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KI6LQE
02-08-2008, 11:50 PM
I was just spinning the VFO last night looking for anything interesting to listen to and when I tried the freqís. for 11 meters I canít pick up anything on my HF rig. I tried AM, USB & LSB (I donít have the FM card installed). With all the folks jamming up the CB band I thought I would hear something.

Using a 20 M dipole. Tried my G5RV but no difference. I think the 20 M dipole should be sufficient for just monitoring. Switching the rig to ďGENĒ receive also made no difference.

My rig is a Yaesu FT-840 with the MARS/CAP mod.

Please no one say buy a CB I only want to know why I canít hear anything when I can scan the freq.ís. I am not looking to transmit or convert my rig.


Any comments or suggestions are appreciated.

Bruce
KI6LQE

WA2ZDY
02-08-2008, 11:54 PM
The 20m dipole is nearly a full wave at 11m so the mismatch would be horrific. That said, 11m is not quite as busy as one might think. Down here in Florida, there are a LOT of cb antennas on cars and pickup trucks, yet the band is dead here for the most part.

You should probably be thankful your ears were spared!

KB3LIX
02-08-2008, 11:55 PM
Consider yourself...........FORTUNATE !

;)

NN4RH
02-08-2008, 11:57 PM
Night during a sunspot minimum isn't the greatest time to pick up distant signals on the upper HF bands.

Plus with a horizontal antenna, your receive is going to be 20 dB down trying to listen to any local CB signals - CBers generally use vertical antennas.

And maybe nobody was transmitting.


Oh and I also have an FT-840 (but not modified for 'extree channels') and I can hear plenty of CB chatter on mine 24x7 whenever I tune around there. But I live less than half a mile from Interstate 95 so I'm picking up the truckers and I have a vertical antenna.

One thing about the FT-840 - it's deaf as a hammer on AM mode. In my opinion. And most of your CBers are AM. Much MUCH better reception on my Kenwood TS-480.

W9GB
02-09-2008, 12:09 AM
When I tuned to 11 meters (Citizens Band), I can’t pick up anything on my HF rig.
Bruce -

Lesson One
A question that needs to be added to those memorize the test answer web sites and booklets.
Polarization matters. Remember polarized sunglasses? You can see better?

For radio, the difference is 20 dB. In other words, if you antenna is horizontally polarized -- and a vertically polarized signal is trying to be received -- that is equivalent to placing a 20 dB attenuator in front of your receiver!

CB operators use vertically polarized antennas (semi-trucks, mobiles and most base stations) .... and many amateur radio fixed stations use horizontally polarized antennas (beams/yagi, dipoles, etc.) from 20 meters through 10 meters.

Yes, the "bounces" off the ionosphere can minimize some of this polarization effect.

How many HF amplifiers do you think are sold .. due to not understanding this concept?? Wow, you mean it was my antenna?

w9gb

AG3Y
02-09-2008, 12:09 AM
I've always kind of wondered why the receiver portion of a transceiver HAS the capability of receiving DSB AM. Using a standard product detector set to either LSB or USB, you can zero beat an AM station just fine, and if anything, the signal will actually be easier to copy than it is with the standard diode detector! It does take some skill to do this, of course, and maybe that is why most modern sets do have the capability of defeating the product detector and receiving AM with a standard diode detector.

Try it some day, and see if the signal doesn't pop out of the background!

73, Jim

N8YX
02-09-2008, 12:11 AM
I've always kind of wondered why the receiver portion of a transceiver HAS the capability of receiving DSB AM. You can zero beat an AM station just fine, and if anything, the signal will actually be easier to copy than it is with a standard diode detector! It does take some skill to do this, of course, and maybe that is why most modern sets do have the capability of defeating the product detector and receiving AM with a standard diode detector.

Try it some day, and see if the signal doesn't pop out of the background!

73, Jim


And it'll work right up until the first off-frequency station shows up...annoying heterodynes and all...

AG3Y
02-09-2008, 12:15 AM
And it'll work right up until the first off-frequency station shows up...annoying heterodynes and all...


That's what a VFO is for ! ! ! :p

You get just as many hetrodynes with two AM carriers in there, as you do with a Product detector! Do you remember, or did you ever hear how the bands used to sound before SSB became popular? Cacophony ! ! !

73, Jim

KA4DPO
02-09-2008, 12:29 AM
I was just spinning the VFO last night looking for anything interesting to listen to and when I tried the freqís. for 11 meters I canít pick up anything on my HF rig. I tried AM, USB & LSB (I donít have the FM card installed). With all the folks jamming up the CB band I thought I would hear something.

Using a 20 M dipole. Tried my G5RV but no difference. I think the 20 M dipole should be sufficient for just monitoring. Switching the rig to ďGENĒ receive also made no difference.

My rig is a Yaesu FT-840 with the MARS/CAP mod.

Please no one say buy a CB I only want to know why I canít hear anything when I can scan the freq.ís. I am not looking to transmit or convert my rig.


Any comments or suggestions are appreciated.

Bruce
KI6LQE


You obviously have a very tasteful radio. :D

N8YX
02-09-2008, 12:38 AM
That's what a VFO is for ! ! ! :p

You get just as many hetrodynes with two AM carriers in there, as you do with a Product detector! Do you remember, or did you ever hear how the bands used to sound before SSB became popular? Cacophony ! ! !

73, Jim

It's a LOT worse when passed through a product detector. Given a conversation with, say, three people...all of whom are off frequency by different amounts...one is going to find the experience to be very tiresome.

At times like this I'll reach for one of my R7s or TR7s...turn off the set's BFO and engage the 4, 6 or 8KHz filters...then tune the PBT control for optimum clarity. Unless everyone is exactly on frequency, it's no fun listening to them with an SSB set.

SWBC is another matter entirely. When I'm prowling the 90M SW segment, for example, I use SSB detection almost exclusively. Makes it a LOT easier to dig out the weak ones.

CT2JUT
02-09-2008, 01:09 AM
I was just spinning the VFO last night looking for anything interesting to listen to and when I tried the freqís. for 11 meters I canít pick up anything on my HF rig. I tried AM, USB & LSB (I donít have the FM card installed). With all the folks jamming up the CB band I thought I would hear something.

Using a 20 M dipole. Tried my G5RV but no difference. I think the 20 M dipole should be sufficient for just monitoring. Switching the rig to ďGENĒ receive also made no difference.

My rig is a Yaesu FT-840 with the MARS/CAP mod.

Please no one say buy a CB I only want to know why I canít hear anything when I can scan the freq.ís. I am not looking to transmit or convert my rig.


Any comments or suggestions are appreciated.

Bruce
KI6LQE



Hello Bruce!

I have finally found someone using the same rig as me!!! LoL :)

I guess that we need to go for a QSO, as i donīt want to kill HF anyway! ;)

But regarding your problem, which may not be... The CB bands are almost dead around here aswell (Portugal).

I have nothing against them, but i hear a lot of nonsense on the 11m about radios, propagation, antennas, etc... So i decided not to hear them!

Although my transceiver is fully unlocked, and sometimes i just get in touch with a friend of mine to save up the phone bill (expensive rates over here).

Before i came into the HAM business i was a really broadcasting dxīr. And that have never died.

So i decided to buy the optional filters for the rig (CW and AM), also the FM board which works great! :)

And YES! The AM filter made a huge difference for AM broadcasting listening, and also for the CB band! As the filter is quite expensive i suggest you not to buy it for listening to CB band! LoL Itīs like a crime for me, i only use it to pick up AM broadcasting.

Also remember that CB band has now SSB modes working, mainly LSB here.

My antenna is also an array of horizontal wire dipoles, verticaly aligned. The FC-10 ATU selects the better way to match each band.

I can pick up very easily far CB stations, and also TX on the band without any issue.

I guess that there is nothing wrong with your rig!

By the way, do you have the FC-10?

If you have some electronic skills, i can tell you a couple of tricks to get the best of the FT-840! :)


Regards from Portugal!

Miguel

W4INF
02-09-2008, 04:28 AM
<hangs head>Are you sure your a general class operator? Now Im embarrassed to be called a general</hangs head>

W6TMI
02-09-2008, 05:54 AM
I spin through CB as well sometimes, and I've got a verticale mag loop tunable through 10 meters, I hear 2 guys talking to each other on 1 channel (I forget which - it's been a few months that I have done this) other then that, it's pretty dead, I hear some truckers now and then.

At least around here the thing is pretty dead.

KI6LQE
02-09-2008, 06:16 AM
<hangs head>Are you sure your a general class operator? Now Im embarrassed to be called a general</hangs head>

Thanks to all who responded with an answer to my question.


W4INF
Yes, I am sure I am a general class operator. Sorry to embarrass you with my question. I see you are one of the forumites who needs to give your negative two cents worth rather than just not answer if you think a "General" should already know this.

I was wondering if I should even post my question thinking I would get a response like yours but the only stupid question is the one not asked. So I asked anyway. Great way to encourage new hams.

KI6LQE

W8ZNX
02-09-2008, 10:15 AM
I've always kind of wondered why the receiver portion of a transceiver HAS the capability of receiving DSB AM. Using a standard product detector set to either LSB or USB, you can zero beat an AM station just fine, and if anything, the signal will actually be easier to copy than it is with the standard diode detector! It does take some skill to do this, of course, and maybe that is why most modern sets do have the capability of defeating the product detector and receiving AM with a standard diode detector.

Try it some day, and see if the signal doesn't pop out of the background!

73, Jim

no not at all
AM on a good multi mode receiver
like a 2A, A4, 115, 101, sounds much better
with the mode switch in the AM pos

listening to am using exalted carrier sounds like (blank)
use it only under battle conditions

when using a xceiver like the FT-102 on AM
im not about to crank on the mode switch
when going between receive and transmit

8YX
is right
in any kind of round table you will spend all your
time cranking on the main tuning knob

ever try to copy the Tim Tron's sbe rig
using exalted carrier

mac

2E0RPS
02-09-2008, 11:32 AM
by experience on 11m i hear few CB's station from time to time however you need to be on FM mode.

W0UZR
02-09-2008, 12:11 PM
Can I trade you even up?

All my HF gets is CB

N8YX
02-09-2008, 01:16 PM
by experience on 11m i hear few CB's station from time to time however you need to be on FM mode.

In territories outside the U.S....yes...but our CB service is limited to AM/SSB only.

N8YX
02-09-2008, 01:16 PM
Can I trade you even up?

All my HF gets is CB

Try going below .100 some time.

W4HAY
02-09-2008, 01:30 PM
I live near I-81 and no better source for road conditions exists than Channel 19! In the evening the frequency will be dead, then suddenly come alive with chatter as a group of truckers pass. I think in bad weather they like to "convoy up" to cross the mountains.

At other times the channel will be a mass of hetrodynes.

I use my trap dipole, which is a pretty lousy match on 10 Meters anyway.

W4INF
02-10-2008, 03:22 AM
LQE, you know, your right. I know Ive asked some off the wall questions and you didn't deserve that reply.

Peace.
Andrew

AG3Y
02-10-2008, 04:16 AM
no not at all
AM on a good multi mode receiver
like a 2A, A4, 115, 101, sounds much better
with the mode switch in the AM pos

listening to am using exalted carrier sounds like (blank)
use it only under battle conditions

when using a xceiver like the FT-102 on AM
im not about to crank on the mode switch
when going between receive and transmit

8YX
is right
in any kind of round table you will spend all your
time cranking on the main tuning knob

ever try to copy the Tim Tron's sbe rig
using exalted carrier

mac

You know, Mac, I have an old Knight Space Spanner AMBC/SW receiver, which is essentially an "All American 5" with a transformer power supply, and multi-band tuning capability. I have to admit that when you tune it to an AM signal, it sounds better than my Icom 720a in ANY mode ! But I am willing to bet that that is because of the over 5khz IF bandpass, and the class A tube-type audio amplifier, which probably passes well above that, audio frequency-wise. Actually the thing sounds "hi-fidelity" in comparison to the less than 3khz bandpass of the SSB rig !

However, for communications purposes, I would NEVER trade the one receiver for the other! There is certainly a place for both types of receivers. I admit that the AM function in the Icom is a severe compromise when compared to a radio which was designed primarily for the mode. Of course, the Space Spanner is a severe compromise when it comes to SSB !

73, Jim

NA0AA
02-10-2008, 04:19 AM
I scan CB on my scanner from time to time but in my area there is little/no activity - once in a while I'll hear some guys who haul gravel shooting the breeze, but that's about it.

Don't forget that if you have a horizontally polarized antenna you lose 6 db plus or minus - most CB is vertically polarized.

AG3Y
02-10-2008, 04:40 AM
I scan CB on my scanner from time to time but in my area there is little/no activity - once in a while I'll hear some guys who haul gravel shooting the breeze, but that's about it.

Don't forget that if you have a horizontally polarized antenna you lose 6 db plus or minus - most CB is vertically polarized.


The number is more like 26dB more or less ! Considerable loss due to cross polarization. This is ground wave, of course. Skywave is more random in nature, so when the "skip" is in, a horizontal antenna will probably pick up those signals almost as good as a vertical would. ( CBers call it "working the flat side", if I recall correctly)

The reason verticals were the antenna of choice for Class "D" was the fact that mobiles were commonly set up that way, and a base station was commonly called upon to work to a mating mobile. I have seen horizontally polarized antennas used on cars in the past ( called a halo design ) but not at all commonly, if at all, on the HF bands. A halo for 6 meters is a BIG antenna !

73, Jim

W9GB
02-10-2008, 04:49 AM
Don't forget that if you have a horizontally polarized antenna you lose 6 db plus or minus - most CB is vertically polarized.
Courtesy of Dr. Jim Akers, W5VZF; Dept. of Electrical and Computer Engineering; Mississippi State University.

Loss (in DB) = 10*(log base 10)(cos(theta))^2

Where theta is the angle between the polarization vectors.
Therefore, if a Vertically Polarized antenna is used to copy a vertically polarized signal, the loss due to polarization is zero DB.

If they are at 90 degrees, Cross Polarized, the loss is INFINITE.
I have been able to demonstrate this to electrical and RF students, in the classroom, using 10 GHz equipment, an isolation of greater than 40 DB between vertical and horizontal polarizations. My equipment would only measure to -40 DB so I don't really know how far I could have gone with this.

In real life with reflections and Faraday rotation, etc., the loss would be less than whatever I could show in the classroom.

A great reference book for this is: "Antennas" 1st or 2nd edition by J.D. Kraus. This can be extended to CP waves and antennas as well. Look at the discussion on polarization by Kraus for a better understanding.

Just for grins, check the loss at 45 degrees :-)

N4AUD
02-10-2008, 05:24 AM
I've got a TS-570s and a horizontal loop, and I hear all kinds of activity on the CB frequencies. I live in a very rural area.
The op should be able to hear something on the CB band.

WA2ZDY
02-10-2008, 02:00 PM
GB is correct about theoretical cross-polarisation losses. The practical effects seem to lessen though. At microwaves, TV satellites transmit two distinct "channels" on the same frequency, one vertical and one horizontal. The satellite receiver switches between the two by switching only the polarity of the receive antenna.

At VHF I've generally heard the accepted figure for cross polarisation loss at 24dB. That's like having a 100w transmitter heard with the signal strength of a 1 watt transmitter outside of town.

Ionospheric propagation causes rotation of the wave so cross polarisation loss is no longer considered a practical issue.

I'm sure any errors I've made in my post will be corrected by others. I do apologise for not thinking of this factor in my original response to the question.

AG3Y
02-10-2008, 03:06 PM
The null between the correct polarization and the "cross polarization" is so deep and sharp at satellite frequencies, that there is a requirement that technicians must meet when setting up "DirecWay(tm)" two-way satellite internet service for a customer. It is called, simply enough the "cross-pol" test, and if the null is not set properly, the two-way system will not work properly !

Chris is right, however, that at HF frequencies, a true 24 or so dB difference is rarely experienced. But it certainly can be high enough on direct-wave transmissions that someone used the opposite polarization will probably never hear the other station.

73, Jim

KI6LQE
02-10-2008, 06:01 PM
LQE, you know, your right. I know Ive asked some off the wall questions and you didn't deserve that reply.

Peace.
Andrew


Andrew, W4INF

Thanks,

Bruce
KI6LQE

kd5kfl
02-10-2008, 06:46 PM
Regarding these posts about "20 db loss" and "Infinite loss"... with cross polarization.

At VHF and above, yes. At 30 MHz... - no.

N6HPX
02-10-2008, 09:25 PM
Did you try other radio's like a shortwave radio other than that particular radio and if so did you get the same results. I get some dx static at times even in my home in the Philippines.

73's and Happy dxing

Larry n6hpx/mm
enroute to KH2

K8ERV
02-10-2008, 09:45 PM
You obviously have a very tasteful radio. :D

Love it!!

TOM K8ERV Montrose Colo

KC2LNB
02-10-2008, 09:45 PM
Consider yourself...........FORTUNATE !

;)

"Yes" what he said

WA9CWX
02-10-2008, 10:06 PM
I was just spinning the VFO last night looking for anything interesting to listen to and when I tried the freq’s. for 11 meters I can’t pick up anything on my HF rig. I tried AM, USB & LSB (I don’t have the FM card installed). With all the folks jamming up the CB band I thought I would hear something.........
Any comments or suggestions are appreciated.

Bruce
KI6LQE

Yes....

Your radio knows what is best.....

Frank

G0GQK
02-10-2008, 10:43 PM
You should go down on your knees every night and give thanks that your rig is a deaf as a post on 11 metres.

G0GQK

AB8MA
02-10-2008, 10:55 PM
You should go down on your knees every night and give thanks that your rig is a deaf as a post on 11 metres.

G0GQK

Excellent QRZ pun.

KC9JIQ
02-10-2008, 11:40 PM
I got a Radio Shack DX-398, and a long wire. I usually listen to the guys on 1.919. I tried to compare it to my 1/4 wave home made vertical. NO CONTEST, I couldn't even *hear* any station on the longwire, but the vertical was hoping with activity.

W5HTW
02-11-2008, 02:19 AM
Some radios will receive 11 meters. However, usually after listening to it for more than about 11 seconds, they tend to throw up their 11 meter guts and there is just nothing you can do to make them go back. You can try re-installing the "Patented Pound Bucket" and maybe realign the "Little SWR's" circuit, but it probably won't work. You may can remove the name of your radio from the front panel, and create a label that reads "Swinging Skip Shooter Wadidio" and fool the radio briefly into receiving a signal. This is very dangerous, though, as the "wadidio" may never again work on the ham bands.

Ed

AC0FP
02-11-2008, 04:00 AM
My radio has never been subjected to signals from the 11 meter band.

As for attenuation to cross polarized signals. In the real world, on an antenna field strength range at VHF & UHF, the best attenuation I've ever been able to measure is 15 dB.

73,

Frank:)

KJ3N
02-11-2008, 05:18 AM
I canít hear 11 meters on my HF rig?

This is a problem how? ;) :D

W4GLM
02-11-2008, 04:56 PM
Truly a blessing in disguise.....Mac

VK2XXL
02-13-2008, 11:43 AM
His radio is alive. It has an intelligent mind!!!!!!!!!!!!!!!! Mwwwwaaaahaaaaaa!!!!!

CT2JUT
02-13-2008, 06:14 PM
You should be proud of your station not to get 11meter (CB band).

Yesterday i tried to be friendly in a channel with another operator.

He told me a bunch of "&&#$%&/#($/()" ofensive words...

Offensive talk on the entire CB band here in Portugal! And at the end, he said that it was his frequency for everyday work (trucker), i was wasnīt suppose to TX there.

What more to say???

KI6LQE
02-14-2008, 03:15 AM
Quite a response. I have written a letter of apology to my HF rig. Burned incense and sacrificed a Dukes of Hazard video.

I think this worked, as I was able to work South America on 20 meters.

All is well in HF land,

KI6LQE

Thanks everyone for all the antenna info

VE7DCW
02-14-2008, 04:05 AM
Quite a response. I have written a letter of apology to my HF rig. Burned incense and sacrificed a Dukes of Hazard video.

I think this worked, as I was able to work South America on 20 meters.

All is well in HF land,

KI6LQE

Thanks everyone for all the antenna info

....and don't forget to put a stake through that C.W. McCall recording,it will make sure that it won't rise again!:p

73

WZ9O
02-14-2008, 12:20 PM
I canít hear 11 meters on my HF rig?



Consider yourself lucky. Your radio has the highly-sought-after ďIDIOTĒ filter already installed in it.

:D

KC4UMO
02-14-2008, 12:40 PM
Quite a response. I have written a letter of apology to my HF rig. Burned incense and sacrificed a Dukes of Hazard video.

I think this worked, as I was able to work South America on 20 meters.

All is well in HF land,

KI6LQE

Thanks everyone for all the antenna info

cb + QRZ + ham operators = pile-up :p

VK4AGK
02-14-2008, 01:54 PM
This must be a bite!
More of a sitrep than anything else --- Out here near the black stump (yes there is one) , but looking at that i'll invite politics and type , near the gender/colour non specific stump , 27mhz is practically not used as in the old days , truckers ect all went to uhf cb , recently i drove 24,000 kilometers with a chook bander sitting on ch 8 am (the truckers channel) and 40 uhf (the other truckers) and heard 2 truckers just the "other" side of the gender/colour non specific stump talking on channel 8 , in 24,000 ks -6 months around vk!

And all this chook band stuff here in this thread , does no one listen to 80/40/20m :confused: , a troll , LoL , ryme..

I hear more on the ham? bands that should be on Chook bands , me included , as to contain the real words that want to pop out when one comes across them is very very hard , then i be the Bad one?..

Calling Cq Cq 80 or 40 and ya hear Qrz? , Duh? , just who is calling who aye! Then a "comment" for ignoring them/it , LoL .

= Chook band...

No SOP - sTANDARD oPERATING pROCEDURES any more ,

Only Intelligence! :rolleyes:

ps: i have grew up with 3bd loss via hf cross-polarization in brainbox , correct or not .

N8YX
02-14-2008, 01:55 PM
cb + QRZ + ham operators = pile-up :p

You left out "the 'Bowl" in that equation... ;)

KC9GUZ
02-15-2008, 02:51 AM
Hmmmmm a lot of snide, snotty, "I think im hoiler than thou because im a 20 WPM Extra class ham" typical ham responsed to a CB question, but YET no real straight answer to the original post!!!! HAHAH! Typical on QRZ!:D
BTH for the original poster dont be spourised that you dont hear much. CB is pretty dead in my area as well. All i ever hear is some chit chat on 19 from drivers looking for someof the local factoires and there are a few locals that run CH 30 and thats all folks!! When the next DX cycle starts we will hear all kinds of chatter!!!:rolleyes:

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