[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: HELP: Question for M2 Antenna 23CM35 users...



Rick:

We had a somewhat similar problem on our 432CP30. The
factory suggested we check the resistance to each of the
driven elements to make sure there was less than .1 ohms
between the F connector and the element.

In our case, two of the elements were bad. One had 34 ohms
and the other was something like 4 ohms.

M2 uses aluminum elements. In order to be able to solder
these to the F connectors inside their connection block,
they crimp a copper wire inside the end of the aluminum
element. I believe that, over time, corrosion takes its
toll.

So what I did was replace the driven elements on ours with
1/8" brass rod. It is sturdy, tins well, is inexpensive, is
the same size, and is easily obtained at local hobby shops.

In your case, I see the driven element is a folded dipole
with a balun inside, so I don't know exactly what the
connection inside the block is like, but check the
resistance and see if that might be the source of your
problem.

On ours, after I replaced all four driven elements like
this, the antenna shows 1:1 SWR at 432, and only 1.1:1 at
435.


Good luck,
Art, N3OY


Rick Fletcher wrote:
> 
> I recently installed an M2 23CM35 L-band antenna for use as an uplink on
> AO-40 but am getting a really bizarre SWR curve.  At 1250MHz, I get a 1.5:1
> SWR; at 1269MHz, a 2.1:1 SWR and 1.2:1 at 1280MHz (measured with a Diamond
> SX-1000 SWR Meter).  This is the best I've been able to get by adjusting the
> distance between the dipole feed and the first driven element and,
> unfortunately, the poorest match seems to be right at the uplink frequencies
> for L1/L2 on AO-40.
> 
> Any one seen this before?  Any ideas as to what to do/look at next?
> 
> Thanks in advance for any help offered.
> 
> 73s,
> 
> Rick
> KG6IAL
> 
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home