Hi Don I have done that using the Marconi for RX, then touching up for TX. I understand 40 is a combo of 30 & 40 settings. After carefully retuning (done it several times) the best I can get on 40 is about 60 to 75 mW. 30 makes better than 2 watts. The menu for power out is set to 2.0 on 40. Receive sensitivity is 10 to 15 dB down from 30 meter receive.
I read that the windings on T3 and T4 are critical. I have counted the turns and verified which side #1,2,3 and 4 are coming off the core. Both T3 and T4 appear to be fine. There is enough wire left over in the box the radio was in so I can rewind T3 or T4. From what I see on the schematic T4 would most likely be the suspect (if it is the transformer.) I am going to borrow an RF Power meter with probe and check 30 vs 40 meter readings on the Premix in & out and the RF filter in & out. That will greatly help pinpoint the issue. 73 Dave wo2x -----Original Message----- From: Don Wilhelm <donw...@embarqmail.com> Sent: Wednesday, May 20, 2020 11:39 AM To: rocke...@gmail.com; elecraft@mailman.qth.net Subject: Re: [Elecraft] K1-4 low power and poor receive on 40 meters Dave, Refer to the K1FL4 instructions and re-tune the trimmers on the filter board. They MUST be done in the proper band sequence - 30 meters before 40m, 15m before 20m. The PreMixer portion is usually the most critical for power output. 73, Don W3FPR On 5/20/2020 11:20 AM, rocke...@gmail.com wrote: > Hi All, > > > > I am going to sell a K1-4 (4 band 40, 30, 20, 15) for the estate of my > Elmer. In testing the radio I found 40 meters is about 15dB less > sensitivity than 30 and power out about 75 mW. I have double checked > the values of components on the filter board to ensure they are > correct and installed correctly. I also checked T3 and T4 which can > cause issues on 40. T3 has 23 turns on the secondary with three turns > on the primary. T4 has 24 turns on secondary and two turns on primary. > Another symptom is the CH trimmer cap seems to be at one end of tuning range > (not seeing double peak). > > > > Note - the radio does not have the ATU option and 30 meters is set for > 10.1 MHz and not 10.0 (double checked crystals). > > > >>From what I can measure so far the relays seem to be working "as designed". > When I switch from 15 meters to 40 meters I can see the pulses to the > relays to switch them (latching relays. I did notice in the 4 band > filter manual it says K6 relay is not active on 40 but I do see it > active and looking at the schematic K6 switches between 15/20 > operation and 30/40 so I think there is a typo in the filter board manual at > the bottom of page 23. > > > > I am using a Marconi service monitor for testing. I have not built an > RF probe yet and hoping someone has seen this symptom before. I would > like to get the K1 fully operational as the proceeds are going to my > Elmer's widow 100% > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
