Yaesu 857 to Kenwood stereo

Discussion in 'Mobile Radio Systems' started by KI7FAN, May 1, 2018.

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  1. KI7FAN

    KI7FAN Ham Member QRZ Page

    Did a search and no joy.

    I would like to put my audio output from the Yaesu to the Kenwood DMX 7704s stereo. The Kenwood is new and the mfr states it takes a 3.5 mm jack to RCA plugs. So I would need to run the audio to the Yaesu with the left and right RCA channels. As I understand the Yaesu is putting out mono on the output to the 3.5mm jack. So it would be from the Yaesu 3.5mm out to RCA to RCA to 3.5 mm to AV in at the Kenwood.

    Anyone done this? Is it possible? Will I fry both radios? Thanks for any help.
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    It is a can do.

    You need to feed the stereo with Line Level audio, So you need to pad speaker level to line level audio for best results.

    Have Fun.
  3. KI7FAN

    KI7FAN Ham Member QRZ Page

    This is a guess as to what you mean. Match audio level output from the Yaesu to the expected level of the Kenwood. That close?
  4. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    There are some big ifs here.

    Both transceivers use a grounded audio output, so you shouldn't have an ground loop problems. But... The Kenwood has outputs for "both sides", so separate speakers can be used. Cross connecting both transceivers to the same input may defeat the "stereo" output of the Kenwood.

    You didn't want to hear this, but you're going to be better off using operate speakers for the transceivers. Or one speaker with due voice coils. You'll find out why, once you compare using the vehicle stereo vs. communication speakers.
  5. KI7FAN

    KI7FAN Ham Member QRZ Page


    Both transceivers? I have only one transceiver in this vehicle, The Yaesu FT-857. I know I have two in my signature line. But only have the one in this truck. I am thinking that you mean I will have a one side only mono output at the Kenwood stereo. I hope it is the drivers side!
  6. K0BG

    K0BG Platinum Subscriber Platinum Subscriber QRZ Page

    That is what I meant.

    I know lots of folks use their stereo inputs for their amateur gear. The truth is, the bandwidth of a decent vehicle stereo is about 15kHz. Even though the specific stereo has equalizers, they still allow way too much hash to reach your ears. While it might be passible (?) for FM, for SSB, forgetaboutit!
  7. NG1H

    NG1H Ham Member QRZ Page

    FM may be passable, but it is still worse than the stock speaker. For no other reason than the repeater tones can now be heard. As K0BG said, SSB is particularly bad.

    I know it sounds counterintuitive but the higher fidelity does not improve SNR compared to the stock or especially comms speakers.
  8. W6ELH

    W6ELH Ham Member QRZ Page

    Not a direct answer to your question, but take it for what it's worth - I had an FT-857 in my Jeep Wrangler. The stock speakers in the Jeep seemed pretty good, so I thought it would be fine business to funnel the audio through the input jack on the AM/FM radio. It was dreadful. Really poor.

    I later mounted one of the dedicated ham speakers with noise reduction circuitry, and it was a vast improvement. YMMV, of course... Jim W6ELH
  9. KI7FAN

    KI7FAN Ham Member QRZ Page

    Thanks for the info Alan. A dedicated speaker is where I am headed as I cannot get the sound to work on the aux input.
  10. KI7FAN

    KI7FAN Ham Member QRZ Page

    I know this is old hat, but I finished the FT-857 install tonight. After all the work received WWV very clearly. More work to do. But contact (one way) has been made.

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