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Posted

There is a GMRS repeater that is about 40 miles from me and I'm told the antenna is about 500'.  In my yard shed / woodshed / ham shack I have a Diamond x200A antenna and a Connect Systems CS800D.  My ability to hit the repeater is spotty somewhat however today someone told me that I'm hitting the repeater but it is darn near impossible to hear me over the floor noise.   Forehead smack.  Mic gain. 

Adjusted and then carried on a lengthy conversation with someone.  First time ever.   I put my "Farsometer" on it and am putting out about 37-38 watts at an SWR of 1.40.  Also I have an adapter (N to SO239 so there may be a little loss there).  I'm wondering if I grab an MTX500 or KG1000G where the tiny bump in wattage (hopefully 43 or a bit more) would make any real world difference.   Also the filtering may be better on a dedicated GMRS radio.  The CS800D is a VHF and UHF radio that covers the GMRS bands or at least it did when I bought some years back. 

Even if I've got this situation squared away, none of what I've said may stop me from buying a new radio anyway.  Because that's what I do.  

Looking for some solid advice from those who may have been in a similar situation where you were just barely hitting a repeater.  I can't really push my antenna up much further.  Just wondering if a few extra watts with a straight PL-259 to SO-239 connection on a DEDICATED GMRS radio tuned to optimize output for that band of brothers will get a bump in performance. 

Decent performance bump or gigantic waste of money?

Please don't bring up the rules on the radio I'm currently temporarily using. I'm familiar with all that. 

Posted
53 minutes ago, WRJZ939 said:

I put my "Farsometer" on it and am putting out about 37-38 watts at an SWR of 1.40.  Also I have an adapter (N to SO239 so there may be a little loss there).  I'm wondering if I grab an MTX500 or KG1000G where the tiny bump in wattage (hopefully 43 or a bit more) would make any real world difference.  

The bump in wattage will make no difference whatsoever. 
Quadrupling your power to 150 watts would only make a single point of difference on the S-meter.

Posted

How high is your antenna and what type of coax are you using?

The loss from the N Type to SO239 adaptor will be minimal. 37-38 watts should be plenty as long as you have a good clear line of sight to the repeater tower. An extra 10 watts won't make much difference.

The local GMRS repeater is 21.5 miles away from me. I run my KG-1000G on medium power and get in just fine. My 20 watt KG-XS20G gets into the repeater just as good as the KG-1000G does.

Posted
1 hour ago, WRXP381 said:

What gain in the antenna are you working with.     A 20w radio will do over 200miles line of site.  What do you have in The way?  Trees, homes, buildings….. can you get your antenna up higher?   

I’m at sea level surrounded by the Croatan National Forest. Tough to punch through 

Posted

That Diamond x200A is cut for 2m & 70cm. Yes, it is very close to the GMRS freq range, but it could be making a little difference. I would look at all of your connections and the N to PL259 shouldn't make that much difference. Also those trees love to suck up RF signals. Just my 2 cents- Mike- K9YS/ WSBQ206

Posted

Thanks for all the replies!  Much appreciated.

Probably still going to buy a new radio though!  9 or 10 is simply not enough. 

John

New Bern, NC

KN4FMV

WRJZ939

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Posted

Dual band HAM antennae are essentially compromised and not efficient for GMRS freqs.

You need to determine what is your target freq for efficiency and get the antenna that resonates the best on that freq and take the hits on the other freqs.

Posted

Occasionally you get lucky and a 2m/70cm dual band antenna will also have SWR of 1.8 or lower on the GMRS channels/frequencies. But not all dual band antennas will work for GMRS.

I get a SWR of 1.8 or less on GMRS with my Comet GP9 dual band base antenna and a SWR of 1.8 or less on my Comet 2X4SRNMO mobile antenna.

As mentioned, the best is to get a GMRS specific antenna that is tuned properly. A good one is the Comet CA-712EFC.

Posted

If you are spotty into the repeater, a directional antenna with higher gain could help.  Downside to that is it's going to be directional and only effective talking to that specific repeater.  If you only use that repeater, then it's not really as big of a issue. 

But you need to get a commercial frequency antenna and NOT something for ham.  And more elements leans more directional gain.  So look for something with 6 or 8 elements.   Going from spotty to solid signal into the repeater might not be possible though.. But it will be an improvement.  Of course, use the best cable that you can reasonably afford and will work with your installation. 

Posted
On 3/30/2024 at 6:05 PM, Irish47 said:

That Diamond x200A is cut for 2m & 70cm. Yes, it is very close to the GMRS freq range, but it could be making a little difference. I would look at all of your connections and the N to PL259 shouldn't make that much difference. Also those trees love to suck up RF signals. Just my 2 cents- Mike- K9YS/ WSBQ206

Ham since 1969- US Air Force Radio Maintenance 1965- til 1985

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