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| Duplexer http://interceptradio.com/bbs/viewtopic.php?f=3&t=4169 |
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| Author: | the Outlaw [ Tue May 11, 2010 11:56 am ] |
| Post subject: | Duplexer |
So I'm thinking feeding one antenna from two radios. Duplexer work for this? Do they have the band pass filters built into them already? |
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| Author: | Jim [ Tue May 11, 2010 12:11 pm ] |
| Post subject: | Re: Duplexer |
the Outlaw wrote: So I'm thinking feeding one antenna from two radios. Duplexer work for this? Do they have the band pass filters built into them already? Are you going to be transmitting on either of the radios? |
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| Author: | the Outlaw [ Tue May 11, 2010 2:36 pm ] |
| Post subject: | Re: Duplexer |
Yes, 2 meter. Chicken Band on the other (for the Interstate). It would be good if I could get broadcast/2mtr/11mtr on one antenna. Triplexer? Jim wrote: the Outlaw wrote: So I'm thinking feeding one antenna from two radios. Duplexer work for this? Do they have the band pass filters built into them already? Are you going to be transmitting on either of the radios? |
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| Author: | kb7dqh [ Tue May 11, 2010 3:41 pm ] |
| Post subject: | Re: Duplexer |
I am guessing you already have some sort of "chicken stick" that works on 2 meters??? I know the Hustler collinear 2 meter antenna will play on 10 meters, no problem... Most "broadcast" receivers don't really care what they use for an antenna so the issue there is to keep the transmitted RF from either the chickenbox or 2 meter rig out of the other devices. Duplexers are generally a low pass/high pass combination with three ports... Common port connects to one end of a pair of filters, the other ports connect to the other end of the filters. Cutoff frequencies depend on the box you get... With a big junkbox, something to measure RF power and a signal generator you could likely "roll your own" and save a buck or two. Other than designing the RF networks the tricky part is making sure the lowpass and highpass filter sections have enough RF isolation from each other... If you intend on doing both AM and FM broadcast as well as CB and 2 meters you actually would need to build a curiously connected low pass/ dual band pass/ high pass four-filter doofliggy and may need to have notch filters in there also to keep the RF from the transmitters from smoking the front end of your AM/FM device. One way to help this process a bit is to use a directional coupler to help isolate the broadcast receiver from the transmitter energy... This works well unless you have high SWR on any of your transmitter frequencies! Have fun... Eric |
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| Author: | SpudGunMan [ Tue May 11, 2010 3:43 pm ] |
| Post subject: | Re: Duplexer |
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| Author: | the Outlaw [ Tue May 11, 2010 5:32 pm ] |
| Post subject: | Re: Duplexer |
Probably just as easy to leave the broadcast alone and tinker with a 10/2 meter antenna/duplexer. |
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| Author: | Rich [ Tue May 11, 2010 5:52 pm ] |
| Post subject: | Re: Duplexer |
Run 11m on its own antenna. If you really need 10m on the same antenna get the broadband Antenex. I doubt you will find a combo 2m/11m antenna. If you do it probably won't work worth a hill of beans. You really need two antennas for this scenario. For the 2m antenna you have all sorts of options for size, gain, and extended rx range. Depends on what you are looking to do with it. |
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| Author: | kb7dqh [ Wed May 12, 2010 1:05 pm ] |
| Post subject: | Re: Duplexer |
Yeah, what he said... I hold in my hot little hand a Comet CF-360. One port does 1.3-30 Mhz, the other, 49-570 Mhz. Fits... Get that big Hustler 2 meter antenna. 5dB gain on 2 meters, and when tuned up to work there it WILL resonate as a 1/4 wavelength on 10 meters. Has 3/8-24 threaded mount, standard CB-style mounts are OK... provided they are installed properly. Get the antenna mounted to a REALLY good groundplane... I had trouble getting it to play properly when I had it mounted to a roof rack... probably worse on a "mirror mount"... I actually have personal experience doing this... I KNOW it works... Eric KB7DQH |
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| Author: | the Outlaw [ Wed May 12, 2010 4:36 pm ] |
| Post subject: | Re: Duplexer |
I was going to stick it out on the hood (pick 'em up type). Currently I use a mag 1/4 for the 2 meter. Nothing on the 11 yet as a replacement's in the mail. I just don't like a bunch of antennas sticking out on my POV. |
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