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mch wrote:

From: mch <mch@...>

If you have 100W output and 10W reflected power. Only 50W is getting to
your antenna due to the 3 dB loss. Of that, to produce a reflected power
of 10W at the transmitter means you must have 20W reflected at the
antenna. You have a 3 dB loss in each direction. The specific power
levels don't matter much; the ratios are the same. 50W output and 20W
reflected (at the antenna) is significantly higher than 2:1. I don't
have a chart handy, but around 9:1 sounds in the ballpark.

73,
Joe, KR3P

Joe is right, line has loss in both directions.

Kevin

Try CAS. Should work much better.

Don WA1PXT

Hello All,

Our club repeater a GE MASTER II UHF, just quit working and we decide
to replace it with another GE MASTER II or may be EXEC II radio. So
any body out there with a spare unit we will be glad to buy it and
you can help us back on the air again.

Thanks,

_______________________________________________________________
Get Free Email and Do More On The Web. Visit

Hi All,

I was wondering if any one could help me with a problem I am haing with
my repeater. I am currently using a Motorola Suitcase Repeater, basically
based on the MX series of portables, this unit is fully self contained with
high power PA, mobile type duplexer, repeater controler, and even a power
supply (OF which I am not currently using, I am using an Astron 35amp unit)
I am also using about 50 feet of LOW loss 75 ohm coax that I got from the
Cable Company, however, I am unsure of the exact type of cable, RG6 or RG11
or whatever. I am also usiung a Ringo Ranger antenna, mounted on the top of
my building 6 stories up. I know it isn't the most ideal setup, but I am
just looking for some local coverage, a couple of miles worth, maybe 3 or 4
on 5 watt portables. Now to the problem,

The unit works flawlessly when within about 7 to 10 blocks away,
however, once passed that point, or even closer when in a house, building, or
basement, the reciever opens, and stays open the entire time of the signal,
however there is a low pitched, I guess it would be called a "HUM", that
completely covers the audio of the signal. I thought that maybe it was the
duplexer, but I tested that by disabling the transmitter while recieving a
"HUMING" signal, with no improvement. I then thought it was the antenna and
the connections, but I have an SWR of about 1.4, so I wasn't that concerned
with the antenna. However, I once read somewhere that the way the Ringos
carry the RF, it wasn't good for the duplexer, so I swapped it out with an
Antenna I picked up at a hamfest, and according the literature with the
antenna, it has been successfully used with other repeaters, along with
replacing the connectors at both ends of the coax. This new antenna did
improve on the humming problem, signals that before would "HUM" didn't,
however, the antenna was physically smaller, so I lost alot of the output
gain, and the reciever wouldn't pick up signals that before it would, without
dropping out, but were humming. So, I switched back to the Ringo thinking
that maybe the connectors were the problem, however, they weren't as I am now
getting the HUM again.

I was wondering if anyone had any ideas or suggestions that might help.
I was thinking about adding a MICOR recieve preamp, thinking that maybe the
signals just aren't strong enough, and that is why I am getting them HUM, but
I think that there is something else going on.

Also, can anyone tell me, can I install the MICOR preamp in the coax that
leads from the duplexer to the reciever, or does it have to be after some
sort of reciever circuitry.

Thanx in advance for any help you may be able to provide.
Mike

contact gene diehl via phone at 219-495-5715 after 1200 hours or email
n9lcf@... snail mail is 4705 n 725 e fremont, indiana
46737







At 02:06 AM 4/29/99 PDT, you wrote:

From: " " <dx_ing@...>

Hello All,

Our club repeater a GE MASTER II UHF, just quit working and we decide
to replace it with another GE MASTER II or may be EXEC II radio. So
any body out there with a spare unit we will be glad to buy it and
you can help us back on the air again.

Thanks,

_______________________________________________________________
Get Free Email and Do More On The Web. Visit

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I am taking a survey, Please vote only once. Kevin

We are trying to make an older model RC-1000 controller by MicroComputer
Concepte work with a VHF Micor. The audio sounds very harsh and tinny.
Anyone have any experience or advice to make the repeat audio sound better?

Thanks for the ideas!

-Matt

Sounds like an emphasis/de-emphasis problem. Seems to me years back I had a
similar problem, if the audio was
taken off the discriminator, feed it back into the pl input.
Flat audio out, flat audio in.

Seems to me that solved the problem.

Terry VE6TDW

Tony Lelieveld wrote:

Whatever the negative aspects, I'd give it a try anyway. If your TX
can handle the 2:1 VSWR it may just work. The antenna may not be as
effective when off tune by the amount you indicated but you have the
height. 2:1 VSWR is still 88.9% of the power being transmitted and
11.1 % being reflected.

Original message:

I acquired a 2 bay, 6 meter Sinclair antenna at our main
repeater site. It was tuned for 45 Mhz and that was verified
by checking the return loss. At my 6 meter repeater output,
the return loss is about -10 db (a little over 2:1 SWR).

If 10% (-10 dB) of the power is being reflected back at the transmitter
and not the antenna, you need to consider line loss. You said the
feedline is nearly 500 feet, and at 50 MHz, 1/2" heliax (which is what I
believe you said you were using) has approximately a 0.5 dB loss per
hundred feet, or approximately 2.5 dB over the entire run. For arguments
sake, let's call it 3 dB.

If you have 100W output and 10W reflected power. Only 50W is getting to
your antenna due to the 3 dB loss. Of that, to produce a reflected power
of 10W at the transmitter means you must have 20W reflected at the
antenna. You have a 3 dB loss in each direction. The specific power
levels don't matter much; the ratios are the same. 50W output and 20W
reflected (at the antenna) is significantly higher than 2:1. I don't
have a chart handy, but around 9:1 sounds in the ballpark.

For a good SWR (1.5:1) with 100W output, you should see no more than 1W
of reflected power with the losses that you have. (50W at the antenna
with 2W reflected at the antenna)

73,
Joe, KR3P

Hi Fellow Hams,
I just acquired a Master II Repeater and interfacing a Cat 300 DX
controller to it. I have everything done except I wish to use the
RUS line for COR input. The RUS line goes high for a split second till
the exciter keys and then goes low. There must be another place to pick
up RUS that will stay high as long as the receiver is unsqelched. I am
hoping that someone knows of this location. Using the RUS as COR is in
light of having mobil flutter problems on a previous converted Master II
mobile.
Another thing that I need is where to pick up a CTCSS output from the
factory G.E. pl board. I need to go high on a line when P.L. is
present. I didn't find anywhere on the backplane that gave me this.
Any help would be apperciated very much. Thanks, Tom Butler, N5KWN..

I used a 1 uf in mine also. Sounds great, I dont remember for sure but
there may be a small voltage on this line. I have found experimenting with
capacity in line with about all the connections will work wonders. I have
an RC1000 and 2 of the less expensive ones, and they all work great.

believe it or not i have used a 2.2k resistor in-series with the rx audio lead
and the controller and from the point where the audio lead from the radio and
the resistor is i tied a .055 uf cap to ground it fixed the problem on my micor
odd value but it worked and sounds pretty good i use the standard c558a ht to
work the repeater and it sounds just like my ht on simplex others may have
other fixes but u may want to experiment with the values

Matthew Janusauskas wrote:

From: Matthew Janusauskas <w21@...>

Hi group,

We are trying to make an older model RC-1000 controller by MicroComputer
Concepte work with a VHF Micor. The audio sounds very harsh and tinny.
Anyone have any experience or advice to make the repeat audio sound better?

Thanks for the ideas!

-Matt

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I am taking a survey, Please vote only once. Kevin

--
Brent DeSalvo (KF4TNP)

Grid Square: EM65
ICQ UIN# : 17430698
Mailto:bug1@...

Where are you injecting the audio? Mic input? PL input? Try the other, try
using a cap in series, like 1 uf or so...

I'm not familiar with the options for configuration on the RC-1000; does it
have an impedance selector? If so, set it to low. Also, is there an output
range selector? Hi or low level?

73, John NI0K

Ted.

Whatever the negative aspects, I'd give it a try anyway. If your TX can
handle the 2:1 VSWR it may just work. The antenna may not be as effective
when off tune by the amount you indicated but you have the height. 2:1 VSWR
is still 88.9% of the power being transmitted and 11.1 % being reflected.

Gd. luck .. 73 Tony VE3DWI

Hi group,

We are trying to make an older model RC-1000 controller by MicroComputer
Concepte work with a VHF Micor. The audio sounds very harsh and tinny.
Anyone have any experience or advice to make the repeat audio sound better?

Thanks for the ideas!

-Matt

Hi all<

I want to thank everyone who answered my request for a master 2 uhf
radio...The response was over whelming.....I did find what i was looking
for and it's on it's way....I can't believe how easy it was to
find.....Thanks again to all the e-mailed me...

Mike KA2NDW

In a message dated 99-04-28 20:57:34 EDT, Matthew Janusauskas
<w21@...>
wrote:

<< Hi group,

We are trying to make an older model RC-1000 controller by MicroComputer
Concepte work with a VHF Micor. The audio sounds very harsh and tinny.
Anyone have any experience or advice to make the repeat audio sound better?
>>

One thing we did with some RC1000's we've used here in Raleigh (mostly as
short-term controllers 'til we can upgrade to something with more features)
was to replace ALL of the tantalum electrolytic capacitors with same value,
non-polarized. I was fortunate to have a friend who could get me engineering
samples of a ceramic-type, in just about the same physical size.

What I had learned was that tantalum caps, while normally very 'capacitive'
for its size, do not do well with >passing< audio. And it was made even
worse the day I was doing some work on the controller and managaed to key up
the HT too close to the controller board. It basically fried the tantalums.
This was confirmed by an other tech in an engineering design department that
tantalums do fry with too much RF. Made the audio icky-poo, for lack of a
better term. Very distorted. Can't remember if there was a hi-freq. or low
freq. effect. Just that it happened.

Replaced said tant's with the others, audio became more wonderful.

Ron does a nice controller for the price. It's response to programming
commands leaves a bit to be desired, but for getting on the air, cheap, with
a patch, it's OK.

Chuk Gleason
kb4mdz

On Wed, 28 Apr 1999 12:15:06 -0400, Ed Bathgate, RMA Repair Dept x8785 wrote:

Well, that will make for an interesting experiment.
I would agree to use a tuner between the feedline and
the repeater. My suggestion would be to tune for lowest
tx swr. You probably will lose some on the rx, but bad
sensitivity is easier to live with than fried PA transistors!

My feeling exactly! We have a rigger coming to change our
VHF antenna and feedline at the same site (different tower),
so I may ask him how much he would charge just to install a
shorting strap on each dipole (can't make it much worse, hi).


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...

Tedd Doda wrote:

From: "Tedd Doda" <lazer@...>

On Wed, 28 Apr 1999 12:15:06 -0400, Ed Bathgate, RMA Repair Dept x8785 wrote:

Well, that will make for an interesting experiment.
I would agree to use a tuner between the feedline and
the repeater. My suggestion would be to tune for lowest
tx swr. You probably will lose some on the rx, but bad
sensitivity is easier to live with than fried PA transistors!

My feeling exactly! We have a rigger coming to change our
VHF antenna and feedline at the same site (different tower),
so I may ask him how much he would charge just to install a
shorting strap on each dipole (can't make it much worse, hi).

Tedd Doda CET CEO

I wonder about the use of a shorting strap. We
use VHF loops (DB-224)from commercial stuff on 2
meters by adding a stub on the end of the loop.

So the total length is what counts. If you strap
the loop, it may go up in freq, but I bet not much.
Unfortunately, the loops are probably frozen and can
not be smacked shorter.

Good luck, I do not want to rain on the parade,
but it may be worth trying on the ground first,
this one knows how much to "strap short" or
shorten the elements 73 carl w7exh

On Wed, 28 Apr 1999 09:17:47 -0400, Ed Bathgate, RMA Repair Dept x8785 wrote:

How high is the antenna? Is it feasible to get it down and trim it to the
correct freq?

The antenna is 400 feet up, on the side of a 600+ foot tower.
We were contemplating getting a rigger up and at least put
a shorting bar on the dipoles, but the TV station is replacing
the Tower within the next 3 years and we (the club) can't
justify it at this time.

How much feedline is between the ant and the tuner???

It's 1/2" Andrews Heliax, and from the antenna to the shack
I would say maybe about 475 feet? The shack is about 75
feet from the tower, plus the 400 feet to the antenna.

Your feedline is
going to increase its loss if the swr is high. That in and of itself may make
the antenna gain zero or lossy!

Agreed. I guess we'll find out this weekend. It will
only cost us a few man hours to reroute the heliax.


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...

On Wed, 28 Apr 1999 08:22:57 -0400, DPW wrote:

And if I might add... I would run a circulator and harmonic filter on
this one, especially if you run a solid state PA.

Do they make circulators for 6 meters?


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...

On Wed, 28 Apr 1999 06:44:01 -0500, John wrote:

Gain is also a function of frequency. You can suffer the loss in a matching
network, but your antenna gain will be lower, too. I wouldn't recommend it
unless you have no other choice.

Yes, I agree. But Gain is also a function of height, and this
thing is 400 feet higher than my Ringo, hi! I guess we'll find
out how the Mastr II likes SWR's of 2 to 1 this weekend, after
we reroute the Heliax to our shack.

I presume you meant that you would avoid the antenna?


Tedd Doda CET CEO

Lazer Audio and Electronics

packet ve3tjd@va3sed
e-mail lazer@...