[Boatanchors] Dx40 and VF1

[Hal Dale]

Guy's few of the early(Novice) transmitters had adequate power supplies. Heath was also guilty up and until the DX60.. Developing multi voltages from a single winding using high wattage dropping resistors is and was not efficient...But, it was cheap....I guess at the time, this at the novice level was acceptable...Hal/WB4AEG ---- On Wed, 07 Nov 2018 11:55:10 -0500 RAY FRIESS <rayfrijr at msn.com> wrote ---- Is the HG 10 vfo less of a load on the DX 40 than the VF1? ________________________________ From: Glen Zook <gzook at yahoo.com> Sent: Wednesday, November 7, 2018 7:57 AM To: RAY FRIESS; boatanchors; Boatanchors QTH Subject: Re: [Boatanchors] Dx40 and VF1 The VF-1 was actually designed to be used with the AT-1 transmitter. Then, they came out with the DX-35 which had a transformer that failed on a regular basis without any additional load on the transformer and only a relatively small percentage of DX-35 transmitters still have an original working transmitter. Then, Heath came out with the DX-40. That transmitter had a slightly better transformer than the DX-35. Unfortunately, the transformer still failed on a regular basis but not quite as many as in the DX-35. It was not until the DX-60 series that the transmitter had a really reliable transformer. The added load from powering the VF-1 from either the DX-35 or DX-40 is often just enough to cause a transformer that is just on the edge of failure to fail. Running the VF-1 from a separate regulated power supply also helps prevent "chirping" because of varying voltage. The VF-1 can be greatly improved in both stability and tendency to chirp by replacing the 6AU6 with a 6AH6 and replacing the 0A2 screen regulator with an 0B2. Neither tube replacement requires and modification to the VF-1. Then, use the 0A2, removed from the VF-1, to regulate an external power supply that provides 150 VDC regulated to the VF-1. This lower plate voltage works fine. On CW, let the VF-1 run constantly when transmitting and chirp just doesn't happen. Of course, you have to put the VF-1 in standby when receiving. This can be accomplished with a set of relay contacts that are connected to a phone plug plugged into the back of the VF-1. Glen, K9STH Website: http://k9sth.net ________________________________ From: RAY FRIESS <rayfrijr at msn.com> To: boatanchors <boatanchors at mailman.qth.net>; Boatanchors QTH <boatanchors at qth.net> Sent: Wednesday, November 7, 2018 12:08 AM Subject: [Boatanchors] Dx40 and VF1 I'm a bit puzzled by something. I keep reading things about the problems or dangers of powering a VF1 from the DX 40 instead of using a separate power supply. What puzzles me is would Heath engineers really have built the vfo to be powered by the 40 if it was going to be a problem? Or would they really have put a power supply into the 40 that was so underrated and overtaxed that it couldn't handle a VFO??? ______________________________________________________________ Boatanchors mailing list Home: http://mailman.qth.net/mailman/listinfo/boatanchors Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Boatanchors at mailman.qth.net List Administrator: Gary Harmon, K5JWK ** For Assistance: gharmon at idworld.net ** This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html