PL/SO adapters but I believe that is due to the number of connectors sold rather than the manufacturing costs.

 

[SteveShannon]

Here's a video that (overly) dramatizes the differences in SWR and insertion losses for UHF connectors vs. N connectors.  However, while the narrator makes it seem pretty dramatic, the actual numbers don't represent noticeable differences in real life.  Reflected power isn't truly lost unless you are using lossy cable and the reflected power is converted to heat. However, for a person obsessed with having nearly perfect metrics, the differences might cause a loss of sleep. 

Finally, a word about adapters.  Adapters are convenient, but if you're ordering cable custom made, just get an N male on one end and a PL-259 on the other and make sure they're good connectors, such as M&P.

[nokones]

My repeater station has a female "N" connector for the transmitter and a female BNC for the receiver.

As for my mobiles, all of my XTL5000 XTL2500 radios have a female mini UHF connector and my Midland MXT500 and Kenwood TK880 radios have a SO239 connectors. No CCRs for me.

[WRZP701]

So after a bit of a rabbit hole on the LMR400 vs M&P, I landed on the M&P Airborne 10.  Between that & the Comet, I think I'm on the right path.  All good stuff.  Appreciate everyone's feedback.  I'll report back in a couple weeks once it's all in place.  Thanks all.

[WSAA254]

I think I will pretty much echo what everyone else has been saying.

1.  Elevation/line of site is king.  see the below chart regarding my own situation.  I can hit the repeater with 5 watts at 50 miles, but if it were not for the elevation, there is no way.  folks have hit the same repeater with a hand held from this area.

2.  Quality coax.  I use LMR 400.  one end has the pl 259 connector the other has a n type connector into a antenna switch.  This is a build your own cable through dx engineering. The shot below shows the antenna connection to the switch.   switch can select from gmrs to sdr.

3.  SWR, its more important for xmit, but a tuned matching circuit is better than one that is not.  Bottom line is you want as much real energy getting to the antenna, or from the antenna during reception.

Best of luck, all the information presented here is good stuff.

[WSAM454]

1 hour ago, WRZP701 said:

So after a bit of a rabbit hole on the LMR400 vs M&P, I landed on the M&P Airborne 10.  Between that & the Comet, I think I'm on the right path.  All good stuff.  Appreciate everyone's feedback.  I'll report back in a couple weeks once it's all in place.  Thanks all.

You should be happy with the M&P coax, which actually has a bit  less loss than LMR400 but is not as widely known (yet!)   Comet antennas are pretty well regarded, so the station should perform well.    Curious to learn the final results in a few weeks.

 

[SteveShannon]

2 hours ago, WRZP701 said:

So after a bit of a rabbit hole on the LMR400 vs M&P, I landed on the M&P Airborne 10.  Between that & the Comet, I think I'm on the right path.  All good stuff.  Appreciate everyone's feedback.  I'll report back in a couple weeks once it's all in place.  Thanks all.

Comet makes nice antennas. M&P cables are excellent. I haven’t tried the Airborne. It’s lighter in weight than their Ultraflex or Hyperflex because it uses copper clad aluminum as the center conductor (exactly like LMR400). 
 

[WRZP701]

Finally got everything in and some good weather to get up on the roof.  Before I tore everything down I went ahead and tested the current setup.  Up at the antenna after running through the 10' coax from the radio to the arrester, then from there to the antenna via a 50' coax, my SWR was reading at about 1.46 and wattage indeed cut in half as Steve suggested it might.  Read at 25.23W.  After running the new M&P (a 9' and a 50') and the new Comet antenna, SWR is about 1.44 and the wattage was 33.0W.  Definitely able to hit the repeater I'm trying to get to.  Able to hear folks responding to my callout--albeit with static.  But I could hear it.  I think at this point geography is the limiting factor but I can live with that.

Original antenna & coax...

 

 

New antenna and coax...

 

Antenna mount...

[WSAM454]

16 hours ago, WRXP381 said:

Haha this would only matter on transmit.  Not receive so the op was asking about receiving. 

Yes, SWR is a transmit function, but losing 3 dB is still signal loss, so yes, the length of the cable WILL effect receive!

[BoxCar]

On 4/21/2024 at 5:40 PM, WRXP381 said:

Haha this would only matter on transmit.  Not receive so the op was asking about receiving. 

Cable loss is loss period. It's the amount by which the signal is reduced going through the cable. It doesn't matter the direction, it affects all signals, incoming and outgoing.

[Socalgmrs]

3 hours ago, Sshannon said:

So at 450 MHz RG213 loses 5.2 dB in 100 feet, so in 60 feet you’re losing a little more than 3.12 dB. That’s half of your power. 
That also affects your measurement of SWR if you’re measuring right at the radio because you truly are not measuring the power that reaches the antenna and the reflected power measurement is much lower than it truly is. 
Try temporarily shortening your cable and measure the SWR right at the antenna. 

Haha this would only matter on transmit.  Not receive so the op was asking about receiving.