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Re: VHF MTR2000 Poor Receive Performance

 

I may have missed something but have you tried this ?

Hook a transceiver to the antenna and see what kind of range you are getting.? If as expected, hook the repeater receiver input directly to the antenna and see if you are getting about the same from a distant station.

Have you tried cutting the transmitter off and on while receiving a signal to check for desense ?

When you injected the signal did you up it a db or two to compensate for the loss in the duplexer ?


Ralph ku4pt



On Wednesday, November 2, 2022 at 08:19:18 AM EDT, Jared Smudde <computerwhiz02@...> wrote:


So last night, I measured the MTR at 0.4uV at the receiver port and 0.5uV at the duplexer antenna port.

I injected a signal into the receiver port of the MTR that had just barely had no noise and when I injected it through the duplexer into the repeater, there was noise present. It wasn't heavy noise but it still had noise on the signal.

Re: Got a trimble thunderbolt E need more info.

 

Thanks Cliff, will order one as soon as I have the trimbler?working.

Still searching for a suitable?24 volt power supply as my trimble has the internal voltage controller?that takes care of the?+5?+12 and -12 volts signal. Still have not connected it yet as I also search for the mini connector type that is in front of the device. I will try to inject 24 volts from my test power supply first. surely this weekend.

Tks for the info again

Pierre
VE2PF

Le?ven. 28 oct. 2022 ¨¤?12:11, k1iff <k1iff@...> a ¨¦crit?:
I would also recommend getting one of .? Also comes in kit form for a bit less.?

Gives you four filtered and amplified outputs.? I use all four - two for my NXDN repeaters and two for the service monitors.

73 Cliff, k1iff

Re: TKR-851 power issue

 

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Connect the repeater to a power supply that can tell you how much current is being drawn. Determine if it¡¯s low or in the expected range.?

If low, troubleshoot the DC power circuitry. If it¡¯s as expected, troubleshoot the RF path/cabling circuitry.?

tnx
Mike / K5JR?
Alpharetta GA

On Nov 2, 2022, at 8:50 AM, Brandon Vetter <Brandon@...> wrote:

?

Hi Group,

????????????? I have a TKR-851 that I thought had bad finals. It had about 2 watts output. Installed a new transmitter board with new driver and final transistors and now I get 3 Watts output. If I drop it to low power, I get less than 1 watt. The power in the software is turned up. The power adjustment pot does not seem to be functional. There are no PLL errors flashing. Anyone have any thoughts on what might be going on?

?

Brandon Vetter

N7IRG

?

?
Re: VHF MTR2000 Poor Receive Performance

 

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Jared,

I think your SM allows you to read dBm directly.? Please consider using that measurement unit instead of uV, because it requires less conversions and makes more sense in the end.

Taking your two measurements of 0.4uV and 0.5uV the equivalent dBm for each is -115dBm and -113dBm respectively - or a difference of 2dB.? You stated your duplexers IL is 1.67dB - I consider that pretty darn close.

There is no free lunch.? A duplexer allows you to use one antenna in a duplex system - - at the expense of signal loss.?

In my book - .4uV (-115dBm) bench sensitivity is pretty deaf - but you don't say what you're referencing at that level.? Is that the level where you achieve 12dB SINAD?? 20dB of quieting?? The cracklies are totally gone??

Kevin

On 11/2/2022 8:19 AM, Jared Smudde wrote:

So last night, I measured the MTR at 0.4uV at the receiver port and 0.5uV at the duplexer antenna port.

I injected a signal into the receiver port of the MTR that had just barely had no noise and when I injected it through the duplexer into the repeater, there was noise present. It wasn't heavy noise but it still had noise on the signal.

Re: VHF MTR2000 Poor Receive Performance

 

Yes, the TX side was terminated into a dummy load, I forgot to mention that.
Re: VHF MTR2000 Poor Receive Performance

 

Hopefully he did the test below with the TX disabled. If not, they don't tell us much.

Mike
WM4B

On November 2, 2022 at 8:36 AM John <jhaserick84@...> wrote:

Hello Jared,
I have not been following these threads very carefully, but the thought occurred to me wondering if your transmitter might have spurs when connected to the duplexer? It would be easy enough to check with a spectrum analyzer connected via a lossy T between the TX and duplexer, (if not already checked.)? I had just finished working on a Spectrum repeater that did have spurs close to the TX frequency, corrected by retuning each stage while watching the spur level drop until they disappeared.

John W1GPO
On 11/02/2022 8:19 AM Jared Smudde <computerwhiz02@...> wrote:


So last night, I measured the MTR at 0.4uV at the receiver port and 0.5uV at the duplexer antenna port.

I injected a signal into the receiver port of the MTR that had just barely had no noise and when I injected it through the duplexer into the repeater, there was noise present. It wasn't heavy noise but it still had noise on the signal.

?

?

Re: TKR-851 power issue

 

Did you measure the voltage at the PA transistor? I'd look at that first. Also measure the exciter output and see what it's doing. If I recall correctly, the repeater uses a relay to switch in and out a dropping resistor for backup DC operation. I've seen that really fail or the circuit land open up. I had a TKR 750 that acted the same way but it had been underwater for 7 weeks after tropical storm Harvey! It worked for about 10 minutes until the microprocessor went crazy.

Chris WB5ITT?

On Wed, Nov 2, 2022, 7:50 AM Brandon Vetter <Brandon@...> wrote:

Hi Group,

????????????? I have a TKR-851 that I thought had bad finals. It had about 2 watts output. Installed a new transmitter board with new driver and final transistors and now I get 3 Watts output. If I drop it to low power, I get less than 1 watt. The power in the software is turned up. The power adjustment pot does not seem to be functional. There are no PLL errors flashing. Anyone have any thoughts on what might be going on?

?

Brandon Vetter

N7IRG

?

?
TKR-851 power issue

 

¿ªÔÆÌåÓý

Hi Group,

????????????? I have a TKR-851 that I thought had bad finals. It had about 2 watts output. Installed a new transmitter board with new driver and final transistors and now I get 3 Watts output. If I drop it to low power, I get less than 1 watt. The power in the software is turned up. The power adjustment pot does not seem to be functional. There are no PLL errors flashing. Anyone have any thoughts on what might be going on?

?

Brandon Vetter

N7IRG

?

?
Re: VHF MTR2000 Poor Receive Performance

 

Hello Jared,
I have not been following these threads very carefully, but the thought occurred to me wondering if your transmitter might have spurs when connected to the duplexer? It would be easy enough to check with a spectrum analyzer connected via a lossy T between the TX and duplexer, (if not already checked.)? I had just finished working on a Spectrum repeater that did have spurs close to the TX frequency, corrected by retuning each stage while watching the spur level drop until they disappeared.

John W1GPO

On 11/02/2022 8:19 AM Jared Smudde <computerwhiz02@...> wrote:


So last night, I measured the MTR at 0.4uV at the receiver port and 0.5uV at the duplexer antenna port.

I injected a signal into the receiver port of the MTR that had just barely had no noise and when I injected it through the duplexer into the repeater, there was noise present. It wasn't heavy noise but it still had noise on the signal.

Re: VHF MTR2000 Poor Receive Performance

 

So last night, I measured the MTR at 0.4uV at the receiver port and 0.5uV at the duplexer antenna port.

I injected a signal into the receiver port of the MTR that had just barely had no noise and when I injected it through the duplexer into the repeater, there was noise present. It wasn't heavy noise but it still had noise on the signal.
Re: Somewhat OT... imaging a hard drive...

 

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Hi guys,
Taxing the brain, With XP, one had to mod the registry to go back to the bios for
the disk driver if the motherboard IDE or SATA driver changes. Then at first boot
on the new hardware, it will install the appropriate hard disk driver and video drivers.

Can anybody remember the details?

Alan VK2ZIW

On Wed, 02 Nov 2022 01:49:04 -0700, M M wrote
> I asked the seller which version of Ghost he was providing as I was looking for 7 or later.
> He replied "I think this is version 3 or older, Not what you are looking for."
>


> But thanks for the suggestion.?? It turns out that older versions of Hiren had Ghost.
>
>


> Three of the suggestions made here were for a bootable RescueZilla, a bootable CloneZilla and a bootable GParted.
>
> It looks like one of those will do what I need.
>
> Mike

---------------------------------------------------
Alan VK2ZIW
Before the Big Bang, God, Sela.
OpenWebMail 2.53, nothing in the cloud.

Re: Somewhat OT... imaging a hard drive...

 

I asked the seller which version of Ghost he was providing as I was looking for 7 or later.
He replied "I think this is version 3 or older, Not what you are looking for."


But thanks for the suggestion.?? It turns out that older versions of Hiren had Ghost.

Three of the suggestions made here were for a bootable RescueZilla, a bootable CloneZilla and a bootable GParted.

It looks like one of those will do what I need.

Mike
Re: Connecting Yaesu DR2X Repeater to Raspberry Pi/Allstar?

Chris Smart
 

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Thanks Steve.

?

?

?

73,

Chris

?

?

From: [email protected] <[email protected]> On Behalf Of N8AR
Sent: November 1, 2022 9:09 PM
To: [email protected]
Subject: Re: [repeater-builder] Connecting Yaesu DR2X Repeater to Raspberry Pi/Allstar?

?

Here is a link to a program called PiTone which can be used to create a CTCSS tone.? PiTone runs on a Raspberry Pi (can be the same one that is running Allstar).? It uses a D/A converter connected to the I2C bus to create a stepped sinewave which is easy to filter to a "pure" sinwave.



We have used it on our local repeaters (DR-1X and Micor) for more than 4 years.

Steve - N8AR

Re: Connecting Yaesu DR2X Repeater to Raspberry Pi/Allstar?

 

Here is a link to a program called PiTone which can be used to create a CTCSS tone.? PiTone runs on a Raspberry Pi (can be the same one that is running Allstar).? It uses a D/A converter connected to the I2C bus to create a stepped sinewave which is easy to filter to a "pure" sinwave.



We have used it on our local repeaters (DR-1X and Micor) for more than 4 years.

Steve - N8AR
Re: VHF MTR2000 Poor Receive Performance

 

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Jared,

We need to quantify why (and when) the repeater is "deaf".

Next time you're at the site, do the following:

1 - Disconnect the repeater from the duplexer.?
2 - Connect the repeater antenna to the receiver - directly.?
3 - Terminate the transmitter into a suitable dummy load.
4 - Get a friend to help or use the service monitor to produce a weak signal into the repeater.? This must be a stable emission that's repeatable.? It can't be full quieting - some noise needs to be preset to detect a change in quieting.
5 - Reconnect the antenna to the duplexer, and receiver to the duplexer, but do NOT connect the transmitter - - leave it on the load.
6 - Compare the signal quality (quieting) between the antenna being connected directly to the receiver and additionally through the duplexer.? At 1.67 dB IL - they should be virtually identical.
** If there is little/no difference between the signal level with the antenna connected directly to the receiver and through the receive path of the duplexer, the 'disappointment' is not the duplexers' fault.? You could swap in a different receiver, even a HT temporarily to see how well it hears in comparison.? Just remove whatever you substitute and reconnect the repeater's receiver before you continue.
7 - Remove the transmitter from the load and connect the transmitter to the duplexer.
8 - Wire a toggle switch into the PTT lead to instantly disable the repeaters transmitter.
9 - Compare the weak signal with the transmitter "ON" and "OFF".? They should be virtually identical.

A - If there's a notable difference in quieting with the antenna connected directly to the receiver and then through the receive path of the duplexer - the RX path insertion loss isn't really 1.67dB.
B - If there's a difference in quieting between when the repeater transmitter is on and off - you have classic desense.

Let us know the results.

Kevin

On 11/1/2022 6:55 PM, Jared Smudde wrote:

So the transmit side cavities all have 29db-32db of return loss at pass frequency, 30db of notch rejection and 0.4db of IL at the pass frequencies.

I went to the receive cavity causing trouble and slid the tuning rod all the way up and cleaned the rod with some fine sandpaper and wiped it down with denatured alcohol. I then took the rod and ran it up and down the cavity several times all while rotating the rod at the same time. I was able to get the return loss to 30DB on the cavity. Probably had to clean some varnish off of the rod and tuning fingers.

I reattached the harness and each side had about 1.67db of insertion loss and I was able to get the notch over 105db on each side.

I hooked up the repeater and was met with disappointment, repeater is still deaf with no improvement.

Re: Windows 7 config

 

Hey, we are all human :)
--
-
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
Re: VHF MTR2000 Poor Receive Performance

 

I think we need to redefine 'deaf'. What are the current 12dB SINAD 1) at the receiver port, and 2) at the antenna port of the duplexer? (Those values were previously reported as 0.40 and 0.53 uV respectively.)

Originally the problem was reported as " basically deaf to 5 watt portables barely a mile from my house, mobiles work a bit further" and about 1 dB of desense was reported.

We need to make sure we're comparing apples to apples. At this point, portable or mobile coverage and anything to do with the antenna system (except the duplexer) needs to be OUT of the equation.

Measurements all need to be made using the same test cables and the same signal generator/service monitor. Anything else introduces errors/uncertainties. The receiver itself (with no TX engaged) needs to be baselined to see if it meets specs (0.35 uV for 12 dB SINAD I believe), and if it does not, that needs to be addressed. Adding in the duplexer, sensitivity should decrease only by the amount of loss previously recorded in the Pass. If the Pass is measured as 'X' and the receiver sensitivity decreases by more-than-'X', than something is amiss at the Circle K and investigation needs to determine the cause.

Sometimes it's helpful to take a day off, go poke .45 caliber holes in paper, then come back to it with a fresh mind, starting over at square one.

My 2-cents worth.

Mike
WM4B

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of MILLIN SEE
Sent: Tuesday, November 1, 2022 8:09 PM
To: [email protected]
Subject: Re: [repeater-builder] VHF MTR2000 Poor Receive Performance

Sounds like your forcing that duplexer outside it's parameter.

Millin
----- Original Message -----
From: Jared Smudde <computerwhiz02@...>
To: [email protected]
Sent: Tue, 01 Nov 2022 16:55:15 -0600 (MDT)
Subject: Re: [repeater-builder] VHF MTR2000 Poor Receive Performance

So the transmit side cavities all have 29db-32db of return loss at pass frequency, 30db of notch rejection and 0.4db of IL at the pass frequencies.

I went to the receive cavity causing trouble and slid the tuning rod all the way up and cleaned the rod with some fine sandpaper and wiped it down with denatured alcohol. I then took the rod and ran it up and down the cavity several times all while rotating the rod at the same time. I was able to get the return loss to 30DB on the cavity. Probably had to clean some varnish off of the rod and tuning fingers.

I reattached the harness and each side had about 1.67db of insertion loss and I was able to get the notch over 105db on each side.

I hooked up the repeater and was met with disappointment, repeater is still deaf with no improvement.
Re: VHF MTR2000 Poor Receive Performance

 

Sounds like your forcing that duplexer outside it's parameter.

Millin

----- Original Message -----
From: Jared Smudde <computerwhiz02@...>
To: [email protected]
Sent: Tue, 01 Nov 2022 16:55:15 -0600 (MDT)
Subject: Re: [repeater-builder] VHF MTR2000 Poor Receive Performance

So the transmit side cavities all have 29db-32db of return loss at pass frequency, 30db of notch rejection and 0.4db of IL at the pass frequencies.

I went to the receive cavity causing trouble and slid the tuning rod all the way up and cleaned the rod with some fine sandpaper and wiped it down with denatured alcohol. I then took the rod and ran it up and down the cavity several times all while rotating the rod at the same time. I was able to get the return loss to 30DB on the cavity. Probably had to clean some varnish off of the rod and tuning fingers.

I reattached the harness and each side had about 1.67db of insertion loss and I was able to get the notch over 105db on each side.

I hooked up the repeater and was met with disappointment, repeater is still deaf with no improvement.
Re: VHF MTR2000 Poor Receive Performance

 

So the transmit side cavities all have 29db-32db of return loss at pass frequency, 30db of notch rejection and 0.4db of IL at the pass frequencies.

I went to the receive cavity causing trouble and slid the tuning rod all the way up and cleaned the rod with some fine sandpaper and wiped it down with denatured alcohol. I then took the rod and ran it up and down the cavity several times all while rotating the rod at the same time. I was able to get the return loss to 30DB on the cavity. Probably had to clean some varnish off of the rod and tuning fingers.

I reattached the harness and each side had about 1.67db of insertion loss and I was able to get the notch over 105db on each side.

I hooked up the repeater and was met with disappointment, repeater is still deaf with no improvement.
Re: Windows 7 config

 

I am not using a repeater. Just using vara fm and winlink. Will be using a cdm1250. Just looking for information on the software side. Sorry for stirring the pot


On Tue, Nov 1, 2022 at 11:15 AM, Chris Boone
<setxtelecom@...> wrote:
Ok...I obviously missed the data part lol...

Chris WB5ITT?

On Tue, Nov 1, 2022, 12:59 PM Scott Currie <scott.d.currie@...> wrote:
Correct, we're not talking about repeaters here. We are taking discriminator audio to the sound card interface for decoding, and sending modulated data from the sound card to the modulator. Obviously if you set the transmit gain too high you will cause interference on adjacent channels. And it will also destroy the data being sent, so a really bad idea.

This discussion would be better handled on the Winlink and Vara forums:

/g/VARA-MODEM/topics

-Scott, NS7C

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