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   Home   Help Search  
Pages: Prev 1 [2] 3 4 5 6 7 ... 10 Next
 11 
 on: Today at 06:21:16 PM 
Started by KE2KB - Last post by W8JX
Given age of  unit if cap is original and would replace it and any in series with it. 

 12 
 on: Today at 06:20:32 PM 
Started by VE6MB - Last post by VE6MB
Surely I'm not the only one that is amused by this particular eBay ad which seems to show up periodically. I wish the seller all the luck in the world.....

http://www.ebay.com/itm/YAESU-FT-912R-1-2GHZ-23CM-MICROWAVE-HAM-Amateur-Radio-REPEATER-GASFET-DUPLEXER-/122414412129?hash=item1c8077b161

Enjoy reading the description.....

Tino, VE6MB


 13 
 on: Today at 06:15:53 PM 
Started by W5KUB - Last post by W8JX
All this crap makes me laugh. No matter who holds it, someone is gonna bitch. No matter where it is held, somebody is gonna bitch. No matter when it is held, someone is gonna bitch. if I didn't know better I would have sworn this thread was written by a bunch of old women. Huh

And some will insist it smells sweet when its a pile of manure....

 14 
 on: Today at 06:08:39 PM 
Started by W4BOW - Last post by W4BOW
 I haven't participated in contesting much, so I have a question. At the end of the contact after I give the signal report to the contestant,  they asked for a number. What number are they asking for??

Thanks for the help! W4BOW

 15 
 on: Today at 05:50:18 PM 
Started by KC1GCG - Last post by WB6BYU
Quote from: KC1GCG

...also the manual says for best protection do not use antenna position one and to instead put a pl259 connector with the center  and ground shorted.  Cant put My head around what they are doing with that either...




That's pretty clear without seeing the manual.  I assume that position 1 is the default position
selected when the power is off.  Rather than an antenna, putting a ground jumper there shorts
the coax to ground for protection in the off state, and none of the antennas are connected to
the center conductor of the coax, which gives you a little bit more protection.  (Not that a
lightning bolt that has traveled a couple miles through the air won't also be able to jump
across the contacts, of course.)

 16 
 on: Today at 05:49:58 PM 
Started by W5KUB - Last post by K2GWK
All this crap makes me laugh. No matter who holds it, someone is gonna bitch. No matter where it is held, somebody is gonna bitch. No matter when it is held, someone is gonna bitch. if I didn't know better I would have sworn this thread was written by a bunch of old women. Huh

 17 
 on: Today at 05:45:56 PM 
Started by KE2KB - Last post by WB6BYU
Don't use RF sensing.  Instead, have your external circuit key the standard PTT circuit on the HW-100
and let that key the relay in the rig.  That way you don't need to make any internal changes - just a
connection to the mic jack (assuming you are operating SSB.)

And it may be even easier than that:  I suspect that the HW-100 pulls the PTT line to ground to
switch into TX mode.  So you provide an external switch that does that, and also switches (via the
same contact to ground, or a second contact on a DPDT switch) the antenna for the SDR.

For example, say I need to ground a connection to enable the protection on the SDR.  Then I can
connect both the control leads to the switch, with a simple diode in series with each so they
don't interact, but grounding the switch contact controls both at the same time.  Otherwise, if your
protection circuit needs a grounded contact in RX mode and open in TX mode, wire that to the
other contact of a SPDT switch and ground the common, so the ground is switched either to the
RX on receive and the TX on transmit.

You do, however, need to make sure that you have some delay in your switching circuit to maintain
the protection on the SDR until the TX relay drops out.  Slowing down the relay in the HW-100 will
give you protection when you switch to TX, but will make it worse when you switch back to receive.

 18 
 on: Today at 05:34:55 PM 
Started by N6AF - Last post by W8JX
Very nice outcome to a potentially dangerous issue...  Nice work!


Dangerous if you leave gas for burner on maybe. Otherwise it is a low current ignition arc for burners than will not start a fire without a fuel source.

 19 
 on: Today at 05:30:11 PM 
Started by KE2KB - Last post by KE2KB
Put an ohmmeter on it and see if it's shorted.
I don't think it's actually damaged inside. It's the case that is damaged, but not enough that it leaks or shorted. I'm only concerned that after time, the damaged aluminum case would start leaking. It's easy enough for me to replace it - just that I want to get another opinion, as I think I might hold off on placing another order for parts, as I am still working on other projects for which I need to order, and don't want to order just the one cap for $1.30 and pay $4.00 shipping.

 20 
 on: Today at 05:28:57 PM 
Started by KC8MWG - Last post by WB6BYU
I don't know where the use of un-uns on end-fed wires started, perhaps in receive applications, but
such wires can work perfectly fine without them, and sometimes better.  Especially when the wire
runs straight to a tuner (though I've also plugged one end of a wire straight into the back of the
rig and used it that way.)  I've used a lot of end-fed wires over the years, and never with an un-un.


If you run the wire to a tuner, then an un-un probably is NOT the right method of matching, unless
your tuner has a very limited matching range and you know that the un-un will transform the impedance
into that range.  (It's actually rather uncommon.)  Most common tuner circuits are better at
matching high impedances than lower ones, so skipping the un-un avoids any losses in it, as well
as reducing tuner losses.

You do still have to provide a ground system to the tuner, of course.


Plugging it into the back of the radio (or the output of an SWR meter, etc.) works for 1/4 wave or
3/4 wave wires, though I've made the wire a bit longer and added series capacitors to bring it to
resonance.  A 3/4 wave wire actually works well with many tube transmitters.  Again, you need a
good ground system, of course.

For a half-wave (or multiple thereof) end-fed wire I generally use an "L" network or a parallel-
tuned circuit with the coax tapped a few turns up the coil.  That often is more efficient than trying
to find the right ferrite mix.  In one case I used a stepping relay from an old slot machine to
switch through networks for each band that were installed at the feedpoint.


Why would anyone use an un-un at all?   Well, if you want to feed a remote random (or semi-random)
wire with coax, an un-un at the feedpoint may lower the SWR on some bands and reduce
the losses in the coax, if you can't think of a better way to match it.

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