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@...
?
toggle quoted message
Show quoted text
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!? ?
WARNING: Do not click links or attachments unless you recognize the sender and know the email is safe.
?
|
Hi Brandon,
?
Interesting that your converted from mid band DB225 has a less robust , but more direct clamping to a tower leg, more like the on the DB212.
?
If I were you I would do away with the director and the extra length of boom, especially if you currently have 6.5 inches of air space between the inner tubing side and the mounting mast or tower leg, or remake the boom so that you do have that space and at the same time make the inside half the fed side, just like on a DB212.
?
That got me thinking that for the low band version with a lot more boom length, I would consider not only removing the director element, but also removing the heavy bulky boom mounting pipe, just reverse the boom now without the driven element so the boom points toward? a tower instead of away, then with U bolts fasten the antenna to 2 adjacent tower legs so the leg to element air space is 6.5 inches for a 50 ohm feed.?
?
You could, for 2 antennas in phase, change the element to coax connection to a waterproofed N female on a flange, use an odd multiple of 75 ohm coax to an N tee to the feedline. (See pic)
?
John
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
|
Re: Quantar CPN1048G Power Supply
Lead acid and AGM have different charge profiles. Something like 14.2V for most of the charge then a float at around 13.4V for lead acid and 14.7V charge 13.8V float for AGM. The Quantar CPS has battery options for Lead Acid_LIN, Lead Acid_NON and NiCad. NiCad would definitely be a different charge profile from Lead Acid. I think the LIN and NON is simple charging vs having a periodic maintenance charge added or similar.?
|
Re: Quantar CPN1048G Power Supply
28 volts is the normal charging voltage for a 24 volt battery bank... Just like 13.8 is the normal charging for 12 volt battery?
Chris WB5ITT?
I've had one running with a pair of 12V 90AH AGM batts for a couple of years and I need to visit the site to check battery condition, otherwise its held up through a few power outages. I've also run one temporarily from a pair of Costco 100AH deep cycple batts. You need to calculate current draw off battery and size your battery to last through a worst case power outage or a trip to the site to deal with it and that could amount to a lot of battery needed. I program my Quantars for 25W when on battery power to extend batt life a little.?
|
Re: Quantar CPN1048G Power Supply
I've had one running with a pair of 12V 90AH AGM batts for a couple of years and I need to visit the site to check battery condition, otherwise its held up through a few power outages. I've also run one temporarily from a pair of Costco 100AH deep cycple batts. You need to calculate current draw off battery and size your battery to last through a worst case power outage or a trip to the site to deal with it and that could amount to a lot of battery needed. I program my Quantars for 25W when on battery power to extend batt life a little.?
|
Are there extender cards or cables to aid in Quantar module troubleshooting and tuning?? Other than some content on the W9CR website, which was very useful, I have not been able to find a thing.? ?It seems like I may end up having to use a stripped down Quantar Chassis for this purpose.
?
Thanks!
Jeff? KC8VFN
|
Re: Quantar CPN1048G Power Supply
What battery do folks usually use for this purpose?? Does it truly need to be a 28V and opposed to a 24 volt battery for safe, reliable operation?? Other than cordless drills and such, 28V batteries seem to be rather rare and expensive.
?
Thanks!
Jeff KC8VFN
|
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
|
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
|
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:
toggle quoted message
Show quoted text
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: ?
?
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?
?
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:
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.
?
|
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.?
|
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:
?
?
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?
?
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:
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.
?
|
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.?
|
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:
toggle quoted message
Show quoted text
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: ?
?
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?
?
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:
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.
?
|
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:
toggle quoted message
Show quoted text
Just for you Chuck Kelsey
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.
|
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
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
|
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.?
?
|
Hudson, John@CalOES
Chris Boone WB5ITT
Brandon DX
MIke Ryan