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eHam Forums => VHF / UHF => Topic started by: N4NYY on August 17, 2017, 06:54:05 PM



Title: Yaesu FT-8800R power out question
Post by: N4NYY on August 17, 2017, 06:54:05 PM
Selling this radio. Lightly used (mostly RX). Very little TX. So I have not fired it up in a few months. So I get a buyer and test it out. I hit the repeaters full quieting. I have a Diamond SX-200 meter which only does up to 200 MHz. I measure the power out on all settings into a dummy load, and it measures 5/10/20/30. It is supposed to be 50 high on VHF, yet only measuring 30W. I did check the SWR on my antenna and it was 1.4. I highly doubt it is a final transistor failure as the power levels all are accurate except the high power.

I could really care less if I was keeping the radio. But as I am selling it, I think it is important to tell the buyer and I have already notified him.

Any expertise is appreciated.


Title: RE: Yaesu FT-8800R power out question
Post by: K5LXP on August 17, 2017, 08:57:35 PM
High power requires a stiff supply and a good DC cable.  If your supply is struggling or you have an iffy fuseholder you will see it under heavy draw. 

Mark K5LXP
Albuquerque, NM


Title: RE: Yaesu FT-8800R power out question
Post by: W9FIB on August 18, 2017, 08:56:55 AM
Put a volt meter across your power supply preferably at the plug on the radio, and check it again. If you see a large voltage drop, it will lower your output. I think you will find Mark to be correct. This test will verify that.


Title: RE: Yaesu FT-8800R power out question
Post by: N4NYY on August 18, 2017, 05:58:54 PM
Astron RS-35M


Title: RE: Yaesu FT-8800R power out question
Post by: WB8VLC on August 20, 2017, 03:53:04 PM
Have you performed the VHF TX POWER output adjustment from page 13 of the service manual?

http://www.radioamatoripeligni.it/i6ibe/ft8800/8800servizio.pdf


Title: RE: Yaesu FT-8800R power out question
Post by: N4NYY on August 21, 2017, 04:57:12 PM
Have you performed the VHF TX POWER output adjustment from page 13 of the service manual?

http://www.radioamatoripeligni.it/i6ibe/ft8800/8800servizio.pdf

No. The unit it unmodded and stock. The buyer took it. When he got home, his Bird meter verified 50W out. I supposed my meter is not cut for 2M even though it is rated for up to 200 MHz


Title: RE: Yaesu FT-8800R power out question
Post by: K4JJL on August 23, 2017, 09:48:33 AM
No. The unit it unmodded and stock. The buyer took it. When he got home, his Bird meter verified 50W out. I supposed my meter is not cut for 2M even though it is rated for up to 200 MHz

Ham grade meters (especially ones with a wide frequency range) are typically only good for an indicator or viewing changes (like tuning tuners or amps).  I wouldn't trust the scale on them.


Title: RE: Yaesu FT-8800R power out question
Post by: N4NYY on August 27, 2017, 08:01:23 PM
No. The unit it unmodded and stock. The buyer took it. When he got home, his Bird meter verified 50W out. I supposed my meter is not cut for 2M even though it is rated for up to 200 MHz

Ham grade meters (especially ones with a wide frequency range) are typically only good for an indicator or viewing changes (like tuning tuners or amps).  I wouldn't trust the scale on them.