| Home |
| Search |
| Today's Posts |
|
#1
July 16th 04, 07:31 AM
|
|||
|
|||
What to do with lots of receivers and lots of antennas?
Hi...
I currently have four Sony HF radios which will shortly be joined a JRC NRD-545. I also currently have two antennas, a longwire and a di-pole. Time for a tidy-up! What does everybody do when they want to share two or three antennas amongst several radios (short of constanly unplugging and replugging everything)? Can I simply build myself a switch box? Put each antenna onto a common bus and use switches to assign to the various outputs that are connected to the various receivers? Can it be that simple? And what of using two antennas at once? Anybody experimented with this? Any gain (no pun intended) in doing that? I'm thinking of feeding all the record outputs to a small multi-channel mixer. (I currently have a home recording studio, so I can then feed the output to a nice amp and set of speakers). Mark. |
|
#3
July 16th 04, 03:05 PM
|
|||
|
|||
|
"Mark" wrote in message ... Hi... Can I simply build myself a switch box? Put each antenna onto a common bus and use switches to assign to the various outputs that are connected to the various receivers? Mark. That's what I did. I used a 6-position rotary wafer switch that gives me 6 antenna positions. The output of the rotary switch feeds into a single-pole-double-throw toggle switch. I also added a switched home built attenuator between the wafer and toggle switch which gives me 0 to 35dB attenuation selectable in 5dB steps.Now I can feed any of six antennas to either of two receivers with just the flip of 2 switches. From a purity point of view this is not the best setup as there is some crosstalk between the antennas. But for a receive only situation, it works great and you would have a hard time proving the crosstalk is of any real concern. Easy, fun, and low cost too! Al KA5JGV San Antonio, Tx. |
|
#4
July 16th 04, 03:13 PM
|
|||
|
|||
|
|
|
#5
July 16th 04, 03:13 PM
|
|||
|
|||
|
Mark wrote:
I currently have four Sony HF radios which will shortly be joined a JRC NRD-545. I also currently have two antennas, a longwire and a di-pole. Time for a tidy-up! What does everybody do when they want to share two or three antennas amongst several radios (short of constanly unplugging and replugging everything)? Can I simply build myself a switch box? Put each antenna onto a common bus and use switches to assign to the various outputs that are connected to the various receivers? Can it be that simple? Yep! What kind of connectors do you have on the antennas? A simple thing you could do is put PL-259 connectors (the same kind generally used on CB antennas) on each antenna. Get a rotary coax switch (available at ham shops such as http://www.aesham.com or http://www.hamradio.com or http://www.mfjenterprises.com) for each receiver. Use T-connectors and short coax jumpers to wire each antenna to the same position on all five switches. That way, you can assign any antenna to any radio. (it wouldn't be particularly hard to build a switch box yourself either, if you're good at soldering. There are no special construction techniques; just keep wire lengths reasonably short (6" or less) and try to keep the wires for the various antennas away from each other. (otherwise signal will "leak" from one to the other) There's nothing wrong with using the same antenna on more than one radio at the same time. A multicoupler is certainly the "right" way to do it, but is probably overkill for what you're doing. And what of using two antennas at once? It'll be relatively hard to design a switching arrangement that does this while still allowing any receiver to access any antenna. But if you can work it out, two antennas at once is no problem. People have been known to tune the same station with two different radios, each hooked to a different antenna. The fading patterns are often different on different antennas, so when the station fades out on one it may fade up on the other. I'm thinking of feeding all the record outputs to a small multi-channel mixer. (I currently have a home recording studio, so I can then feed the output to a nice amp and set of speakers). That's certainly a good way of handling the audio. Please don't let people tell you you shouldn't hook shortwave radios to a high-fidelity amplifier/speakers. Having decent audio quality makes listening a lot more comfortable & enjoyable. You can always use the selectivity controls on the radio to eliminate noise & interference. (and in your case, the EQ controls on the mixer - maybe you have some other audio gear that can be used to "scrub" the SW audio too?) -- Doug Smith W9WI Pleasant View (Nashville), TN EM66 http://www.w9wi.com |
|
#6
July 16th 04, 03:16 PM
|
|||
|
|||
|
I have several antennas with 6 position switch boxes on them.
"Mark" wrote in message ... Hi... I currently have four Sony HF radios which will shortly be joined a JRC NRD-545. I also currently have two antennas, a longwire and a di-pole. Time for a tidy-up! What does everybody do when they want to share two or three antennas amongst several radios (short of constanly unplugging and replugging everything)? Can I simply build myself a switch box? Put each antenna onto a common bus and use switches to assign to the various outputs that are connected to the various receivers? Can it be that simple? And what of using two antennas at once? Anybody experimented with this? Any gain (no pun intended) in doing that? I'm thinking of feeding all the record outputs to a small multi-channel mixer. (I currently have a home recording studio, so I can then feed the output to a nice amp and set of speakers). Mark. |
|
#7
July 16th 04, 03:20 PM
|
|||
|
|||
|
Doug Smith W9WI wrote: Mark wrote: I currently have four Sony HF radios which will shortly be joined a JRC NRD-545. I also currently have two antennas, a longwire and a di-pole. Time for a tidy-up! What does everybody do when they want to share two or three antennas amongst several radios (short of constanly unplugging and replugging everything)? Can I simply build myself a switch box? Put each antenna onto a common bus and use switches to assign to the various outputs that are connected to the various receivers? Can it be that simple? Yep! What kind of connectors do you have on the antennas? A simple thing you could do is put PL-259 connectors (the same kind generally used on CB antennas) on each antenna. Get a rotary coax switch (available at ham shops such as http://www.aesham.com or http://www.hamradio.com or http://www.mfjenterprises.com) for each receiver. Use T-connectors and short coax jumpers to wire each antenna to the same position on all five switches. That way, you can assign any antenna to any radio. Just make sure that those rotary switches would not ground un-used antennas. The very best way is to use a amplified multicoupler, as others have stated. Anything else results in signal loss. But do what you want. It's not my signal you're losing! dxAce |
|
#8
July 16th 04, 03:50 PM
|
|||
|
|||
|
Hi Mark--The best thing I have done is to add some HF and VHF
multicouplers to run multiple rigs off the same antenna. The best performing ones I've found are made by Stridsberg Engineering in Louisiana. Visit their website at www.stridsberg.com . I use the active 4-port versions of each and get no discernable crosstalk or signal attenuation. In other words the channel isolation is excellent on these units. Obviously, if you wanted to switch between antennas you could add some switches in-line as well. Hope this helps. Chuck Mark wrote: Hi... I currently have four Sony HF radios which will shortly be joined a JRC NRD-545. I also currently have two antennas, a longwire and a di-pole. Time for a tidy-up! What does everybody do when they want to share two or three antennas amongst several radios (short of constanly unplugging and replugging everything)? Can I simply build myself a switch box? Put each antenna onto a common bus and use switches to assign to the various outputs that are connected to the various receivers? Can it be that simple? And what of using two antennas at once? Anybody experimented with this? Any gain (no pun intended) in doing that? I'm thinking of feeding all the record outputs to a small multi-channel mixer. (I currently have a home recording studio, so I can then feed the output to a nice amp and set of speakers). Mark. |
|
#9
July 16th 04, 04:35 PM
|
|||
|
|||
|
(AComarow) wrote:
Mark, A multicoupler. The creme de la creme can be found at www.stridsberg.com/index.htm. Internally, Stridsberg uses Mini-Circuits multicouplers. You can buy the packaged deal from Mini-Circuits directly for significantly cheaper than Stridsberg. I'm not knocking Stridsberg -- I have several of their multicouplers myself -- but you pay more for them (him) to put the mini-circuits component on their own PC board and package. Eric -- Eric F. Richards, "Making me root for a sanctimonious statist blowhard like Kerry isn't the worst thing Bush has done to the country. But it's the offense that I take most personally." -- http://www.reason.com/links/links071304.shtml |
|
#10
July 16th 04, 04:58 PM
|
|||
|
|||
|
"Mark" wrote:
Can I simply build myself a switch box? Put each antenna onto a common bus and use switches to assign to the various outputs that are connected to the various receivers? Can it be that simple? And what of using two antennas at once? Anybody experimented with this? Any gain (no pun intended) in doing that? Well, you could buy a coax switch to switch between your antennas and then use multicouplers to distribute the RF around. I made a simple phasing box that couples two antennas and allows me to select one, the other, both in phase and 180 degrees out of phase. It works, but... You only get 3dB gain on a good day, and that is certainly lost among the couplers and isolation transformers needed. Occasionally I get spectacular results in eliminating phasing, but overall the project was a failure. The advantage of feeding from multiple antennas is reducing fading and steering the reception pattern. To do that properly a better system than my passive arrangement needs to be done. See Ron Hardin's post about using ANC-4s as phaser-combiners. Eric -- Eric F. Richards, "Making me root for a sanctimonious statist blowhard like Kerry isn't the worst thing Bush has done to the country. But it's the offense that I take most personally." -- http://www.reason.com/links/links071304.shtml |
Linear Mode
