Made a discovery

[banjo5stringleon]

I made a discovery with the Comet DS-150S antenna and the tripod mount I was trying to use.

For future reference. You cannot use both the antenna and tripod in an attic. The reason is because once you set the antenna on top of the tripod they bond together forming one whole unit. In other words. They become one whole antenna and the tripod interferes with reception. Once I took the antenna off of the tripod. The antenna performed as it should. Go figure?

 

[dave3825]

Do you have any pics?

 

[banjo5stringleon]

Yes I do. I tried to upload but the picture is to large. Trying to figure out making it smaller.

 

[banjo5stringleon]

Here is the picture showing both the antenna and tripod. Still needing to move the tripod and cut back some coax. Hopefully getting even better reception? Which I"m now getting the weather alert station. I was not getting that until after I took the antenna off the tripod. Now all is good and the big antenna is now performing like the antenna that came with the unit. Which started the problem in the first place.

 

[dave3825]

Was only on first cup of coffee. What happens if you use a piece of pvc in the tripod and attach the comet to that? Would the comet and tripod still be bonded? There is also another solution that's very cheap if your attic has a wood floor and or you do not mind screwing something into the floor. Get a threaded pipe flange mount and a section of pvc or schedule 40 threaded pipe. Screw flange down and thread in short piece of pvc and use 2 hose clamps to attatch the comet.

 

[banjo5stringleon]

Yeah Dave that sounds like a good idea. I also had thought if you put like a piece of foam rubber or electrical tape between the resting antenna on the pipe of the tripod. That might work too. But my brother-in-law and myself decided to leave things as they are for now. Antenna hanging from the ceiling of the attic. I’m still monitoring of course and deciding for sure if how things are with the antenna staying in place where it’s at. I will pass this on to Tim and see what he thinks. Thank for your suggestion.

 

[Ubbe]

Here is the picture showing both the antenna and tripod.

Antennas are extreamly location dependent if you do not have them high above any obstacles and have line of sight to the transmit source. Just moving a few feet might change the signal level a lot when having the antenna in a closed enviroment like an attic.

Try to bring your scanner up to the attic and connect to the coax and then move the antenna around, also in hight, to try and find the best spot for a system or frequency that are hard to receive and that you would like to monitor. It might make other systems harder to monitor so try to test all frequencies that are important to you before deciding for a final position.

Having several antennas connected to several scanners are always a good solution. Even antennas 3 ft apart will probably have different reception from different systems that makes it worthwhile to have several coaxes and antennas installed.

/Ubbe

 

[banjo5stringleon]

/Ubbe
I do have another question. The coax that I have on the antenna is roughly right at 50’. Some of the cable is laying on the floor. I just talked with another friend. And he said just snake the coax and hang it up high. My question is, should I maybe cut some coax to hopefully improve reception. Or could that make or jeopardize the reception? John said snaking the coax would work. At this time I’m satisfied with what I’m receiving although with the extra coax I didn’t know if maybe cutting some would improve.

 

[banjo5stringleon]

Thank you for your info. Can you tell me that if I cut back the roughly 50’ coax, could that change the reception? Thanks

 

[Ubbe]

Thank you for your info. Can you tell me that if I cut back the roughly 50’ coax, could that change the reception? Thanks

It depends of the coax type. If its RG58 and you monitor UHF frequencies then every foot counts. Even a high quality coax used in the 700-900MHz range will have a noticeable attenuation at a 50ft length. But if you only can cut it down to 40ft then it hardly wont matter and you'll also have the extra risk of creating problems when refitting connectors to coax.

/Ubbe

 

[banjo5stringleon]

The coax type is RG6. I listen to the 800MHz frequency’s. Low band 800MHz and the high band UHF Which is the weather station. Mostly what I monitor. Anything else at this time I’m not interested in.

Being a newbie those are the bands and frequency’s I looked up.

 

[Ubbe]

The coax type is RG6. I listen to the 800MHz frequency’s.

It can have up to 3dB attenuation at 900MHz and 50ft and cutting it down to 25ft would gain you at most 1,5dB. Probably not worth doing and absolutly not if it ends up longer than that.

/Ubbe

 

[banjo5stringleon]

/Ubbe
I’m wanting to get the extra off the floor. With getting a little bit of gain I’m willing to take that chance with regard of being careful how much I cut back. There are transmissions that I miss parts of the actual talk. Thinking what little bit I could gain might be enough to catch all the action. With splicing I’m not sure, but we should get a good splice and if it ends up not being better we can always ad back what we might mess up? My brother-in-law will be coming back over within the next few days. We’ll see what happens. Being a newbie is no fun. But having input from those who’ve given their advice of course is always helpful and appreciated. Thanks

 

[popnokick]

Splicing? Hoping you mean cutting, attaching a new connector to the RG-6, and then reconnecting to the radio. If you decide you need to extend the cable again, use a double female (barrel) connector to connect to a male connector. There is no practical way to "splice" coaxial cable and maintain its signal transmission characteristics.

 

[banjo5stringleon]

Yeah I mean cutting. But I did just talk with Tim and he says he’ll take the connector off the antenna and pull the coax thru the tripod. And that’s another thing. There is still about 2 feet going thru the tube of the tripod. Another hindrance to reception. All we did was hang the antenna after removing it from the tripod. Coax is still thru the tripod. Another reason for kind of starting over with the coax.

 

[dave3825]

There are transmissions that I miss parts of the actual talk. Thinking what little bit I could gain might be enough to catch all the action.

What exactly are you scanning when this happens? Conventional or trunked? Analog or digital? And what kind of scanner are you using? It could just be a setting in the scanner that needs to be tweaked. It could be simulcast distortion. It could just be reception. Can you post a link to the system your missing calls on?

There is still about 2 feet going thru the tube of the tripod. Another hindrance to reception.

You can just unscrew the coax from the antenna and take it out of the tripod and screw it back onto the antenna. I seriously doubt 2 feet of coax is going to have any noticeable outcome.

 

[banjo5stringleon]

I’m scanning mostly the trunked system. I also have the airports programed too. But mostly I listen to the 800. The scanner is the sds200 plus I have the hand held sds100. The 100 seems to outperform the 200. I also read where you can’t do the test of seeing which one works better having them in the same area. I understood from what I read. They fight for the reception. That’s what I thought about the setting in the scanner. But being a newbie and looking on YouTube for help. I know little about these scanners. Although the reviews say the sds100 is the best scanner to have. I wanted the sds200 because I spend more time in the recliner being new in retirement. The sds100 I take to the bedroom when I go to bed. Plus I’ve taken it in the car a couple of times. As far as posting a link I’ve not done that as of yet.

As far as just unscrewing the connector from the antenna would be great. But the bottom of the tripod where the hole is, is a little bigger than the coax that it has to go through. The connector has to come off to thread it back through the hole. Per the reason of thinking just go ahead a cut some coax off.

 

[dave3825]

I also read where you can’t do the test of seeing which one works better having them in the same area. I understood from what I read. They fight for the reception.

Can you link where you read that they would fight for the reception? I have been using regular tv splitters with my scanners for years off the same antenna and have not had any issues or noticed one scanners reception drop when another scanner was turned on. I am heavily into sdr now and I do not see the signal change when using 1, 2 or even 5 different receives at the same time. Yes, signal does get reduced when splitting but I run an lna (low noise amp) to counter that.

If you could name the system where you are missing part of the calls that could narrow it down. If its digital p25, there are p25 threshold settings to play with that basically fine tune. So with sds we can most likely rule out simulcast distortion . Could be a setting or reception.

As far as just unscrewing the connector from the antenna would be great. But the bottom of the tripod where the hole is, is a little bigger than the coax that it has to go through.

Got you. I see the antenna has UHF female, SO-239 connector. Those connectors can be had a few different ways. SO-239 solderable, crimp and SO-239 to F. Type F is what's found on most cable tv wire. Your brother in-law has a crimper or soldering iron for that?

 

[banjo5stringleon]

Dave,
I cannot link where I read that from. I’ll try and find it again. I read roughly a month or so ago that having two scanners sitting close to each other. That can happen. But I don’t remember where I read it.

I also have found out as I age memory is tough sometimes. Since I said it I will look to see where that came from other than me. Being a newbie I took what I heard verbatim.

I have just learned in scanner talk if you say something and anything pertaining to scanning make sure what you’ve read you can back it up. Newbie! 🥴

I’m still searching for where I got that information.

I even took the sds100 out to the kitchen on Bluetooth and left the base where I set in the recliner. To see if I could notice anything different. The answer is no. But this was before I ever installed the antenna up in the attic. Both antennas were being used that came with the scanners at those times.

 

[banjo5stringleon]

Can you link where you read that they would fight for the reception? I have been using regular tv splitters with my scanners for years off the same antenna and have not had any issues or noticed one scanners reception drop when another scanner was turned on. I am heavily into sdr now and I do not see the signal change when using 1, 2 or even 5 different receives at the same time. Yes, signal does get reduced when splitting but I run an lna (low noise amp) to counter that.

If you could name the system where you are missing part of the calls that could narrow it down. If its digital p25, there are p25 threshold settings to play with that basically fine tune. So with sds we can most likely rule out simulcast distortion . Could be a setting or reception.



Got you. I see the antenna has UHF female, SO-239 connector. Those connectors can be had a few different ways. SO-239 solderable, crimp and SO-239 to F. Type F is what's found on most cable tv wire. Your brother in-law has a crimper or soldering iron for that?

I found this right from Radio Reference. But this isn’t what I read. This is different from what I said about two scanners interfering with each other. Here’s what I found.


Member. You cannot just parallel multiplereceivers to the same center pin of a single antenna coax fitting; they willinterfere with one another. You need adevice known as a multicoupler to isolate the receivers from one another.May 4, 2009

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