CP200 Antenna Analysis - adapters?

[VE3XYU]

I'm looking for an adapter that will allow me to test and analyze antennas for Motorola CP200/CP200d radios.
There are plenty of adapters that allow you to test the radio itself, or to adapt to other types of antennas (male "Motorola" to SMA/BNC), but I cannot find anything that would be female "Motorola" to any other type of connector.
In another post, "Tony Soprano" said this connector type is "4.15mm coaxial BNC" but I'm having no luck finding anything with that information.
Any help would be appreciated.

 

[Project25_MASTR]

How would you plan on testing the antenna if you had an adapter?

 

[VE3XYU]

With a VNA

 

[prcguy]

With a VNA

With a VNA and hopefully a test fixture that emulates a handheld ground plane and plenty of feedline decoupling to the antenna test fixture. Otherwise you’re wasting VNA time.

 

[VE3XYU]

Still just looking for an adapter. I know what else is involved. Thank you.

 

[Project25_MASTR]

With a VNA and hopefully a test fixture that emulates a handheld ground plane and plenty of feedline decoupling to the antenna test fixture. Otherwise you’re wasting VNA time.

If I remember correctly (it's been a decade since I last looked at the service manual in that much detail for a CP200) there is a LC matching network that is bypassed when you screw the service adapter into the antenna nut which would also imply the antennas aren't 50 ohm impedance. Historically the MX connector based antennas have been 38 ohm impedance if I remember correctly.

 

[VE3XYU]

If I remember correctly (it's been a decade since I last looked at the service manual in that much detail for a CP200) there is a LC matching network that is bypassed when you screw the service adapter into the antenna nut which would also imply the antennas aren't 50 ohm impedance. Historically the MX connector based antennas have been 38 ohm impedance if I remember correctly.

Interesting, thanks. So the connector type is called MX? Or is this just shorthand for Motorola

 

[Ubbe]

I used a empty chassi from a Motorola radio and its antenna connector had a thin coax with a BNC connector that came out at the bottom. I held the chassi as a normal user would do with his radio and measured antennas using a SiteMaster. I also tested by having a signal generator connected and did a sweep over the frequency range and had a scanner in search mode connected to another antenna as far away as possible and set the signal generator to a somewhat noisy signal from the scanner and checked how it compared to other antennas as well as how the bandwidth was of the tested antenna and also how sensitive it was to how the antenna where tilted.

/Ubbe

 

[VE3XYU]

I used a empty chassi from a Motorola radio and its antenna connector had a thin coax with a BNC connector that came out at the bottom. I held the chassi as a normal user would do with his radio and measured antennas using a SiteMaster. I also tested by having a signal generator connected and did a sweep over the frequency range and had a scanner in search mode connected to another antenna as far away as possible and set the signal generator to a somewhat noisy signal from the scanner and checked how it compared to other antennas as well as how the bandwidth was of the tested antenna and also how sensitive it was to how the antenna where tilted.

/Ubbe

Thank you, that is a good idea. (Un)fortunately these radios never die, so I don't have any dead ones. Of my fleet of 60, I still have about ten in daily service since we bought them in 2006. Maybe there's a "parts only" one on ebay.

 

[Ubbe]

At the radioshop I worked we had tons of old parts in scrap bin like dented and mangled chassis for different radios and if anyone asked I would give away unusable parts for free, being it mobile phones, 2-way radios or pagers. Listen with the closest radioshop if they have any chassis, it doesn't matter in what condition, with a reversed female SMA connector that Motorola use for their radios.

/Ubbe

 

[VE3XYU]

At the radioshop I worked we had tons of old parts in scrap bin like dented and mangled chassis for different radios and if anyone asked I would give away unusable parts for free, being it mobile phones, 2-way radios or pagers. Listen with the closest radioshop if they have any chassis, it doesn't matter in what condition, with a reversed female SMA connector that Motorola use for their radios.

/Ubbe

Thanks again