Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
What exactly are you trying to accomplish?
If the notch filter effectively gets rid of the noise generated from the rouge transmitter, what more do you need? I presume the BpBr can Bob spoke of would do this nicely.?
Dean K2WW
What is the standard method to measure phase noise? Most measurement?systems have pretty wide skirts that seem to be phase noise generated by themself, not actual phase noise from the transmitter.
Would this idea work: Characterize a notch filter, calibrate the notch filter to zero it out so it is a flat line with the notch filter in place, and then transmit through the notch filter tuned for the transmit frequency? ?
Not unless you're talking about the PLL G.E. exciter.? In the offset frequency range of 12 kHz to 3 MHz a Kenwood TK-880 mobile has lower phase noise, as much as 20 dB lower at some offsets.
Bob NO6B
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
What is the standard method to measure phase noise? Most measurement?systems have pretty wide skirts that seem to be phase noise generated by themself, not actual phase noise from the transmitter.
Would this idea work: Characterize a notch filter, calibrate the notch filter to zero it out so it is a flat line with the notch filter in place, and then transmit through the notch filter tuned for the transmit frequency? ?
Not unless you're talking about the PLL G.E. exciter.? In the offset frequency range of 12 kHz to 3 MHz a Kenwood TK-880 mobile has lower phase noise, as much as 20 dB lower at some offsets.
Bob NO6B
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
Thanks? for the graph Bob.
Kenwood? looks?? nice?? ?
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At 1/17/2021 08:41 AM, you wrote:
>Do not forget? the issue? of? phase npise on? a? TX? or? the? RX? local oscillators.
>GE MII and? MOT?? are usually?? a? lot cleaner.
Not unless you're talking about the PLL G.E. exciter.? In the offset frequency range of 12 kHz to 3 MHz a Kenwood TK-880 mobile has lower phase noise, as much as 20 dB lower at some offsets.
Bob NO6B
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Re: Motorola XPR8300 repeater, no USB comms
Hi Matt, Also make sure the network cable is unplugged.?
~Ross
On Jan 17, 2021 1:25 AM, Mark <skylane.mark@...> wrote: Hi guys.? I have an issue with USB comms to an early model XPR8300 repeater.? ?It's has been extremely stubborn.? ?I've tried everything, different PC's, different cables, both CPS16, and CPS2,? tried the rear USB on the TX and RX bricks individually, tried as USB-2 hub, still NOTHING.? No USB comms on all 3 connections.? Just keep getting comm errors, no USB problems like this with my other trbo radios and the same programming gear.? ??
?
The thing that's DIFFERENT on this repeater vs. my others is ver. 1.04.01.???My others that are Ver. 1.06.20 have no problems with USB ports.? ?Obviously, I can't even upgrade the firmware if? I can't talk to it.? Anyone seen this?? Thanks so much in advance!
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Re: Low Band Motorola Base
Yes, the "intermittent duty" heat sink was a lot like the MOCOM.
But not quite.
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Re: Low Band Motorola Base
Located in Florida panhandle, in Niceville. ?
Model number is C71RTB-3146D
It is Micor based, although, as has been pointed out, it has a Mocom 70 PA. ?
As for modules, whatever is in the picture. ??
It¡¯s currently on 45 something. ?
I hope that helps,
Will
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On Jan 17, 2021, at 1:12 PM, Jim Strohm <jim.strohm@...> wrote:
? Model / modules?
Location?
Those are important facts.
If I saw this at a swapfest, I'd load it off your trailer and into my truck for free .....
73 Jim N6OTQ
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
At 1/17/2021 09:33 AM, you wrote: Very true on the TX phase noise point. I?€?ve fought with a user at 451MHz using an icom mobile with no bandpass or isolator. They were a few MHz away and desensing ? us bad.?
It turns out my desense was from their phase noise, luckily they were not mixing. Small bandpass cavities had no help, we needed a realllly narrow skirts fat guy to get their phase noise off our input. What would've worked better in that situation is a pass-notch cavity from a duplexer. I've been lucky enough to find a couple standalone BpBr cans at Dayton & local swap meets. While designed for 3 or 5 MHz spacing, many of them will tune down to a few hundred kHz spacing with only a reduction in notch depth. I have a pair on a RX that's co-located with a TX only 320 kHz away. At that spacing the notch depth is only 20 dB, but that's enough to keep the preamp on the RX from going into compression. Bob NO6B
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
At 1/17/2021 08:41 AM, you wrote: Do not forget the issue of phase npise on a TX or the RX local oscillators.
GE MII and MOT are usually a lot cleaner. Not unless you're talking about the PLL G.E. exciter. In the offset frequency range of 12 kHz to 3 MHz a Kenwood TK-880 mobile has lower phase noise, as much as 20 dB lower at some offsets. Bob NO6B
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Re: Low Band Motorola Base
That almost looks like a MOCOM 70 heat sink hanging out of the rack panel there.
On Jan 17, 2021, at 12:18 PM, Glenn "Butch" Kanvick < hotlrv1@...> wrote:
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What part of Low Band are you looking for?
Model / modules?
Location?
Those are important facts.
If I saw this at a swapfest, I'd load it off your trailer and into my truck for free .....
73
Jim N6OTQ
--
Glenn (Butch) Kanvick
KE7FEL/R
1-406-655-1232
?
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Re: Motorola XPR8300 repeater, no USB comms
thank you Matt!, I have some old CPS still in my folders, will try, and report back.? 73's,? Mark
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
There are reasons why a repeater like a Quantar cost >$10,000.00.
A clean transmitter is one.? I have run a Quantar on 2 meters at 600 kHz split? with no desense on an 80 dB 4 can duplexer.
Toughness is another.? At work we had multiple Quantars spitting out control channel 24 hours a day continuously for 25 YEARS - on the original PA.
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
The old GE mastr ll repeaters were nothing but the same circuits for the most part but the amplifier was available in 2 types.? Intermittent and 100 % duty so to speak.? The only difference was the size of the heat sink.? I am not sure if they did turn the power up or down , but think the mobile was rated for 110 watts were the repeater was rated 100, but a slight turn of a pot would set that.?
For a long time I ran a mastr ll mobile sitting on a table top as a repeater with an external controller.? It was a 110 watt unit and I ran it about 90 watts .? I sat it off the table top an inch or so and had a muffin fan blowing long ways so that the air went past the heat sink and over and under the unit.? Used an AAR GASFET preamp with it. No desense at all.? Probably partly because the preamp was mounted to the 6 cavity duplexer.
Ralph ku4pt
On Sunday, January 17, 2021, 04:19:29 PM EST, Bob Dengler <no6b@...> wrote:
At 1/17/2021 05:24 AM, you wrote:
>On 1/16/2021 10:53 PM, TGundo 2003 via groups.io wrote:
>> To retort:
>>
>> Many, if not most, current "factory" repeaters today are nothing more
>> than 2 mobiles in a box
>
>Not always true.?? For example, the Motorola R1225 repeater appears to be
>a mobile, but the heat sink is much larger than on the regular M1225 mobile.
...and that makes it a "factory" repeater?? No different then adding a fan to a commercial mobile radio, which BTW is what I've been doing for the past 30+ years ;)
Bob NO6B
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
At 1/17/2021 05:24 AM, you wrote: On 1/16/2021 10:53 PM, TGundo 2003 via groups.io wrote:
To retort:
Many, if not most, current "factory" repeaters today are nothing more
than 2 mobiles in a box Not always true.? For example, the Motorola R1225 repeater appears to be
a mobile, but the heat sink is much larger than on the regular M1225 mobile. ...and that makes it a "factory" repeater? No different then adding a fan to a commercial mobile radio, which BTW is what I've been doing for the past 30+ years ;) Bob NO6B
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
Eric,
I've gone both routes with my 900 repeaters - first, I built one out of 2 mobiles tied to a controller and, then I built one from a purpose-built - a Motorola MSF5000.? (FWIW, I sold the "homebrew" repeater, but I recently learned that it is still in service in Kenosha, WI.)
Probably the biggest advantage of buying a purpose- built station is that it is designed for full duty transmit capability.? Mobiles are - at best - considered intermittent duty,? maybe 10% transmit, unless steps are taken to cool the PA on the "transmitter" radio, or you eliminate the final PA and use the radio to drive an external PA, or both. (Use the relatively low-power output of the mobile to drive a final high-power PA.)
Some manufacturers make purpose-built "desktop repeaters" out of mobiles as you describe - Motorola has done it for years with such repeaters as the R1225, and the Kenwood TKR-x20 series was another example of such a "desktop" repeater.
As far as being "expensive", the MSF5000 stations are available for the cost of a good mobile anymore... I picked up *three* 900 MHz MSF5000 stations nearly 10 years ago for $100 each.? Not what I would call expensive for a practically complete station.? I say "practically" because yes, I did need to add an HSO and a duplexer to make it a fully stand-alone repeater, but it was fully operational in the environment from which it came.
The teason6many of the MSF5000 / MSR2000 stations appear to be so expensive is that the reseller doesn't know the true market value of the station. Sure, it probably cost upward of $10k when new... but now, it is WORTHLESS to public safety / commercial users because of narrowband mandates.? As an example, the stations I bought were from a statewide trunked system that had been upgraded.? The seller wanted to sell the system as a lot, complete with microwave backbone.? As part of a group of Amateurs interested in purchasing just the stations, we made our bids to the company.? Another purchaser wanted just the micriwave backbone, but bought the whole package as a lot...
So we made the same offer to him as we did the initial seller.? This guy countered with a demand of $500 per station.? We politely told him "NO."? After realizing that he was goning to be "stuck" with approx. 140 stations he didn't want - and the associated shipping costs to get it off of the initial seller's hands - he quickly acquiesced to our offers.? I think our group ended up taking all 140+ stations off his hands...
Other brands are also available as complete, purpose-biilt repeater stations at value prices.? Kenwood readily comes to mind, as well as older Motorola and GE stations, but those can be crystal-controlled and as such are more difficult to get on the frequency of your choice.? Some like Tait, but I have no personal experience with them.? Look for stations that have been decommissioned because of "narrowband" mandates... There was a flood of these that became available a few years ago - you don't need anything "brand new", because Amateurs aren't bound by the narrowband mandate on 2m or 70cm... or anywhere else, for that matter.? Unless you want features like DMR or P-25 digital voice capabilities.
As a final note, of the 3 MSF5000 station I bought, two were put on-the-air, and the third was for back-up parts.? Other than a final PA failure in my station, both are still on the air.? The third station has been partially parted-out - I sold the control tray to another guy who needed one.? The rest sits in my garage at the moment...
Hope that helps answer your question.
73 de Mark - N9WYS?
Please excuse all typos... Fat fingers and hyperactive spell check at work!
On Sat, Jan 16, 2021 at 20:59, Eric Fort <Eric.fort.listmail@...> wrote: It seems many individuals and groups when they want to put up a repeater opt to just buy a sometimes expensive box like a quantar, msf5000, msr2000, ge, kenwood, virtex, icom, etc and call it a day. Others will simply take 2 mobiles, tie them to a controller and call it a repeater (I¡¯m leaving out the duplexer and antenna, etc for simplicity assuming they are equal in both cases. What does one get for going the commercial box route vs the 2 transceiver route with a controller Tying them together?
Eric
Af6ep
Sent using SMTP.
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Re: Low Band Motorola Base
What part of Low Band are you looking for?
Model / modules?
Location?
Those are important facts.
If I saw this at a swapfest, I'd load it off your trailer and into my truck for free .....
73 Jim N6OTQ
-- Glenn (Butch) Kanvick KE7FEL/R 1-406-655-1232 ?
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Glenayre 9T97A125 UHF Amplifier schematic
I have a little bit of logic troubleshooting to do on one of these amps. I have a operating manual, which has two pages of the desired schematic. However, page 7-17 is a schematic, page 2 of 2. The page in front it 7-16 is labeled "logic board". but the drawing is a base station hook up. Obviously, a mistake on the manual. I'm missing a whole bunch of information on the logic board.
Does anyone have an update manual that shows the rest of the logic board?? This misprinted manual is USER MANUAL PN 9110.00116??? REV C
Thank you
Tom Bosscher K8TB
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Re: Looking for a Motorola Quantar
If there are no Quantar equipment limitations for operating a Range 2 Quantar on 146.730/146.130 MHz then I'm open for that. But, I was generally referring to the Range 1 Quantars with 125w PA. I don't intend on running P25 but will interface to an external controller so any wireline card will suffice. Preferably would want the AC power supply.
The site I have access to is RF heavy so I need some serious repeater equipment.?
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Re: Clamp meter mistake -- watch for a balanced meter movement if analog
Hello Karl !
Explanation --
It¡¯s balanced ¨C not balance.
For example, my trusty old Simpson 260 is an almost balanced meter movement.? Even with it, when holding it in different planes (lying down, sitting up, sitting on its side) the meter reads differently since the resting point of the meter needle changes.
At least for the Simpson I¡¯m using these days the manufacturer specifies accuracy with the meter on its back.? I don¡¯t know if this was changed as the series progressed.? Certainly my oldest Simpson, dating from before there was a series designation on the meter face is quite not balanced.
I have 3 clamp ammeters ¨C one analog meter, a Triplet, ?is usable in any plane, one (I hate to admit it ¨C a Radio Shack) changes meter needle position 10 to 15 percent with position, and the third (a Fluke) has a digital readout.? The Triplet model 10 clamp adaptor that goes atop a model 310 multimeter works in any plane ¨C move it around and the meter doesn¡¯t move off zero.
And so there you are ¨C some meter movements are balanced, and some aren¡¯t ! If you have some old panel meters lying around, try rotating them into different planes.? Some will stay stable, others will undergo significant motion of the meter needle which will come to rest off zero.
I hope this clarifies the balanced meter (movement) effect !
Incidentally ¨C the same goes for a number of early timepieces.? They were designed so that their regulators [escapements] (we¡¯d call them mechanical time-bases) was fully accurate in only one orientation, not by design but by the constraints of mechanical escapements at the time.
That¡¯s it !
Mike/
K5MGR
_________________________________________________ ? Mike Langner
929 Alameda Road NW
Albuquerque, NM 87114-1901
(505) 898-3212 home/home office
(505) 238-8810 cell
mlangner@... ?
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Re: Low Band Motorola Base
Model / modules?
Location?
Those are important facts.
If I saw this at a swapfest, I'd load it off your trailer and into my truck for free .....
73 Jim N6OTQ
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Re: Why use a purpose built repeater box as a repeater rather than a transmitter, receiver, and controller tied (lashed) together?
Eric,
I've been building, modifying and servicing repeaters since 1977. I started out with the tube equipment running separate sites then a single site with separate antennas but migrated to the? IC-20 radio in separate bud (radio) boxes. Built and my parent sold about 25 of them, some of them in other countries. Also, controllers, auto-patch and many other projects. Many types, and brands, from a mobile to base commercial products.? Over the decades I've improved methods and specifications. I do it because I enjoy creating things to help others. Perhaps if you have the time, check out my techi page for my story. The parent page has stuff too.? And, of course check out RB's page. Kevin and others have done a great job providing information for the amateur community. I refer to it often. Here's a shortcut to what I do.
https://www.srgclub.org/LinkRadios.html
--
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
-
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n9wys
Glenn (Butch) Kanvick
Andrew Grimm (K8ATG)
Karl Shoemaker