sah@cs.purdue.EDU (Sean Hershberger) (08/15/90)
I have a WWV radio which interfaces to a computer on our network to provide us with an accurate time clock. Due to recent construction nearby, our reception has gotten much worse. The radio cannot maintain a good signal long enough or often enough to stay in High Spec mode. I was wondering whether a preamp would be effective in inproving the reception. Local TV and Radio stores claim not to have a preamp for 5 and 10 MHz signals, but it seems to me a preamp for a television should work. What do people out there suggest? Any and all comments would be appreciated. Thanks in advance. ______________________________________________________________ Sean Hershberger sah@arthur.cs.purdue.edu COMPUTER Hardware Engr. Computer Science Dept. Purdue University
myers@hpfcdj.HP.COM (Bob Myers) (08/17/90)
>I have a WWV radio which interfaces to a computer on our network to >provide us with an accurate time clock. Due to recent construction >nearby, our reception has gotten much worse. The radio cannot maintain >a good signal long enough or often enough to stay in High Spec mode. > >I was wondering whether a preamp would be effective in inproving the >reception. Local TV and Radio stores claim not to have a preamp for >5 and 10 MHz signals, but it seems to me a preamp for a television >should work. Not necessarily; for one thing, a commercially-built TV preamp will likely have a tuned stage in the front end which will eliminate signals below the TV range, so as to help cut out interference. For a good basic design for a HF preamp, I'd consult the ARRL's _Radio- _Amateur's_Handbook_. (When I was at Purdue, I'm pretty sure the engineering library kept a current copy, or you might check with the ham club.) For example, my '81 copy has some good info in Chapter 8, "Receiving Systems." It shouldn't be too hard to find someone there who can throw something together. You didn't mention, however, what type of antenna you're using. You might be able to get sufficient improvement in the signal simply by moving the receiver or attaching a high, long wire as an external antenna. Bob M. KC0EW Purdue BSEE '79 Ft. Collins, CO <---No problem getting WWV HERE! :-)
thad@cup.portal.com (Thad P Floryan) (08/17/90)
sah@cs.purdue.EDU (Sean Hershberger) in <11370@medusa.cs.purdue.edu> writes:
I have a WWV radio which interfaces to a computer on our network to
provide us with an accurate time clock. Due to recent construction
nearby, our reception has gotten much worse. The radio cannot maintain
a good signal long enough or often enough to stay in High Spec mode.
I was wondering whether a preamp would be effective in inproving the
reception. Local TV and Radio stores claim not to have a preamp for
5 and 10 MHz signals, but it seems to me a preamp for a television
should work.
[...]
Sounds like you have the Heath clock (which I do, too, for the same purpose).
Don't even think of a TV pre-amp; that's for 50MHz on up.
What you need to do is string an external antenna per the instructions that
accompanied the clock depending whether you want 5MHz, 10MHz, 15 Mhz, or some
combination.
My situation is really severe: I'm practically on the Great Circle route
between WWV (Ft. Collins, CO) and WWVH (in Hawaii). Thus, I had to rig an
inverted VEE antenna and cant it towards Ft. Collins to avoid the delayed
signal from Hawaii.
To figure all that out, I had to first write a Great Circle routing program;
gee, learned a LOT about haversines and such! From the geographic coords of
each site (WWV and thadlabs) I determined the direction to WWV.
Then, using coax, a balun, and good ol' 10ga. antenna wire, rigged up the VEE
whose apex is on my TV tower (up 45') with its legs "facing" WWV. Given that,
and with the reasonably good discrimination in the Heath receiver, I can get
the time signal (which I provide for others besides the computers on my own
networks; if I ever can get some more phone lines here, I may even make the
service publicly available).
If you don't have a good antenna, a pre-amp is gonna amplify all the crud,
reflections ("multi-path" in FM parlance), noise, and other junk along with
the desired signal. Antenna wire, a balun, connectors, coax, and &tc.,
should run about $50-$60 or so.
Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]