?

?

?

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>

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>

On 04/07/2025 5:55 PM EDT 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

On 03/30/2025 2:23 PM EDT Brandon DX via groups.io <rfburnz@...> wrote:

?

?

I found a ferrule that came off another DB dipole (can't remember which one)

I measured some flooded coax and managed to solder to it.

this before any weatherproofing applied

Its a nasty job!? I'd much rather use something like you fabbed there

Reid? W6MTF

On 03/30/2025 1:42 PM EDT Chuck Kelsey via groups.io <wb2edv@...> wrote:

?

?

I've always used unslotted tubing. Get the length set, drill hole all the way through, tap all the way, use stainless steel machine screw. Never gave me any trouble. Have a few in the air for 10-plus years (probably 20 years).

Chuck

On 3/30/2025 1:14 PM, John via groups.io wrote:

Hi Reid,

?

Yes, neat idea extending the mid band loops. Can't you just use those shredded stainless steel scouring pads? (not steel wool) to remove the outside anodizing? I find they work great on aluminum and leave a smooth surface.

?

The tubing from DX Engineering is the weaker 6063-T5, instead of the stronger 6061-T6 probably on the Scala. I get my 6061-T6 aluminum from Online Metals. Just mark the cut end with black magic marker -4 lines at 90 degrees, place? the tubing in a vise, and cut the 4 slots in about 1 inch with a hacksaw. I like 4 slots rather than 2 slot lines so the slots are thinner for the same amount of ID reduction and the slots do not have to be as long as with 2. I did get the vinyl cap with the hole drilled for the wire from DX Engineering. Permaseal Ultra Blue was used for waterproofing.(no acetic acid and really adheres to aluminum and a good dielectric).

?

The extended N was from Dave's Hobby Shop (used) Be sure to use stranded wire. We used silver plated Teflon.?

?

John

?

?

On 03/30/2025 12:05 PM EDT Brandon DX via groups.io <rfburnz@...> wrote:

?

?

John,

That is an interesting termination you made, definitely waterproof!

I have enough DB212's. see pic, already de-dimpled and set to the proper lengths for 52megs

I need to cross cut the ends of the extension pieces.

I found DX Engineering has the exact dia tube w/ ends already cross cut for hose clamps.

I have to replace the gold colored pieces that came off a Scala yagi because they are anodized (!)?

If I had access to a water tower I'd place them around the diameter like they did in Nixa MO.

I just looked at their website but don't see 6M any longer. Maybe they have them on 10M, since they have two 10M repeaters (!)

Reid? W6MTF

Hi Reid,

?

Yes, neat idea extending the mid band loops. Can't you just use those shredded stainless steel scouring pads? (not steel wool) to remove the outside anodizing? I find they work great on aluminum and leave a smooth surface.

?

The tubing from DX Engineering is the weaker 6063-T5, instead of the stronger 6061-T6 probably on the Scala. I get my 6061-T6 aluminum from Online Metals. Just mark the cut end with black magic marker -4 lines at 90 degrees, place? the tubing in a vise, and cut the 4 slots in about 1 inch with a hacksaw. I like 4 slots rather than 2 slot lines so the slots are thinner for the same amount of ID reduction and the slots do not have to be as long as with 2. I did get the vinyl cap with the hole drilled for the wire from DX Engineering. Permaseal Ultra Blue was used for waterproofing.(no acetic acid and really adheres to aluminum and a good dielectric).

?

The extended N was from Dave's Hobby Shop (used) Be sure to use stranded wire. We used silver plated Teflon.?

?

John

?

?

On 03/30/2025 12:05 PM EDT Brandon DX via groups.io <rfburnz@...> wrote:

?

?

John,

That is an interesting termination you made, definitely waterproof!

I have enough DB212's. see pic, already de-dimpled and set to the proper lengths for 52megs

I need to cross cut the ends of the extension pieces.

I found DX Engineering has the exact dia tube w/ ends already cross cut for hose clamps.

I have to replace the gold colored pieces that came off a Scala yagi because they are anodized (!)?

If I had access to a water tower I'd place them around the diameter like they did in Nixa MO.

I just looked at their website but don't see 6M any longer. Maybe they have them on 10M, since they have two 10M repeaters (!)

Reid? W6MTF

On 03/30/2025 12:05 PM EDT Brandon DX via groups.io <rfburnz@...> wrote:

?

?

John,

That is an interesting termination you made, definitely waterproof!

I have enough DB212's. see pic, already de-dimpled and set to the proper lengths for 52megs

I need to cross cut the ends of the extension pieces.

I found DX Engineering has the exact dia tube w/ ends already cross cut for hose clamps.

I have to replace the gold colored pieces that came off a Scala yagi because they are anodized (!)?

If I had access to a water tower I'd place them around the diameter like they did in Nixa MO.

I just looked at their website but don't see 6M any longer. Maybe they have them on 10M, since they have two 10M repeaters (!)

Reid? W6MTF

On Saturday, March 29, 2025, 10:52 PM, Hudson, John@CalOES via groups.io <john.hudson@...> wrote:

I’d love to have a conversation with you, I have two on 42MHz and looking to modify them for 6 and phase them together, both have directors.

?

John, WA6HYQ

jake@...

?

From: [email protected] <[email protected]> On Behalf Of Brandon DX via groups.io
Sent: Saturday, March 29, 2025 10:16 AM
To: [email protected]
Subject: Re: [repeater-builder] 6 m repeater antenna

?

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

?

This thread got me thinking of my DB224. thats me holding it.

I measured the spacing from DE to director this morning and its a just under 14"

I don't know what freq it was delivered on but most of the antennas I acquired in a lot were on 70 MHz with the exception of one on 39 something MHz.? to alter the spacing I would need to cut and weld onto the boom, its all one piece.? ? ?

I was planning to use it at a site with a bare 300ft tower, it was at 3800ft ele and was pristine (meaning low noise floor) and perfect for 6M.

It had served a religious TV station that went dark and the site owner gave an OK for me to go up on 6M.

Along came some enterprising soul that installed an Internet distribution antenna and was selling service to residents of the small city below the site. He was going in and out sometimes several times a day and annoyed the old timer who controlled site access and the owner finally said that was enough, no hams allowed!? ?

Reid

WARNING: Do not click links or attachments unless you recognize the sender and know the email is safe.

?

?

?

?

On 03/29/2025 1:16 PM EDT Brandon DX via groups.io <rfburnz@...> wrote:

?

?

This thread got me thinking of my DB224. thats me holding it.

I measured the spacing from DE to director this morning and its a just under 14"

I don't know what freq it was delivered on but most of the antennas I acquired in a lot were on 70 MHz with the exception of one on 39 something MHz.? to alter the spacing I would need to cut and weld onto the boom, its all one piece.? ? ?

I was planning to use it at a site with a bare 300ft tower, it was at 3800ft ele and was pristine (meaning low noise floor) and perfect for 6M.

It had served a religious TV station that went dark and the site owner gave an OK for me to go up on 6M.

Along came some enterprising soul that installed an Internet distribution antenna and was selling service to residents of the small city below the site. He was going in and out sometimes several times a day and annoyed the old timer who controlled site access and the owner finally said that was enough, no hams allowed!? ?

Reid

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:

?

?

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.

?

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.?

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:

?

?

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.

?