Vertex Standard FT-60R Specifiche Scaricare il pdf (Pagina 6)

From February 2005 QST © ARRL

Tom Frenaye, K1KI

Director, ARRL New England Division

During the K1KI multioperator-single transmitter effort in the October

CQWW SSB Contest, we used one FT-1000MP without and one Mark V

FT-1000MP with the International Radio roofing filter. They were used on

several bands during the weekend. For the single operator November ARRL

Sweepstakes CW contest an FT-1000MP with the roofing filter was used as

the main radio, and one without the roofing filter was used as a second radio.

In trying to figure out what could be said about the radio’s performance

with the roofing filter, what stands out is what

doesn’t

happen. In the past

when there were very loud signals (S9+20 dB or so) on the band, we’d often

hear extra IMD products on our frequency, even if the loud signals were 10

to 20 kHz away. With the roofing filter installed, we just don’t hear them at

all, unless they are very close in frequency. Listening to other stations on

CW or SSB is less stressful without the extra noises!

When looking for a clear spot on 40 meter SSB, the radio with the roofing

filter is able to find more “holes” between the S9+40 dB international broad-

cast stations, and able to copy other stations that would not have been heard

in the past.

After the first Ten-Tec Orions hit the bands in late 2003, there were sev-

eral times when good friends with new Orions seemed to start up too close

to our frequency. It turned out they couldn’t even hear us. It became clear

that the performance of that radio was superior to the FT-1000MPs used

here. With the International Radio roofing filter, the situation seems to be

back to even again in the never-ending goal to keep up with the competition!

How The Roofing Filter Sounds

(or Doesn’t Sound) on the Air

terfering signals may be audible at all,

until the second one shows up and the

3OIMD signal appears within the listen-

ing bandwidth.

Enter International Radio

International Radio (InRad) has been

providing high quality selectivity setting

filters for years, and has now responded

to the need for roofing filters as well. They

have designed a (almost) plug and play

roofing filter for the Yaesu FT-1000MP

series transceivers with a bandwidth of

4 kHz instead of the stock 12 kHz unit.

The InRad filter has steeper skirts as well.

Note that this bandwidth will start to im-

prove intermod problems resulting from

signals farther apart than a 1 kHz spacing

(+2 in Table 2), and that is what we ob-

served. Note that the downside is that this

receiver will be sharp (barely communi-

cations quality) for AM reception and use-

less for FM. Fortunately, the MP series

radios have a second receiver that can be

used for these modes. Most serious con-

testers and DXers will be happy to make

that trade.

Hooking it Up and Checking it Out

ARRL Lab Engineer Michael Tracy,

KC1SX, has installed and tested a roofing

filter in two versions of the FT-1000MP

series so far—a Mark V FT-1000MP and

an early FT-1000MP. The first of these

versions require that two small wires be

soldered to existing pads on a PC board to

provide pins for attachment. Other ver-

sions have the pins already in place and

the filter can drop in. The filter module

includes an amplifier to compensate for

the filter insertion loss. Figure 3 shows a

close-up of the filter board, while Figure

4 shows how it fits under the chassis (top,

center) of the Mark V.

Before and after lab testing for both

radios is shown in Table 2 and the im-

provement is notable. Note that the filter

also improves a related parameter—

blocking dynamic range. BDR is a mea-

sure of how much stronger than the noise

floor an off-frequency signal needs to

be to reduce the gain of the receiver by

1 dB. Generally, this is less of a problem

than 3OIMD, but can still be troublesome

since it only requires a single out of band

signal. A strong CW signal that you can’t

hear can result in the receiver gain going

up and down, for example. While this is

not great, it’s usually not as bad as hav-

ing a 3OIMD signal right on top of the

one you’re trying to copy.

We have no clear answer for why the

results differ between the two radios

tested. It should be clear that the better

the original filter is, the less improvement

there will be. It is also possible that the

radio with the least improvement (an ear-

lier version) was generating some level

of 3OIMD response in the mixer ahead

of the filter. In any case, the filters re-

sulted in notable improvement in both

cases. The sidebar relates to the radio

with the least difference.

Manufacturer: International Radio,

13620 Tyee Rd, Umpqua, OR 97486;

tel 541-459-5623; fax 541-459-5632;

www.qth.com/inrad/. Price: $165.

Reviewed by Larry Wolfgang, WR1B

Senior Assistant Technical Editor

A friend recently gave me a 12 V, 100

ampere hour (Ah) gelled electrolyte bat-

tery that had been pulled from service in a

bank of emergency power backup batter-

ies. The commercial communications ser-

vice my friend works for replaces the

entire bank of batteries if one of the bat-

teries drops below about 80% capacity. My

West Mountain Radio PWRgate and

Computerized Battery Analyzer

The ARRL Handbook for Radio Communica-

tion

, 2005 edition, pp 17.41-17.44. Avail-

able from the ARRL Bookstore for $39.95

plus shipping. Order number 9280. Tele-

phone toll-free in the US 888-277-5289, or

860-594-0355; www.arrl.org/shop/.

main reason for having the battery is to

have a power source to run some radio

equipment so I can demonstrate ham radio

when I go camping with Boy Scout groups.

I needed a convenient way to keep the

battery charged and ready to go for week-

end campouts. I contemplated various

additional pieces of equipment that I

might need to safely keep the battery

charged and also be able to connect my

station equipment to exercise the battery

occasionally. I have used a small portable

solar panel and a Micro M + charge con-

troller

to recharge the battery after sum-

1 2 3 4 5 6 7 8 9

Commenti su questo manuale

Nessun commento

Vertex Standard FT-60R Specifiche Pagina 6

Commenti su questo manuale

Prodotti e manuali riguardandi Misurazione, test & controllo Vertex Standard FT-60R