LeoG

Well I was wondering about that but never asked the question. Since the wideband was tuned flat(ish) I was wondering if it might restrict the power. Just another compromise when doing this type of system I guess. Was pretty shocked to see 70 watts out of the transmitter. Thought maybe 60 at the most. Hopefully the receive will give me the same boost as the transmit.

OK Boyz and Girlz, here we go. I opened up the Btech RPT50 repeater to remove the original wideband duplexer First thing I did was check the output wattage from the transmitter. The power supply was set at 13.8 volts and it was putting out 71 watts into the duplexer. Had 42 watts out of the duplexer. And not the best SWR on my 50 ohm dummy load. Right at the edge of spec. I turned the voltage down to about 11.5 volts and it showed about 65 watts out. Probably the lowest I can get it. Then I swapped the original wideband duplexer for the one that Marc so graciously tune to a single frequency for me (600). I relabeled it so some future person doesn't think it's wideband. I should probably strip the other frequencies out of the channel selection also. And I tested it and got about 48 watts from it. I said what the heck and boosted the voltage a bit and got it to put out 50 watts. I haven't put it back into service yet, soon. And testing won't be done until it cools off from the 98ºF it currently is. Says it's going to be low 70s tonight. Probably be to excited to test things at midnight, so likely around 10 or so I walk my route. Of course I'll key it up on the way home, at home on the base and try an HT from inside the air conditioned house. LOL Most of the duplexers I looked at said "40-80 watts (50 watts)" so hopefully I don't melt this one. The replacement was accepting the 71 watts without blinking and the original had the power supply set for 12.5 volts which is about 67 watts into the duplexer.

Well I am actually going to find that out tonight. I have a Btech 50w repeater and it has a wideband duplexer in it and soon I will be changing that out for a single channel tuned duplexer. The receive should be more sensitive. The receiver will be the same, but the desense should be much less with the >-85db vs the >-45db of the wideband duplexer

Or I got luck and got one that was fairly accurate. I have two of them and they both read the same for power and SWR. I had one on my home base and when I got the new one I swapped out to see if it would read the same. It did, so I didn't even swap them back. Just took the older one and it'll go into my shop setup.

Not going to be the receiver sensitivity that'll be the issue. The wideband duplexer is what is really going to limit the sensitivity.

My Surecom 102 seems to be pretty accurate. 4.7 on a 5w HT, 48w on a 50w mobile, 25w on a 20w mobile. Might not be perfect but seems close enough.

All they have to do is put "up to" and there ya go.

Of that I am very aware. These are mostly leaf trees so there's that.... Always had issues from the house to the shop which holds the repeater. 50w vs 25w. I could always come in mostly clear to the house, but from the house it was hit or miss. Then I got a 50w radio for the house and the problem is mostly gone, certainly not R9 reception but easy to talk and understand. Needed the extra wattage to punch through the leaves it seems. On top of that what helped later on was swapping out to the Comet 712EFC. Eventually the repeater will have that same antenna and upgrade from the Retevis 7.2dBi. So sometimes a little more wattage works. And since the 1st wideband duplexer was swapped out for the 2nd wideband duplexer I've been able to hit the repeater mostly successful with a 5w HT. R7 at best, no communication at worst. Duplexer is coming in today

Since the radios have a real off switch that physically disconnects the battery from the radio when off it really doesn't matter a whole lot as long as you turn the radio off when you charge it. I've been using the charging stand since I've got the H3s and I only charge them when they are turned off. Sometimes I charge the batteries separately when I need a new battery now and pull from my extra pile, then that weak battery gets charged out of the radio. Just don't charge the battery while the radio is on and you shouldn't have any issues.

Did my walk around the block with to have a record of the 2nd original duplexer. Since I do these things late at night I have a digital recorder I use to "listen" to me. I do the test of the repeater and then switch to talk around to let me know where I am in case the repeater test doesn't go through. There are a few spots on my walk that are iffy. Like I've mentioned in other threads I have 1.6KM of dense forest in the way of my signal, 70' trees with my antenna at 40'. After the new single channel tuned duplexer is installed I'll try to do the same test in the same spots.

I could do a Radio Mobile calculation to let you know if you have line of site or not. I would need pretty specific gps location to do so.

Looks like the duplexer is on the way and should get here late Wed if things go well.

Not for me at 19:11

We have 4 or 5 that semi regularly use the repeater. My wife isn't one of them but on rare occasions she'll chime into a conversation. She has no problem contacting me though our repeater though. I still think she thinks it's our private frequency. I know it's not.

You know how women like to talk.....

My wife is heading up to NYs to babysit our 2 grandsons while my boy does his bowling tournament thing. I came home for lunch to see her off. After she got settled into the car I took off and by the time I got to the shop she's calling me on the radio. She doesn't have a radio in her car so she was in the house. Turns out she couldn't find her phone and radioed me to call it so she could hear where it was. I did, she found it LOL. And that's why a radio is better than a phone, in this case LOL.

Yep, mine to. But lots of sites run quick. But that does answer the question about if there is a delay. Yes, transmit stays on for predetermined time. I guess my brain was off when I was thinking about that. Not the first time, and I"m sure not the last.

Wasn't really talking about testing, but real world conditions. The conditions between my house and repeater are sort of at the fringe even though it's only 1.9 miles as way of the crow. And while walking around my neighborhood I can usually reach the repeater and transmit audio through my 5 watt HT. There are times where I can hit the repeater and get nothing, just a blank receive from the repeater for the whole transmission and then the courtesy tone. I have a courtesy tone on my repeater so I know when I hit it with absolute certainty. But I've never heard what I would consider an oscillation. This theoretical oscillation would only happen as long as the HT is keyed up.

Spanish for "bear"

OK, I'm thinking again....sorry LOL So you have a repeater and an HT that is near the receive limit of the repeater. Why doesn't it oscillate? You transmit with the HT, the repeater receives the signal activates the transmitter, desenses the receiver and the transmitter stops and then the HT signal is received again and it oscillates back and forth on this. Is there a delay or something designed in a repeater to prevent this? I also have observed that there is a point where you can activate the repeater and keep it up but you can't push your audio through it, not ever scratchy audio, it's basically blank. But get a bit closer and you get scratchy audio. I assume that's when you are able to overcome the desense of the system?

Here's another vid showing a tune of a duplexer on a non vna.

Send them that bug report.

You're as bad as me for staying up late. LOL Ya, I saw how they painted the screws. Shot them from one side to help lock them in I suspect. Didn't think about how that might impact re-tuning though. Thanks for the tour. Do you know how to read the circular graph? The curly cue lines are intriguing, really curious how they are read.

I guess the receiver sensitivity is what it is, but if you are able to receive better with the new duplexer that's real world sensitivity not theoretical receiver sensitivity. I get exactly what you are saying. And I'm pretty sure you know what I mean too. If I could hit the repeater at 5 miles and not 6. Then install the new duplexer and can hit the repeater at 7 miles but not 8. I would consider that an increase of sensitivity. But in reality it's the duplexer allowing the receive signal to still be heard while the repeater is re-transmitting and not causing desense.

That's what I meant