Hi Stranger, > "rfburnz" <rfpo...@...> wrote: > Having used the DB-212 for a 6M repeater project, I can assure > you they work extremely well (unless you are on a rf noisy > hilltop like I was (emphasize WAS!)
I measured about 11 dB of 53MHz desense at what I believe is the site you're talking about, which is better than the measured 13dB desense down at 42MHz. Although it's not great, it is quite usable. Let's put your six meter box back on the air... or do your ten meter box... > This is because they have more metal hanging out there to > capture signals (half wave) but more important they are a > side mtd antenna withe a cardioid pattern. I'm a strong believer in having more antenna real estate to improve what I informally call the available antenna surface area target, which gets even more important as the frequency gets into the UHF band (rises). A side mounted antenna will probably never be a true omni pattern and the cardioid pattern can be used to null problems and/or enhance coverage areas (the obvious). > Well, before someone pipes in, yes, for omnidirectional > coverage you need two or four or, if you have LOTS of tower > space, combine SIX of them like the 6M repeater in Nixa, > MO that I posted info on recently. I'm using modified Kreco and Sinclair SD-110 Antennas. > Here's a link to modification instructions on both the > DB-201 and DB-212 > http://www.xanaduu.com/db201/ Interesting... thanks. I just drew out the information for the 70 MHz Decibel Folded Dipole. I have to get that scanned into pdf to make it available but it will get done. > OT = If someone knows where a 37 MHz DB antenna might be > available please let me know, thanks > W6MTF I'm letting you know... you're overdue for a visit anyway. Email me direct when you get a spare moment. skipp > > --- In Repeater-Builder@yahoogroups.com, "Tyke" <tyke1954@> wrote: > > > > good morning Martin, > > > > Why not use a db-201 folded loop ground plane instead? It is half the > > length of the db-212 which needs at least 2 bays to be halfway decent. > > (they make em with 3 and 4 bays also. the pattern off of the 4 bay is the > > best for coverage. The 3 bay has too much 3 leaf clover effect). > > > > Anyhow, I have 4 of the db-201s' right now that i'm shortening for 6m. > > It is only about 51-52 inches total height(1/2 wave folded loop). these > > antennas' have no gain , but are DC grounded and will side mount Ok. Put it > > about 4 ft. out from the tower. > > > > It seems to me that if you are restricted on antenna space and height > > then it can't be a good location or have very good coverage to begin with. > > just my opinion!!! These antennas areplentiful. just look for old > > busunesses or Police , fire and city gov. locatons that used to use > > low-band many years ago.a j-pole for repeater use is ok too, just real > > long!!! > > >
