Re: Circularly-polarized antennas for two-way?
Circular polarization eliminates a lot of mobile flutter due to reflections. Radio broadcast industry normally uses right hand circular polarization on FM and left hand circular polarization on the HD signals. Television is now leaning more toward elliptical with 70% in the horizontal and 30% in the vertical. If I recall the test that was mentioned in the earlier email was written up in Bill Pasternak's "All you wanted to know about FM and repeaters" book. The CP array that was built used two Cushcraft four poles mounted at 45¡ã off of vertical in each direction. Basically a 4 bay turnstile turned on its side.
I thought about building a CP for 6m. The Nicom series in FM broadcast is real easy to duplicate and works rather well. On 2 meters it would be even easier since the size would be smaller.
Chris WB5ITT?
I've gone down this rabbit hole as well.? There's some ancient documentation out there showcasing some experiment?where a linear and circular antenna at a repeater site were choosable by the users (via DTMF) I guess to get a consensus?which one offered?what the users' observed?as "mo better."? Apparently?the CP won the election.
It's said even with vertical mobile antennas, the randomness of reflections of things can cause fluttering and such and CP on the mountain top alleges to help with this.
All this in mind, I'm actually in a position to test exactly this here in Virginia in the upcoming year... so I am.? Stay tuned.
73 John, kx4o? On Sun, Nov 20, 2022 at 5:48 PM Matt Wagner < mwaggy@...> wrote: Howdy,
I went down a little bit of a rabbit hole reading about the use of circular polarity in antennas. I'm curious if anyone's experimented with it for repeaters or traditional two-way stuff. But, while I can read lots of theory about circular polarity in antennas, and see people using it for various purposes, I've found absolutely nothing about people running it on traditional two-way systems. Is this something people have played around with? It sounds like it could be useful, but I can't possibly be the first to have thought of this, so I wonder if it ends up not working out well?
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Re: Circularly-polarized antennas for two-way?
I believe there was some research using both horizontal and
vertical polarity with pagers back in pager days.
I think it was Bogner that made the antennas for 900 Mhz. Pagers
are seldom vertical or horizontal. The test were in deep urban
areas. What I remember about the results was about a 3dB
improvement in receiving pages.
They decided that down tilt was more effective for a lower cost.
On 11/20/2022 5:12 PM, John Huggins
wrote:
toggle quoted message
Show quoted text
I've gone down this rabbit hole as well.? There's some
ancient documentation out there showcasing some
experiment?where a linear and circular antenna at a repeater
site were choosable by the users (via DTMF) I guess to get a
consensus?which one offered?what the users' observed?as "mo
better."? Apparently?the CP won the election.
It's said even with vertical mobile antennas, the
randomness of reflections of things can cause fluttering and
such and CP on the mountain top alleges to help with this.
All this in mind, I'm actually in a position to test
exactly this here in Virginia in the upcoming year... so I
am.? Stay tuned.
73
John, kx4o?
On Sun, Nov 20, 2022 at 5:48
PM Matt Wagner < mwaggy@...>
wrote:
Howdy,
I went down a little bit of a rabbit hole reading
about the use of circular polarity in antennas. I'm
curious if anyone's experimented with it for repeaters
or traditional two-way stuff.
But, while I can read lots of theory about circular
polarity in antennas, and see people using it for
various purposes, I've found absolutely nothing about
people running it on traditional two-way systems. Is
this something people have played around with? It sounds
like it could be useful, but I can't possibly be the
first to have thought of this, so I wonder if it ends up
not working out well?
|
Re: Circularly-polarized antennas for two-way?
If you are considering CP for a repeater station I would suggest diversity reception using as a second antenna a horizontal loop. Use two identical receivers and a voting comparitor.?
--
The Real RFI-EMI-GUY
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Re: Circularly-polarized antennas for two-way?
I've gone down this rabbit hole as well.? There's some ancient documentation out there showcasing some experiment?where a linear and circular antenna at a repeater site were choosable by the users (via DTMF) I guess to get a consensus?which one offered?what the users' observed?as "mo better."? Apparently?the CP won the election.
It's said even with vertical mobile antennas, the randomness of reflections of things can cause fluttering and such and CP on the mountain top alleges to help with this.
All this in mind, I'm actually in a position to test exactly this here in Virginia in the upcoming year... so I am.? Stay tuned.
73 John, kx4o?
On Sun, Nov 20, 2022 at 5:48 PM Matt Wagner < mwaggy@...> wrote: Howdy,
I went down a little bit of a rabbit hole reading about the use of circular polarity in antennas. I'm curious if anyone's experimented with it for repeaters or traditional two-way stuff. But, while I can read lots of theory about circular polarity in antennas, and see people using it for various purposes, I've found absolutely nothing about people running it on traditional two-way systems. Is this something people have played around with? It sounds like it could be useful, but I can't possibly be the first to have thought of this, so I wonder if it ends up not working out well?
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Circularly-polarized antennas for two-way?
Howdy,
I went down a little bit of a rabbit hole reading about the use of circular polarity in antennas. I'm curious if anyone's experimented with it for repeaters or traditional two-way stuff.
Of particular interest to me is using it only on one end. A lot of satellite comms use circular polarity on both ends, and can get fairly good isolation between right-handed and left-handed circular polarity. But, as I understand it, a lot of broadcast FM uses circularly polarized antennas to listeners with linearly polarized antennas, because there's a blend of vertical and horizontal antennas out there, not to mention the 45-degree pattern seen on some cars now.
From what I've read, about 3 dB is lost when a circularly polarized signal is received by a linear antenna. But what's gained is that the antenna orientation doesn't matter, and you avoid potentially 20-30 dB loss to an antenna in the wrong orientation. (Broadcasters can work around this by stacking a number of FM bays like we do with folded dipole arrays.)
I also read a tiny bit about some experiments on HF, on the theory that multipath fading would be reduced significantly.
It would seem to me that doing something similar on a repeater antenna could be beneficial, especially if you're serving users on portables. The signal strength for a ham repeater I'm listening to in the background is bouncing around by more than 10 dB right now; I suspect part of it is the fiberglass whip on top of a hill flexing a bit with the 30mph wind gusts we're having. I've also found that with somewhat weak signals being heard on an HT, sometimes the signal is greatly improved by tilting the radio in some particular direction, maybe due to various reflections and obstructions along the way.
But, while I can read lots of theory about circular polarity in antennas, and see people using it for various purposes, I've found absolutely nothing about people running it on traditional two-way systems. Is this something people have played around with? It sounds like it could be useful, but I can't possibly be the first to have thought of this, so I wonder if it ends up not working out well?
73, Matt, N1ZYY
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Re: Need documentation for SS-32M tone encoder
And then there's this one. Either I forgot or missed the documentation on RB. It's close to the SS-32SMP but not the same. I've got an email in for Randy.? It's been way long since I've been messing around with these for HTs.  -- - Regards, Karl Shoemaker To contact me, please visit SRG's web site at? for the current email address.
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MIII Programming Software
Group:
I¡¯m looking for the correct software to program a MIII ¡°racing stripe¡± model of GE radio.
I have programmed the older version (no stripes) in the past with these DOS programs:
?
Mastr III Shelf Program 15.0
Station Utility Program 9.00
Station Specials Editor 2.00 (not sure I have used this, or even if it is appropriate)
***
Will these program the racing stripe MIII, or will they brick it?
?
Is better software available for either version of the MIII¡¯s?
Dan K5FVL
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Re: Astro Spectra Consolette audio board
The closest I have is revision 'C'
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Re: GE MSTR 2 special (Factory Repeater?) FREE
That might be a UHF version of a GE AVR simplex repeater that connects to a regular mobile radio.
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Re: Series-mode surge protection
Hi guys,
When working on a PDP-11 (Q-Bus) system, actually an ISI Unix system? at a large printing house in the 1980s,
motor generator systems powered the "precious" computer systems, three phase motor and shaft to an alternator.
(probably with a wound rotor on the 3 phase motor) The Fujitsu eagle disk drive 80Mb required very stable AC mains.
Also in our (DE) (not DEC) cabinets, was an isolation transformer with separate primary and secondary windings to
protect the early generation switchmode power supplies.
Alan VK2ZIW
On Sat, 19 Nov 2022 15:49:40 -0800, rsnyder wrote
> In my home
station I have a SurgeX SA-82 (8-amp) surge protector powering an Iota power
supply which charges two 105 Ah AGM batteries connected in parallel.? All
of the shack loads are 12V, including my computer, monitors, and overhead LED
lighting.? As long as the Iota is powered on and the load does not exceed
30A, the Iota supplies all of the current and the battery just floats at 13.60V.?
The purpose of the SurgeX is to prevent voltage spikes from damaging the Iota
or any downstream components.
>
> I am picturing a similar
arrangement at the repeater site, with a larger surge suppressor, power supply,
and
batteries.
---------------------------------------------------
Alan VK2ZIW
Before the Big Bang, God, Sela.
OpenWebMail 2.53, nothing in the cloud.
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Astro Spectra Consolette audio board
I am working on a Astro Spectra Consolette that has the TRN7391B audio board in it, does anyone have a schematic or documentation for it?
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Re: GE MSTR 2 special (Factory Repeater?) FREE
Thanks.
--
-
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
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Re: GE MSTR 2 special (Factory Repeater?) FREE
Hi Karl, I will keep it for you, and check around for anyone traveling to Spokane. Still haven't found a 25watt UHF CDM750.. Frank N6CES?
On Sat, Nov 19, 2022, 3:02 PM Karl Shoemaker < srg734@...> wrote: Frank I think the best chance is meeting someone half way, like Moses Lake or Ellensburg. Perhaps you know of a traveler, too.
Last thing I want is placing it the hands of the goone squad, AKA UPS.
--
-
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
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Re: International crystal manufacturing
local telco=Southern New England Telephone Company
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On 11/19/2022 12:52 PM, Jamie WW3S wrote: Local telco¡.GTE?
On Nov 19, 2022, at 9:23 AM, Joe <k1ike_mail@...> wrote:
?Hello Kevin,
"Sr Translations Engineer" That's a title that I haven't heard in years. I did translations back in the 1980's for the local Telco here in Connecticut. Sometimes interesting, sometimes boring.
(For those curious, translations=software programming in telephone company lingo)
Joe
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Re: Series-mode surge protection
In my home station I have a SurgeX SA-82 (8-amp) surge protector powering an Iota power supply which charges two 105 Ah AGM batteries connected in parallel.? All of the shack loads are 12V, including my computer, monitors, and overhead LED lighting.? As long as the Iota is powered on and the load does not exceed 30A, the Iota supplies all of the current and the battery just floats at 13.60V.? The purpose of the SurgeX is to prevent voltage spikes from damaging the Iota or any downstream components.
I am picturing a similar arrangement at the repeater site, with a larger surge suppressor, power supply, and batteries.
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Re: International crystal manufacturing
Got Doug it, thanks.?? I'll give them a call around midnight to 3am pacific standard time (Spokane, WA). I hope they speak english !
On the CO saga, in Hilo, we had 4-digit numbers to the homes in the 1960's.?
When GTE bought out Hawaiian Tel. Co. around 1970 they added the CO code of 935.? Coincidentally, the same office code as Chewelah, WA.
--
-
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
|
Re: GE MSTR 2 special (Factory Repeater?) FREE
Frank I think the best chance is meeting someone half way, like Moses Lake or Ellensburg. Perhaps you know of a traveler, too.
Last thing I want is placing it the hands of the goone squad, AKA UPS.
--
-
Regards, Karl Shoemaker
To contact me, please visit SRG's web site at?
for the current email address.
|
Re: Series-mode surge protection
I am not a fan of the SurgeX units.? I have seen little evidence that they do what they claim and there are some serious design flaws for such an expensive unit.? An example would be the obvious one - a ground bonding point.? They don't have one and rely solely on the power safety ground connection which does not provide a good bond for bonding purposes.
You would be much better off installing a Type 2A SPD with SADs and MOVs in replaceable modules at your electric panel plus a Type 3 SPD PDU at your equipment.? This combination takes care of the vast majority of spikes and surges effectively and they do not blow unless there is a very significant incident.? This is the combination specified for communications sites in Motorola R56 and thousands of mission-critical communications sites use this configuration effectively.? I would trust that any day over a snake-oil solution.
Dan Woodie, CETsr KC8ZUM
I recently installed?series-mode surge protection devices (SurgeX SX-1115-RT) on two repeaters that have switched-mode power supplies.? The surge protectors do not use sacrificial components such as Metal Oxide Varistors (MOVs) that are commonly used in low-cost units.??They are designed to withstand up to 1000 occurrences of surge pulse voltages up to 6000 volts, or 500,000 occurrences of 1000 volts.
I don't have any way to monitor line voltage surges or spikes, so I can't tell whether the devices are actually doing anything on a day-to-day basis.
I have two theories:
1. Occasional, small voltage spikes can gradually weaken semiconductors such as MOSFETs used in switching supplies.
2. Large voltage spikes?are most likely to occur at precisely the time when the repeaters are most needed, i.e. during some type of disaster.
The series-mode surge protectors appeal to me because they protect the equipment from a virtually unlimited number of small surges on a day-to-day basis while also handling occasional large spikes without without requiring a human to visit the site to replace a self-sacrificing surge protector.
I am whether anyone else has experience using series-mode surge protection devices at repeater sites.? Are there any downsides to these devices?? For example, are the devices prone to failure due to age, heat, moisture, dust, or vermin?
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Re: International crystal manufacturing
OK, yes, I was talking about the old stuff. I remember as a kid
walking by the local CO when someone was there with the door open.
Remember all the click, click, click sounds and massive pairs of
wires. Also, there was a number you could dial to get what they
called "galloping relays." Party line phones had to enter a 2-digit
prefix to make long distance calls so the billing went to the proper
house.
The number we has back then was 3-2663. That later changed to
753-2663, but you quickly learned that the equipment would respond
fine to 73-2663, skipping the 5. These days we are dialing 10 digits
for any call, including local. Many times I recall tapping out a
number with a phone having no dial, or just doing it because I
could.
Chuck
On 11/19/2022 10:04 AM, Kevin
Magloughlin wrote:
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Show quoted text
But in direct response, telling the CO switch to set up for a
toll call only applied in a mechanical office. The rest of it,
shall we say, is all software now and makes absolutely no
difference in call processing. ? I am dealing with some
databases in northern California where the PUC has mandated
no-prefix dialing. ?Not sure why but I imagine it¡¯s to make a
wireline phone act like a cellphone. ?Just my guess¡
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Re: International crystal manufacturing
Fred was the translations engineer where I worked.? Laurel was a customer service rep that, after a tour if the switch office, thought translations would be interesting.??
The company allowed her to come over one day a week to watch him work.? After a couple of months she transferred into engineering and she was a "wizard" with the translations stuff.
Eric
On Sat, Nov 19, 2022, 10:52 Jamie WW3S < ww3s@...> wrote: Local telco¡.GTE?
> On Nov 19, 2022, at 9:23 AM, Joe <k1ike_mail@...> wrote:
>
> ?Hello Kevin,
>
> "Sr Translations Engineer"? That's a title that I haven't heard in years.? I did translations back in the 1980's for the local Telco here in Connecticut.? Sometimes interesting, sometimes boring.
> (For those curious, translations=software programming in telephone company lingo)
>
> Joe
>
>
>
>
>
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Chris Boone WB5ITT
Don Clark
RFI-EMI-GUY
Matt Wagner
Karl Shoemaker