VHF Cavities and other 220 combining available.... plus MORE
This is a "For What its Worth" post, but maybe it will have some interest.
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I hope posting this here does not violate any group rules, but it seems like the appropriate audience.
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I am clearing out and liquidating a lot of equipment from a closed shop in Las Vegas. Currently I want/need to catalog everything before I start sharing, but in an attempt to save time and shipping expense I am posting the following:
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I have (2) Db Products VHF Combiner racks, (See attached). They stand about 4' high and about 3' square.
(I'm not opposed to parting them out, but initially prefer to see if anyone wants them as? a whole).
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Most of the equipment will most likely be shipped back to the Chicago area to be dealt with, but given the size of these, if anyone is interested in them I would like to know before I screw up the logistics by moving them around.
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As stated, there will be more later, but I also have a LOT of 220 Combining, (Mostly 5 channel racks, but I will part out if necessary), if anyone is interested.
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I also have some of the Securicor 220 repeaters with the PA's as has been discussed. If interested give me a reply (Off Group would be best).
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I am not trying to break anyone's bank on this stuff, but I do have mounting storage and logistical expenses I need to offset, so if anyone is interested, I'm sure we can reach reasonable pricing that benefits both sides.
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Thanks.....
Bob
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PS, As stated, there is a LOT more stuff available that I need to address in ALL bands, (VHF, 220,UHF, 800 & 900), as well as MANY manuals. If you are looking for anything specific, drop me a line, (Off Group) and I'll let you know if I have it.
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I've used TDR to find fault on small JKT(telephone wire) to underground tech cable (10-3)?
The velocity can be anywhere between 50 to 90 % Make sure there is no remaining power connected to any of the wire and I would suggest that you put a known terminating load at the?cable end and make the same test without. This helped me find a lot of strange breaks in the security system cable. And in a oil refinery regulation system.?
Pierre VE2PF
Anyone have experience using a TDR to locate an underground fault for high voltage ?
There's a PUD in central Washing that can't appear to fix an outage for the past three weeks or so.
It's affecting several comm sites and one ski area. It's high up around 7,000 ASL with 20-foot drifts.? The road is derivable around the first or second week of July each season.?
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I'm not sure if it's incompetence or lack of training but the concept seems simple enough to me; send a pulse down the line and watch for the return indicating something is wrong.?
There are several of these units on the market, on line.?
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I also suspect it's not an exact science and requires lots of experience to be effective.?
If I were in the area I suppose I could hook up the (dead) line to a spark plug circuit (from an engine or whatever) and walk the mile line listening for anomalies with an AM radio.?
For now, one leasee is dragging large amounts of propane to keep one site alive.?
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Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
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Re: Suggestions for service monitor
Steve, I have RSP Spectrum Analyzer made for the RSP line of inexpensive SDR receivers and while it works well and is cute, its just a toy. Alignment of repeaters which I take as tuning the receiver for best sensitivity, placing it exactly on frequency, measuring the repeater transmitter frequency, measuring transmit deviation, transmit power then possibly sweeping and aligning the duplexer and associated filters and isolator is beyond what a toy SDR could ever do. Amateurs don't have to abide by most FCC specs when placing an amateur repeater on the air but it still takes some accurate and reliable equipment to align all its parts for proper operation. That can be done with a separate frequency measuring device, signal generator, deviation meter and duplexers/filters can certainly be aligned with a CW signal generator and power/millivolt meter or even a diode detector and oscilloscope.?
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When I started in Land Mobile alignment and repair we had mostly separate instruments to perform everything and when I finally got my hands on a Singer FM10C in the 70s I though I had died and gone to heaven. I can't imagine any SDR receiver performing the type of simple tests an old FM10C can do without a host of other expensive equipment to calibrate it or verify if its even within spec. Heck, just the frequency standard in the old FM10C probably cost way more than the BladeRF SDR mentioned. I would recommend getting the best actual radio service monitor that the OP can afford and trade up in the future to a better model. Many good suggestions have been made here but there are also older more affordable models that will work great to get someone started.
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Not for high voltage, but for fire alarm cabling on utility poles.
I had a Riser Bond TDR that I used for fault location.? A long time ago I was asked to find a fault in a municipal cable that was once used for fire alarm call boxes.? The fault was an open circuit.? One of the things that you have to take into consideration is the velocity factor of the cable that you are troubleshooting.? This is usually impossible to know.? So I used another method.? I measured the fault from either end.? Just for a theoretical example, the TDR measurements were 1000 feet and 500 feet.? The actual physical length of the cable was 1000 feet. Interpolating that, the fault was 666 feet from one end and 333 feet from the other.? Sure enough, we found the cable had visible physical damage at this distance and fixed the problem.
I've never done underground TDR testing, but the same method should apply.? If it is a single hard fault (open, short) you should be able to find it.? Multiple faults could be very hard to find.? Be careful of any stray voltage on the cable, as it can damage the test equipment.? We had an Hewlett-Packard TDR test set that was damaged by voltage on the cable.
Joe, K1ike
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On 4/7/2025 11:38 PM, Karl Shoemaker via groups.io wrote: Anyone have experience using a TDR to locate an underground fault for high voltage ?
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Re: Possibly Quintron PA? Need help identifying transistors
Quintron made a lot of equipment for the 72-75Mhz linking band for paging.
Joe, K1ike
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On 4/8/2025 9:00 AM, Jeff DePolo WN3A via groups.io wrote: I’d have to think it’s highband or midband.
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Re: MTR2000 channel steering
Mornin' John,
> I'm trying to program channel steering in the RSS using GPIO
pins on the 96-pin connector without any optional cards.
In the MTR2000, the GPIO pins on J5, the 96-pin System Connector
only connect to J1 and J2, the Option slots in the cardcage.? The
System Controller is at J3.? To use those pins requires an Aux I/O
See the connector table at:
The To/From column shows where the signal connects.
73,
? Dave
On 4/8/2025 6:55 AM, john ni0k wrote:
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Chris,
I'm trying to program channel steering in the RSS using GPIO
pins on the 96-pin connector without any optional cards. That
section of the RSS isn't very straightforward to me.
73
-de "Curly" John NI0K
call me: 6100271
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Attached is some information on the DB212 antennas.? Perhaps this will help.? This was factory info from a DB212-2 that was tuned to 47.14 MHz. 73 Joe WB4HIS ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Roger willey via groups.io
Sent: Tuesday, April 8, 2025 09:28
To: [email protected]
Cc: [email protected]
Subject: Re: [repeater-builder] 6 m repeater antenna? ?
On Apr 7, 2025, at 5:55?PM, wgwl via groups.io <wgwl@...> wrote: ? Roger,
In hopes of answering your original question, I got my hands on a DB212-2 originally on 37.7MHz and shortened the antennas and matching section for 6?
meters. The 35 ohm matching section (Decibel Products VB-83 cable) was shortened?
to 36.25" end to end. With a UHF T on the end?
and two 50 ohm loads attached resulted in the attached plot. As you can see, the?
exact length is not critical across the band. John,
You mentioned "DB factory lengths" in an earlier post. Do you have access to the?
actual factory length chart for 6M ? If so, please share. How well did the tuning of your antenna on the ground translate to mounting on a tower? What length of pipe did you use when tuning? <6meter DB212-2 matching section.png>
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On Apr 7, 2025, at 5:55?PM, wgwl via groups.io <wgwl@...> wrote:
? Roger,
In hopes of answering your original question, I got my hands on a DB212-2 originally on 37.7MHz and shortened the antennas and matching section for 6?
meters. The 35 ohm matching section (Decibel Products VB-83 cable) was shortened?
to 36.25" end to end. With a UHF T on the end?
and two 50 ohm loads attached resulted in the attached plot. As you can see, the?
exact length is not critical across the band.
?
John,
You mentioned "DB factory lengths" in an earlier post. Do you have access to the?
actual factory length chart for 6M ? If so, please share.
?
Mike,
How well did the tuning of your antenna on the ground translate to mounting on a tower? What length of pipe did you use when tuning?
Greg
WB9TRO
<Matching Section.jpg> <6meter DB212-2 matching section.png>
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On Apr 7, 2025, at 5:55?PM, wgwl via groups.io <wgwl@...> wrote:
? Roger,
In hopes of answering your original question, I got my hands on a DB212-2 originally on 37.7MHz and shortened the antennas and matching section for 6?
meters. The 35 ohm matching section (Decibel Products VB-83 cable) was shortened?
to 36.25" end to end. With a UHF T on the end?
and two 50 ohm loads attached resulted in the attached plot. As you can see, the?
exact length is not critical across the band.
?
John,
You mentioned "DB factory lengths" in an earlier post. Do you have access to the?
actual factory length chart for 6M ? If so, please share.
?
Mike,
How well did the tuning of your antenna on the ground translate to mounting on a tower? What length of pipe did you use when tuning?
Greg
WB9TRO
<Matching Section.jpg> <6meter DB212-2 matching section.png>
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On Apr 7, 2025, at 5:55?PM, wgwl via groups.io <wgwl@...> wrote:
? Roger,
In hopes of answering your original question, I got my hands on a DB212-2 originally on 37.7MHz and shortened the antennas and matching section for 6?
meters. The 35 ohm matching section (Decibel Products VB-83 cable) was shortened?
to 36.25" end to end. With a UHF T on the end?
and two 50 ohm loads attached resulted in the attached plot. As you can see, the?
exact length is not critical across the band.
?
John,
You mentioned "DB factory lengths" in an earlier post. Do you have access to the?
actual factory length chart for 6M ? If so, please share.
?
Mike,
How well did the tuning of your antenna on the ground translate to mounting on a tower? What length of pipe did you use when tuning?
Greg
WB9TRO
<Matching Section.jpg> <6meter DB212-2 matching section.png>
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Re: Possibly Quintron PA? Need help identifying transistors
It definitely looks like a Quintron constructed board.? The white label with the writing on it looks like how they identified boards. The date code may be 1989?? I think that was before they were bought out by Glenayre.? I've worked on several pieces of Quintron/Glenayre equipment but don't remember this board, especially one that had a BNC pigtail on it.? The pigtail looks like it was factory installed and not a modification, unless someone did a nice job of modification.
Joe, K1ike
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Re: Possibly Quintron PA? Need help identifying transistors
Anything with an SRF part number is usually a special-production or binned version of a regular MRF part, but rarely were cross-references (if they existed) published.?? That said, given the amount of inductance in the matching networks, I’d have to think it’s highband or midband. ? ??????????????????????????????????????????????????????????????????????????????????????????????? --- Jeff WN3A ?
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From: [email protected] <[email protected]> On Behalf Of Tyler- WZ5TX via groups.io
Sent: Monday, April 7, 2025 9:29 PM
To: [email protected]
Subject: [repeater-builder] Possibly Quintron PA? Need help identifying transistors? I have this PA and it is labeled “100W PA”. However I cannot find the datasheet for the transistors. Motorola SRF2604. any ideas what the range for this is?
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Re: MTR2000 channel steering
Chris,
I'm trying to program channel steering in the RSS using GPIO pins on the 96-pin connector without any optional cards. That section of the RSS isn't very straightforward to me.
73
-de "Curly" John NI0K
call me: 6100271
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Re: Suggestions for service monitor
The Motorola 2600 series is hard to beat... And can be found reasonably priced if you are patient.
Mike,
This is a Windows program, but I think it's a lot of what you want and you can choose the hardware
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Steve N4IRS
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Re: Suggestions for service monitor
Mike,
This is a Windows program, but I think it's a lot of what you want and you can choose the hardware
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Steve N4IRS
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Re: Possibly Quintron PA? Need help identifying transistors
WZ5TX
David “Tyler” Bufkin
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Well here's an idea, put 12 volts to it, put a service monitor or signal generator into it, broadband watt meter on the output and sweep it and see where you get a peak in RF out driving it with say +10dbm... Probably won't see a hundred Watts
out with that drive but it'll tell you what band it is.
"There are always possibilities"
Famous Vulcan saying
Chris WB5ITT?
Here is a pic of the only numbers I see on the board.
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Re: Possibly Quintron PA? Need help identifying transistors
Well here's an idea, put 12 volts to it, put a service monitor or signal generator into it, broadband watt meter on the output and sweep it and see where you get a peak in RF out driving it with say +10dbm... Probably won't see a hundred Watts out with that drive but it'll tell you what band it is.
"There are always possibilities" Famous Vulcan saying
Chris WB5ITT?
Here is a pic of the only numbers I see on the board.
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Re: Possibly Quintron PA? Need help identifying transistors
Here is a pic of the only numbers I see on the board.
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does anyone have a programming lead for a kyodo kg510 or schematic of one
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Re: Suggestions for service monitor
Third.
Bob NO6B
At 4/7/2025 03:47 PM, you wrote:
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I second this. I had the same
question about a month ago and ended up getting an HP8921A. It?�?s a good
analyzer to learn on and does probably way more than you need.
On Apr 7, 2025, at 6:42?�?PM,
Mike via groups.io <prcradio@...> wrote:
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For non digital stuff the HP/Agilent 8920 series.
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Pierre Martel
Dave WA1JHK
Steve N4IRS
Chris Boone WB5ITT