Re: [Repeater-Builder] db comparisons
Well since were tossing cents here, no 3DB will not give you twice the range, and I will tell you why. I have two antenna's here at the shack, one is a 3 DB gain and the other a 6 DB gain, in preperation of changing the tower for the repeater, I set the repeater on the 3db gain antenna, and no difference, maybe a mile or two. What is even harder for guys to understand, the 6 DB was at 65 feet and the 3db is only at 45 feet. SO even the 20 feet in height did not make a difference. To see a difference, I would have to double the height of the antenna, and that would not double the gain in distance because now I have additonal cable and a different ground pattern. If you want distance, I have to agree with most other Hams, use remote receiver sites. Just my two cents worth, I'd give more, but I am in the poorest county in the state of Indiana. Mathew An old adage given to me by an old timer 20 or 30 years ago is worth mentioning here (I think), "Doubling the height of the antenna reaps you more benfits in terms of range than squaring the output power (ERP)". my 2 cents to the discussionmch wrote: No, it won't. 3dB will give you 1 s-unit increase and slightly more range, but nowhere near double. Joe M. ian wells wrote: just a quick question can anyone give a idea of difference of range when swaping a 6db base ant to a 9 db ant. would it be close to 2x the range in kms Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Re: [Repeater-Builder] db comparisons
One big question? Is every thing rated the same? I.E.: dbd? Not mixed and matched I.E.: dbd/dbi and yes even dbcsmile 73 Russ, W3CH - Original Message - From: Mathew Quaife To: Repeater-Builder@yahoogroups.com Sent: Sunday, August 29, 2004 8:56 AM Subject: Re: [Repeater-Builder] db comparisons Well since were tossing cents here, no 3DB will not give you twice the range, and I will tell you why. I have two antenna's here at the shack, one is a 3 DB gain and the other a 6 DB gain, in preperation of changing the tower for the repeater, I set the repeater on the 3db gain antenna, and no difference, maybe a mile or two. What is even harder for guys to understand, the 6 DB was at 65 feet and the 3db is only at 45 feet. SO even the 20 feet in height did not make a difference. To see a difference, I would have to double the height of the antenna, and that would not double the gain in distance because now I have additonal cable and a different ground pattern. If you want distance, I have to agree with most other Hams, use remote receiver sites. Just my two cents worth, I'd give more, but I am in the poorest county in the state of Indiana. Mathew An old adage given to me by an old timer 20 or 30 years ago is worth mentioning here (I think), "Doubling the height of the antenna reaps you more benfits in terms of range than squaring the output power (ERP)". my 2 cents to the discussionmch wrote: No, it won't. 3dB will give you 1 s-unit increase and slightly more range, but nowhere near double. Joe M. ian wells wrote: just a quick question can anyone give a idea of difference of range when swaping a 6db base ant to a 9 db ant. would it be close to 2x the range in kms Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Re: [Repeater-Builder] db comparisons
Quick answer -- no. Expanding on this -- you will barely be able to detect a difference. Chuck WB2EDV - Original Message - From: ian wells [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Saturday, August 28, 2004 4:27 AM Subject: [Repeater-Builder] db comparisons just a quick question can anyone give a idea of difference of range when swaping a 6db base ant to a 9 db ant. would it be close to 2x the range in kms Thank you Ian Wells Kerinvale Comaudio mail service 1017, Biloela,4715. www.kerinvalecomaudio.com.au 1-email- [EMAIL PROTECTED] 2-email- [EMAIL PROTECTED] 3-email- [EMAIL PROTECTED] Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] db comparisons
On Sat, 28 Aug 2004 18:27:45 +1000 ian wells [EMAIL PROTECTED] writes: can anyone give a idea of difference of range when swaping a 6db base ant to a 9 db ant. would it be close to 2x the range in kms In theory, +3dB gets about 40% range increase; to double requires +6dB. Remember your geometry lessons for area of a circle (Pi R^2) ? Imagine maintaining a minimum depth of a water puddle, as the puddle grows in size.. Substitute minimum usable signal level... Simple example: Say your existing setup gives 10-km range (radius) - that's 314-km^2 of usable signal coverage area. Double the ERP (+3dB) increases the usable area to 628-km^2 -- about 14-km range. At 20-km range, the coverage area is 1256-km^2 -- 4x what you started from; hence +6dB. In Theory And a perfect world. YM(K?)MV. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] db comparisons
No, it won't. 3dB will give you 1 s-unit increase and slightly more range, but nowhere near double. Joe M. ian wells wrote: just a quick question can anyone give a idea of difference of range when swaping a 6db base ant to a 9 db ant. would it be close to 2x the range in kms Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] db comparisons
An old adage given to me by an old timer 20 or 30 years ago is worth mentioning here (I think), "Doubling the height of the antenna reaps you more benfits in terms of range than squaring the output power (ERP)". my 2 cents to the discussion mch wrote: No, it won't. 3dB will give you 1 s-unit increase and slightly more range, but nowhere near double. Joe M. ian wells wrote: just a quick question can anyone give a idea of difference of range when swaping a 6db base ant to a 9 db ant. would it be close to 2x the range in kms Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Re: [Repeater-Builder] db comparisons
To which I agree. Location of antennais the number one criteria for system coverage, bar none (assuming all system components are quality and working as specified). In FM mobile service, a difference in 6 dB is usually just barely perceivable by most users. Now, I'm talking about out in the field and just listening to the signal -- no meters, just your ear. Chuck Kelsey WB2EDV - Original Message - From: Tom Parker To: Repeater-Builder@yahoogroups.com Sent: Saturday, August 28, 2004 12:39 PM Subject: Re: [Repeater-Builder] db comparisons An old adage given to me by an old timer 20 or 30 years ago is worth mentioning here (I think), "Doubling the height of the antenna reaps you more benfits in terms of range than squaring the output power (ERP)". my 2 cents to the discussion Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
RE: [Repeater-Builder] db comparisons
In theory, +3dB gets about 40% range increase; to double requires +6dB. In theory, yes, but your coverage is usually limited not by the inverse-square law (unless you're really running flea power), it's by terrain and earth curvature, so in reality, 3 dB increase in ERP usually provides only a minimal increase in usable service area. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] db comparisons
OK - you're talking about adding other factors (road noise). I was talking about the home use or a controlled environment where the signal strength and the user's ear were the only factors. I guess around diesels, it would take 12 dB to notice any difference. ;- Joe M. Chuck Kelsey wrote: Yes, that's what the book says. However, I'm talking about someone out in a mobile environment where you have many other factors in play, including ambient road noise. Most people are hard pressed to be able to notice a 6 dB change under those conditions. Since we are talking repeaters here, most of our users are on a mobile or HT, outside of a quiet, stable environment. Usually moving a couple of inches or feet is going to make way more difference than 6 dB. That's my real world take anyway. Base station to base station with antennas mounted in the clear and a quiet shack, you'll probably be able to hear 3 dB, assuming you are not already full quieting. Chuck WB2EDV - Original Message - From: mch [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Saturday, August 28, 2004 1:59 PM Subject: Re: [Repeater-Builder] db comparisons I've always been taught and read that a 3dB increase (or decrease) is the point at which the user can first notice that the signal has changed. You can gain 3dB by either doubling your power (or ERP), or by doubling the antenna height. Of course, this does not take hills into account where your height doubling just happens to clear a hill. This assumes that your antenna is in flat land or above the hills (or trees). Joe M. [EMAIL PROTECTED] wrote: In FM mobile service, a difference in 6 dB is usually just barely perceivable by most users. Now, I'm talking about out in the field and just listening to the signal -- no meters, just your ear. Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] db comparisons
--- Chuck Kelsey [EMAIL PROTECTED] wrote: Yes, that's what the book says. However, I'm talking about someone out in a mobile environment where you have many other factors in play, including ambient road noise. Most people are hard pressed to be able to notice a 6 dB change under those conditions. Since we are talking repeaters here, most of our users are on a mobile or HT, outside of a quiet, stable environment. Usually moving a couple of inches or feet is going to make way more difference than 6 dB. That's my real world take anyway. That seems to be my real world also. I have not seen that much maximum range as the the power or antenna gain goes up but it does seem to fill in some of the local holes beter. In the 70's there were some 6 foot long whips for 2 meters. If you could stop the car you would usually get slightly beter range or signal. While in motion they flopped around so much the 1/4 wave whips would out range them. A good stiff antenna would out range the floppy ones that were longer and had more gain. The area I am in (North Carolina) is full of low hills. The repeaters were usually about 300 to 800 feet HAAT at the time. We did some antenna changeing on the same car and it depended on the direction the car was facing and the repeater as to what gave a beter signal. Sometimes the 1/4 wave beat the others. On one repeater a 40 meter antenna mounted on the bumper beat all the others. __ Do you Yahoo!? Yahoo! Mail is new and improved - Check it out! http://promotions.yahoo.com/new_mail Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] db comparisons
I've always been taught and read that a 3dB increase (or decrease) is the point at which the user can first notice that the signal has changed. You can gain 3dB by either doubling your power (or ERP), or by doubling the antenna height. Of course, this does not take hills into account where your height doubling just happens to clear a hill. This assumes that your antenna is in flat land or above the hills (or trees). Joe M. [EMAIL PROTECTED] wrote: In FM mobile service, a difference in 6 dB is usually just barely perceivable by most users. Now, I'm talking about out in the field and just listening to the signal -- no meters, just your ear. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] db comparisons
Yes, that's what the book says. However, I'm talking about someone out in a mobile environment where you have many other factors in play, including ambient road noise. Most people are hard pressed to be able to notice a 6 dB change under those conditions. Since we are talking repeaters here, most of our users are on a mobile or HT, outside of a quiet, stable environment. Usually moving a couple of inches or feet is going to make way more difference than 6 dB. That's my real world take anyway. Base station to base station with antennas mounted in the clear and a quiet shack, you'll probably be able to hear 3 dB, assuming you are not already full quieting. Chuck WB2EDV - Original Message - From: mch [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Saturday, August 28, 2004 1:59 PM Subject: Re: [Repeater-Builder] db comparisons I've always been taught and read that a 3dB increase (or decrease) is the point at which the user can first notice that the signal has changed. You can gain 3dB by either doubling your power (or ERP), or by doubling the antenna height. Of course, this does not take hills into account where your height doubling just happens to clear a hill. This assumes that your antenna is in flat land or above the hills (or trees). Joe M. [EMAIL PROTECTED] wrote: In FM mobile service, a difference in 6 dB is usually just barely perceivable by most users. Now, I'm talking about out in the field and just listening to the signal -- no meters, just your ear. Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
