Yaesu: Yaesu System Fusion Repeater Program (Same but new)

vagrant

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#21
Yes, quite right, those numbers are for the Celwave version. The specs on the 526-4-2 are pretty good. What are you actually getting on isolation and loss? I have read of slightly less isolation and slightly less loss on that model. Still, not everyone's skill set and equipment is the same on tuning. That mobile duplexer I use notes 70dB isolation and 1.0dB of loss, and it is close to that. I should have a friend with better equipment dial it in.

Still, that particular Celwave duplexer looks like it would be the right fit for my use. I have seen prices just under $300 up to $500 and it would handle a 100W amp. If I can eventually get it setup at a particular location/elevation nearby, it would cover a good chunk of central California; even at 20W from about Merced/Los Banos almost to Bakersfield. Of course, a 100W amp would help make up for losses.

Thank you for the heads up on that particular duplexer. I'm figure I will come across one down the line on eBay, QRZ, etc.
 

vagrant

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#22
And another thing, I had the lid off my DR-2X and was disappointed to find cheap looking RG-58 jumpers between the radio chassis and back panel. I'll be swapping those out for RG-142 and silver plated crimp connectors.
At such a short length, how much of a difference will that make, or is it an instance where you have the parts so why not do it? I hear you though, I use 142 jumpers from the radio to the duplexer.
 
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#23
Insertion loss is about 1.5dB and It's difficult to measure the exact isolation being over 100dB. I'm using an HP spectrum analyzer with tracking gen to tune it and have to insert a preamp after tuning the pass cavities to see the notches down in the noise floor. I'm not sure what frequency range my duplexer was originally made for and I could be using it a little out of frequency range of the coax jumpers.

I also have a large mobile duplexer with six 2" wide square cavities and about 70dB notches and still had a little desense on the Yaesu repeater at 20w. The duplexer tuned up just fine but I think the problem is with the repeater and its broad band consumer grade radios inside. I found an article pointing out problems people are having replacing something like a GE Master II with a Yaesu and finding it doesn't work with whatever duplexer was used with the GE since it has a really good front end preselector. Here is a link to the article: Yaesu Fusion vs. G.E. Mastr II — Selectivity Causes Huge Differences In Desensing – Duplexer Repair

I'll probably use an extra can or two on the receiver inputs to the Yaesu and give up a dB or so insertion loss for more selectivity. A few weeks ago I was burning in another Fusion repeater for a local club (their main repeater is on an island) and ran their repeater with a 100W amp into my 526 duplexer and it worked great.

I had several of these 526 duplexers and all but one had problems like frozen tuning rods or they were really noisy. The good one had wrong jumpers at the outputs to the T connector and it would not tune up but I copied jumper lengths from another working one, made new jumpers and it seems fine now. If you go shopping for a 526 series duplexer make sure it works and tunes ok before you pay for it.

Yes, quite right, those numbers are for the Celwave version. The specs on the 526-4-2 are pretty good. What are you actually getting on isolation and loss? I have read of slightly less isolation and slightly less loss on that model. Still, not everyone's skill set and equipment is the same on tuning. That mobile duplexer I use notes 70dB isolation and 1.0dB of loss, and it is close to that. I should have a friend with better equipment dial it in.

Still, that particular Celwave duplexer looks like it would be the right fit for my use. I have seen prices just under $300 up to $500 and it would handle a 100W amp. If I can eventually get it setup at a particular location/elevation nearby, it would cover a good chunk of central California; even at 20W from about Merced/Los Banos almost to Bakersfield. Of course, a 100W amp would help make up for losses.

Thank you for the heads up on that particular duplexer. I'm figure I will come across one down the line on eBay, QRZ, etc.
 

vagrant

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#24
Interesting, a Fusion DR-1X replaced a GE Master II on VHF and our experience was not desense, but rather improved RX. Of course, all GE Master II's are not equal. We used the same cans, but we did need to remove a RX amp that was inline for the GE Master II.

On UHF, I experienced desense when I added a RX amp to my setup, which makes sense with that mobile duplexer, but it was worth testing and learning for me.
 
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#26
Can anyone point to the conversion to DMR or even better P-25 of these repeaters? Does this machine have a tuned receiver front end? If not that's the reason you cannot get the same isolation as a MastrII or Mastr III which I have about 6 of. These had to be highly modified in the front end module since they came from the Marine Operator service. The MastrII sometimes had to have the front end cavity disassembled to clean the cavity due to leftover cleaning solutions causing a growth in them.
 
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#27
I read where on 2m replacing the RG-58 jumpers can help due to leakage and the receiver being bothered by its transmitter 600KHz away. On UHF it may not be a problem but its just wrong to have RG-58 in a repeater path.

At such a short length, how much of a difference will that make, or is it an instance where you have the parts so why not do it? I hear you though, I use 142 jumpers from the radio to the duplexer.
 
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#28
Whenever I add a preamp I always add preselector cavities to provide more isolation at the repeater split than the preamp has gain. Otherwise the preamp is eating up your isolation. At UHF a single can with adjustable loops can provide 15-20dB down skirts 5MHz away but two cans with the right length jumper between them can give the same skirts with less insertion loss.

Interesting, a Fusion DR-1X replaced a GE Master II on VHF and our experience was not desense, but rather improved RX. Of course, all GE Master II's are not equal. We used the same cans, but we did need to remove a RX amp that was inline for the GE Master II.

On UHF, I experienced desense when I added a RX amp to my setup, which makes sense with that mobile duplexer, but it was worth testing and learning for me.
 
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#29
The FTM-400 radios inside the Yaesu Fusion repeater are very wide band front ends. I also ran a fleet of Master II repeaters and occasionally had to tear apart their front end cavities due to little whiskers growing inside that detuned everything. Last few I did I sprayed the inner surfaces with Deoxit R5 then wiped it clean and it seemed to fix that problem.

The DR-1X type Yaesu repeaters have been converted to DMR and I found that with a simple search.

Can anyone point to the conversion to DMR or even better P-25 of these repeaters? Does this machine have a tuned receiver front end? If not that's the reason you cannot get the same isolation as a MastrII or Mastr III which I have about 6 of. These had to be highly modified in the front end module since they came from the Marine Operator service. The MastrII sometimes had to have the front end cavity disassembled to clean the cavity due to leftover cleaning solutions causing a growth in them.
 

vagrant

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#30
Loss is not the issue. Less than optimal isolation between the receive and transmit signal paths inside the repeater due to the generally poor shielding of RG58 is the issue.
I figured the case design would handle that, with the lid on of course. Still, point taken if he is clearly having desense issues. While similar, I have not handled the DR-2X directly and the cost is minimal to implement that.
 

vagrant

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#31
Whenever I add a preamp I always add preselector cavities to provide more isolation at the repeater split than the preamp has gain. Otherwise the preamp is eating up your isolation. At UHF a single can with adjustable loops can provide 15-20dB down skirts 5MHz away but two cans with the right length jumper between them can give the same skirts with less insertion loss.
Agreed. I did that RX amp testing a couple years back and learned that lesson. It paid off when a RX amp was recently suggested for use on a Motorola UHF the club has and I advised of the need for an extra can. Fortunately, someone with vastly more experience chimed in and agreed. In went the RX amp with the notch filter.
 

W9BU

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#32
Remember that the Yaesu DR repeaters are essentially two FTM-400 radios in a box. The RG58 cable that prcguy is talking about are short jumpers from the radios to the bulkhead connectors on the back of the box. It's theoretically possible for the jumper cables to cause some desense inside the box.
 

vagrant

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#33
Remember that the Yaesu DR repeaters are essentially two FTM-400 radios in a box. The RG58 cable that prcguy is talking about are short jumpers from the radios to the bulkhead connectors on the back of the box. It's theoretically possible for the jumper cables to cause some desense inside the box.
Would copper tape on these short RG58 coaxial cables work just as well or better than swapping for RG-142? I am doubtful it would, due to the properties of the RG-142, but that would seem to be a quick fix when dealing with a handful of DR-1X repeaters. Hmm...due to things being theoretically possible internally, would it be prudent to use copper tape on RG-142 as well?

This replacement I received is working well, so time to take the lid off and inspect today.
 
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#34
Quote"
The DR-1X type Yaesu repeaters have been converted to DMR and I found that with a simple search.

True but not an easy process, been searching and reading for 4 hours now. I have an idea how to do it, now the process is buying the modem board and the Pi. Plan to do this to both Mastr III and MSF-5000 repeaters.
 
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#35
Not sure if copper tape would give the same end result. I'm also worried about the unknown plated connectors under the hood. My new RG-142 jumpers will have silver plated connectors and will include the chassis mount N connectors.

Would copper tape on these short RG58 coaxial cables work just as well or better than swapping for RG-142? I am doubtful it would, due to the properties of the RG-142, but that would seem to be a quick fix when dealing with a handful of DR-1X repeaters. Hmm...due to things being theoretically possible internally, would it be prudent to use copper tape on RG-142 as well?

This replacement I received is working well, so time to take the lid off and inspect today.
 

vagrant

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#36
Thank you prcguy and W9BU. I decided to move forward with RG400 inside with the silver connectors. I am replacing my RG142 jumpers with RG400 as well, also with silver connectors.

This thread pointing me in the right direction, along with some additional research, has been educational.
 
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