Diamond D130NJ

[Al1009]

Put up my D130NJ, about 25 feet in the air using LMR400, and I gained some distance in the 450.xxx range but lost my Mass State Police in the 850.xxx range. I was getting MSP using the Diamond RH77CA.

Using a 4 foot R58 patch cable from LMR400 to scanner. Tried going directly from LMR to scanner but no luck.

Any thoughts

 

[Ubbe]

Any thoughts

Maybe too much signal for the scanner, from cellular towers. What scanner model? How much signal level did you used to have from that system? Try to always use a FM broadcast filter with discone antennas.

Set squelch to 0 and listen to the system if you can hear a faint signal or only white noise or some sort of interference. You didn't touch anything on the scanner that changed a setting, lockout, attenuator, service types, or whatever features your scanner have?

/Ubbe

 

[Al1009]

Uniden BCD325P2

With the older antenna I'm getting 4 bars+ with the discone it says searching for control channel on the TGID's.
Imported from RR as NFM.

Haven't changed anything

 

[Ubbe]

Discones have bad reception of frequencies above 500MHz compared to "standard" antennas of different types. The direction of reception are straight down into the ground and up in the sky and very little between the two at the horizon at 800MHz frequencies. When looking at the directional diagrams from different discones the signal drop can be 10-20dB at the horizon for 800MHz signals. Compare that to 6db gain for the RH77CA.

If you cut down the discone elements to half size you will regain the loss. You will then also loose signal strength up to 150MHz but might be good for FM broadcast attenuation but VHF Air will also suffer but are usually line of sight and can be received with almost anything as an antenna.

/Ubbe

 

[jtwalker]

When I raised my D130nj up from about 10‘ to 30’, my BCD536HP went deaf on my county’s 800mhz simulcast system. I think the higher position increased my simulcast distortion. The 536 does fine for the 800mhz simulcast systems that are in counties east, southeast and south of me where I have good line of sight. I added an SDS200 and this resolved my issue with my county.

I don’t notice any issues with 450 or 800 with my discone.

 

[Al1009]

So you think I might be to high, can't lower it to much because the lower radials will hit my roof shingles.
I did have to put on a new N connector on one end, soldered and clamped. Could that have been doe wrong regarding the 800 issue?

The foil covering the dialect, not the braided section, does that have to be removed? It's between the plastic dialect and the braid.

 

[Ubbe]

The foil covering the dialect, not the braided section, does that have to be removed?

It doesn't matter as long as there's no contact with the center lead or pin, making a short circuit. LMR400 are heavy so have it secured properly so it can 't pull on the connector.

What scanner do you have and are the problematic system simulcast? A non SDS scanner and simulcast systems will usually need to reduce signal levels to only receive one site. Using the attenuator setting in a scanner will simulate a lower set antenna. If you open the squelch and listen and you hear the datasignal then it is probably a simulcast issue. But if you hear nothing, just noise or a mix of different transmissions, then it's an antenna/feedline problem or a scanner overload problem.

/Ubbe

 

[Al1009]

BCD325P2
When I set my squelch to "0" there is no noise at all with any antenna, it just scans as usual, might have a little distortion at the end of a transmission but not much

 

[ko6jw_2]

Have you checked the coax? The 130NJ requires a N connector at the antenna end. Did you attach the connectors yourself or did you buy a made up cable ? Any cable problems will be magnified the higher the frequency. LMR 400 is trickier to attach connectors to than RG-8. I use Time Microwave's own connectors. They are expensive, but at specifically designed for LMR400. By the way I have had defective cables with connectors attached in the past. Center pins not soldered etc.

 

[Al1009]

The cable had 1 N connector on it and I attached the other end, soldered and crimped, but I could have screwed that up, 1st time doing it.

At 25 feet is there much difference between RG-6 or 8 and LMR400?

 

[jtwalker]

Try setting attenuation on for the system in question. Can you find any other local conventional channels in 800 band that you could check?

 

[Al1009]

That's the only one.
Can I do that in the ProScan software?

 

[Ubbe]

When I set my squelch to "0" there is no noise at all with any antenna

I forgot to mention that when you have only digital channels in scan you will not hear anything with the squelch set to 0, it will just scan more slowly.

You will have to enter the channel manually as an analog conventional to hear anything. Push hold to stop scan and enter the frequency followed by Enter. It will save the frequency in a quick save group. You can scroll in that edit menu and set it to analog conventional and push Menu several times until you are back at the hold and are now monitoring that frequency. If the squelch are set at 0 you should now have audio.

/Ubbe

 

[ProScan]

That's the only one.
Can I do that in the ProScan software?

The attenuation is set at the conventional channel level and the trunking site level. Same as the BCD325P2.

 

[Al1009]

I changed it at the trunking system only on ProScan and uploaded it to my scanner, still no luck. Once in a while, very rarely, will I hear something and the quality is terrible.