Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a Grundig G5receiver
If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz (1050 kHz to 1419 kHz) the 900 kHz carrier image. Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz WVXX -AM 210 kHz = 1110 kHz WYRM-AM 330 kHz = 1230 kHz WJOI -AM 410 kHz = 1310 kHz WGH-AM 450 kHz = 1350 kHz WGPL -AM 500 kHz = 1400 kHz WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. |
#2
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a GrundigG5 receiver
On Mar 26, 1:56*pm, gccradioscience wrote:
If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz * (1050 kHz to 1419 kHz) *the 900 kHz carrier image. * Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. * The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . * * * I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz *WVXX -AM 210 kHz = 1110 kHz *WYRM-AM 330 kHz = 1230 kHz *WJOI -AM 410 kHz = 1310 kHz *WGH-AM 450 kHz = 1350 kHz *WGPL -AM 500 kHz = 1400 kHz *WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. You are seeing a problem that is common to many inexpensive radios. If you tune down 900khz from a strong nighttime station on the 6mhz band you will hear image signals too. The solution is to pay more for a better designed radio. |
#3
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a Grundig G5 receiver
Radioguy wrote:
On Mar 26, 1:56Â*pm, gccradioscience wrote: If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz Â* (1050 kHz to 1419 kHz) Â*the 900 kHz carrier image. Â* Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. Â* The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . Â* Â* Â* I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz Â*WVXX -AM 210 kHz = 1110 kHz Â*WYRM-AM 330 kHz = 1230 kHz Â*WJOI -AM 410 kHz = 1310 kHz Â*WGH-AM 450 kHz = 1350 kHz Â*WGPL -AM 500 kHz = 1400 kHz Â*WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. You are seeing a problem that is common to many inexpensive radios. If you tune down 900khz from a strong nighttime station on the 6mhz band you will hear image signals too. The solution is to pay more for a better designed radio. Problems like this come from two problems. On some radios, the ferrite antenna used for AM and longwave is not tuned and therefore provides no selectivity that can provide image rejection. This is combined with first IF filters that do not have high ultimate rejection. If ultimate rejection of the first IF is only 30-40 dB, then that is all the image rejection you will see. (What matters here is the rejection of signals 900 kHz away from the center of the filter's passband. |
#4
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a GrundigG5 receiver
Radioguy wrote:
On Mar 26, 1:56 pm, gccradioscience wrote: If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz (1050 kHz to 1419 kHz) the 900 kHz carrier image. Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz WVXX -AM 210 kHz = 1110 kHz WYRM-AM 330 kHz = 1230 kHz WJOI -AM 410 kHz = 1310 kHz WGH-AM 450 kHz = 1350 kHz WGPL -AM 500 kHz = 1400 kHz WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. You are seeing a problem that is common to many inexpensive radios. If you tune down 900khz from a strong nighttime station on the 6mhz band you will hear image signals too. The solution is to pay more for a better designed radio. Or build a preselector for $20 |
#5
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a GrundigG5 receiver
On Mar 27, 6:26*am, dave wrote:
Radioguy wrote: On Mar 26, 1:56 pm, gccradioscience wrote: If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz * (1050 kHz to 1419 kHz) *the 900 kHz carrier image. * Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. * The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . * * * I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz *WVXX -AM 210 kHz = 1110 kHz *WYRM-AM 330 kHz = 1230 kHz *WJOI -AM 410 kHz = 1310 kHz *WGH-AM 450 kHz = 1350 kHz *WGPL -AM 500 kHz = 1400 kHz *WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. You are seeing a problem that is common to many inexpensive radios. If you tune down 900khz from a strong nighttime station on the 6mhz band you will hear image signals too. The solution is to pay more for a better designed radio. - - Or build a preselector for $20 - GCCRS, Or simply Buy a Ready-Made one and use it with a 35~60 Foot long Random Wire {Longwire} Antenna MFJ-956 : Long Wave, AM/BCB Medium Wave and Shortwave Bands Pre-Selector : 150 kHz ~ 30 MHz http://www.universal-radio.com/catal...amps/2964.html http://www.universal-radio.com/catal...s/2964band.jpg idtars ~ RHF |
#6
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a GrundigG5 receiver
On Mar 28, 7:04 am, RHF wrote:
On Mar 27, 6:26 am, dave wrote: Radioguy wrote: On Mar 26, 1:56 pm, gccradioscience wrote: If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz (1050 kHz to 1419 kHz) the 900 kHz carrier image. Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz WVXX -AM 210 kHz = 1110 kHz WYRM-AM 330 kHz = 1230 kHz WJOI -AM 410 kHz = 1310 kHz WGH-AM 450 kHz = 1350 kHz WGPL -AM 500 kHz = 1400 kHz WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. You are seeing a problem that is common to many inexpensive radios. If you tune down 900khz from a strong nighttime station on the 6mhz band you will hear image signals too. The solution is to pay more for a better designed radio. - - Or build a preselector for $20 - GCCRS, Or simply Buy a Ready-Made one and use it with a 35~60 Foot long Random Wire {Longwire} Antenna MFJ-956 : Long Wave, AM/BCB Medium Wave and Shortwave Bands Pre-Selector : 150 kHz ~ 30 MHzhttp://www.universal-radio.com/catalog/preamps/2964.htmlhttp://www.universal-radio.com/catalog/preamps/2964band.jpg idtars ~ RHF . Why should I buy something that cost $60.00 for longwire I cannot not even put up in an apartment????? RHF, I live in a apartment for now best thing I was going to do with the preselector is use it with a KA-35 antenna to eliminate images. I don't have no way for a good alternative to an RF ground. Plus I am not on the second floor elevation for to use outdoor active antennas. If placed outdoor antennas they would be vandalized. gccengineering |
#7
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a GrundigG5 receiver
gccradioscience wrote:
On Mar 28, 7:04 am, RHF wrote: On Mar 27, 6:26 am, dave wrote: Radioguy wrote: On Mar 26, 1:56 pm, gccradioscience wrote: If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz (1050 kHz to 1419 kHz) the 900 kHz carrier image. Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz WVXX -AM 210 kHz = 1110 kHz WYRM-AM 330 kHz = 1230 kHz WJOI -AM 410 kHz = 1310 kHz WGH-AM 450 kHz = 1350 kHz WGPL -AM 500 kHz = 1400 kHz WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. You are seeing a problem that is common to many inexpensive radios. If you tune down 900khz from a strong nighttime station on the 6mhz band you will hear image signals too. The solution is to pay more for a better designed radio. - - Or build a preselector for $20 - GCCRS, Or simply Buy a Ready-Made one and use it with a 35~60 Foot long Random Wire {Longwire} Antenna MFJ-956 : Long Wave, AM/BCB Medium Wave and Shortwave Bands Pre-Selector : 150 kHz ~ 30 MHzhttp://www.universal-radio.com/catalog/preamps/2964.htmlhttp://www.universal-radio.com/catalog/preamps/2964band.jpg idtars ~ RHF . Why should I buy something that cost $60.00 for longwire I cannot not even put up in an apartment????? RHF, I live in a apartment for now best thing I was going to do with the preselector is use it with a KA-35 antenna to eliminate images. I don't have no way for a good alternative to an RF ground. Plus I am not on the second floor elevation for to use outdoor active antennas. If placed outdoor antennas they would be vandalized. gccengineering MFJ makes a combination active antenna/amplifier/preselector that may be perfect for you. I forget the model #. |
#8
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a Grundig G5 receiver
What you are seeing are 3rd order intermodulation products that are being
generated in your 1st mixer. If you will notice, the frequencies that you are hearing the stations on are mathematically related to the station minus 900kHz. The way that you can eliminate them is to use a low-pass filter that cuts off at 500kHz at the antenna input of your receiver. Some of today's receivers use a 1MHz low-pass filter as the first preselector range. Not a good idea, since in the Chicago area, you can get 3rd order mixing products from WGN 720 mixing with WBBM 780, with a resultant on 60kHz. Another example would be WGN 720 mixing with WIND 560. The resultant product would be 720 - 560, or 220kHz. Please note that the 3rd order IMD products are not only difference frequencies, but you can also have the sum of the two frequencies showing up as an upper sideband in addition to the lower sideband that manifests itself in the LW band. That other fellow's post about the (2 X 450kHz) image was a good suggestion, but in this case, you are encountering 3rd order mixing products. Two solutions...............use band limit filters ahead of the receiver's front end, or use a mixer that requires a much higher LO injection level. A diode ring mixer or some kind of FET switching mixer will fill the bill here. The key is having a high enough LO injection level in this case, so that the LO is actually turning on and switching the devices in the mixer instead of the signal that appears at the RF port of the mixer. This is one of the things that you pay for when you purchase a more expensive communications receiver. In the old days, this problem wasn't really an issue, since receivers of that time either used a tracking front end that had a multiple gang tuning capacitor that would tune the input circuits as you varied the frequency...........or, they had a separate preselector control that you would peak to the desired frequency. I hope this helps. Pete "gccradioscience" wrote in message ... If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz (1050 kHz to 1419 kHz) the 900 kHz carrier image. Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz WVXX -AM 210 kHz = 1110 kHz WYRM-AM 330 kHz = 1230 kHz WJOI -AM 410 kHz = 1310 kHz WGH-AM 450 kHz = 1350 kHz WGPL -AM 500 kHz = 1400 kHz WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. |
#9
|
|||
|
|||
900 kHz Image Problem with the Longwave Bands even on a GrundigG5 receiver
gccradioscience wrote:
If you live in a city area or some rural area with a real strong AM station its likely it will be found on the longwave bands from 150 to 519 kHz (1050 kHz to 1419 kHz) the 900 kHz carrier image. Please understand that this station is not a real longwave radio station. Its a image from the broadcast station when the station is strong enough to bleed on other longwave frequencies. The radios that I have is the DX-380, DX-390, DX-392 and the yes the new Grundig G5. It has do something with the dual conversion circuitry . I am hoping that manufactuers, hobbyists, and technicians will use the 900 kHz formula to see other image stations to show that these AM stations should not be on the LW bands. Desired AM Station (kHz) - 900 kHz = Image Station The images I am getting here locally in Virginia Beach, VA on LW is 150 kHz = 1050 kHz WVXX -AM 210 kHz = 1110 kHz WYRM-AM 330 kHz = 1230 kHz WJOI -AM 410 kHz = 1310 kHz WGH-AM 450 kHz = 1350 kHz WGPL -AM 500 kHz = 1400 kHz WPCE-AM AM Band Images that are annoying 550 kHz = 1450 kHz 650 kHz = 1550 kHz Adam E. It's a single-conversion phenomenom usually. Two times the IF, + or - the FOI. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
This group is a mirror image of the ham bands. | Policy | |||
This group is a mirror image of the ham bands. | General | |||
This group is a mirror image of the ham bands. | Policy | |||
This group is a mirror image of the ham bands. | General | |||
This group is a mirror image of the ham bands. | Policy |