Re: [Repeater-Builder] DB224 Antennas
One thing that is over looked when moding a multi-bay antenna such as the 4 bay folded dipole array is the interbay spacing. Depends on who made the antenna, but this should be either 1 free space wavelength or 1/2 of a wave. Changing the element sizes will improve SWR, but without changing the bay spacing you change the electrical beam tilt of the antenna (your "pancake"). This may be useful in valley or on a mountain, but generally not ok for plains. Also don't forget that the phasing harness needs to be resized too, you will need to know the velocity factor of the coax you are working with in order to do this. Instead of all that, I can honestly recommend you try the Tram 1491. Avalible from Repeater-Builder.com through Zimmerman Electronics. http://www.repeater-builder.com/products/VHFantennas.html We put ours up on the 146.64 repeater over the weekend and the repeater works hella-good now. The "cutting chart" was a little lacking in information, only giving 2MHz increments, but some dead reconing and averaging was used to cut the antenna for 146.5. With pwr adjusted for 50W fwd we had approx 200mW reflected. The antenna has a price that can not be beat which will not break anyones budget. I was going to rebuild a station master clone but the cost of the RG-11, brass, epoxy, hot glue, torch to do so out weighed buying the Tram. 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] DB224 Antennas
I just got a good comparison on the DB224, and my Diamond 500 antenna. FOr kick sakes I had a guy about 35 miles from the repeater in a mobile giving about 25 watts out. WIth the DB224, originally designed for the 150-160 Mhz split, VSWR of 1.8:1, at 130' in the air, fed with 150' of 7/8" hardline he was full quieting into the system, claimed there was just a little noise on the repeater, but full scale. I then switched to the Diamond antenna, fed with 160' of 7/8" hardline, up at 92', he lost one bar on the meter and had just a little noise in his signal. I can only think that if the diamond, which has a VSWR of 1.2:1 were at 130' it would out perform the DB224. So if I had a DB224 cut for the ham bands, it would only again out perform the Diamond antenna. So I agree, for $50.00, yes get the antenna that is cut for the ham band. Plans are to purchase a new Antenna this year for the repeater. So if I may ask, what was the price quoted for a new DB224 antenna for the 138-150 Mhz range? Mathew Chuck Kelsey <[EMAIL PROTECTED]> wrote: I believe the down tilt issue only happens with the fiberglass antennas.ChuckWB2EDVwa9ba wrote:> Our new antenna is 1.:1 on > 145.490 and the coverage has increased about 10 or 20 miles. > Apparently we had some downtilt that we no longer have. > I would recommend buying a DB224 cut for the ham bands first, save > yourself trouble.> Bill WA9BA>> 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! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less. YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. 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] DB224 Antennas
I believe the down tilt issue only happens with the fiberglass antennas. Chuck WB2EDV wa9ba wrote: > Our new antenna is 1.:1 on > 145.490 and the coverage has increased about 10 or 20 miles. > Apparently we had some downtilt that we no longer have. > I would recommend buying a DB224 cut for the ham bands first, save > yourself trouble. > Bill WA9BA > > 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/
[Repeater-Builder] DB224 Antennas
Message 4 From: "Chappy" [EMAIL PROTECTED] Date: Thu Apr 6, 2006 9:07pm(PDT) Subject: DB-224 versions We plan to buy a new DB-224 antenna for 146.34/94. We notice the "popular" model covers 150-160 MHz. Also available is a model covering 138-150 MHz, for about $50 more. I've heard many times that the 150-160 model covers 2 meters just fine. In fact we have a DB-264 with 150-160 MHz specs and it seems OK. Is it worth it to look for the 138-150 MHz version ? Thanks -- kd4ss We have had both versions 224b and BD224 E (If I remember the variations correctly) Thw first one we bought at a hamfest, it was cut for 150 to 170 Mhz, we had a SWR of about 1.8:1 after we modified it for 145.49 by adding 1 5/8 inches to each loop. It worked well for about 4 or 5 years, then we started having a few problems with noise. We finally bit the bullet and bought a new one from Primus (no I don't work for them etc). They give ham clubs a discount which amounts to to the wholesale price charged dealers. Our new antenna is 1.:1 on 145.490 and the coverage has increased about 10 or 20 miles. Apparently we had some downtilt that we no longer have. I would recommend buying a DB224 cut for the ham bands first, save yourself trouble. Bill WA9BA 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/
