Cliff, I moved four of these duplexers from the 160 MHz area down into the ham band.? The manual I found in one of them is here:
<http://www.repeater-builder.com/antenna/sinclair/q202-208-218-tuning.pdf>
The only modification I required to get the notches to tune (the band pass worked all OK) was to lengthen the four cables from the Tee back to the Cavities.? I added adapters until I got the notches to tune and then measured the length and made cables that allowed tuning the notches in the ham band.? If they were originally in the 155 MHz area i suspect that no modification at all will be required.
They work quite well and all are still in service.? No maintenance to the cavities themselves were required, but the cabinets had seen better days.?
Give me a shout if I can help.
73 - Jim W5ZIT at YAHOO dot COM
|
I see LUY attached a picture of handmade wire loops with spacers also. Very good! Again, all the data you should need, Skyler!
Hey Skyler,
You absolutely can. There's no real harm in doing it. Here are some considerations:
Two true Bandpass resonators flanking your flatpack will give the total system *better* out of band rejection than a BpBr duplexer would. This results from BpBr duplexers/resonators having poor out of band (<10MHz) attenuation in most cases.
The flatpack will give fair reject isolation (notch depth) if it's for your band segment. -75dB or better.Most 6-packs I can get -80dB to -90dB notches out of. Plenty good. Where the flatpack/mobile duplexer limits you is power handling. I try not to exceed 30W with them. The bandpass cans will happily contend with 250W if VSWR is reasonable. Mobile duplexers are typically rated at 50W with the caveat of low VSWR.
A full-up BpBr duplexer would offer better power handling capability and a more uniform setup. Building the loops & probes is certainly possible for the T1500s. Someone might even want to trade you for your pass loops. If you're going that route, I'd suggest making your new harness with Type N connectors. Better UHF performance, less space, more uniformity. Another gentleman seems to've sent details on a probe assembly while I drafted this email! I don't have the data on hand or I would've. The probes can be fabricated with 1/16th" copper stock. The loops from something like 14AWG copper wire. Keep in mind the wire especially will be softer than that used in original assemblies. Thus subject to more deflection/malforming. The copper used in the OEM assemblies was a differing alloy with other metals for stiffening. The ends are hardened and threaded to accept the thumbnuts & were covered by a plastic bushing to space them from the cavity wall. You can try heating the copper with a torch and quenching it in oil like steel to harden it. That may or may not work. Only do it once or you risk making it too brittle & prone to breakage. Machining copper is harder than other typical metals because of its thermal properties and softness. It tends to be "gummy" the purer it is.
73, Matt W6XC
I agree that it isn¡¯t worth my time to convert a bandpass into a BpBr out of these but I thought i would see if anyone has.?
Is it acceptable to use a Mobile flat pack duplexer and then attach bandpass cavities on each side for additional selectivity?
Hi
Skyler,
The T1500 cavities always were used in BpBr
"mode". See the documentation on this
site.
You could readily make the coupling loops and probes for
this but, time is
money.
There is nothing super special in their
construction.
You will however need GOOD test
gear.
Get the $100 Chinese flat pack (or other s/h complete
unit) and put together a
system.
Starting with, just the cans, building a BpBr duplexer is
quite
hard.
Getting the lengths of the cables between cavities right to reduce interaction was the hardest.
Alan
VK2ZIW
On Fri, 15 Jan 2021 08:11:07 -0700, Skyler Fennell
wrote
> I have
six T1500 cavities and I thought it would be nice to make a duplexer but they
are just
bandpass.?
>
> Anyone here have any info or way to acquire
the notch addons for
these??
>
> Maybe [UTF-8?]it?€?s easier to
combine a Chinese $100 flat pack with four of these bandpass filters to build a
BpBr?
>
---------------------------------------------------
Alan VK2ZIW
Before the Big Bang, God, Sela.
OpenWebMail 2.53, nothing in the cloud.
|
Hey Skyler,
You absolutely can. There's no real harm in doing it. Here are some considerations:
Two true Bandpass resonators flanking your flatpack will give the total system *better* out of band rejection than a BpBr duplexer would. This results from BpBr duplexers/resonators having poor out of band (<10MHz) attenuation in most cases.
The flatpack will give fair reject isolation (notch depth) if it's for your band segment. -75dB or better.Most 6-packs I can get -80dB to -90dB notches out of. Plenty good. Where the flatpack/mobile duplexer limits you is power handling. I try not to exceed 30W with them. The bandpass cans will happily contend with 250W if VSWR is reasonable. Mobile duplexers are typically rated at 50W with the caveat of low VSWR.
A full-up BpBr duplexer would offer better power handling capability and a more uniform setup. Building the loops & probes is certainly possible for the T1500s. Someone might even want to trade you for your pass loops. If you're going that route, I'd suggest making your new harness with Type N connectors. Better UHF performance, less space, more uniformity. Another gentleman seems to've sent details on a probe assembly while I drafted this email! I don't have the data on hand or I would've. The probes can be fabricated with 1/16th" copper stock. The loops from something like 14AWG copper wire. Keep in mind the wire especially will be softer than that used in original assemblies. Thus subject to more deflection/malforming. The copper used in the OEM assemblies was a differing alloy with other metals for stiffening. The ends are hardened and threaded to accept the thumbnuts & were covered by a plastic bushing to space them from the cavity wall. You can try heating the copper with a torch and quenching it in oil like steel to harden it. That may or may not work. Only do it once or you risk making it too brittle & prone to breakage. Machining copper is harder than other typical metals because of its thermal properties and softness. It tends to be "gummy" the purer it is.
73, Matt W6XC
I agree that it isn¡¯t worth my time to convert a bandpass into a BpBr out of these but I thought i would see if anyone has.?
Is it acceptable to use a Mobile flat pack duplexer and then attach bandpass cavities on each side for additional selectivity?
Hi
Skyler,
The T1500 cavities always were used in BpBr
"mode". See the documentation on this
site.
You could readily make the coupling loops and probes for
this but, time is
money.
There is nothing super special in their
construction.
You will however need GOOD test
gear.
Get the $100 Chinese flat pack (or other s/h complete
unit) and put together a
system.
Starting with, just the cans, building a BpBr duplexer is
quite
hard.
Getting the lengths of the cables between cavities right to reduce interaction was the hardest.
Alan
VK2ZIW
On Fri, 15 Jan 2021 08:11:07 -0700, Skyler Fennell
wrote
> I have
six T1500 cavities and I thought it would be nice to make a duplexer but they
are just
bandpass.?
>
> Anyone here have any info or way to acquire
the notch addons for
these??
>
> Maybe [UTF-8?]it?€?s easier to
combine a Chinese $100 flat pack with four of these bandpass filters to build a
BpBr?
>
---------------------------------------------------
Alan VK2ZIW
Before the Big Bang, God, Sela.
OpenWebMail 2.53, nothing in the cloud.
|
If you are putting up a repeater, and you own the site (house site or something), you could use just two of them and do split antennas.?? 20-30' of vertical separation is enough in that case.?? You should be able to even run a preamp, depending on how much transmitter power you use, the quality of your receiver, and how lucky or unlucky you are with actual isolation between the verticals. ?
Andy WJ9J
I have six T1500 cavities and I thought it would be nice to make a duplexer but they are just bandpass.?
Anyone here have any info or way to acquire the notch addons for these??
Maybe it¡¯s easier to combine a Chinese $100 flat pack with four of these bandpass filters to build a BpBr?
|
Skyler,
Part of the fun of armature radio is DIY. Do a little building and make it work. See the probes attached.
Wayne
?
|
Re: The joys of ONAN power supplies in Motorola Quantar repeaters
One of the primary causes of switcher failures is line transients.? Linear PSUs have built-in isolation (transformer) which switchers do not have.? While degraded components, excessive load, environmental issues, and tin whiskers can also cause failures transients and static probably cause more failures than anything else.? Motorola R56 calls for a Type 2A SPD (MOV/SAD Surge Protective Device) at the electrical panel and a Type 3 SPD (MOV) at the device location.? One of the best things that can be done to prevent this kind of thing is to use an on-line UPS in-line with the equipment - not a bypass type UPS that connects the equipment to the line and float-charges the batteries - but a UPS that has a full-current charger and inverter running at all times - so the current used is from the UPS at all times- not directly from the utility.? The MOV/SAD combination in the SPDs will take care of most transients and if it can't it should sacrifice itself and save the equipment.??
High (or low) temperatures and adverse conditions (fumes, carbon dust from elevator motors, dirt, etc), along with age can also increase the odds of a failure - but sometimes failures are just due to poorly designed supplies or cheap or old components failing.? I suspect we are going to see a lot more failures of this kind in consumer electronics as the switchers that have become so prevalent over the last 10-15 years age to the point of failure - many of which likely do not have proper safety features.? Fires are going to become much more common due to these which rarely happened with the old linear wall-wart supplies.??
Additionally it is very important to bond all of your equipment (not to be confused with grounding - though the bonded equipment should also be properly grounded) so that all equipment is at the same electrical potential.? This lessens the chance of damage and failures due to static and lightning while also decreasing chances of electrocution hazards due to wiring faults.? If you ever want to see something interesting and have Cable TV just throw an AC VOM on the shield of your cable TV coax and measure to your electrical ground.? I have seen upwards of 100V on these at times - and most TVs are not grounded to avoid ground loops so it is a serious hazard.? The cable companies are SUPPOSED to bond the cable to your electrical safety ground at the entrance point but very few bother or do it properly.? Another reason I have FTTH.
In regards to fire suppression systems roughly equivalent to Halon the most common that is in use today is FM-200.? While it is not illegal to have or maintain Halon systems no new systems can be installed and no more Halon gas can be produced - so if you need a system FM-200 is likely your best option.? While these can be expensive they can also save a lot of $ depending on the scenario and application.? I still see lots of Halon extinguishers and suppression systems at sites though they are steadily being replaced with FM-200 systems and CO2/ABC extinguishers.? Motorola R56 calls for having a minimum of one ABC and one CO2 extinguisher at any site.
If any of you have not had the pleasure of reading Motorola R56 it is a good read and might open your eyes to some potential problems with your installs that could save some serious $.? It is not easy or cheap to implement all of the recommendations but it can be worth it and generally if you follow that standard site owners will be happy with you and not complain about your install.? The current R56 is the 2017 revision - 68P81089E50-C which is 736 pages of enjoyable reading covering far more than just bonding and grounding.
Thanks,
Dan Woodie, CETsr
On Fri, Jan 15, 2021 at 4:34 PM RFI-EMI-GUY < rhyolite@...> wrote: In General, is there any theory on failure modes on switchers?
Filter cap ESR degrades, duty cycle increases to keep up with current drain, transformer saturates, overheats and fails?
Thoughts?
I have had some switchers that have gotten "stinky" and no obvious capacitor leakage.
--
The Real RFI-EMI-GUY
|
Re: The joys of ONAN power supplies in Motorola Quantar repeaters
In General, is there any theory on failure modes on switchers?
Filter cap ESR degrades, duty cycle increases to keep up with current drain, transformer saturates, overheats and fails?
Thoughts?
I have had some switchers that have gotten "stinky" and no obvious capacitor leakage.
--
The Real RFI-EMI-GUY
|
I currently use a Fluke AC/DC amp clamp and a Craftsman ACD/DC clamp. The craftsman measures down to the microamps, and works well.? That external clamp sounds interesting
Thanks and 73? Dean
On Fri, Jan 15, 2021 at 4:54 PM John J. Riddell < ve3amz@...> wrote:
I have one of the Extech clamp meters and am very happy with it.
It was recommended here by Eric Lemmon (SK)
I used it when I was working for 48 volts DC current readings.
?
I do have a Weston model 633 clamp meter for sale.
It is large and very rugged.
Ranges by a slider switch:
0-10,? 25,? 100,? 250,? 500,? and 1000 amps.
?
If interested please contact me off list at
(My call) @
?
73 John? VE3AMZ
?
lFrom: raysohst@...
Sent: Thursday, January 14, 2021 9:33 PM
Subject: Re: [repeater-builder] Clamp meter
?
For
getting into confined spaces I find a clamp current transformer works better for
me, what i have is a unit about 1x1.5x3" which outputs on a pair of 4mm sockets.
200A:200mA, the DMM can then be in a much better/visible lotation. On
Thu, Jan 14, 2021 at 12:35 PM, Joe wrote:
We had purchased a mini clamp meter for use at the place I used to
work
for. It was similar to the one on Amazon "Extech 380950 Mini AC/DC
80A
Clamp Meter" but I don't remember the brand.
We found that the
mini size meter was able to get into small spaces
where the larger ones,
mostly designed for electrical contractor work,
would not
fit.
Joe
|
I agree that it isn¡¯t worth my time to convert a bandpass into a BpBr out of these but I thought i would see if anyone has.?
Is it acceptable to use a Mobile flat pack duplexer and then attach bandpass cavities on each side for additional selectivity?
Hi
Skyler,
The T1500 cavities always were used in BpBr
"mode". See the documentation on this
site.
You could readily make the coupling loops and probes for
this but, time is
money.
There is nothing super special in their
construction.
You will however need GOOD test
gear.
Get the $100 Chinese flat pack (or other s/h complete
unit) and put together a
system.
Starting with, just the cans, building a BpBr duplexer is
quite
hard.
Getting the lengths of the cables between cavities right to reduce interaction was the hardest.
Alan
VK2ZIW
On Fri, 15 Jan 2021 08:11:07 -0700, Skyler Fennell
wrote
> I have
six T1500 cavities and I thought it would be nice to make a duplexer but they
are just
bandpass.?
>
> Anyone here have any info or way to acquire
the notch addons for
these??
>
> Maybe [UTF-8?]it?€?s easier to
combine a Chinese $100 flat pack with four of these bandpass filters to build a
BpBr?
>
---------------------------------------------------
Alan VK2ZIW
Before the Big Bang, God, Sela.
OpenWebMail 2.53, nothing in the cloud.
|
If you really want to test ground systems the ultimate is the AEMC 6416 and AEMC 6417.? This can test amperage but also accurately tests ground resistance?(without having to use the multiple stakes, long leads, etc as you used to) and can identify ground loops and currents.? These are the current standard tool for testing to meet Motorola R56 compliance of grounding/bonding systems.? I have an AEMC 6416 and it is very informative and easy to use (aside from the loop being huge due to the multiple inductive coils).
Thanks,
Dan Woodie, CETsr KC8ZUM?
On Fri, Jan 15, 2021 at 4:08 AM Steve via <mainline.electronics= [email protected]> wrote:
Hello
I am finding more and more these days that a high resolution
clamp meter to be very useful and time saving when measuring earth
leakage.
The? uni-t ut211b fits my needs.
On 14/01/2021 09:23 pm, Ralph Mowery
via wrote:
I only did a quick look at
that one.? I am not familiar with the brand.? I did not see a
CAT rating for it.? For home use and maybe up to the 240 volt
line the China ones are probably ok.? I have several of the HF
'free' ones.? For any serious and industrial usage ( I worked
on 3 phase 480 volt 400 amp circuits often) I only use the CAT
rated ones.? Such as the Fluke, Simpson, and Amprobe.? I use
them at home most of the time, but if working on low voltage
equipment I grab the HF much of the time.? I found they are
accurate enough to do much of my work plus they are in several
places around the shop and house.
Ralph ku4pt
Looking at the price of the
Extech it should have a CAT rating.
We had purchased a mini clamp meter for use
at the place I used to work
for. It was similar to the one on Amazon "Extech 380950
Mini AC/DC 80A
Clamp Meter" but I don't remember the brand.
We found that the mini size meter was able to get into
small spaces
where the larger ones, mostly designed for electrical
contractor work,
would not fit.
Joe
|
Hi
Skyler,
The T1500 cavities always were used in BpBr
"mode". See the documentation on this
site.
You could readily make the coupling loops and probes for
this but, time is
money.
There is nothing super special in their
construction.
You will however need GOOD test
gear.
Get the $100 Chinese flat pack (or other s/h complete
unit) and put together a
system.
Starting with, just the cans, building a BpBr duplexer is
quite
hard.
Getting the lengths of the cables between cavities right to reduce interaction was the hardest.
Alan
VK2ZIW
On Fri, 15 Jan 2021 08:11:07 -0700, Skyler Fennell
wrote
> I have
six T1500 cavities and I thought it would be nice to make a duplexer but they
are just
bandpass.?
>
> Anyone here have any info or way to acquire
the notch addons for
these??
>
> Maybe [UTF-8?]it?€?s easier to
combine a Chinese $100 flat pack with four of these bandpass filters to build a
BpBr?
>
---------------------------------------------------
Alan VK2ZIW
Before the Big Bang, God, Sela.
OpenWebMail 2.53, nothing in the cloud.
|
Re: The joys of ONAN power supplies in Motorola Quantar repeaters
This makes me want to put a fire retardant system in my IT room.? I hear there's a safer alternative to the old "Halon" systems.
-
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
|
Joe, I should have checked that out since I have had a minor issue of getting the clamp in-between some of the close spaced wires at one site. I'm getting geared up to be able to measure my equipment and my "neighbors" since some sites now charge for power consumed and add it to the rent.? Having said that $50 is cheap (in a positive way) enough to experiment to flatten the learning curve for more serious projects.
--
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
-
|
Re: The joys of ONAN power supplies in Motorola Quantar repeaters
At 1/14/2021 08:49 PM, you wrote: It's not that bad.? It just needs to be recharged with an extra-large can of Magic Smoke.? ?
Those early Onan PSUs are well-known for sometimes spectacular failures but I don't know that I have seen one quite this dramatic. I had an Antec ATX supply that failed so badly it set a HDD on fire. Another Antec supply, while not causing visible damage, destroyed a motherboard. Why to this day if I spot an Antec supply in a computer, it gets replaced immediately. Makes me wonder if there's a connection between Onan & Antec? Bob NO6B
|
The one that I referenced has 1mA resolution.
Keep in mind that I said this one is SIMILAR to the one we used, and is only an example of what is available.
Joe
toggle quoted message
Show quoted text
On 1/15/2021 10:48 AM, Dean LaClair wrote: Do they make a lower current DC version?
On Thu, Jan 14, 2021, 21:33 <raysohst@... <mailto:raysohst@...>> wrote:
For getting into confined spaces I find a clamp current transformer
works better for me, what i have is a unit about 1x1.5x3" which
outputs on a pair of 4mm sockets. 200A:200mA, the DMM can then be in
a much better/visible lotation.
On Thu, Jan 14, 2021 at 12:35 PM, Joe wrote:
We had purchased a mini clamp meter for use at the place I used
to work
for. It was similar to the one on Amazon "Extech 380950 Mini
AC/DC 80A
Clamp Meter" but I don't remember the brand.
We found that the mini size meter was able to get into small spaces
where the larger ones, mostly designed for electrical contractor
work,
would not fit.
Joe
|
I have one of the Extech clamp meters and am very happy with it.
It was recommended here by Eric Lemmon (SK)
I used it when I was working for 48 volts DC current readings.
?
I do have a Weston model 633 clamp meter for sale.
It is large and very rugged.
Ranges by a slider switch:
0-10,? 25,? 100,? 250,? 500,? and 1000 amps.
?
If interested please contact me off list at
(My call) @ arrl.net
?
73 John? VE3AMZ
?
lFrom: raysohst@...
Sent: Thursday, January 14, 2021 9:33 PM
Subject: Re: [repeater-builder] Clamp meter
?
For
getting into confined spaces I find a clamp current transformer works better for
me, what i have is a unit about 1x1.5x3" which outputs on a pair of 4mm sockets.
200A:200mA, the DMM can then be in a much better/visible lotation.
toggle quoted message
Show quoted text
On
Thu, Jan 14, 2021 at 12:35 PM, Joe wrote:
We had purchased a mini clamp meter for use at the place I used to
work
for. It was similar to the one on Amazon "Extech 380950 Mini AC/DC
80A
Clamp Meter" but I don't remember the brand.
We found that the
mini size meter was able to get into small spaces
where the larger ones,
mostly designed for electrical contractor work,
would not
fit.
Joe
|
Re: The joys of ONAN power supplies in Motorola Quantar repeaters
Didn't want to see that, but at least I have a spare :-)
|
Do they make a lower current DC version?
For getting into confined spaces I find a clamp current transformer works better for me, what i have is a unit about 1x1.5x3" which outputs on a pair of 4mm sockets. 200A:200mA, the DMM can then be in a much better/visible lotation.
On Thu, Jan 14, 2021 at 12:35 PM, Joe wrote:
We had purchased a mini clamp meter for use at the place I used to work
for. It was similar to the one on Amazon "Extech 380950 Mini AC/DC 80A
Clamp Meter" but I don't remember the brand.
We found that the mini size meter was able to get into small spaces
where the larger ones, mostly designed for electrical contractor work,
would not fit.
Joe
|
I have six T1500 cavities and I thought it would be nice to make a duplexer but they are just bandpass.?
Anyone here have any info or way to acquire the notch addons for these??
Maybe it¡¯s easier to combine a Chinese $100 flat pack with four of these bandpass filters to build a BpBr?
|
Re: The joys of ONAN power supplies in Motorola Quantar repeaters
Of course, the Motorola supply isn¡¯t immune from exploding either. This is a CPN1047:
toggle quoted message
Show quoted text
On Jan 14, 2021, at 10:49 PM, Dan Woodie <kc8zum@...> wrote:
? It's not that bad.? It just needs to be recharged with an extra-large can of Magic Smoke.??
Those early Onan PSUs are well-known for sometimes spectacular failures but I don't know that I have seen one quite this dramatic.? If any of you have one of these in service there are plenty of 800 MHz Quantars on the market for relatively little $.? I highly recommend you buy one with a newer?PSU (easily identifiable as they have a smaller fan grille that is square - but keep in mind there are some different flavors of these including DC-Only supplies which have a different power switch among other noticeable differences) - then junk the band-specific parts and keep the PSU, chassis, controller (unless it is an EPIC 4 or EPIC 6), and wireline/V.24 boards.? I think I have one of the old Onan supplies floating around that hasn't failed but I would never put it in service - especially since I acquired a few exactly as described above.? I am just waiting for the hamfests to start back up and truckloads of Quantars will be appearing out of garages and storage units - as even the pandemic has not really slowed down their replacement and with End of Life and End of Support both having passed most public safety users are upgrading to GTR8000s which for the most part have been pretty reliable from my experience.??
Once the next generation of base stations is released the GTRs will start finding their way to the secondary market.? Then we get the fun of 6-Pack Chassis, X-Hubs, Option Boards, CSS, etc.? I already have a UHF GTR8000 with a 6-Pack and Standalone chassis.? Despite what some say they can do wideband - and it doesn't require any mods or special software mods - just a specific procedure that is less-than-obvious as they want the majority of users to be forced to Narrowband for good reason.? Many don't realize the GTR8000 has been on the market for close to 15 years now and is in its second generation (released in 2013) due to parts that were NLA and design improvements.
Thanks,
Dan Woodie, CETsr KC8ZUM On Thu, Dec 17, 2020 at 10:18 AM JeffBanke < jeffbanke@...> wrote: Glad I did not have this Quantar in my house when the power supply flamed, it had previously been there for several month during our testing phase. Finally installed about a year ago, and this last week went down. Upon entering the room the repeater was located in, from the very first smell it was obvious something had burned, and boy had it burned!
This picture was after opening it up and finding smoke damage everywhere around the supply, obviously flames had come out of the vents in the front and back. After tearing it apart, this picture is what the bottom of the main board looked like, the PCB burned through. Right above this was a toroid transformer. You can also see the smoke damage to the inside of the case.
Thankfully, a good freind had a newer supply that we could obtain, so we are back on the air, but who knew these ONAN PSU'swere dangerous time bombs like this.
<2020-12-10 10.20.48.jpg>
|
Matt Lechliter
wa5luy
RFI-EMI-GUY
Karl Shoemaker
JeffBanke