RF Limited CR577 Ceramic Microphone "Bulldog's Experience"

[Bulldog-Unit777]

THE INTRODUCTION! I will be posting a three part series on this microphone. The main goal is to keep you folks well informed. Well this week I received a RF Limited CR577 Ceramic Microphone from Sparkys CB Shack. They go for about $47.95 but due to the market that price may change. I have seen that happen more than one time. Been tracking this microphone in the forums and was eager to get one. Lets face it one of the main reasons we swap out microphones tone, clarity and loudness! Below are some of the best pictures you'll see on the web!

All Photos Taken By: Reno "Bulldog - Unit 777"

[Lightning_Bolt]

Looks like a 2018 with a different mic element.

[Bulldog-Unit777]

EXPOSED! Here are a few pictures of the RF Limited CR577 Ceramic Microphone internal electronics.

All Photos Taken By: Reno "Bulldog-Unit 777"

[Bulldog-Unit777]

BULLDOG'S EXPERIENCE! The shape and feel of the RF Limited CR577 Ceramic Microphone is like the Xtreme 2018. The best features are the external volume (amp gain) & tone controls. The ceramic microphone element has a 30-15,000 Hz frequency response. It needs a 9 volt battery which fits tight. No extra noise from the battery moving around and the cover has a pad on the inside to keep it snug. This microphone keys up smoothly and just a hair lighter than the Xtreme 2018. The coiled cord is the same length and material as the Xtreme 2018. Depending how your radio was tuned you will get various results. I tried this microphone on a new version Cobra 148 GTL, 29 LTD "Army Strong" & "Black Chrome" and 2000 GTL. I test the microphone against the Xtreme 2018 and Astatic D104-M6B using the Cobra 148 GTL. It edged the Xtreme 2018 in tone, clarity and modulation just a bit higher. The Astatic was tinny and did not have the useable modulation to sound impressive on this rig. I feel this microphone will work on just about every rig on the market. The four radios I had this microphone on sounded the same. With the exception of the 29 LTD "Army Strong". This radio was extremely loud & clear due to the MOSFET upgrade. The tone control works very well. You can really fine tune it. No big jumps in the tone. Very controllable!

This microphone did have one particular problem. When I used it on the Cobra 29 LTD "Army Strong" & 2000 GTL which are set up as base stations in the house a light hum/transformer noise could be heard with the modulation. When used in a motor vehicle environment it works perfectly. Example the Army Strong radio is powered by a Pyramid PS-12KX. I moved the power supply further away from the radio. Took that out and used a vehicle battery. The hum was still present. Ran jumpers from the microphone internals to explore the best grounding method. Spent about 6 hours. Still had the issue. Heck I tied 3 different batteries: regular, alkaline & lithium. So I rewired it to the Cobra 2000 GTL and hum still present. In both cases if I key the microphone in one hand and touch the chassis with the other it goes away. When I exposed the microphone it was checked all over for poor connections or stray stranded wires. The hum or transformer noise reminds me of a cheap power supply, a mobile on a battery charger or a cap gone bad on back of a mobile power jack.

Gave RF Limited a call and talked with Sam Lewis. He mentioned that Chris Holland of The Radio Shop in Ontario, California is the developer of the CR577 and for me to sent it to him. So I wrote a complete description of the issue and shipped it. Eager to get it back so I can do a few videos. I think this microphone will end up going on the 29 - Army. That radio will do its thing even better now. My girlfirend commented that this microphone so far is the best sound mobile one I had! Guess I am not the only one having the same issue. Is this a hit or miss problem? I really don't know.

[Lightning_Bolt]

Sam Lewis is the man to deal with. My bud's S9 developed a problem with the compressor chip and he made sure they sent it as a warranty product. RF Limited really does take care of their customers

[john doe]

i am glad to see they used a decent size element for the mic .you didnt do any audio testing ??

[Bulldog-Unit777]

John Doe check out the first paragraph in Bulldog's Experience. I made a few sample recordings to refer on. The microphone is in shipment so it can be worked on for the hum issue. Once it comes back I will do a video or two.