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Re: Can I use a low power programming cable to program high power astro spectra?

 

This article will answer a bunch of your spectra questions.
?
As to computers, my primary field programming computer is a Toughbook CF-30 running 32-bit Win7pro.
I also have a CF-31 running Win10-64 for the newer stuff (like Moto APX).
Both live in a hiking backpack and get used at least once a week.
In fact on monday I was at one of the Sheriffs stations programming a couple of the volunteer's radios.

Here's probably too much on field programming computers, I should edit it and update it.


Mike WA6ILQ
?


Re: Quantar CPN1048G Power Supply

 

That supply has battery revert and will charge a 28v battery and the CPS has a couple of options for batteries. I don't have the software running to see but I think its lead acid or AGM type. Not sure what the harness P/N is but they show up on eBay for reasonable prices. If the fan intake gets dusty do not try to clean the dust off while the PS is running. When the fans inhale the dust the PS can fail and I've seen this first hand.?


Quantar CPN1048G Power Supply

 

Friends,
?
My 125W VHF Quantar has a CPN1048G Power Supply in it, but my documentation has nothing on that model power supply.? I found some threads in this group with tables that suggest this unit has a battery charger feature and that is about all I know.? It does have what looks like a high-power DC edge connector on the back panel, but no DC harness / pigtail.? Thus, I have the following questions:
?
1. Does anyone have any documentation on it to share?
2. Does it have the battery revert feature and if so, does it charge the battery?
3. What type of battery would work with it?
4. What is the proper DC harness for it?
5. Any other advice on it?
?
Thanks!
Jeff KC8VFN


Re: 6 m repeater antenna

 

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John,

As an aside, although I have never experimented with it, the spacing between the D.E. and the director would likely need to be altered if using in the original configuration.

Yes, as I recall the front end of the antenna can be detached. It may already be the correct length to reverse the direction. Actually, from a manufacturing standpoint it would make sense.

Chuck
WB2EDV



On 3/28/2025 7:29 PM, John via groups.io wrote:

Yes Chuck, I noticed that also. The only way to find out is to actually try it both ways, as it appears from the pictures that the boom disassembles, and it probably will be possible attach the pipe mount to that shorter outside section of the 2"x3" boom. The DB212 is designed to couple RF into the tower to reduce the? back side null range? loss, and it may be just the reverse with the beam????
?
I have not yet been able to get my paws on a DB225.
?
John
On 03/28/2025 5:35 PM EDT Chuck Kelsey via groups.io <wb2edv@...> wrote:
?
?
John,

I believe the 225 has the feed attached to the "outside" of the top element while the 212 has it attached to the "inside" of it. In other words the 225 has the attachment closest to the director, the 212 attachment is closest to the tower. If one where to cut off the boom to eliminate the director, this could be taken into consideration accordingly. Do you agree?

Chuck
WB2EDV



On 3/28/2025 9:21 AM, John via groups.io wrote:
That is indeed a DB-225 (see catalog pic). Notice the? 1.5 SWR bandwidth at 50 MHz is only 0.5 MHz compared to the a DB212 which has a bandwidth slightly more than 1MHz on 6M. Therefore, if duplexing with a? 1MHz split, in order to keep the duplexer from detuning, if you can get it mounted to the leg so the air space between the inner loop tubing and the tower leg to be 6.5 inches like it is on a DB212, then I would saw off the 3"x2" boom beyond the dipole loop, because the director is limiting the bandwidth. . That air distance is critical for a 50 ohm match.?
?
Drill out all of the dimples holding the 5/8'OD loops with a 1/4" drill bit and tap them out. Saw off the needed amount off the 3/4" OD or 7/8 " OD straight tubing, but exercise extreme care not to break the element insulator in the process! (did it on one)
?
DB factory lengths for your frequency was 50 7/8" from edge of 3" boom to tip on each half, or 104 3/4" overall tip to tip, however I found for 1.0 SWR, the upper loop ends up about 3/4" shorter than the lower because of the coax center conductor pig tail radiating and the top is a loop, the bottom just a wide element. (basically a J pole antenna.)
?
John
?
?
?
? ?
On 03/28/2025 12:55 AM EDT Hudson, John@CalOES via groups.io <john.hudson@...> wrote:
?
?
image2.jpeg

John N. Hudson III, Regional Emergency Communications Coordinator?California, Governor’s Office of Emergency Services

Public Safety Communications

Tactical Communications Unit, Southern Region

1291 Pacific Oaks Place, Suite 100?Escondido, CA?92029

Cell??????????619-250-9063????? Desk????????760-738-7521

FAX?????????760-738-7529?

John.hudson@...


On Mar 27, 2025, at 13:29, Roger willey via groups.io <kc4jnn@...> wrote:

This Message is From an External Sender
This message came from outside your organization.

?

I think they should be on the same side of the tower 12 feet apart. My frequency is ?53.050 input is 52.050?

On Mar 27, 2025, at 2:56?PM, John via groups.io <jhaserick84@...> wrote:

?
If the coax to the T is 50ohms, then yes , an electrical 1/4 wavelength of 35 ohm coax from the T to the feedline. You could? less ideally alternatively do two? 1/4 wavelength 75 ohm coaxial cables in parallel . Try to use polyethylene jacketed coax for longer life.. Both 50 coaxial cable antenna pigtails need to be the same length, but can be any length.? ?
I recommend mounting both antennas on the same tower leg.Those UHF T connectors are difficult to waterproof. without using butyl rubber under Scotch 88. First tape one layer of 88 , then squeeze and mold the butyl rubber, then 2 layers of 88 on the outside, to make it easier to remove the butyl rubbber when it eventually gets disassembled. Messi and Paolini in Italy make great 75 ohm direct bury type coax, if you are forced to go that route.
?
John
?
?
?
?
?
?
?
?
?
?
?
if the?
On 03/27/2025 12:32 PM EDT Roger willey via groups.io <kc4jnn@...> wrote:
?
?

?

Begin forwarded message:

From: Roger willey <kc4jnn@...>
Date: March 26, 2025 at 2:45:40?PM EDT
To: [email protected]
Subject: 6 m repeater antenna

I have a 6 m folded dipole antenna, two of them with coaxial lines going to a T what length of cable should I use out of the T to get The impedance and the length? I was thinking maybe 35 Ohm
WARNING: Do not click links or attachments unless you recognize the sender and know the email is safe.

?




Re: 6 m repeater antenna

 

The tower is the reflector, but it is of course not as good of a reflector for forward gain as it would be with closer to 1/4 wavelength between tower leg and dipole driven element.
?
John

On 03/28/2025 6:23 PM EDT Mike via groups.io <prcradio@...> wrote:
?
?
Wonder why they didn't make it a driven element with reflector, either space the driven element out from a tower leg for the reflector or include a reflector. That seems like it could be factory tuned and used with different mounting schemes with less affect on the tuning.?


Re: 6 m repeater antenna

 

Yes Chuck, I noticed that also. The only way to find out is to actually try it both ways, as it appears from the pictures that the boom disassembles, and it probably will be possible attach the pipe mount to that shorter outside section of the 2"x3" boom. The DB212 is designed to couple RF into the tower to reduce the? back side null range? loss, and it may be just the reverse with the beam????
?
I have not yet been able to get my paws on a DB225.
?
John

On 03/28/2025 5:35 PM EDT Chuck Kelsey via groups.io <wb2edv@...> wrote:
?
?
John,

I believe the 225 has the feed attached to the "outside" of the top element while the 212 has it attached to the "inside" of it. In other words the 225 has the attachment closest to the director, the 212 attachment is closest to the tower. If one where to cut off the boom to eliminate the director, this could be taken into consideration accordingly. Do you agree?

Chuck
WB2EDV



On 3/28/2025 9:21 AM, John via groups.io wrote:
That is indeed a DB-225 (see catalog pic). Notice the? 1.5 SWR bandwidth at 50 MHz is only 0.5 MHz compared to the a DB212 which has a bandwidth slightly more than 1MHz on 6M. Therefore, if duplexing with a? 1MHz split, in order to keep the duplexer from detuning, if you can get it mounted to the leg so the air space between the inner loop tubing and the tower leg to be 6.5 inches like it is on a DB212, then I would saw off the 3"x2" boom beyond the dipole loop, because the director is limiting the bandwidth. . That air distance is critical for a 50 ohm match.?
?
Drill out all of the dimples holding the 5/8'OD loops with a 1/4" drill bit and tap them out. Saw off the needed amount off the 3/4" OD or 7/8 " OD straight tubing, but exercise extreme care not to break the element insulator in the process! (did it on one)
?
DB factory lengths for your frequency was 50 7/8" from edge of 3" boom to tip on each half, or 104 3/4" overall tip to tip, however I found for 1.0 SWR, the upper loop ends up about 3/4" shorter than the lower because of the coax center conductor pig tail radiating and the top is a loop, the bottom just a wide element. (basically a J pole antenna.)
?
John
?
?
?
? ?
On 03/28/2025 12:55 AM EDT Hudson, John@CalOES via groups.io <john.hudson@...> wrote:
?
?
image2.jpeg

John N. Hudson III, Regional Emergency Communications Coordinator?California, Governor’s Office of Emergency Services

Public Safety Communications

Tactical Communications Unit, Southern Region

1291 Pacific Oaks Place, Suite 100?Escondido, CA?92029

Cell??????????619-250-9063????? Desk????????760-738-7521

FAX?????????760-738-7529?

John.hudson@...


On Mar 27, 2025, at 13:29, Roger willey via groups.io <kc4jnn@...> wrote:

This Message is From an External Sender
This message came from outside your organization.

?

I think they should be on the same side of the tower 12 feet apart. My frequency is ?53.050 input is 52.050?

On Mar 27, 2025, at 2:56?PM, John via groups.io <jhaserick84@...> wrote:

?
If the coax to the T is 50ohms, then yes , an electrical 1/4 wavelength of 35 ohm coax from the T to the feedline. You could? less ideally alternatively do two? 1/4 wavelength 75 ohm coaxial cables in parallel . Try to use polyethylene jacketed coax for longer life.. Both 50 coaxial cable antenna pigtails need to be the same length, but can be any length.? ?
I recommend mounting both antennas on the same tower leg.Those UHF T connectors are difficult to waterproof. without using butyl rubber under Scotch 88. First tape one layer of 88 , then squeeze and mold the butyl rubber, then 2 layers of 88 on the outside, to make it easier to remove the butyl rubbber when it eventually gets disassembled. Messi and Paolini in Italy make great 75 ohm direct bury type coax, if you are forced to go that route.
?
John
?
?
?
?
?
?
?
?
?
?
?
if the?
On 03/27/2025 12:32 PM EDT Roger willey via groups.io <kc4jnn@...> wrote:
?
?

?

Begin forwarded message:

From: Roger willey <kc4jnn@...>
Date: March 26, 2025 at 2:45:40?PM EDT
To: [email protected]
Subject: 6 m repeater antenna

I have a 6 m folded dipole antenna, two of them with coaxial lines going to a T what length of cable should I use out of the T to get The impedance and the length? I was thinking maybe 35 Ohm
WARNING: Do not click links or attachments unless you recognize the sender and know the email is safe.

?



Re: 6 m repeater antenna

 

Wonder why they didn't make it a driven element with reflector, either space the driven element out from a tower leg for the reflector or include a reflector. That seems like it could be factory tuned and used with different mounting schemes with less affect on the tuning.?


Re: 6 m repeater antenna

 

开云体育

John,

I believe the 225 has the feed attached to the "outside" of the top element while the 212 has it attached to the "inside" of it. In other words the 225 has the attachment closest to the director, the 212 attachment is closest to the tower. If one where to cut off the boom to eliminate the director, this could be taken into consideration accordingly. Do you agree?

Chuck
WB2EDV



On 3/28/2025 9:21 AM, John via groups.io wrote:

That is indeed a DB-225 (see catalog pic). Notice the? 1.5 SWR bandwidth at 50 MHz is only 0.5 MHz compared to the a DB212 which has a bandwidth slightly more than 1MHz on 6M. Therefore, if duplexing with a? 1MHz split, in order to keep the duplexer from detuning, if you can get it mounted to the leg so the air space between the inner loop tubing and the tower leg to be 6.5 inches like it is on a DB212, then I would saw off the 3"x2" boom beyond the dipole loop, because the director is limiting the bandwidth. . That air distance is critical for a 50 ohm match.?
?
Drill out all of the dimples holding the 5/8'OD loops with a 1/4" drill bit and tap them out. Saw off the needed amount off the 3/4" OD or 7/8 " OD straight tubing, but exercise extreme care not to break the element insulator in the process! (did it on one)
?
DB factory lengths for your frequency was 50 7/8" from edge of 3" boom to tip on each half, or 104 3/4" overall tip to tip, however I found for 1.0 SWR, the upper loop ends up about 3/4" shorter than the lower because of the coax center conductor pig tail radiating and the top is a loop, the bottom just a wide element. (basically a J pole antenna.)
?
John
?
?
?
? ?
On 03/28/2025 12:55 AM EDT Hudson, John@CalOES via groups.io <john.hudson@...> wrote:
?
?
image2.jpeg

John N. Hudson III, Regional Emergency Communications Coordinator?California, Governor’s Office of Emergency Services

Public Safety Communications

Tactical Communications Unit, Southern Region

1291 Pacific Oaks Place, Suite 100?Escondido, CA?92029

Cell??????????619-250-9063????? Desk????????760-738-7521

FAX?????????760-738-7529?

John.hudson@...


On Mar 27, 2025, at 13:29, Roger willey via groups.io <kc4jnn@...> wrote:

This Message is From an External Sender
This message came from outside your organization.

?

I think they should be on the same side of the tower 12 feet apart. My frequency is ?53.050 input is 52.050?

On Mar 27, 2025, at 2:56?PM, John via groups.io <jhaserick84@...> wrote:

?
If the coax to the T is 50ohms, then yes , an electrical 1/4 wavelength of 35 ohm coax from the T to the feedline. You could? less ideally alternatively do two? 1/4 wavelength 75 ohm coaxial cables in parallel . Try to use polyethylene jacketed coax for longer life.. Both 50 coaxial cable antenna pigtails need to be the same length, but can be any length.? ?
I recommend mounting both antennas on the same tower leg.Those UHF T connectors are difficult to waterproof. without using butyl rubber under Scotch 88. First tape one layer of 88 , then squeeze and mold the butyl rubber, then 2 layers of 88 on the outside, to make it easier to remove the butyl rubbber when it eventually gets disassembled. Messi and Paolini in Italy make great 75 ohm direct bury type coax, if you are forced to go that route.
?
John
?
?
?
?
?
?
?
?
?
?
?
if the?
On 03/27/2025 12:32 PM EDT Roger willey via groups.io <kc4jnn@...> wrote:
?
?

?

Begin forwarded message:

From: Roger willey <kc4jnn@...>
Date: March 26, 2025 at 2:45:40?PM EDT
To: [email protected]
Subject: 6 m repeater antenna

I have a 6 m folded dipole antenna, two of them with coaxial lines going to a T what length of cable should I use out of the T to get The impedance and the length? I was thinking maybe 35 Ohm
WARNING: Do not click links or attachments unless you recognize the sender and know the email is safe.

?



Re: 6 m repeater antenna

 

开云体育

Yes, this is the real deal, not a clone. What a difference a good picture can make.

Chuck
WB2EDV






On 3/28/2025 1:26 PM, Hudson, John@CalOES via groups.io wrote:

Just for you Chuck Kelsey

image0.jpegimage1.jpegimage2.jpegimage3.jpeg


On Mar 28, 2025, at 08:43, Lonney K1LH via groups.io <lonney9@...> wrote:

?
This Message is From an External Sender
This message came from outside your organization.


Already covered above, but here are a number of ways to feed multiple antennas with 50 ohm feed-points.
?
2 x 50 ohm antennas:
?
?
Stacking distances also affect the compression of the elevation beam-width and the resulting peak gain figure, that matters for horizontal VHF DX work where we trade some gain away (under-stacking them at lower heights above ground) for a wider elevation beam-width to better hear signals arriving at different angles.
?
:-)
?
--
Lonney, K1LH
North Pole, AK.
?
?
WARNING: Do not click links or attachments unless you recognize the sender and know the email is safe.




Re: Receive

 

Robby,

I checked and they both match...
I'm not sure what you mean by this. The DMR IDs both match between the radio and the node?

On the phone you indicated that the PTT on the MMDVM was not being activated, but the dashboard was showing a valid incoming call. Thinking about this further, you would need to be connected to a parrot node to receive anything back from a simplex hot spot, correct? (Sorry I've not configured may simplex radios. I've mostly configured full-duplex repeaters.)

To test the PTT functionality directly, Go to the MMDVM cal menu in Pi-star. More info here:

Use the spacebar to toggle the PTT on and off. You can also select various DMR test patterns to help tune the txinvert setting and the TX level.

You don't need to worry about the frequency or offsets since the MMDVM board is connected to an outboard radio.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531

On 3/28/2025 1:01 PM, Robby via groups.io wrote:
I checked and they both match
On Mar 28, 2025, at 11:34?AM, Scott Zimmerman via groups.io <n3xcc@...> wrote:

?Robby,

Did you get my personal e-mail reply to your question yesterday?

Here is my response to you sharing your MMDVM.ini file screenshots:
------------------
Robby,

Try changing SelfOnly=0. If it is set at '1' it will only respond to a radio that has a matching DMR ID. If it is NOT set for self only, any DMR ID can access the node. I'm guessing in your case the DMR ID in your radio does NOT match the DMR ID (3190603) of the node.

This should at least get you past the "no PTT" hurdle. Once you have the board activating the PTT (and thus making the radio transmit) you can play with the TXinvert in the MMDVM screen and the txlevel pot on the board to get the node to successfully handshake with your radio.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531

On 3/28/2025 12:18 PM, Robby via groups.io wrote:
can anyone help with this I have a MMDVM STM32 with a Kenwood D700 it’s receiving but no audio coming from handheld anytone 878uviii plus I can see the signal strength full scale on both radios just no audio
Robby/AA5AF





Repeater Quality Antenna Need - FLORIDA

 

开云体育

Hello Group, I am still looking for a repeater quality antenna, preferably a set of 4 exposed dipoles for a project in SW Fla. This is to replace a current antenna that is in service but needs to be replaced. I don’t mind driving to pickup the ‘right’ antenna of course. Should be something useable in the amateur VHF/2mtr spectrum of course.? Thanks in advance for reading. – Mike, K4CVL


Re: 6 m repeater antenna

 

Nice work, Mike!? You really don't need the grey element spacers for 6M, as I see you left them off, possibly to reduce wind load.. Sometimes the end braces are needed in their place, if icing or high winds. Also a good idea to invert so the fed half is on the bottom, so the stronger half is on the top to better resist falling ice, or someone climbing the tower stepping on the coax! . Then be certain to place a drain hole just above where the insulator begins.That will be inside the center brace, if you angle the hole upwards. When you have the end piece off, is the time to measure where the top of the insulator is located.
?
King Starboard (ultra high density, UV protected polyethylene) from a marine supply company is a good source for the element brace.
?
Really great 6M repeat antenna, especially two on the same leg. Had a pair last over 35 yrs at 3500 ft, high winds, multiple lightning strikes, feet of rime ice, etc.No precip static if wrapped with vinyl tape, and because side mounted close in, no? coronal discharge noise
?
John

On 03/28/2025 10:32 AM EDT Mike via groups.io <prcradio@...> wrote:
?
?
Its not related to a J-pole, the DB Products dipoles are simply a center fed dipole with a fat grounded element and the driven element is a folded monopole. Probably much lower impedance than a typical dipole of 72 ohms in free space due to its girth but when placed really close to a tower leg the impedance gets pulled way down.?
?
I recently picked one up at a swap meet and used some excellent info from this group and tuned it for 6m.?
?


Re: 6 m repeater antenna

 

开云体育

Just for you Chuck Kelsey

image0.jpegimage1.jpegimage2.jpegimage3.jpeg


On Mar 28, 2025, at 08:43, Lonney K1LH via groups.io <lonney9@...> wrote:

?
This Message is From an External Sender
This message came from outside your organization.


Already covered above, but here are a number of ways to feed multiple antennas with 50 ohm feed-points.
?
2 x 50 ohm antennas:
?
?
Stacking distances also affect the compression of the elevation beam-width and the resulting peak gain figure, that matters for horizontal VHF DX work where we trade some gain away (under-stacking them at lower heights above ground) for a wider elevation beam-width to better hear signals arriving at different angles.
?
:-)
?
--
Lonney, K1LH
North Pole, AK.
?
?
WARNING: Do not click links or attachments unless you recognize the sender and know the email is safe.



Re: Receive

 

I checked and they both match

On Mar 28, 2025, at 11:34?AM, Scott Zimmerman via groups.io <n3xcc@...> wrote:

?Robby,

Did you get my personal e-mail reply to your question yesterday?

Here is my response to you sharing your MMDVM.ini file screenshots:
------------------
Robby,

Try changing SelfOnly=0. If it is set at '1' it will only respond to a radio that has a matching DMR ID. If it is NOT set for self only, any DMR ID can access the node. I'm guessing in your case the DMR ID in your radio does NOT match the DMR ID (3190603) of the node.

This should at least get you past the "no PTT" hurdle. Once you have the board activating the PTT (and thus making the radio transmit) you can play with the TXinvert in the MMDVM screen and the txlevel pot on the board to get the node to successfully handshake with your radio.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531

On 3/28/2025 12:18 PM, Robby via groups.io wrote:
can anyone help with this I have a MMDVM STM32 with a Kenwood D700 it’s receiving but no audio coming from handheld anytone 878uviii plus I can see the signal strength full scale on both radios just no audio
Robby/AA5AF





Re: Receive

 

Robby,

Did you get my personal e-mail reply to your question yesterday?

Here is my response to you sharing your MMDVM.ini file screenshots:
------------------
Robby,

Try changing SelfOnly=0. If it is set at '1' it will only respond to a radio that has a matching DMR ID. If it is NOT set for self only, any DMR ID can access the node. I'm guessing in your case the DMR ID in your radio does NOT match the DMR ID (3190603) of the node.

This should at least get you past the "no PTT" hurdle. Once you have the board activating the PTT (and thus making the radio transmit) you can play with the TXinvert in the MMDVM screen and the txlevel pot on the board to get the node to successfully handshake with your radio.

Scott

Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531

On 3/28/2025 12:18 PM, Robby via groups.io wrote:
can anyone help with this I have a MMDVM STM32 with a Kenwood D700 it’s receiving but no audio coming from handheld anytone 878uviii plus I can see the signal strength full scale on both radios just no audio
Robby/AA5AF


Receive

 

can anyone help with this I have a MMDVM STM32 with a Kenwood D700 it’s receiving but no audio coming from handheld anytone 878uviii plus I can see the signal strength full scale on both radios just no audio?
Robby/AA5AF


Re: WACOM WP-641 vs. Sinclair Q2330E

 

And the reason why the Ns have less notch?

Kit Parsons himself told me when I ordered my 220 652s in 1984. He sent a handwritten note with the invoice to my PO box...I had ordered with type Ns..he wrote "Chris, call me collect if you need to...they are better with UHF connectors!"?

So I called him in my dime lol ..he explained the notch in the BpBr depends on the height of the T above the cavity..Ns are taller than UHFs...he said if they could make the cable connection right on top of the can, they could see 110 to 120db notch vs 90 to 95 on the WP641s for example...he didn't like using BNCs which are shorter because of the loose fit of the bayonet.. TNC probably would have done it..but hey he was the engineer and owner. I wasn't going to argue ?

I sure miss Kit and WACOM...great customer service and I helped sell a lot of his products in SE TX..offered to represent WACOM at Dayton one time but Kit got back to me and said the lawyers said no... Ugh..and the LMR Expo was at the same time then..oh well?

Now you know the reeeeest of the story
(as one of my ex coworkers used to say)

Chris?


On Thu, Mar 27, 2025, 8:41 PM Kevin Custer via <kuggie=[email protected]> wrote:
The WACOM WP-641 provides 93 dB of rejection at 1.5dB of insertion loss at 600 kHz - if it's a UHF connector version.? If it's an N connector version the rejection is 91 dB or so (yes it's less).? It's easy to tune with simple equipment.? If the cavity interconnect cables say "Modified RG214" you should consider replacing that cable with real RG214/U.? While the cable supplied is double shielded - it's not silver plated.

The Sinclair Q2330e provides nearly 100dB of rejection at 1.5dB of insertion loss at 600 kHz.? This duplexer is considerably more difficult to tune, requiring a VNA (or RLB) to set the pass frequencies.

You don't state what your receive sensitivity is, or whether or not you're going to use a preamp.? If not - either duplexer is sufficient for the MSR-2000.? If you want more reserve isolation - use the Sinclair.

Kevin W3KKC

On 3/27/2025 6:27 PM, Mike Besemer - WM4B via wrote:

I have both of these duplexers available to replace an existing system.? The site itself is a water tower with an existing DB224 that has been made available to me.? It is mounted at the very top-center of the tank.? There is a backup fire department repeater at the site on UHF.? I dont even think its plugged in.

The tower also has 5G panels mounted all the way around the perimeter.

Given that space is not a consideration and all things being equal, which of the subject duplexers would you choose to put behind an MSR-2000 running 50 60 watts out of the PA?? I have experience with the WP-641, but not the Sinclair.

73,

Mike

WM4B



Re: 6 m repeater antenna

 

Already covered above, but here are a number of ways to feed multiple antennas with 50 ohm feed-points.
?
2 x 50 ohm antennas:
?
?
Stacking distances also affect the compression of the elevation beam-width and the resulting peak gain figure, that matters for horizontal VHF DX work where we trade some gain away (under-stacking them at lower heights above ground) for a wider elevation beam-width to better hear signals arriving at different angles.
?
:-)
?
--
Lonney, K1LH
North Pole, AK.
?
?


Re: IC FR4000 flat audio for MMDVM and DMR conversion?

 

At 3/28/2025 03:22 AM, you wrote:

Looking at the manual that you provided, you have the correct point marked

Chris WB5ITT

"Splutter filter"?? Must be related to the "Lipple Filter" found in many Kenwood service manuals ;)

Bob MO6V


Re: 6 m repeater antenna

 

Its not related to a J-pole, the DB Products dipoles are simply a center fed dipole with a fat grounded element and the driven element is a folded monopole. Probably much lower impedance than a typical dipole of 72 ohms in free space due to its girth but when placed really close to a tower leg the impedance gets pulled way down.?
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I recently picked one up at a swap meet and used some excellent info from this group and tuned it for 6m.?
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