COM-425 Radio Exchange

[andresmith76]

I recently completed my RV-6's panel upgrade with an HDX system, including a new SV-COM-425 radio transceiver. This past weekend flying @ 8,500' over eastern Colorado, I called Denver Center to request Flight Following and the reception was extremely poor - very noisy, staticky and nearly unintelligible. I called Dynon Tech support to discuss and was told they've had problems with the COM-425 radio (the transceiver, not the remote head) and offered to swap with a Trig replacement. When asked if the mounting hole spacings would be the same, the tech wasn't sure. Does anyone have any information about how similar or different these radios are in regards to mounting/installing? I'm concerned I will need to rework my sub-panel with new nut-plates, extend wires/coax, etc. to accommodate the replacement Trig transceiver.

 

[Marc_J._Zeitlin]

The installation manual clearly shows differences between the mounting of the C25 and X25 systems in chapters 16 and 17.

 

[andresmith76]

Thanks Marc - I didn't realize the SV-COM-T25 was the Trig replacement Dynon was sending me. After reading your post, I do see the differences outlined in the installation manual. Looks like I am not done with my Skyview installation!

 

[cjohngraham]

Not sure if it's relevant, but I have the COM 425 and early in Phase 1 there was a lot of static with transmissions. Dynon told me to put a bonding wire from the case of the intercom to the case of the COM unit, and that took care of the problem.

 

[andresmith76]

You had issues with your transmissions (Tx-talk) or reception (Rx-listen)? I hear no complaints from others while transmitting, only when I'm receiving. Interesting Dynon had you add an additional ground wire from the SV-INTECOM-2S to the SV-COM-425, as there are already many grounds connecting the 2, shown in the connection diagram on pages 23-20/21 of the installation manual
I'm wondering what the main differences are between the C25 (COM-425) and the X25 (COM-T25)?
Has anyone seen a full-scale/actual size drawing of the X25?

 

[RV8JD]

I'm wondering what the main differences are between the C25 (COM-425) and the X25 (COM-T25)?

The information below was posted years ago on this Forum by a Dynon rep. I've shortened it a bit.

The SV-COM-425 is an analog radio transceiver designed and engineered by Dynon many years ago. This transceiver generally has very good reception performance, but sometimes had poor transmission quality. Noteworthy is the fact Dynon chose to engineer an analog radio transceiver to reduce cost compared to modern digital radios. Few if any other companies have produced a new analog radio transceiver for the aviation market in a very, very long time.

Not long after the Dynon radio was released, Dynon partnered with Trig Avionics to manufacture a digital radio transceiver capable of the narrower frequency spacing required in Europe. Trig made that transceiver compatible with Dynon’s radio control panel (the SV-COM-PANEL), and it has proven to be a very reliable and well-performing combination.

Several years ago Dynon understood that both the company and its customers (both Experimental and Certified) would be better served by selling the Trig transceiver in the US market as well as internationally. However, Dynon was reluctant to raise the price of its radio product for the US market as would be required by the more expensive Trig transceiver. But in late 2019 Dynon finally chose to stop manufacturing that device and sell only the Trig SV-COM-T25 with the Dynon SV-COM-PANEL.

 

[andresmith76]

The information below was posted years ago on this Forum by a Dynon rep. I've shortened it a bit.

The SV-COM-425 is an analog radio transceiver designed and engineered by Dynon many years ago. This transceiver generally has very good reception performance, but sometimes had poor transmission quality. Noteworthy is the fact Dynon chose to engineer an analog radio transceiver to reduce cost compared to modern digital radios. Few if any other companies have produced a new analog radio transceiver for the aviation market in a very, very long time.

Not long after the Dynon radio was released, Dynon partnered with Trig Avionics to manufacture a digital radio transceiver capable of the narrower frequency spacing required in Europe. Trig made that transceiver compatible with Dynon’s radio control panel (the SV-COM-PANEL), and it has proven to be a very reliable and well-performing combination.

Several years ago Dynon understood that both the company and its customers (both Experimental and Certified) would be better served by selling the Trig transceiver in the US market as well as internationally. However, Dynon was reluctant to raise the price of its radio product for the US market as would be required by the more expensive Trig transceiver. But in late 2019 Dynon finally chose to stop manufacturing that device and sell only the Trig SV-COM-T25 with the Dynon SV-COM-PANEL.

Thank you for posting this. It does confirm the X25 is superior to the C25, being a digital transceiver vs. analog. Although I'm a bit unsure the X25 will solve my noisy reception issues due to the sentence "This transceiver generally has very good reception performance, but sometimes had poor transmission quality."
To add a bit more info - I used about 10' of RG-400 coax (double-shielded) to connect my sub-panel mounted C25 transceiver to the antenna, so I doubt coax loss/Rx signal attenuation is an issue.

There is also some recent discussion going on in the Van's Air Force forum: https://vansairforce.net/community/showthread.php?t=182310

 

[RV8JD]

For clarification of the radio nomenclature, I'll add this:

The SV-COM-C25 is an integrated VHF Com Radio consisting of two modules, the SV-COM-PANEL and the SV-COM-425 transceiver.

The SV-COM-X25 is an integrated VHF Com Radio consisting of two modules, the SV-COM-PANEL and the SV-COM-T25 transceiver.

The SV-COM-X25 replaced the SV-COM-C25 in late 2019.

 

[andresmith76]

For clarification of the radio nomenclature, I'll add this:

The SV-COM-C25 is an integrated VHF Com Radio consisting of two modules, the SV-COM-PANEL and the SV-COM-425 transceiver.

The SV-COM-X25 is an integrated VHF Com Radio consisting of two modules, the SV-COM-PANEL and the SV-COM-T25 transceiver.

The SV-COM-X25 replaced the SV-COM-C25 in late 2019.

Perfect. Do you know where I can find a real-size/full scale drawing of the mounting tray used on the SV-COM-T25? If I had that, I could begin configuring my sub-panel while I wait for the transceiver to arrive. Is it the same tray used for the SV-XPNDER-261?

 

[RV8JD]

Perfect. Do you know where I can find a real-size/full scale drawing of the mounting tray used on the SV-COM-T25? If I had that, I could begin configuring my sub-panel while I wait for the transceiver to arrive.

Page 17-6 of the SkyView System Installation Guide - Rev AH, has the info you need. Here is a snippet:

 

[andresmith76]

Page 17-6 of the SkyView System Installation Guide - Rev AH, has the info you need. Here is a snippet:

Awesome. Page 11-3 of the same Installation Guide confirms the mounting tray dimensions used on the SV-COM-T25 & the SV-XPNDR-261 are identical.
Thank you!

 

[Kent Crews]

I need an avionics shop in Colorado willing to swap out my dying 425 for the X25. I have the new radio in hand. So far, no one is interesting in working on anything Dynon. I have a Pipistrel Sinus LSA (glider) certification with HDX1100 panel. Does anyone in the Denver/Fort Collins area have a suggestion?

Thanks,
Kent Crews
N317ZE

 

[Carl_Froehlich]

Dynon will sell you the jumper to make your new radio work without changing any wiring or connectors. It takes in the old 15 pin connector and translates it to the new 25 pin for the TRIG radio. Easy Peasy.

Carl