low SSB power low FM modulation Yeticom MK-3

[Hotspring 44]

I just got a Yeticom optima MK3 and discovered that the sideband power is low; averaging below 10 watts but will peak my very inexpensive 100 watt meter to well above 50 with whistle and peak around 20 with loud voice but only at certain tones, no matter how loud I yell into the mic only certain tones will reach highest 'average' peak power (much lower than peak swing from whistle); normal talk volume will be mostly below 10 watts unless the very narrow voice tones are there then it will max to about 17 on those peaks for a very short time like a spike.

Radio power output specs say "Power output: SSB / FM 50 Watts PEP AM: 12 Watts Average / 50 Watts PEP”.

AM dead-key is 15 watts is as is the spec says but no 50 watt swing (?), and FM is ~ 49 to 50 watts close enough to call it on spec.

Also I thought the FM was not modulating but if I turn the volume all the way up to max on the test radio (receiver) I can hear clean modulation, just at a very, very low level and if I put the mic close the receiver's speaker it will generate feedback.

I have looked at the wiring for the “Phantom Powered” stock mike and have found in my research that an Icom IC-HM-36 microphone will work on the MK3 out of the box and that the made in Japan one is the only one of the Icom microphones worth getting for the MK3. Too much $$$ for me for it not being a power mic.

The Icom IC-HM-36 mic schematic diagram shows the 8V+ from the radio (pin 2) is not connected to anything on that mic as it is out of the box.

This brings me to the real questions... But first I will give some insight of what I am considering... ...I have a CR-577 that could be wired to a correct 8 pin plug to test the audio because 4 pins are all that are necessary to use to test audio-- 2 for microphone audio output and 2 for PTT... ....Soooo...

I don't want to send the radio back to Yeticom just yet or at all if I can avoid it and I will not void the 1 year warranty by breaking the seals on the radio....

...so...that being said...

...I have 2 questions: My first question is: Is there anything in the so-called “phantom Powered” stock microphone that comes with the optima MK3 that is adjustable to amp up the mike output?

...Second question:
As long as I don't use the 8V+ from the radio's pin 2 at all and/or don't short-circuit or overload that 8V+ output and correctly wire the 4 pins (the first time), is there any likelihood that the power mike(CR 577) would cause damage to the Optima MK3?

Thanks in advance from: Hotspring 44.

[MDYoungblood]

There are a couple of members that have a MKIII, let's see if they chime in. Now for the mic, yes you can wire it to the radio and with a little ingenuity use one of the unused wires to power that mic, eliminating the battery. RF Limited made a few mics that way just for the Magnum 257.

3's

Greg

[Hotspring 44]

Thanks MDYoungblood.
I looked that up and noticed the microphone plug is a 6 wire and the MK3 is an 8 wire but 2 of the pins on the MK3 are unused.
The one I found from RF Limited is Magnum 257 Echo Microphone and the casing and controls look identical to the CR-577 but with 2 switches on top (nonresistant on the CR-577) and the control wheels are “Echo Volume” and “Echo Delay” instead of “Volume” and “tone”.


So I'm thinking; with a wiring diagram schematic of that Magnum 257 Echo Microphone, I could (in theory) use that to figure out where to connect the 8V+ from radio's pin {?... ...and maybe what other components to add for powering the microphone head... ...if any?} and be able to mod a RF Limited CR-577 using an 8 pin microphone plug and a couple of momentary micro switches (plus one resistor for the up and down shift function switches) for the MK3.

If so it would have all functions as the stock mike plus the added benefit of tone control and power mike that never has to have the battery changed .That would be really cool!! .

Even if I decide to use the 9 volt battery instead of risking frying the 8V+ power regulator it would hopefully be a vast improvement over the dead-ish stock mic.

[MDYoungblood]

There are 8pin to 4pin adapters on the market, I wire the mic just for that radio, I'm not one to switch them all the time. The 257 uses only a 6pin setup to be different even though the radios are made by the same factory, they have a hot lead and use a resistor in the frequency/channel changing buttons, really not a good idea but it's the way they wanted them.
The Icom HM-36 is an excellent mic, electrolytic element powered by the 8v source, there is an adjustment but the mic needs to be opened to do it, once set, just forget it. I've seen them running around $20 shipped, not a bad price, I have one for my 735 HF radio.
The CR-577 is a great mic too, to wire it and add the switches you may need to change the cord to an 8 wire version or like you said don't do the power change.

3's

Greg

[Hotspring 44]

Thanks MDYoungblood I appreciate your input.

A 6 wire mike cord is whats necessary for all functions (as far as I can determine) from microphone for the MK3 as far as the cord itself is concerned but for the experimental testing I will use the battery in the CR 577 that I already have until I am absolutely certain of how to wire the power from pin 2 (8V+) from the radio to power the mike if that microphone works well enough on the MK3 to go any further with it.
Either way, I thought it to be prudent to get a 6 wire microphone cord, I see no need for an 8 wire microphone cord.

I already ordered the 4 pin male microphone jack, the 8 pin female microphone plug, and a 6 wire microphone cord so I can wire the adapting cord for the existing 4 pin CR 577 as it was wired straight out of the box to the 8 pin microphone plug that will plug into the 8 pin radio jack on the MK3 so I can test the modulation and power on SSB and FM, that way I don't have to spend so much money on another CR 577 or other microphone... ...At least until I find out if a microphone is all that will be needed to get the SSB power and FM modulation where it should be at.

There are only 6 pins used on the MK3 microphone so it seems to me that it would only be necessary for PTT (2 wires) and audio signal from the microphone to test the audio of the CR 577mic to MK3.

The way the ICOM HM-36 microphone is wired out of the box works on the MK3... ...And low and behold, according to the schematic I got from an ICOM website the 8V+ pin (pin 2) is not connected to anything in that microphone; and the shift switches are N/O momentary that are connected to the PTT switch (switches ground to open circuit when keyed which prevents changing frequency while transmitting) frequency shift up is direct circuit to ground and the down is connected through a 470 (could be 470K ohm ?) ohm resistor to ground.

It looks to me to be easy enough for me to do the microphone mod using the 9 volt battery in the CR 577 as it is already designed and set up for but a bit more care has to be put into the mod to get the power from radio (pin 2 / 8v+) and the other power source (ground or ?) to complete the circuit to power the microphone's preamp.
As of yet I don't have enough knowledge to feel confident enough in my knowlege to attempt that part of the mod just yet but all the other aspects of testing and wiring I am sure I can do.

Of course I will use a volt meter on the radio's microphone jack to definitely locate pin 2 (8V+) to be sure NOT to confuse pin 6 with pin 2!.. ...I will check and confirm that all adapter cord, wiring is correct before, during, and after soldering the adapting microphone cord before I plug it into the radio and power it up.

NOTE: (as far as I can tell) The diagram schematics below (one from an ICOM web page and the other from Optima MK3 manual) are where microphone plug's pins are and where the cord wires are to to be soldered and NOT the plug's end.

I claim no responsibility for any incorrect description herein.
It ts each person's own responsibility for their own actions; If you ruin, or in any other way make or cause your radio or microphone to not function or severe damage from mismatch of wiring arrangements or any other based on wording and/or diagrams/schematics herein, IT IS ON YOU and nobody else!

That being said, I hope this is more informative than not and that it is useful to someone else too.

-- Wednesday, 07 January 2015, 21:18 PM --

I tried to post this but it seemed that it did not take.
Instead it went to sign-in and seemed to erase what I tried to post. So if for some reason it posts twice; I did not mean it.

Anyway:

Update:
I was successful with wiring a 4 pin (Stock as was out of the box CR-577) to work on the MK3.
Surprisingly enough it only needed 3 of the 4 pins to key and modulate.

I removed Pin 2 from the 8 Pin plug so as to never accidentally short-circuit the radio because that pin is not being used anyway.

I connected all (2) 'grounds' (shield/mic and the PTT ground side switching) on one pin at the male 4 pin chassis mount on the 4 Pin adapter end.

On 8 Pin Plug, Pin 7 and 6 are both 'grounds' and are soldered to each other on 4 pin adapter end:
(shield/mic and PTT ground side switching) and go to pin 3 of 4 Pin adapter (as is in microphone wiring for the Galaxy DX 979 as illustrated in CB tricks as:
“Mic Plug Solder Cup Side”); {On 8 pin plug end, Both pin 6 & 7 wires are always connected @ the 4 pin adapter end on pin 3 as stated above.

Pin 5 on 8 Pin Plug is PTT switching (Open = Receive, Keyed {Closed} goes to ground = Transmit) and goes to Pin 1 of 4 Pin adapter (as is in microphone wiring for the Galaxy DX 979 as illustrated in CB tricks as: “Mic Plug Solder Cup Side”).

Pin 2 on 4 pin end is microphone 'hot' and goes to Pin 1 of 8 Pin plug.

It worked and I did not use the 6 wire mic cord yet and actually a 5 wire cord should work for adding the up / down channel switching if one decides to install the 2 switches and resistor in/on the microphone.

For the adapter wire, I just used a very short length of CAT-5 Ethernet cable and used 2 pairs of the 8 wires and there was no RF interference but I am not running any RF amplifiers, just the radio;s power.

The CR-577 did increase the modulation like the modulation was compressed and the best setting for me was 5 Volume and 5 Tone, it did not help with the RF power output so I am guessing that the SSB ALC in the radio needs to be adjusted for full SSB power output.... ...Any thoughts on that from the radio experts here?






-- Wednesday, 07 January 2015, 21:21 PM --

Woops! 2 8 pin photos but no 4 pin photos in that last post.
Here is the 4 pin photo:


-- Thursday, 08 January 2015, 14:02 PM --

Update 2:

I was able to get full SSB power by adjusting SSB P Pot by turning it CCW about 50°.

The frequency response is still about the same with both microphones as it was before but the stock mike seems to be better than the CR-577.
I opened the stock mic and discovered (as far as I can tell) that it is most likely not preamplified because there are no transistors on the component side of it's board; I did not remove the board from the mic housing so I suppose there is a slight possibility that there may be one on the other side of the board, but I doubt it.

Here are 2 photos, one is a close-up of the adj SSB (power) adj pot and the other one is of the tuning adj side of the board of the Optima MK3.

[hecsab]

Greeting.

There is a defective optima, I'm looking for the parts marked on the photos. And wiring diagrams, service manuals, setting values.
Thanks.


(edited by MDY, removed links, contact admin)

[hecsab]

Hello .. there is an optima mk2 there are some missing parts. See the photos. I’m looking for a wiring diagram and setup description. Thanks

(edited by MDY, removed links, merged topics and edited)

[295 antenna]

I noticed very low audio and the power level is lower than advertized..but on that note the board is well marked so i turned up the audio and purchased a MFJ-299 mic and put a nice Kl-503 behind it and its loud and proud and i get anywhere i need to go..weather permitting. The mic is the thing that really made a difference.

[MDYoungblood]

Hello hecsab,
Welcome to the forum. As you can see I removed the links to the pics you posted, the website you were using wasn't family friendly for this forum. Another reason is you are a new member and pics aren't allowed until a period of time and your post count increases. I also combined the 2 posts you made since they are asking the same question. If there is a problem you can contact any of the admin's or mod's to the forum.

As a new member could you start out again posting an intro in the "Welcome to the Forum" topic, click here; http://www.cbradiotalk.com/viewforum.php?f=89 , so other members can say "Hi" , thanks.

3's

Greg

[pabxone]

The owners manual / user guide is here :- http://www.cbradio.nl/yeticom ... II_ENG.pdf

You would need to contact Yeticom NZ to get the circuit diagram / board layout and wiring - IF they will release them to you ?

Their email is :- yeticomnz@gmail.com