Re: Strange V9.0 problem
- Hi Don,
Thanks for the update, good to hear you have finally got to the bottom of it. Sometimes these things do defy logic or reason.
73, Bob G8VOI
--- In firstname.lastname@example.org, "dldietmeyer" <dld@...> wrote:
> Bob, and all,
> A local friend who has been informed of my problem and attempts to
> fix it, suggested "put up a folded dipole, or if you want to keep
> the bow tie, replace the coax feed line with a balanced transmission
> line. Could even try zip cord." I did replace the coax with zip
> cord, and the appearance of WIBA (1310 kHz) at the LO frequency from
> 25 t0 33 MHz was gone!! There is a local 10 meter beacon so I know
> the V9 is working on 10 meters.
> I don't have a good understanding of what was going on, but the
> shield of the coax was acting as part of the antenna and brining a
> very strong signal to the V9. It may have been strong enough to
> couple to the op amps bypassing the BPF and mixer, as you suggested
> all along.
> Thanks for your help,
> --- In email@example.com, "g8voip" <g8voi.reeves59@> wrote:
> > Hi Don,
> > Are you using the switched BPF module with the v9.0 RX or the manual plug-in ones?
> > If you are using the switched BPF module, which version of the firmware are you using to control the filter module?
> > If you are using Fred's v15.10, the 'ABPF' mode is the best one to use as it is compatible with all of the SDR software. Check the three filter cross over points are set to 4, 8 and 16MHz, which is their default state.
> > One test you could do is to disconnect the lead linking the main board J3 to the connector on the filter module, and without any jumpers fitted to JP1 or JP2, that will select the band 4, 16 - 30MHz BPF correctly.
> > I cannot really think of anything actually with the filter that could allow the MW broadcast through, except perhaps if L11 was open circuit, but even then I find that very unlikely.
> > Its the fact that you say it is always at the exact centre frequency, and not affected if you move the LO frequency that makes be believe it is direct pick-up, and not a result of an image or mixing process.
> > I suppose it could be pick up in the op-amp part of the main board, but the capacitors C29 / C30 should cause the frequency response to roll off well before the MW broadcast frequency.
> > Last comment, do you have your v9.0 in a screened metal box, or is it just running open on the bench?
> > 73, Bob G8VOI
> > --- In firstname.lastname@example.org, "Donald L. Dietmeyer" <dld@> wrote:
> > >
> > > Bob,
> > > I pulled the audio line: no more WIBA on 10 meters. Then I put it
> > > back and
> > > pulled the antenna from the V9.0. Again no more WIBA. I just used
> > > Travelquest
> > > to find that I am about 6 miles from the transmitter. It seems to me
> > > that the
> > > problem is in my V9.0, perhaps the BPF?
> > > Don
> > >
> > > --
> > >
> > > Donald L. Dietmeyer
> > > 2211 Waunona Way
> > > Madison, WI 53713-1619
> > > (608) 222-3663
> > > dld@
> > >