Update changed bnc bulkhead in 536hp

[mitbr]

Awhile back I posted in the forums that my 536hp bnc bulkhead on the back of the scanner became damaged and passed an intermittent signal due to the center tabs in the bnc becoming too wide.
This was caused by frequent changing of ant and too much stress being place on the bnc connector.


The scanner is now out of warranty so I decided to replace the bnc bulkhead with a new one. Before anyone asked I did call Uniden they said the part was available but was on back order and they couldn't tell me its cost or when it would be off back order so I ordered one elsewhere .

The stock bnc bulkhead is really cheap, no name crimp on style.

The bulkhead I replaced it with is this one....Amphenol RF - 031-2221 - 50 ohm solder cup term front mount bnc bulkhead receptacle rf coaxial connector - Allied Electronics

Amphenol 031-2221.

Replacing this was extremely easy....because the one that came with the radio was a crimp on I simply cut the heat shrink tubing with an exacto knife taking care not to damage the cable underneath.

Then I pulled gently on the cable at the bnc connection and voila it came loose and I didn't loose any length of the cable.

On the other end of the cable you will find a brass plug simply pull the plug out where it is at the pcb.

When placing the new bnc Bulkhead I had to make the hole in the back of the radio slightly bigger.

Yea it fits..... before securing the Amphenol into the radio I place a small amount of solder in the solder cup.

I did this with the bnc adaptor not in the radio to avoid any solder ending up on the pcb very bad.

The toughest part of the entire replacement was stripping the cables outer sheathing and then inner sheathing to reveal the this center wire which is connected to the solder cup in the Amphenol.

Now I secured the new bnc bulkhead into the rear of the scanner I placed a rag underneath on the pcb to protect it from any debris or solder.

When soldering the cable into the solder cup on the Amphenol make sure to get some of the plastic sheathing that surrounds the center wire into the solder joint this will give the connection additional support and strength.

The reason for doing this was to replace the 10 cent crimp on bnc bulkhead with a better quality one and I was not disappointed.

So if you are comfortable doing basic soldering I would highly recommend this.

If you have any questions feel free to ask.
Tim

 

[kruser]

Awhile back I posted in the forums that my 536hp bnc bulkhead on the back of the scanner became damaged and passed an intermittent signal due to the center tabs in the bnc becoming too wide.
This was caused by frequent changing of ant and too much stress being place on the bnc connector.
Tim

I did the same with both of my 536HP's. The Amphenol connector is much better quality.

I actually used a flange mount on one of the radios. The kind with the 4 hole flange. That one was a bit trickier as one needs to make sure no chassis shaving fall into the radio when drilling the flange holes. I only used two holes as that was plenty strong.
I used this jack to make sure I had a decent ground mainly after the center contacts of the OEM jack failed.
It was also an Amphenol BNC jack but I forget the part number.

Cheap antenna jacks on both Uniden and GRE/RS radios have always been my number one failure point.
On some of the larger Uniden's, I replaced the BNC jack with N if there was room as that is what is on the LMR-400 or Belden 9913 coax feeding indoors. For the radios with BNC jacks, I do use a short LMR-??? coax jumper with female N to male BNC so there is not much stress on the radios BNC jack.

Using N connectors was probably overkill as there is really no loss difference between a decent BNC and an N connector at the frequencies the typical scanner tunes but I had the flange mount N jacks in the parts bin so figured I'd use some of them up.

 

[mitbr]

My bnc jack failed after only 30 or so mating cycles. I fear that many people will suffer a bnc failure eventually and providing this info will be helpful to those who wish to fix it themselves.

Kruser can you tell me what type of plug that the rg316 cable plugs into the pcb ?I cant tell if its an mcx or mmcx.
Tim

 

[troymail]

Oh no, another problem?????

 

[kruser]

My bnc jack failed after only 30 or so mating cycles. I fear that many people will suffer a bnc failure eventually and providing this info will be helpful to those who wish to fix it themselves.

Kruser can you tell me what type of plug that the rg316 cable plugs into the pcb ?I cant tell if its an mcx or mmcx.
Tim

Sorry Tim, I'm not good with sizing those plugs like the 536HP uses.
If I take one apart again though, I'll measure it and get the specs.

My little plug was hot glued in place but like every other place Uniden used hot glue to try and fix cables in place, the hot glue was doing absolutely nothing. I've always found the hot glue they use to only be stuck to one surface. When their radios are brand new, the hot glue is stuck to both surfaces and does prevent ribbon cables from coming out but I find it only takes about a month or so before the hot glue fails and comes off one surface or the other. In some cases, the hot glue is just hanging by the whisker created when they pull the glue gun away!

I don't know what else they can use though that would leave the radio serviceable but the hot glue they use is not the answer.
Perhaps they just need a better hot glue.

edit: you know, I may very well have the main board connector plug info as I recall needing to change the plug end at the pc board on the one I used a flange mount. I'll look through my Mouser purchases and spare parts and see if I can find your answer as I know I would have purchase more than one plug end.

 

[kruser]

Oh no, another problem?????

Ha! Mine took many more than 50 disconnect cycles before failing but I must admit that having 9913 hanging straight off the connector did not help in one of my cases!
Just a tad heavy and stiff on a portable model.

The bad thing is it was to be a one time hookup to test a new antenna but ended up being permanent on a portable that I did move around a lot.

This was not on the 4 or 536HPs either.

One of my 536's was ruined from a damaged BNC plug. I did not know the center pin was bent until it ruined another radios BNC jack (Icom ham rig).

But yes, the OEM jacks are not of the highest quality.
Probably okay with the radio in a firmly mounted position with the coax supported evenly but repeated disconnects due seem to wear out the jacks faster than normal.

 

[mitbr]

Ha! Mine took many more than 50 disconnect cycles before failing but I must admit that having 9913 hanging straight off the connector did not help in one of my cases!
Just a tad heavy and stiff on a portable model.

The bad thing is it was to be a one time hookup to test a new antenna but ended up being permanent on a portable that I did move around a lot.

This was not on the 4 or 536HPs either.

One of my 536's was ruined from a damaged BNC plug. I did not know the center pin was bent until it ruined another radios BNC jack (Icom ham rig).

But yes, the OEM jacks are not of the highest quality.
Probably okay with the radio in a firmly mounted position with the coax supported evenly but repeated disconnects due seem to wear out the jacks faster than normal.

Yea I now use a right angle bnc so the right angle adaptor takes the mating cycles and not the main bnc bulkhead.

I also used buryflex to the radio before I realized how poor the 536hp bnc was.
I now use a jumper of rg6 to take the strain off the radios bnc.
Tim

 

[kruser]

Yea I now use a right angle bnc so the right angle adaptor takes the mating cycles and not the main bnc bulkhead.

I also used buryflex to the radio before I realized how poor the 536hp bnc was.
I now use a jumper of rg6 to take the strain off the radios bnc.
Tim

I wonder if you could put some type of clamp like they use with RG6 mounted to the grounding threaded hole in the center rear of the 536.
Pass the cable through the clamp and then tighten the clamp to the 536 grounding hole. I'm pretty sure it is a metric threaded hole with marking stamped on the chassis showing the thread size and max length but for some reason, I don't remember if Uniden included the screw!

Keep the right angle adapter and use the clamp to secure your cable if you don't need to undo it often. That clamp would keep the RG6 from ruining the right angle adapter or the chassis mount BNC. But... if you disconnect often, then clamping the RG6 would be a pain.

At one time, I actually had a short 6 inch long mini RG-213 coax cable jumper with a female N on one end and a male BNC on the other. It was funny looking with the huge N jack hanging off one end of that tiny coax!
I was worried that it was causing loss on weak signal 800 trunked sites until I removed it one day and found that it was not hurting my signal at all.
I finally broke the heavy female N jack off the end of the jumper and never bought another. That little cable worked very well though as it was so light and flexible.
I still use a similar jumper conversion cable on my Home Patrols but it is SMA male to BNC male. I like it as I no longer need to have a stiff hunk of small coax sticking out the side of the home patrol. I also had right angle SMA adapters but they were cheaply made (Chinese I'm sure) and they broke at their threaded nut part that screwed onto the home patrol. They did not cause any signal loss though and I know they saved my home patrol SMA jack for pretty long. I did finally break the SMA jack in the HP1 but was able to purchase a new one from Mouser and it was not that hard to swap out.
That's when I bought the little short RG-213 SMA to BNC adapter cables. Those little adapter cables sure do take the stress off the scanners SMA jack though. One if about ready to break though as I have it hooked into the scanner and then it wraps around the rear of the HP1. The problem is the sharp bend where it comes out of the radio and turns to the back of the radio. That sharp bend will eventually fail.
I don't recall where I bought the little jumpers but I know they were made with Amphenol connectors and a short hunk of quality coax.
One of those with the right connectors would probably be a good choice on a 536 also. I either bought them through Mouser or a person that assembled them here in the USA and sold them on his eBay store.

You may wish to check your right angle adapter on an 800 MHz system and make sure it is not affecting your signal. I had a few cheap right angle BNC adapters that would not pass anything much above 500 MHz for anything. When I'd remove the right angle adapter, my 800 MHz signals would come right back. It was weird but it acted like the 800 MHz signals were hitting a brick wall at the 90 degree bend inside the adapter.
I did finally purchase some decent name brand right angles and never had the problem again. Using the right angle adapters is a good idea though!

 

[mitbr]

I wonder if you could put some type of clamp like they use with RG6 mounted to the grounding threaded hole in the center rear of the 536.
Pass the cable through the clamp and then tighten the clamp to the 536 grounding hole. I'm pretty sure it is a metric threaded hole with marking stamped on the chassis showing the thread size and max length but for some reason, I don't remember if Uniden included the screw!

Keep the right angle adapter and use the clamp to secure your cable if you don't need to undo it often. That clamp would keep the RG6 from ruining the right angle adapter or the chassis mount BNC. But... if you disconnect often, then clamping the RG6 would be a pain.

At one time, I actually had a short 6 inch long mini RG-213 coax cable jumper with a female N on one end and a male BNC on the other. It was funny looking with the huge N jack hanging off one end of that tiny coax!
I was worried that it was causing loss on weak signal 800 trunked sites until I removed it one day and found that it was not hurting my signal at all.
I finally broke the heavy female N jack off the end of the jumper and never bought another. That little cable worked very well though as it was so light and flexible.
I still use a similar jumper conversion cable on my Home Patrols but it is SMA male to BNC male. I like it as I no longer need to have a stiff hunk of small coax sticking out the side of the home patrol. I also had right angle SMA adapters but they were cheaply made (Chinese I'm sure) and they broke at their threaded nut part that screwed onto the home patrol. They did not cause any signal loss though and I know they saved my home patrol SMA jack for pretty long. I did finally break the SMA jack in the HP1 but was able to purchase a new one from Mouser and it was not that hard to swap out.
That's when I bought the little short RG-213 SMA to BNC adapter cables. Those little adapter cables sure do take the stress off the scanners SMA jack though. One if about ready to break though as I have it hooked into the scanner and then it wraps around the rear of the HP1. The problem is the sharp bend where it comes out of the radio and turns to the back of the radio. That sharp bend will eventually fail.
I don't recall where I bought the little jumpers but I know they were made with Amphenol connectors and a short hunk of quality coax.
One of those with the right connectors would probably be a good choice on a 536 also. I either bought them through Mouser or a person that assembled them here in the USA and sold them on his eBay store.

You may wish to check your right angle adapter on an 800 MHz system and make sure it is not affecting your signal. I had a few cheap right angle BNC adapters that would not pass anything much above 500 MHz for anything. When I'd remove the right angle adapter, my 800 MHz signals would come right back. It was weird but it acted like the 800 MHz signals were hitting a brick wall at the 90 degree bend inside the adapter.
I did finally purchase some decent name brand right angles and never had the problem again. Using the right angle adapters is a good idea though!

On my hp1 and 436hp along with the patch cable for strain relief I use the Diamond sma to bnc adaptor.
This one here...
Diamond® Antenna ~ SMA to BNC Adapter

I put a washer on the radio at the sma connector then place the Diamond adaptor on top. This gives additional strain relief off the sma on the radio as well as saves on the mating cycles.

Don't know if you know but the sma connector has the lowest number of mating cycles of the commonly used rf connectors at only around 50 verses the bnc connector at around 500. These cycles are on good quality connectors not the cheap garbage they put on Uniden scanners. So its a good idea to use an adaptor in both cases and use a wide base sma to bnc for strain relief.
Tim