More Power?

[WSAL750]

I can open a repeater that is a in an area 60 miles away. I do not have a direct line of site so I am surprised I can open it. My handheld will not transmit any voice , can it be that I have power to open repeater but not enough to transmit?  Three of my handhelds will "Kurchunk" it ,but none with audio.  Is this normal? Thanks for any ideas.

[BoxCar]

Yes.

[WRXB215]

Although the situation you describe certainly does happen, verify your testing method. Often times voice is getting through the repeater but the person's test method is faulty and they think they aren't getting through. The most common problem in this is the transmit radio and the receive radio being too close together creating desence on the receive radio essentially causing it to "go deaf" to the repeater.

[StogieVol]

21 minutes ago, WSAL750 said:

I can open a repeater that is a in an area 60 miles away. I do not have a direct line of site so I am surprised I can open it. My handheld will not transmit any voice , can it be that I have power to open repeater but not enough to transmit?  Three of my handhelds will "Kurchunk" it ,but none with audio.  Is this normal? Thanks for any ideas.

I am able to hit 2 repeaters that are over 50 miles from me on my handheld. It is a 5W handheld. I am in Campobello SC and they are in NC. Sounds like your offsets may not be right. If its 462.5000 the offset is 467.5000 etc, etc. 

[WRXL702]

Repeater Antenna HAAT & ERP Has A Lot More To Do With Access & Reception From A Site When In Comparison.

One Cannot Evaluate Different Site Performance Results If All Parameters & Infrastructure Elements Are Not Equal.

Your Observation Has Nothing To Do With Offsets In Programming.

[WRUE951]

Yes,   i can cur-chunk a repeater with my HT here in the Desert 80 miles away but i can't talk on it.    With my mobil, no problems..   

[WSAM454]

The repeater may 'hear' the rf signal from your HT, and while it may be enough to key the repeater, the signal from your HT is most likely so weak that no intelligible audio will come through.   Think of someone you have monitored who is very noisy into the repeater;  it is not always possible to understand what they are saying, yet the repeater is keyed by them.   Probably what is happening in your situation.   If you are too noisy someone helpful may come back giving you a poor signal report, but more likely you will just be ignored.  If you are that noisy, they may not even be able to understand what you are saying at all, and will not respond.

[BoxCar]

4 minutes ago, WSAM454 said:

The repeater may 'hear' the rf signal from your HT, and while it may be enough to key the repeater, the signal from your HT is most likely so weak that no intelligible audio will come through.   Think of someone you have monitored who is very noisy into the repeater;  it is not always possible to understand what they are saying, yet the repeater is keyed by them.   Probably what is happening in your situation.   If you are too noisy someone helpful may come back giving you a poor signal report, but more likely you will just be ignored.  If you are that noisy, they may not even be able to understand what you are saying at all, and will not respond.

As a follow-up, it also depends on the repeater's receiver. If the repeater is a retuned commercial/public safety unit, the receiver will be more sensitive to RF than a Retevis or Midland "suitcase." Your carrier signal that carries your voice can reach further than the rest of your signal.

[WRKC935]

OK, been meaning to explain this and this is a good time.

The commercial guys here will all tell you there are three tests that we perform when installing a new repeater system out in the field.

First test is 12dB sinad with the service monitor connected to the duplexer wit no antenna.

Second test is for something called isolation.  We drop the input signal down to where the repeater squelches, or stops transmitting and then increase the signal slowly until the receiver just opens back up.  What we then look for is the repeater to drop again when the transmitter comes up and then drop back out.  If the duplexer isn't tuned correctly, the repeater will 'ping pong' up and down because the TX frequency is getting into the receiver and deafening it to some degree.  If it does start to ping pong, we increase the signal level in in TENTH's of a dBm until it stops.  At that point, we usually stop the testing, touch up the duplexer tuning and run through all the tests again.  The last test is antenna desense.  An isolation Tee is connected to the duplexer antenna port and a dummy load is then connected to the output.  The tap port has signal injected on it to the point the receiver opens and the signal level is noted.  Then the signal is removed, and the dummy load is unhooked and the antenna is connected.  The signal is injected again on the tap and increased to the point that the receiver opens again.  The difference in the required signal level is the antenna desense for that antenna and repeater system at that site.

Now, here's how that applies to what YOU are seeing.

With the 12dB Sinad test, you need to understand what that measurement is.  That being a ratio of signal to noise in the receiver.  Here's a good explanation.

https://en.wikipedia.org/wiki/SINAD

 

But it's NOT the minimum signal level that the repeater can hear and open up.  That is actually the LAST test (antenna desense) where the signal level is just above the noise floor enough for the receiver to recognize it and hear the PL /DPL.  On a repeater running CSQ, the level is going to be lower, because it doesn't need to hear the tone above the noise, just the RF.  These readings are gonna be 6 to 12 dB different in their levels.  And the basis of where I make the statements about needing to be able to increase signal level a BUNCH to get a noisy signal to be full quieting.  It's not a watt or two, unless you are only running 1 watt or less to begin with.  That's based on using dB and specifically dBm numbers for power output in place of watts.  An example is 30dBm is 1 watt, 33 dBm is 2 watts, 36dBm is 4 watts.  on the upper end, 50dbm is 100 watts and 53dBm is 200 watts.  So when you look at it that way, and start realizing that to go from just opening a repeater receiver at -119dBm to 12 dB SINAD at -110dBm or so, that 9dB signal level change is HUGE in the percentage of power change when you convert it back to watts. 

And the best part is you can calculate all this if you have the information about the equipment in play. 

You need the antenna model (so you know the gain) the coax type and length (to calculate the cable loss) the number and type of jumpers (again cable loss) the duplexer model (insertion loss).  Then you need YOUR power level in watts (converted to dBm) and your antenna system numbers as well.  The last part is the distance between the antenna's to calculate something called PATH LOSS.  With all that you can calculate what the actual signal is at the repeater input from your radio transmitter from miles away.   And yes, I have tested this and found that it's accurate within a dB or two.  The difference is from signals that bounce off other things and arrive out of phase to the antenna and cancel put part of the signal.  This is called Rayleigh effect.  (Again, go look it up, NOT typing it all out) but that also explains sitting in traffic and the repeater fading out.  Moving 2 feet and the repeater signal coming back. 

 

[ULTRA2]

On 12/6/2024 at 1:22 PM, WSAL750 said:

Is this normal?

Are your tones to that repeater programmed if not you will hit the repeater, but no audio will be heard

[tcp2525]

I can get into a repeater full quieting 25 miles away with just 100 milliwatts. Does that count?

[WRXB215]

2 hours ago, tcp2525 said:

I can get into a repeater full quieting 25 miles away with just 100 milliwatts. Does that count?

NO! Because I have trees, so it's not fair!

[WRKC935]

11 hours ago, tcp2525 said:

I can get into a repeater full quieting 25 miles away with just 100 milliwatts. Does that count?

Count for what? 

 

[BoxCar]

9 hours ago, WRKC935 said:

Count for what? 

 

Being the south end of a north bound donkey?

[tcp2525]

20 hours ago, WRKC935 said:

Count for what? 

 

Can you do it?

[WRKC935]

42 minutes ago, tcp2525 said:

Can you do it?

Hit a repeater at 25 miles with .1 watt?  Yeah, it's not hard.  Several ways to do it. 

First is vertical height, if you get the radio in the air far enough it's not hard.  Aircraft will do it in any situation. Beyond that, two tall hills over a valley would work as well.   Issue is to have unobstructed line of site.

Second is antenna gain.  Lots of it.  Toss up a 12 foot dish that you can pull close to 30dB of forward gain.  Same way I do it with 23dBm (200 milliwatts) for 23 miles at 4.9Ghz.  Of course path loss at 4.9 is WAY higher at that distance than 460 Mhz.  At 460 the path loss is 117dB.  At 4.9Ghz it's 137dB.  SO 20 dB more.

You have to remember that a repeater, or at least one with reasonable coverage is going to have vertical height already.  Repeaters with antenna's at 50 or 100 feet don't talk 25 miles period.  The curvature of the earth makes the line of site horizon 14 miles for a 100 foot high antenna.  Beyond that you need to increase height to maintain LOS.

 

[OffRoaderX]

34 minutes ago, WRKC935 said:

Hit a repeater at 25 miles with .1 watt?  Yeah, it's not hard.  Several ways to do it. 

First is vertical height, if you get the radio in the air far enough it's not hard.  Aircraft will do it in any situation. Beyond that, two tall hills over a valley would work as well.   Issue is to have unobstructed line of site.

Second is antenna gain.  Lots of it.  Toss up a 12 foot dish that you can pull close to 30dB of forward gain.  Same way I do it with 23dBm (200 milliwatts) for 23 miles at 4.9Ghz.  Of course path loss at 4.9 is WAY higher at that distance than 460 Mhz.  At 460 the path loss is 117dB.  At 4.9Ghz it's 137dB.  SO 20 dB more.

You have to remember that a repeater, or at least one with reasonable coverage is going to have vertical height already.  Repeaters with antenna's at 50 or 100 feet don't talk 25 miles period.  The curvature of the earth makes the line of site horizon 14 miles for a 100 foot high antenna.  Beyond that you need to increase height to maintain LOS.

 

Yah, but which is more effective: Risperidone or Aripiprazole?

[WRTC928]

5 minutes ago, OffRoaderX said:

Yah, but which is more effective: Risperidone or Aripiprazole?

That depends on what you want to treat. Both are effective for bipolar disorder but risperidone is often more effective for the mixed form. On the other hand, if the patient is in a manic episode with severe agitation, aripiprazole may be a better choice. Similarly, they will both treat schizophrenia, but if agitation is a feature, aripiprazole is the go-to again. Aripiprazole is useful in Tourette's Syndrome while risperidone shows some promise in treatment of infantile autism. I could go on, but those are the high points.

[WRUU653]

35 minutes ago, OffRoaderX said:

Yah, but which is more effective: Risperidone or Aripiprazole?

Ask your doctor if GMRS is right for you. Don’t use GMRS if you are allergic to GMRS. 

[BoxCar]

9 hours ago, WRUU653 said:

Ask your doctor if GMRS is right for you. Don’t use GMRS if you are allergic to GMRS. 

You forgot to say GMRS can cause excessive spending on new radios and antennas.

[WRUE951]

33 minutes ago, BoxCar said:

You forgot to say GMRS can cause excessive spending on new radios and antennas.

Isn't that so.........  True

[LeeBo]

1 hour ago, BoxCar said:

You forgot to say GMRS can cause excessive spending on new radios and antennas.

#truestory