Anybody got an idea where I can buy or get a circuit diagram to make one up?

John

Anyone out there have any good 2m yagi plans?

Looking for 3 or 4 elements for SSB on 2m

Cheers
Richard

Hello to all,
I have just bought a Ground plane adaptor off Ebay (yeah I know!) (China!
Yeah I know!) it was advertised as a PL259/SO239 male/female thread to
enable a groundplane to be fitted to a mobile antenna.

I assumed wrongly that there was an International standard with regard to
the PL259/SO239.

Naturally when a known part number is advertised, one would expect that the
normal 5/8" x 24 threads per inch standard (UNEF) would be followed.

Not so! What was sent was a 16 x 1mm adaptor.

Naturally the language difference is making it hard for me to convince the
seller that he MUST advertise the adaptor on Ebay having a metric thread.

Can anyone tell me if there is a move towards the metrification of the
PL259/SO239 connectors?

If this happens all hell will break loose, imagine trying to connect antenna
to coax at say a field day or even worse in an emergency situation?

John
VK2KCE

Hi, all, my current project requires a high phase stability (<1 mill
degree @ 10 MHz / oC) resonant surface coil. I am trying to use a LC
resonant circuit to drive this surface coil, but its phase stability
is really poor (about 40-80 mill degree @ 10 MHz / oC ). I guess the
main problem comes from the used capacitor whose value is easily
changed by temperature. so my question is that can the crystal
oscillator help me more? or is there any other method to achieve this
requirement?

Thanks a lot.

I have a Tennamast rotator cage. I want to install a Cushcraft MA5B beam at
the bottom and a 9 element crossed Tonna beam for 2 meters with a 2m
collinear on top of that.

What should the minimum distance be from the rotator cage to the MA5B?

What should the minimum distance be from the MA5B and the 9 element crossed
Tonna?

What should the minimum distance be from the 9 element Tonna to the 2 meter
collinear?

Thanks

Andy

Hi:

Most cell phones and wireless internet routers, modems, and access
points that use spread spectrum usually broadcast and receive their data
on FM-radio waves. Just out of curiosity, I ask, why not use AM?

Let's say a DSSS/FHSS type of spread-spectrum is transmitted and
received using the AM radio waves in the UHF spectrum [i.e. spread info
for transmission throughout the UHF band and receive AM radio waves
throughout all UHF frequencies]. What would be the disadvantages of this?

Normally DSSS and FHSS are transmitted/received on FM radio waves. So I
ask what would be the disadvantages of using AM instead of FM for this?

AM radio tends to be more vulnerable to unwanted magnetic disruptions
than FM, however this only affects analog reception. Digital reception
on AM should be unaffected even by the strongest-interfering analog RF
magnetic signal. Right?

Digital cell phones do use FM. Even if the signal being
transmitted/received is digital, it's carrier wave is still analog.
Right? IDEN phones use a 4 subcarrier 16-QAM [not spread-spectrum] but
still on an FM main carrier.

I have about 1500 feet of lmr400llpl (its plenum) for sale if you know
anybody who needs it please e-mail me unlimitedtch@yahoo.com.thankyou.

Hello all,
I have a real doosey.

I built an Octopus, along the lines of the one which was featured in the Dec
2007 issue of QST. This article was written by Geoff Haines N1GY.

The Octopus is a 4 band rotatable dipole, using either Hamsticks or Workman
mobile whips

I fitted the following Workman whips: 75m, 40m, 20m & 15m.

I can tune all but the 20m whips, there is naturally an interaction between
each of the whips, but 20m simply cannot be tuned. its resonance is around
13.6mhz, and no matter what I do with the whip length it cannot be bought
into resonance.

I stress that 75m, 40, and 15m are great.

I have tried the 20m whips on their own as a single antenna and they tune
well, but as soon as I offer the second whip to complete the dipole, the
resonance drops to 13.6mhz.

When I refit all the other elements, it makes not much difference to the 20m
whips as far as their resonance is concerned, it does shift a bit which is
understandable.

Many years ago (~30) I built a simple antenna analyzer consisting of a
passive network of resistors, capacitors and diodes. This was placed
in-line between the TX and the antenna.

The network had 5 DC voltage monitoring points, selected by a 5-way
switch.

Having measured the 5 voltages, you then had to plot on graph paper a
set of circles and lines that were proportional to the voltages -- as I
recall, 3 circles and 2 lines. The point of intersection of the 3
circles was a measure of the R +/- jX components of the antenna
impedance.

I would like to re-create the analyzer, but I can't find the schematic
anywhere. I think I first saw it in a UK ham radio magazine, probably
some time in the 1970s.

Does anyone here remember it and/or can tell me where I can find it?

Horizontal Vee Beams

I have been searching for information on the horizontal vee beam
antennas.

I am looking for information on the real ones that are more than 1/2
wave, not a hamstick dipole bent forward and claiming to have 3-6 db
gain over a dipole.

Thank you
--
73 for now
Buck, N4PGW

www.lumpuckeroo.com

"Small - broadband - efficient: pick any two."