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Title: Hallicrafters SX117 and HT44 Post by: KB5MD on September 28, 2020, 02:41:45 PM I am currently working on a SX117..HT44 hallicrafters combination. My question is has anyone ever ran these two units in a transceiver setup successfully?
I have the proper cables for connecting the two. The transmitter is supposed to operate using the receiver vfo as a slave unit. The problem is that anytime I switch to the receiver vfo and transmit the vfo is pulled off frequency. I have installed a regulator tube in the screen supply for the vfo but the problem is still there. Installing the regulator tube greatly improved the stability of the receiver operation by itself but not when using the receiver vfo as a slave in transceiver mode. Any suggestions are more than welcome!!! Title: Re: Hallicrafters SX117 and HT44 Post by: Pete, WA2CWA on September 28, 2020, 04:51:40 PM Cable length of RG-62 should be close to 28 inches.
Is it the receiver VFO oscillator getting pulled when you transmit or is it the oscillator/buffer in the transmitter that is being pulled? Title: Re: Hallicrafters SX117 and HT44 Post by: Jim, W5JO on September 28, 2020, 08:32:45 PM Roy that is a difficult task but can be done. Follow the directions to the letter. I had a pair that I ran in transceive and it took some work to make it happen.
Title: Re: Hallicrafters SX117 and HT44 Post by: kt4ae on October 02, 2020, 08:14:21 PM I would quibble with the term "slave". There's not a master-slave relationship. It's just that only the receiver VFO is used in transceive mode. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
With the switch on the back of the HT-44 set to XCVE, the transmitter uses the Crystal Oscillator and the VFO of the receiver. The transmitter VFO isn't used. I have experimented with this and it works well. My problem with it is that with the cables connected it seems to load the receiver slightly, at least according to the S-meter and the S-meter is stingy enough as it is. Actually, I think it's loading the Crystal Oscillator but it's been a long time. I never noticed any pulling of either. All you get in transceive is that you don't have to reset the dial on the transmitter when changing frequency on the receiver. But you do have to reset the bandswitch, driver and final controls. It's so easy to re-zero this pair that I never thought that it was worth the trouble. As far as stability, even though the manual says that the crystals can be "warped" to some extent, I found that receiver stability is greatly improved if each band is aligned at the crystal native frequency. The receiver and transmitter are both rock-solid after a few minutes. Also, band-to-band alignment is near perfect. Of course, this depends on the crystals being on frequency which isn't always the case as they are just getting older. Me too. Hi, Jim. Harry, KT4AE Watkinsville, Georgia |