What happens if I have a strap running horizontally nailed flat on a
wall and I need to go vertically down with another strap to tied onto
it making a T. This vertical strap would also be nailed flat on the
wall. Wouldn't this sharp corner present a high impedance?
Yes, to some degree, but
Hi Jeff
Just wondering why silver? Lower impedance or higher melt
temp or both?
Strength and melting point.
Note that silver soldering isn't soldering using soft solder that has some
silver in it, such as tin+silver or tin+silver+copper. Those kinds of soft
solder are often called silver
-Builder] Ground Strap Installation.
Best way to run it?
Thanks Jeff
I have just learned something new today.
So you would need an acetylene torch to provide enough heat
for doing this.
Randy
On 2010-03-20, at 2:04 PM, Jeff DePolo wrote:
Hi Jeff
Just wondering why
How about this. I'll ask Rick if he'll send me a demo unit, and I'll
compare it to my Eagle, using my VNA as the reference (Agilent E5070B).
--- Jeff
First thing I would say is that if Rick is selling it, assume
it works.
I run an Eagle unit and
betting that Rick's will hold it's own against the Eagle
(which I've
always thought was overpriced.)
Chuck
WB2EDV
- Original Message -
From: Jeff DePolo j...@broadsci.com mailto:jd0%40broadsci.com
To: Repeater-Builder@yahoogroups.com
mailto:Repeater-Builder%40yahoogroups.com
Rick at Amtronix is now selling a bargain-priced return loss bridge - $69
kit, $109 assembled and tested. Covers 400 kHz to 1 GHz. Directivity spec
is 30 dB. No, it doesn't turn your TG/SA into a $50k VNA, but for a little
over
a Franklin, it looks like quite a deal.
Details and specs on
The problem with the Glenayre exciter is trying to figure out how to
program it to the ham bands. There is a company in Illinois
that still
fixes Quintron/Glenayre stuff, I think they could program one
for you.
There is one on eBay right now. I maintained a 900MHz
Glenarye digital
Anyone care to comment on the quality of the Amphenol Connex
line of RF connectors? They have a pretty good price point,
but only if they aren't junk.
lh
It is my understanding that Connex was started as a division of Amphenol
after some kind of a buy-out of another manufacturer that
I have three (3) Antel [BCD 80010] 806-900 mHz vertical
antennae that I would like to mount on the three legs of my
tower for omni pattern (Rec. only). Several questions come to mind.
1.) At the rated frequency, how many inches should the side
arm place the ant. from the tower?
When I say the notch presents a short it is not really a
short but a very low impedance of say a few ohms. But by
having the unwanted source impedance high rather than at 50
ohms it is much easier to pull the high impedance down with
the few ohms short circuit than it would be if we were
Well, there seems to be a bit of a mystery. The schematic in the
base/repeater station manual I have shows:
C531
43L
30M
24H
But the parts list shows:
C531
43L
36M
24H
So is it 30 or 36 pF? Who you gonna believe?
I checked a mobile Micor manual, and it's listed as 30 pF in the parts list;
What is the difference between real and un-real RG214?
There are some non-mil-spec RG214 varients out there. Sometimes they are
labeled as RG214 TYPE, or RG214 Commercial. These typically have double
braid like real RG214, but unlike real RG214, the braids are bare copper
instead of
A while ago someone was looking for Motorola vibrasponder reeds for paging
tones, and I responded back that I had a bunch of them but had to find them.
I've since lost that person's name/email address. I finally found them
(accidentally). If you're the person that wanted them, please email
On Sun, 28 Feb 2010, Mike Morris WA6ILQ wrote:
2) the pair that was receiving the problem was a high
impedance load
or an unbalanced load (i.e. one side grounded). Use an
ungrounded 600
ohm winding from a transformer on each end of each pair.
The nominal impedance of a copper pair
In a station, the 9.6 volt circuitry *could* be run from 12 volts, as
long as its regulated. I'm not suggesting someone does that, because
the circuits were optimized for 9.6 volts, but I'm trying to
make a point.
Point taken, but to add to your cautionary note, there are some circuits
I have a odd situation where I need to run long audio cables
between my
repeater controller and two repeaters. In this case, the
repeater controller
will be connected to 2 repeaters in the same cabinette. The other two
repeaters will connected thru about 140 feet of wiring to the
other
The diagram for the adapter box also shows +13 Vdc is also routed
to one of the pins in the same plug (as well as ground) so I have
to figure out if that's a requirement or just an addition to the
adapter package. I did see where +13 Vdc was supplied to another
location on the repeater
My initial idea was to run an antenna switch from the
convertacom to the amps so I can manually select which one
the signal goes to. Then on the output side of the amps I
thought about using an antenna duplexer on the output of the
amps to feed the antenna.
I think you'll find that
On 2/23/2010 3:11 PM, Jim WB5OXQ inb Waco, TX wrote:
Is it possible the AM signal is getting into an audio stage
instead of the
receiver front end? I had that happen once.
Same here. All audio inteconnects are now tiny coax cables at
that site
now, installed with shield
I'm considering an ICE broadcast high-pass filter that cuts off at
1.8Mhz (model 402). I have an email into them to see how well
it might
work at 448 Mhz.
Tony
Before you spend any real money, you might just try a shorted quarterwave
stub. If you want, I can make one up quick and see
Think about it this way. If you made a dipole, would you
cut one side 5% longer than the other?
Maybe, if you had a reason for offset feed... but most offset
Dipoles are not 5% different. I thought the subject was about
1/4 wave ground planes and not dipoles... they are not the
same
On Mon, 22 Feb 2010, Jeff DePolo wrote:
Kinda along the same lines as always make the cable from the
connector on the transmitter to the connector on the
duplexer an even
half-wave.
The reason for doing that is that if the duplexer presents a
short-circuit, said short-circuit won't
Yes, I don't know why the db-201 has such ridiculously long
radials, but that is how they were designed. Go figure. I
would like to know why though if someone knows...
73
Apologies in advance, this is going to wander a little off-topic and ended
up getting long...skip to the bottom if you
So, if we take the 1250Khz signal or 1.25Mhz x 4 = 5Mhz. I
realize that
the 4th harmonic of a 5KW broadcast station isn't very powerful
Well...it *shouldn't* be very strong. It has to be attenuated 43 + 10 * log
(Pwatts) as measured in the field (not at the transmitter output terminals).
Various ARRL publications cite the 5% longer rule. Right or
wrong, who
knows?
Chuck
WB2EDV
At the risk of offending someone somewhere, the fact that the ARRL cites the
5% rule without backing it up with the analysis behind the rule doesn't
really suprise me...
Think about it this way.
The 4 WaCom UHF 10 cavities I believe were designed to be
part of a simple duplexer for a UHF-Lo repeater. They
*should* tune up to the 440 ham band based on what Telewave
has listed for specs on the current modern day model number.
Current config is Pass RX Reject TX on 3 cans and Pass
.
--- Jeff WN3A
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo
Sent: Wednesday, February 17, 2010 12:24 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] Micor Community Repeater Supplement
I just got some Bomar crystals (Not my choice) for the clubs
UHF Micor. The TX was off 14 to 39 kHz, Had to add a 10pF cap
to get the trimmer in the center range. Strangely the RX was fine.
That's probably not indicitive of Bomar making a bad rock; you almost always
have to change out the
I am in need of a micor UHF community repeater station
supplement number is 68-81025E55, or 68P81025E55. Email me at
my callsign at yahoo
Jim
I have it in paper, but not electronic. Is there a particular section you
need that I could scan?
--- Jeff
I just recieved 2 new DB224A harnesses from Andrew. They were
made in Mexico (no surprise there, they have been making them
there for some time).
Curious if you had any problems ordering them, and if I may ask, what did
they run you?
I need it to work on
147.225/147.825. I got a 1.68:1
It depends on what kind of EM interface it is. There are several (5, IIRC)
physical EM signalling/voltage types. Depending on which one it is, it
might be as simple as wiring COR and PTT directly to the E and M leads, or,
if the interface only will work with -48 VDC battery voltage levels,
I've disassembled and compared the ham-split PD633-6A-1N and regular 450-470
PD633-6A-2N. The resonators are identical; they're the same length. The
difference is where they are tapped - the low-split model is tapped about
1/4 further up the resonator than the 460 MHz version. The semi-rigid
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo
Sent: Saturday, February 06, 2010 10:55 PM
To: Repeater-Builder@yahoogroups.com
Subject: RE: [Repeater-Builder] RFS TDE-7780A
I've disassembled and compared the ham-split PD633-6A-1N and
regular 450-470
PD633-6A-2N
I'll confirm also, 12 from last cavity to antenna tee, RG214. Intra-cavity
is 11.5. Measurements are tip-to-tip on the type N connectors. I've done
the harnesses for the older PD 526's that had RG8 on them. Some of the
newest 526's have RG400 coax instead of RG214 FWIW.
, were your inter cavity jumpers Type RG-8A/U cable? Just
wondering..Joe
Jeff DePolo wrote:
I'll confirm also, 12 from last cavity to antenna tee,
RG214. Intra-cavity
is 11.5. Measurements are tip-to-tip on the type N
connectors. I've done
the harnesses for the older PD 526's
Phil,
The Motorola TLE1713A Power Amplifier is rated at 75 watts
continuous duty
for 450-470 MHz. It is a component of the MICOR C64RCB
station. All of the
technical data is in Service Manual 6881025E50. The bad news
is that the
manual is NLA from Motorola, but the good news is that
Have chance to install a DB 224 at 450' and another one
anywhere below it. Using LDF6 on both runs. RF solid state
110 watts out. Wanting to know the pros or cons of running
both antenna close together for more height with duplexer or
spacing antennas for isolation without duplexer?
All
Can anyone burn a 2716 Prom chip for a GLB ID-1 Ide'er?
Not a standard hex file. have some docs.
Thanks
Fred
wa2...@arrl.net mailto:wa2cam%40arrl.net
I'm not sure what not a standard hex file means, but I can burn 2716's no
problem. I can read any standard format (bin, mot, hex,
Use to have SuperStation Masters with Rx at 450' and 150
watts Tx at 240' many years ago on this tower before it got
moved. Had no desense and very good coverage. Will be running
WP-641 split. Just wondering about the Rx Tx vertical
separation. Would Rx at 450' and Tx at 375' be without
If you're patient on Ebay you can sometimes catch a deal on
this type of duplexer... Ebay Item Number: 110486323682
I've caught these units used from prices of $50 up toward
$150 is a pretty good deal.
back later...
s.
An oldie but a goodie, Sinclair R2B12 for wide split (and it's a
I've never seen one for a DB224, though I have seen them for a DB408 (4-bay
UHF) with 9 degrees of downtilt.
A DB224 has a pretty fat 16 degree beamwidth in the elevation pattern. You
sure you really need downtilt? If your problem is dead spots extremely
close to the base of the
I plugged the same values as before into CommShop, but this
time with a 1
MHz split, and the result is about 85 dB isolation, which can
be met with
about 7.75 miles of horizontal separation.
snip
The definitive method for testing whether your transmitter is causing
desense to your
Not directly, but you can use the ASR to get the lat/lon, then do a database
search (wireless.fcc.gov, click on Databases) using those coordinates.
A lot of times the license coordinates don't match the ASR coordinates
exactly (due to a number of reasons), so do a radius search, specifying
Use the FCC ULS search feature. From the ULS page select
find license. From that page on the right hand side select
Site based search. This will bring up a form that you can
search on several items including the ASR number. The result
will be the call signs of everyone on that tower.
Try here:
http://www.mcmaster.com/#hex-locknuts/=5bcw46
Click on Flex-top Expanding Lock Nuts
I have some T-1504 type cavities/duplexers, but not here so I can't measure
the thread.
--- Jeff WN3A
-Original Message-
From:
Ouch. Maybe a regular nylon lock nut would work acceptably well and be a
little cheaper? Isn't the outer sleeve (the one that the lock nut threads
onto) slotted? If so, will it tighten up enough to keep the shaft from
beint turned if you just use a a regular nut?
Sal's idea of using small hose clamps is starting to look good ;)
Use a regular nut and Locktite :-)
Eric I was just relaying what I was told (by a gov radio
tech) about how
the repeater handels encrypted communications. It just passes audio
straight through be it encrypted or analog. That way someone at the
repeater site can not eavesdrop on the secure communications going
through the
Nothing gave me more pleasure than spending my long distance
charges on
sending fidmail packets from my BBS to the hub in st. Louis
that were LADEN
with snide remarks straying further and further off topic.
You actually *paid* for long distance modem calls back then ??!?? :-) :-)
:-)
No tone service where I was.
Ha! Whistle up 2600 on an 800 call and the world was your oyster...
I first box I actually owned outright is a timex Sinclair
1000 with the 16k
ram pak sitting out in the shed/shack
Mine was a Trash-80 Model I. I cut my teeth on a VAX-11/750 at a local
Does anyone have any two-way or microwave engineering contacts at Duke
Energy or Texas Eastern (pipeline)? Along the same lines, does anyone know
if they maintain their own microwave network or if they subcontract the
maintenance out?
--- Jeff WN3A
I also recall that the source Z of CAS and RUS isn't the same (I'm pretty
sure CAS is lower than RUS), maybe somebody can confirm. And doesn't RX
MUTE only source current, not sink? I thought there was a protection diode
in series with the exposed RUX MUTE line to prevent someone from sourcing
If the monitor was one of the older units, then the modules have proper
factory calibration data loaded in them for the entire spread up to 1000 MHz
(plus the 1700-2000 segment). The firmware reads the cal data on startup.
If it's one of the newer units that doesn't have modules which were
as CDMA-based cellphone development is starting to wind
down in favor
of W-CDMA and LTE.
-Brian
On Fri, Dec 11, 2009 at 11:28 AM, Jeff DePolo j...@... wrote:
Pros over the 8924C: The display color CRT is replaced
by a EL panel,
lower burn in. Duplex and Antenna connectors are N
The older ones were general-coverage like the 892x series (100 kHz to 1 GHz,
and 1700-2000 or something like that). The newer ones were limited to the
cellular and PCS bands. It's not only a difference in firmware but also
hardware (i.e. you can't take one of the newer ones and back-rev the
Pros over the 8924C: The display color CRT is replaced by a EL panel,
lower burn in. Duplex and Antenna connectors are N instead of BNC,
better frequency range (older units)
Cons: Spectrum Analyzer Is Optional, No Squelch knob, No auto
frequency counter, 2.5W max input, does not decode DPL,
The RN in the part number tells me it's the grey fire-retardant jacket.
Unless Andrew changed what they make the jacket out of, it should NOT be
used outdoors, it degrades quickly from UV. It's primarily intended to be
used as a plenum-rated cable indoors. I remember scrapping about 800' of
'twas me that did the RC-85 and RC-96 firmware hacks. Email me direct.
--- Jeff WN3A
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of Pointman
Sent: Sunday, December 06, 2009 7:15 PM
A quick check of the datasheets shows that the only difference is pin 14
which is a second chip-enable line on the smaller device, whereas it's the
most significant address bit on the larger device. The Syntor can address
either the smaller or bigger part depending on jumpers. If your radio was
That's pretty good. But what I had were the actual cutting dimensions for
the elements, cables, etc. right from Decibel, similiar to what I posted for
the Phelps-Dodge/Celwave dipoles. I know I have it *somewhere*...
--- Jeff
-Original Message-
For small-diameter cables, I have Paladin CST Vario strippers. These are
completely adjustable - you insert/remove the blade cartridges to get the
strip dimensions you want for 3-level stripping, and you adjust the depths
of the blades for each strip level for whatever cable you're using (i.e.
I uploaded a file to Yahoo that contains a scan of the Celwave lowband
dipole dimensions, harness cable lengths, and other tech info. It's
entitled Celwave Lowband Dipoles.pdf. Maybe Mike or someone else might want
to put it on repeater-builder.com as well.
I found some notes I had on the
After letting it cool, I key'd it up again. It immediately went up to
only 20 watts, then after about 30 seconds it hit 75 watts
and finally
after close to a minute and a half, it hit 100 watts. I let it cool
again, and same thing. This appears to be the way this amp is as
nothing I can
Comprod makes dipole arrays with a screen reflector, at least for VHF, not
sure about UHF. I'm looking in the catalog and it shows a backside null
close to 20 dB down from the main lobe.
The screen reflector should be nominally about 1/4 wave behind the radiator
for maximum forward gain. It
mzfb2001 wrote:
I was looking in the files section and may have missed it, but I am
looking to improve the transmit audio quality on my UHF transmiter.
I've noticed that the audio is lacking in lows its not tinny but its
not what I would call normal audio from a Micor. The audio
Has anyone got the dimensions of these for a 4 cavity for
450 ish, they are the ones with 2 BNC sockets and a capacitor...Thanks
Andy
G8VLL
I'll take one apart if nobody else responds. I have both the ham band
28-66-02 duplexers (100 dB isolation, 0.6 dB loss, 5 MHz split) and also the
I have dimensional data for both Decibel and Celwave lowband folded dipoles
*somewhere*. If there's interest I'll hunt for them.
I think the Celwave design (with the stingers) would be easier to
fabricate - no bending involved.
--- Jeff WN3A
-Original
On most fiberglass omnis, the lighting spike at the top is an extension of
the last element in the array which is actually a shorted quarter-wave
section. This shorted quarter-wave section at the far end of the radiator
serves to put the entire antenna at DC ground.
Some of the cheaper
The repeater might be getting into the PA stage of the APRS
radio. Try
powering off the APRS radio during the time that you hear the weird
noise. I would bet that the noise goes away as soon as the APRS radio
in powered off.
What kind of radio is being used for APRS? If it's something
I added several new Sitemaster sweeps to the antenna sweep repository. I
also scanned a bunch of factory hardcopy plots I had in my files for various
Decibel and Sinclair dipole arrays (I don't have pre-install Sitemaster
sweeps for these, they're all installed and on the air). Antennas that
Standard broadcast AM is 10KHz, and is wider than most other
forms of AM
(except CB, where they will do anything they want with the signal).
Standard AM *audio*, in the US, is low-pass filtered at about 10 kHz, so the
RF bandwidth is about 20 kHz (double sideband).
CB is substantially
You should be tuning the bandpass for maximum return loss, not least
insertion loss.
I've found that older Wacom duplexers develop center plunger contact
problems as they age. I trashed quite a few 900 MHz duplexers and combiner
cavities because the insertion loss was intermittantly high; the
Beyond just turning off the other repeaters, try terminating their antenna
feedlines with a dummy load instead of leaving them connected to the
equipment. See if that makes any difference.
-Original Message-
From: Repeater-Builder@yahoogroups.com
I don't know which repeater it came out of, but it was probably a CR1000 or
CR1010. Here's the manual for a CR1010, should get you in the ballpark.
http://efjohnson.com/PDF/manuals/CR1010Repeater-ServiceMan.pdf
BTW, if anyone knows of a source of those mondo dual banana plugs that EFJ
used, I
contact me off the group, so it does not get tied up.
Terry KM5UQ
From: Jeff DePolo j...@broadsci.com
To: Repeater-Builder@yahoogroups.com
Sent: Sunday, September 20, 2009 10:16:59 AM
Subject: RE: [Repeater-Builder] UHF Duplexers
You should
I'm most familiar with Maxtrac's with regards to less than
full power operation, i.e. that they can produce spurs
other undesirables when run that way.
So other radios can have the same issues?
Many do, but not all, hate to over-generalize...
I read that it is
because when running
I can't find the numbers listed below on the board with the
exception of a large 6 etched out of copper on the board. I
might now assume the unit is the 30-36 MHz unit mentioned
below unless the pc board label is printed somewhere not within
obvious view.
Skipp,
Look over by the
1/2 or 3/8 LDF has always been my preference for jumpers, never had a
problem related to a connector damage due to lack of flexibility causing
over-stress at a connector, either at the antenna or at the main
transmission line. Maybe there are some ham-grade antennas where a
less-flexible jumper
Oh, by the way, forgot to mention, Phelps-Dodge/Celwave used to ship a RG8
jumper with Stationmasters. Some time in the fairly recent past they
stopped doing that. I guess they figured everyone was tossing them out
anyway...
--- Jeff
Being an analytical guy I modeled the antenna system in both
Ansoft Designer and an antenna modeling program. In Ansoft
Designer the antennas were modeled as a series RLC load with
50 ohms at resonance and a Q of 15. Transmission lines were
modeled with VF equal to that of RG-58A/U coax.
Milt said:
The
chart in the document was developed specifically for the
Spectrum series
series fed LB antenna. THE MEASUREMENTS IN THE CHART WILL NOT
WORK WITH
SHUNT FED COILS!
So as I guessed, the secret sauce is the type of antenna/loading coil used.
It might be a worthwhile
Scotch Super 33 tape is great stuff, but Scotch Super 88 is
even better-
it's thicker, has a better adhesive, and it has better UV
resistance. Cloth
tape, AKA friction tape, should be pitched into a trash can.
I haven't had friction tape in years. I remember finding rolls of it in my
Speaking of tools, how about the specialized wrenches that
can take the SMA connector
nut loose on, oh, say, Yaesu VX 5 or FT-50's?
Ray, KB0STN
I don't have either of those radios, but are you talking about a spanner
wrench or spanner driver?
Retaining ring pliers sometimes work too.
back from
him, I'll let the list know the *proper* name and how to get some.
Scott
Scott Zimmerman
Amateur Radio Call N3XCC
474 Barnett Road
Boswell, PA 15531
Jeff DePolo wrote:
Speaking of tools, how about the specialized wrenches that
can take the SMA connector
nut loose on, oh
All inappropriate.
What's inappropriate? If what he's talking about is a spanner nut, you use
a spanner wrench or a spanner driver to remove it. The thing you posted
from eBay is just a four-size spanner driver. Just because it's marketed
for radio purposes doesn't make it any more
This is my preferred method as well for sealing connector splices. However,
I do three layers each time (one layer up, down, up again of 88, then the
same of splicing tape, then again of 88). Overlap each successive wrap
about 50%.
Always, always, always do the last wrap in each direction
I'd tend to think it might be a little better, less oxidation of the braid
and foil, and less movement. I only buy the direct burial (DB) version of
LMR400 anyway, it's only a few pennies more per foot, I figure it's worth
the little extra protection if it gets a nick in the jacket. And, of
OK, now that NTSC video is gone, so are my handy local video
carriers that
I used to use to check the frequency accuracy of my signal
generators. However, I understand that there are pilot
carriers buried
within the 8VSB DTV signals that can be used for the same purpose. A
couple of
I drill a hole perpendicular to the axis of the cable through the RG59
reducer (in the smooth area above the threads) so you can get solder to
flow into it, maybe that's what Chuck was referring to?
For 3/8 Superflex, the OD of the cable shield is just a tad too big to
screw into a PL-259
pin last.
Chuck
- Original Message -
From: Jeff DePolo j...@broadsci.com
mailto:jd0%40broadsci.com mailto:jd0%40broadsci.com
To: Repeater-Builder@yahoogroups.com
mailto:Repeater-Builder%40yahoogroups.com
mailto:Repeater-Builder%40yahoogroups.com
Sent: Tuesday, September
Seems to me the three most-likely causes of your problem are:
1. Antenna itself is bad/noisy. Substituting antennas may help rule this
out.
2. Not enough isolation between radiating antenna and equipment. The 100'
of horizontal separation may not be enough to keep the strong RF out of your
of the imagination).
--- Jeff
--- In Repeater-Builder@yahoogroups.com
mailto:Repeater-Builder%40yahoogroups.com , Jeff DePolo
j...@... wrote:
Seems to me the three most-likely causes of your problem are:
1. Antenna itself is bad/noisy
I'm not familiar with those particular duplexers, but the Celwave duplexers
Eric mentioned are easily damaged by over-power. Usually the insulators at
the open end of the resonators (the ends with the tuning slugs) arc over
and/or develop carbon-ish deposits. In cases of mis-tuning, sometimes
The late 60s/70s brought along ignorant antenna designs, like the
windshield-integrated dipole and the 45-degree swept-back dipole. Now
we've got even more ignorant designs like the 45 degree stubby on the
roof of cars (06 or newer Hyundai Santa Fe is a good example of this
mistake), or
There seems to be confusion mystery in the crowd of radio
buffs that I han out with (not in this group!) on the subject
of connecting cable lengths for cavity duplexer use. I've
heard that the manufacturers of such devices also tend to be
mum on this.
It seems to me that if these
OK. Thanks anyway. Just thought there might be some
experimentors out there in RF land. Do you think a 420-430
antenna work on the 3rd hanmonic, similar to using a 2 mtr.
antenna with a 440 transmitter, as I have seen mentioned here
on occaision There isn't a lot out there in
Well, just turn your 2m handie talkie even with a rubber
ducky on its side note the drop in signal strength. Cross
polarization losses, e.g. linear V to linear H (or vice
versa) can be up to 30 dB!
In the absence of multipath, or more correctly, obstructions causing
reflections that
Here's a seldom-talked about issue: effective sensitivity .
Actually, it's talked about fairly regularly here, and there are several
articles on the web site about it including how to measure it.
That's why I think it's important to be able to routinely
monitor the noise level at the site
Yes, CP does cause more multipath esp. in urban environments.
Turns out there are a large number of buildings the
preferentially reflect V better than H. CP gives V energy
othwise lacking (mostly) in a strictly H xmt situation. What
you get with strictly H pol. is quite a glorious
WN3J wrote:
No, it was WN3A that wrote that. A as in agitator :-)
It wasn't until car
radios with vertical whip antennas started to gain
popularity did vertical
polarization start to become important, and CP resulted as a
solution to
satisfy listeners using either horizontal or
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